Title of Invention	INSTALLATION AND METHOD FOR PRODUCING ACTIVE CARBON
Abstract	The invention relates to an apparatus or installation for producing active carbon, in particular by carbonization and subsequent activation of polymeric, organic, preferably sulphonated, starting materials, wherein the apparatus or installation comprises optionally a drying device for drying the starting materials, optionally a sulphonating device, arranged downstream of the optionally present drying device, for sulphonating and/or peptizing the optionally previously dried starting materials, a carbonizing device, arranged downstream of the optionally present drying device and/or the optionally present sulphonating device, for carbonizing the optionally previously dried and/or sulphonated and/or peptized starting materials, as well as an activating device, arranged downstream of the carbonizing device, for activating the starting materials previously carbonized in the carbonizing device, wherein the apparatus or installation also comprises at least one exhaust-gas treatment device for treating the exhaust gases formed in the carbonizing device and/or in the activating device during operation.

Title of Invention

INSTALLATION AND METHOD FOR PRODUCING ACTIVE CARBON

Abstract

The invention relates to an apparatus or installation for producing active carbon, in particular by carbonization and subsequent activation of polymeric, organic, preferably sulphonated, starting materials, wherein the apparatus or installation comprises optionally a drying device for drying the starting materials, optionally a sulphonating device, arranged downstream of the optionally present drying device, for sulphonating and/or peptizing the optionally previously dried starting materials, a carbonizing device, arranged downstream of the optionally present drying device and/or the optionally present sulphonating device, for carbonizing the optionally previously dried and/or sulphonated and/or peptized starting materials, as well as an activating device, arranged downstream of the carbonizing device, for activating the starting materials previously carbonized in the carbonizing device, wherein the apparatus or installation also comprises at least one exhaust-gas treatment device for treating the exhaust gases formed in the carbonizing device and/or in the activating device during operation.

Full Text	INSTALLATION AND METHOD FOR PRODUCING ACTIVE CARBON The present invention relates to the technical field of producing activated carbon. The present invention relates more particularly to an apparatus and also a process for producing activated carbon, in particular by carbonization and subsequent activation of suitable polymeric starting materials, such as sulphonated polymers. Activated carbon has highly non-specific adsorption properties and for this reason is the most widely used adsorbant. Statutory requirements as well increasing environmental awareness are leading to an increasing demand for activated carbon. Activated carbon is generally produced by carbonization and subsequent activation of suitable carbonaceous starting materials. Starting materials which lead to economically viable yields are generally preferred, since the weight losses caused by detachment of vola- tile constituents during carbonization and by burn-out during activation are appreciable. For further details concerning the production of activated carbon, see for example H. v. Kienle and E. Bader, Aktivkohle und ihre industrielle Anwendung, Enke Verlag Stuttgart, 1980. Carbonization, also known as pyrolysis, describes the conversion of the carbonaceous starting material into carbon. The process of carbonizing the aforementioned polymeric, in particular sulphonated, organic starting materials has the effect of detaching volatile con- stituents such as SO2 in particular to destroy the func- tional chemical groups, sulphonic acid groups in par- ticular, to form free radicals which effect the pro- nounced crosslinking without which there would be no pyrolysis residue (= carbon). Carbonization is followed by activation. The basic principle of activation consists in some of the carbon generated by carbonization being selectively and delib- erately broken down under suitable conditions. This gives rise to a large number of pores, cracks and fis- sures, and the surface area per unit mass increases ap- preciably. Activation thus involves a deliberate burn- out of the previously carbonized material. Since carbon is broken down during activation, this operation leads to a loss of substance which is appreciable in some in- stances and which under optimum conditions equates to an increase in the porosity and an increase in the in- ternal surface area and of the pore volume. Activation is therefore effected under selective/controlled, gen- erally oxidizing, conditions. The condition or constitution of the activated carbon produced - finely or coarsely porous, firm or brittle - is also dependent on the starting material. Customary starting materials are coconut shells, wood wastes, peat, bituminous coal, pitches, but also particular plastics, which play a certain part in the production of woven activated carbon fabrics inter alia. Various forms of activated carbon are used: carbon pow- der, splint coal, granulocarbon, moulded carbon and also, since the end of the 1970s, activated carbon in spherical form ("spherocarbon"). Spherical activated carbon has a number of advantages over other forms of activated carbon such as carbon powder, splint coal, granulocarbon and the like, making it valuable or even indispensable for certain applications: it is free- flowing, hugely abrasion-resistant (i.e. dustless) and very hard. Owing to its high price, however, its use is essentially limited to protective suits and high- performance filters for noxiants in air streams. Spherocarbon is in great demand on account of its spe- cific shape, but also on account of its extremely high abrasion resistance for particular fields of use for example, examples being sheet filters for protective suits against chemical poisons and filters for low noxiant concentrations in large volumes of air. For in- stance, when reticulated, large-cell polyurethane foams are loaded with activated carbon as described in DE 38 13 563 Al, only a very free-flowing carbon can be used if optimal coverage of the inner layers of the foam material as well as the outer layers is to be achieved. The manufacture of protective suits against chemical poisons on the lines of DE 33 04 349 C3 for example can likewise utilize only a highly abrasion- resistant carbon, and only spherocarbon fits this de- scription. Spherocarbon is currently still being mostly produced by multistage processes which are very costly and in- convenient. The best-known process consists in spher- ules being produced from coal tar pitch and suitable asphaltic residues from the petrochemical industry and oxidized (to render them unmeltable), carbonized and activated. For example, spherocarbon can be produced from bitumen in a multistage process. These multistage processes are very cost-intensive and the associated high price of this spherocarbon prevents many applica- tions wherein spherocarbon ought to be preferable by virtue of its properties. There have consequently been various attempts to pro- duce high-grade spherocarbon in some other way. It is prior art to produce spherocarbon by carbonization and subsequent activation of new or used ion exchangers containing sulphonic acid groups, or by carbonizing ion exchanger precursors in the presence of sulphuric acid and subsequent activation, wherein the sulphonic acid groups and the sulphuric acid respectively have the function of a crosslinker, and the yields obtained, which do not depend on whether ready-produced cation exchangers or unsulphonated ion exchanger precursors are used as starting materials, being about 30% to 50%, based on organic/polymeric starting material. Such processes are described for example in DE 43 28 219 Al and in DE 43 04 026 Al and also in DE 196 00 237 Al, including the German patent-of-addition application DE 196 25 069 Al. But these processes are disadvantageous and problematic particularly because of the large amounts of sulphur dioxide released (about 1 kg of SO2 per kg of end product) and also because of the (partly) associated corrosion problems in the manufacturing equipment. When used ion exchanger resins, in particu- lar used cation exchanger resins, are used as starting materials, there is also the problem that these, al- though they have been washed with acid, are contami- nated with cations which then accumulate in the end product, so that the production of major amounts of spherocarbon in consistent quality is consequently very difficult. When ion exchanger precursors, i.e. polymer spherules without exchanger groups like sulphonic acid groups, are used, it is additionally necessary to use large amounts of sulphuric acid and/or oleum for the crosslinking during the carbonization. WO 98/07655 Al describes a process for producing spher- ules of activated carbon wherein a mixture comprising a distillation residue from diisocyanate production and a carbonaceous processing assistant with or without one or more further added substances is processed into free-flowing spherules which are subsequently carbon- ized and then activated. This process likewise re- leases, in the course of the carbonizing step, large pulses of decomposition products, which is associated with the problems described above. Commonly assigned WO 01/83368 Al relates to an improved process for producing activated carbon wherein the req- uisite process steps of carbonization on the one hand and activation on the other are carried out separately from each other in that the carbonization is carried out as a continuous operation while the postcarboniza- tion and activation is carried out as a batch opera- tion. This process is mainly based on the separation of the corrosive phase (i.e. precarbonization, associated with SO2 emissions) from the high-temperature phase (ac- tivation) . This is because precarbonized starting mate- rial is no longer corrosive; i.e. corrosive materi- als/gases are no longer formed when the temperature is raised any further. Furthermore, the commonly assigned printed publications DE 10 2004 036 109 Al, DE 10 2005 036 607 Al and also WO 2005/016819 Al disclose apparatuses for producing activated carbon. However, the processes and apparatuses for producing activated carbon which are known from the prior art are usually concerned with improving partial aspects only and do not provide a holistic approach which takes ac- count of all problems arising in activated carbon pro- duction, particularly the high energy requirements, the use of cost-intensive starting materials and chemicals, the emission of offgases, the loss of energy in the in- dividual processing stages, and the like. The problem underlying the present invention therefore consists in providing a novel apparatus and process for producing activated carbon wherein the previously de- scribed disadvantages associated with the prior art shall be at least partly avoided or at least amelio- rated. The apparatus and process shall make it possible to produce activated carbon in a less inconvenient, ide- ally less cost-intensive and also ecologically as well as economically improved or more efficient manner. To solve the problem described above, the present in- vention therefore proposes an apparatus for producing activated carbon as per Claim 1, a process for produc- ing activated carbon as per Claim 33 and the use of the inventive apparatus as per Claim 65; further, advanta- geous developments each form subject matter of respec- tive subclaims. It will be readily understood that particular develop- ments and embodiments which have been described only in connection with one aspect of the present invention also apply mutatis mutandis in relation to the other aspects of the present invention without this being ex- pressly stated. As for the rest, a person skilled in the art may, for a particular application or on a one-off basis, depart from the hereinbelow recited numbers, values and ranges without thereby going outside the scope of the present invention. The present invention accordingly provides - in accor- dance with a first aspect of the present invention - an apparatus for producing activated carbon, in particular by carbonization and subsequent activation of polymeric organic, preferably sulphonated, starting materials, the apparatus including - optionally a drying means for drying the starting materials, - optionally a sulphonating means for sulphonating and/or peptizing the optionally previously dried starting materials, in particular downstream of the optional drying means, - a carbonizing means for carbonizing the optionally previously dried and/or sulphonated and/or pep- tized starting materials, in particular downstream of the optional drying means and/or the optional sulphonating means, - downstream of the carbonizing means, an activating means for activating the starting materials previ- ously carbonized in the carbonizing means, wherein the apparatus also comprises at least one offgas-treating means for treating the offgases formed in operation in the carbonizing means and/or in the ac- tivating means. In general, the offgas-treating means comprises at least one thermal afterburning (TAB) stage. Thermal afterburning (TAB) herein is to be understood as referring to an operation wherein the offgases formed in the carbonization and/or activation are burned at temperatures above 900°C. This operation con- verts gases in the offgases, in particular hydrocar- bons, carbon monoxide and elemental hydrogen, into wa- ter and carbon dioxide generally and essentially com- pletely. The remaining offgases are thus less inconven- iently and consequently less costly to clean/purify and the resulting heat can be fed back to the carbonization and/or activation process, saving energy. In a preferred embodiment of the present invention, the apparatus of the present invention comprises at least one offgas-treating means for treating the offgases formed in operation in the carbonizing means on the one hand and at least one offgas-treating means for treat- ing the offgases formed in operation in the activating means, on the other. The carbonizing means in the apparatus of the present invention can customarily be constructed as follows: In general, the carbonizing means comprises at least one rotary tube, in particular at least one rotary tube oven. It will be found advantageous for the carbonizing means to form a closed system and/or be operable under inert conditions. A closed system for the purposes of the present inven- tion is, in particular, a system which exchanges very little energy with the environment. Similarly, an ex- change of matter with the environment, except for the supplied process gases (for example water vapour, car- bon dioxide, etc.) and the removed offgases, shall ide- ally be avoided or at least minimized; thus, any ex- change of matter only takes place under precisely de- fined and policed conditions. By "inert conditions" herein it is meant, in particu- lar, that the apparatus of the present invention is op- erated with an inert gas atmosphere and that the proc- ess of the present invention is conducted under an in- ert gas atmosphere, said inert gas atmosphere prefera- bly comprising a noble gas and/or nitrogen atmosphere, more preferably a nitrogen atmosphere. The inert gas atmosphere prevents any unintended excessive oxidation or a burn-out of the material used. According to the present invention, the carbonizing means may be operable continuously or quasi- continuously. Furthermore, the temperature of the car- bonizing means may be continuously or steppedly vari- able in operation. In a preferred embodiment of the present invention, the temperature of the carbonizing means is adjustable in operation such that two or more, in particular at least two, preferably four to eight, temperature zones having temperatures which each differ from the others, pref- erably having the temperature of the individual tem- perature stages each rising in the upstream direction, are present. Alternatively, however, a temperature gra- dient may also be present, preferably having a tempera- ture profile which rises in the upstream direction. A temperature zone for the purposes of the present in- vention is a heating zone or a region of at least es- sentially constant temperature. The rise in temperature in the process flow direction via two or more tempera- ture zones occasions a relatively constant emission of sulphur oxides SOX from the starting material to be car- bonized. More particularly, no spikes in sulphur oxide emission, in particular in sulphur dioxide emission, are obtained, so that the means for capturing and treating the offgases can be made smaller than would be possible in the event of spikes occurring in the emis- sion of sulphur oxides. In addition, it is only the continuous and constant release of sulphur oxides, in particular sulphur dioxide, that permits a hereinbelow recycling operation for the sulphur oxides, which would otherwise be impossible to carry out. The temperature of the carbonizing means in operation can vary between wide limits in the realm of the pre- sent invention. The range in which the temperature of the carbonizing means is variable is generally from 20°C to 1200°C, in particular from 30°C to 1100°C, preferably 50°C to 1000°C. It will be found particu- larly advantageous when a first temperature zone, pref- erably situated at the inlet or in the process flow di- rection at the upstream end of the carbonizing means is adjustable in operation in the range from 50°C to 500°C, in particular 200°C to 450°C. It may addition- ally be contemplated that a further temperature zone, preferably situated at the outlet or downstream end of the carbonizing means, be adjustable in operation in the range from 800°C to 1200°C, in particular 850°C to 950°C. However, for a particular application or on a one-off basis, it is possible to depart from the afore- mentioned values without thereby going outside the scope of the present invention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. In a particularly preferred embodiment of the present invention, the carbonizing means is subdivided into at least two sections. A first section, preferably dis- posed upstream, may be formed by a heatable vibrating chute and a second section, preferably disposed down- stream of the first section, may be formed by a rotary tube, preferably a rotary tube oven, in particular hav- ing a rising temperature profile or temperature gradi- ent in the process flow direction in the operating state. Vibrating chute herein is to be understood as meaning a chute or some other conveying means, such as a conveyor belt for example, which ensures good commixing and uni- form heating of the material to be carbonized, by sys- tematic vibration. In one particular embodiment of the present invention, the first section of the carbonizing means may be con- structed to be settable to a constant temperature or may be constructed to be adjustable to a rising tem- perature profile or temperature gradient in the process flow direction, while the second section may be con- structed to be adjustable to a rising temperature pro- file or temperature gradient in the process flow direc- tion. It will be found advantageous in the realm of the present invention for the temperature in the first sec- tion of the carbonizing means in the process flow di- rection to be continuously or steppedly adjustable. The temperature in the first section of the carbonizing means in the process flow direction may vary within wide limits. The range in which the temperature in the first section of the carbonizing means in the process flow direction is variable generally extends from 50°C to 500°C, preferably from 200°C to 450°C. Nonetheless, for a particular application or on a one-off basis, it is possible to depart from the aforementioned values without thereby going outside the scope of the present invention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. In an embodiment which is preferred according to the present invention, the temperature in the second sec- tion of the carbonizing means in the process flow di- rection is adjustable to rise, in particular steppedly or steplessly, in the process flow direction. More par- ticularly, the temperature in the second section of the carbonizing means in the process flow direction is ad- justable to rise in two or more temperature zones or with a temperature gradient in the process flow direc- tion. The temperature in the second section of the car- bonizing means in the process flow direction may vary within wide limits. In general, the temperature in the second section of the carbonizing means in the process flow direction is settable to rise in the range from 300°C to 1200°C, preferably from 350°C to 950°C, in the process flow direction. Nonetheless, for a particular application or on a one-off basis, it is possible to depart from the aforementioned values without thereby going outside the scope of the present invention. A de- cision to do so is within the ability or discretion of a person skilled in this field to decide. In an again particularly preferred embodiment of the present invention, the carbonizing means includes, preferably at the inlet or in the process flow direc- tion at the upstream end of the carbonizing means, in particular at the inlet or in the process flow direc- tion at the upstream end of the second section of the carbonizing means, an injective spraying or jetting means for injective spraying or jetting of water va- pour, in particular in the form of a water vapour-inert gas mixture. The proportion of water vapour in the wa- ter vapour-inert gas mixture may vary within wide lim- its. In general, the proportion of water vapour in the water vapour-inert gas mixture is adjustable in the range from 1% to 30% by volume, in particular 2% to 20% by volume, preferably 5% to 15% by volume. Nonetheless, for a particular application or on a one-off basis, it is possible to depart from the aforementioned values without thereby going outside the scope of the present invention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. It is preferable in the realm of the present invention when the injective spraying or jetting means for injec- tive spraying or jetting of water vapour, in particular in the form of a water vapour-inert gas mixture, is situated in the first third, preferably in the first quarter, of the carbonizing means. It will further be found to be advantageous in the realm of the present invention when the carbonizing means includes, preferably at the outlet or in the process flow direction at the downstream end of the carbonizing means, an injective jetting means for in- troducing oxygen, in particular in the form of an oxy- gen mixture with at least one further gas, preferably in the form of air. The volume stream of the introduced oxygen into the carbonizing means may vary within wide limits. In general, the injected volume stream of oxy- gen, in particular in the form of an oxygen mixture with at least one further gas, preferably in the form of air, is adjustable in the range from 10 to 500 l/min, in particular 25 to 250 l/min, preferably 50 to 100 l/min. Nonetheless, for a particular application or on a one-off basis, it is possible to depart from the aforementioned values without thereby going outside the scope of the present invention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. It will be found to be particu- larly advantageous when the injective jetting means for introducing oxygen is situated in the last third, pref- erably in the last quarter of the reaction sector in the carbonizing means. The injective jetting or spraying of water vapour and/or oxygen substantially prevents, by oxida- tion/burning of the pyrolysis gases, any condensing of pyrolysis gases in the base pore system of the acti- vated carbon being formed; secondly, the heat released can be used for heating the carbonizing means, saving the corresponding amount of heating energy. However, when adding oxygen or an oxygen mixture, care must be taken to ensure that it comes into contact with the py- rolysis gases only and not with the carbonizate in or- der to prevent burn-out thereof. In general, the carbonizing means has an offgas- treating means for treating the offgases formed in op- eration in the carbonizing means connected to/positioned downstream of it. It may be contemplated here in particular that the offgas-treating means comprises at least one thermal afterburning stage. In a particularly preferred embodiment of the present invention, the offgas-treating means includes, in par- ticular upstream of the thermal afterburning stage, at least one heat exchanger for cooling the offgases re- sulting from thermal afterburning. The heat released can be used either for heating the carbonizing means and/or for heating the hereinbelow described oxidizing means for sulphur oxides. Optionally, a drying means for drying the cooled offgases is positioned downstream of the thermal after- burning stage and the heat exchanger. The drying means in turn has a heating means for heating the dried offgases optionally positioned downstream of it. The drying of the cooled offgases can be effected either physically, for example by adsorption, or chemically, for example by reaction with concentrated sulphuric acid or phosphorous pentoxide, in which case drying the offgases chemically is preferred in the realm of the present invention. It will be found particularly advantageous in the realm of the present invention when the offgas-treating means comprises an oxidizing means for preferably catalyti- cally oxidizing the sulphur oxides, in particular sul- phur dioxide, present in the offgases formed in opera- tion in the carbonizing means, to form sulphur triox- ide, preferably downstream of the thermal afterburning stage and the optional heat exchanger, drying means and/or heating means. It may be contemplated that the oxidizing means includes at least one oxidation cata- lyst, preferably vanadium and/or platinum based. It may further be contemplated that the oxidizing means in- cludes a returning means for returning the sulphur tri- oxide into the sulphonating means. The returning of the sulphur trioxide into the sulphonating means is option- ally effected via an interposed producing means for the sulphonating agent. The sulphur trioxide formed can therefore be returned into the sulphonating means either directly or indi- rectly. Directly here is to be understood as meaning that gaseous sulphur trioxide is returned into the sul- phonating means without intervening space or time. In- directly in relation to the mode of returning the sul- phur trioxide into the sulphonating means, however, is to be understood as meaning that the sulphur trioxide is first washed out of the gas stream, in particular with water or concentrated sulphuric acid in an inter- posed means, and that the sulphur trioxide is therefore returned into the sulphonating means in the form of thus generated concentrated sulphuric acid or oleum. In one particular embodiment of the present invention, the oxidizing means includes a separating means for separating the sulphur trioxide from the other con- stituents of the offgases, in particular carbon oxides and/or water vapour and/or nitrogen oxides. It may be contemplated here that downstream of the separating means for separating the sulphur trioxide from the other constituents of the offgases there is optionally provided a washer for washing the separated- off other constituents of the offgases. The activating means downstream of the carbonization may generally be constructed as follows: In general, the activating means is operable batchwise. In a preferred embodiment of the present invention, the activating means forms a closed system; more particu- larly, the activating means is operable under inert conditions, in particular at the start of the activat- ing and/or the start of the heating-up phase. Concern- ing the terms "closed system" and "inert conditions", reference can be made to the above observations. The temperature of the activating means in operation can vary within wide limits. In general, the tempera- ture of the activating means is variable in operation in the range from 300°C to 1800°C, in particular 400°C to 1500°C, preferably 500°C to 1250°C. Nonetheless, for a particular application or on a one-off basis, it is possible to depart from the aforementioned values with- out thereby going outside the scope of the present in- vention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. More particularly, the temperature of the activating means in operation is steplessly and/or continuously variable. It may be contemplated that the activating means includes at least one heating means, in particu- lar an electrically operated heating system. In general, the activating means includes at least one feeding means for introducing, in particular by jetting and/or blowing, at least one activating gas, in par- ticular water vapour and/or carbon dioxide and/or oxy- gen and/or ammonia. It may be contemplated in the con- text of the present invention that the feeding means includes at least one temperature control means for ad- justing the activating gas (for example water vapour) to be introduced into the activating means. In one preferred embodiment of the present invention, the feeding means includes at least one feeding means for introducing, in particular by jetting, spraying and/or blowing, water vapour, in particular in the form of a water vapour-inert gas mixture. The proportion of water vapour in the water vapour-inert gas mixture can vary within wide limits. In general, the proportion of water vapour in the water vapour-inert gas mixture is adjustable in the range from 5% to 70% by volume, in particular 10% to 50% by volume, preferably 15% to 40% by volume. Inert gases for the purposes of the present invention comprise gases or gaseous mixtures which have little if any reactivity under the conditions prevail- ing in the activating step, and/or the reactions of which have no or at least no negative influence on the processes taking place in activated carbon production; the inert gases used for the purposes of the present invention comprise in particular nitrogen and/or noble gases (for example argon), preferably nitrogen. None- theless, for a particular application or on a one-off basis, it is possible to depart from the aforementioned values without thereby going outside the scope of the present invention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. It may be contemplated that the water vapour is introducible at temperatures of from 500°C by jet- ting, spraying and/or blowing. In a particularly preferred embodiment of the present invention, the feeding means includes at least one feeding means for introducing, in particular by jet- ting, spraying and/or blowing, carbon dioxide, in par- ticular in the form of a carbon dioxide-inert gas mix- ture. With regard to the inert gases used, reference can be made to the above observations. It may be con- templated in this case that the carbon dioxide is in- troducible at temperatures of from 800°C by jetting, spraying and/or blowing. The burn-out behaviour of the crude activated carbon and thus its later porosity is chiefly influenced by the temperature during the activating step and, where appropriate, the CO2 content in the activating means during the activating step. In another particularly preferred embodiment of the present invention, the feeding means for introducing the activating gases is supplied by and/or connected to at least one stockkeeping receptacle which contains the at least one activating gas. In general, the activating means has an offgas-treating means for treating the offgases formed in operation in the activating means connected to and/or positioned downstream of it. It will prove to be particularly ad- vantageous when the offgas-treating means comprises at least one thermal afterburning stage. The offgases from the activating means vary with the activating gases used and comprise in general and at least essentially hydrogen and carbon oxides, in particular carbon monox- ide . It may be provided according to the present invention that the offgas-treating means includes, in particular upstream of the thermal afterburning stage, at least one washer for washing the offgases coming from the thermal afterburning stage. After passing through the optional washer, the offgases which, owing to the thermal afterburning, consist over- whelmingly of carbon dioxide and water vapour are emit- ted. However, any excess offgases are supplied to the washer, i.e. offgases which cannot be further utilized in the operation. The overwhelming proportion of the offgases from the activating step is - as described hereinbelow - utilized as energy supplier in the indi- vidual operating stages of activated carbon manufac- ture. In a very particularly preferred embodiment of the pre- sent invention, the offgases coming from the offgas- treating means, in particular from the thermal after- burning stage, downstream of the activating means are used for indirect, in particular, heating of the acti- vating means and/or via a supply line for heating the stockkeeping receptacle containing the at least one ac- tivating gas, or the at least one activating gas and/or for heating the drying means, in particular for creat- ing a fluidized bed. For this purpose, the apparatus can be designed in par- ticular such that the hot offgases at about 1000°C com- ing from the thermal afterburning (TAB) of the offgases from the activating means are led on the outside along the activating means and heat the latter indirectly, so that at least about 10% to 20% of the activation energy requirements can be covered in this way. The hot offgases, which are then still at about 800°C, can sub- sequently be used for heating the activating gases, in particular the water vapour. Alternatively, the offgases of the thermal afterburning stage can also be used directly, i.e. without prior conducting along the activating means, for heating the activating gases. It is particularly preferred according to the present in- vention when the offgases, optionally after passing through the stockkeeping receptacle for the activating gases and/or the heating of the activating gases, are used for drying the starting materials needed for acti- vated carbon production, in particular for creating a fluidized bed, in particular after they have been cooled down to about 150°C by dilution with air. The cooled-down offgas can then be emitted via a washer, in which case - as already indicated above - excess, un- used offgas can at any time be removed via a washer and subsequently emitted. The drying stage upstream of the optional sulphonating means can be embodied in particular as follows: In general, the drying means is operable in a fluidized bed. In particular, the drying means, in particular the fluidized bed thereof, is operable and/or heatable by means of offgases from the offgas-treating means, in particular from the thermal afterburning stage, in par- ticular by means of offgases from the offgas-treating means for the activating means. It can be contemplated in the realm of the present in- vention that the drying means is operable batchwise. The temperatures at which the drying means is operable can vary within wide limits. In general, the drying means is operable at temperatures in the range from 100°C to 400°C, in particular 100°C to 200°C. Nonethe- less, for a particular application or on a one-off ba- sis, it is possible to depart from the aforementioned values without thereby going outside the scope of the present invention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. The sulphonating means placed downstream of the op- tional drying means can be constructed in particular as follows: It can be contemplated in the realm of the present in- vention in particular that the optional sulphonating means is operable batchwise. The temperatures at which the sulphonating means is op- erable can vary within wide limits. In general, the sulphonating means is operable at temperatures in the range from 25°C to 400°C, in particular 50°C to 300°C. Nonetheless, for a particular application or on a one- off basis, it is possible to depart from the aforemen- tioned values without thereby going outside the scope of the present invention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. It will prove advantageous in the realm of the present invention when a classifying means for classifying the carbonizate coming from the carbonizing means is pro- vided between the carbonizing means and the activating means. This permits classification of the resulting ac- tivated carbon according to particle size and hence ac- cording to use properties. Subsequent, purposive mixing of the individual classes can be used to conform the resulting activated carbon specifically to the require- ments needed. This ensures that only carbonizate which is desired with regard to its particle size passes into the activating step. The present invention further provides - in accordance with a second aspect of the present invention - a proc- ess for producing activated carbon, in particular by carbonization and subsequent activation of polymeric organic, preferably sulphonated, starting materials, the process comprising the following process steps: (a) providing polymeric organic starting materials; then (b) drying the starting materials if appropriate (i.e. in the case of undried or moist starting materi- als) ; then (c) sulphonating and/or peptizing the possibly previ- ously dried starting materials if appropriate (i.e. in the case of unsulphonated starting mate- rials) ; then (d) carbonizing the possibly previously dried and/or sulphonated and/or peptized starting materials; then (e) activating the previously carbonized starting ma- terials; wherein the offgases from the carbonizing (d) and/or from the activating (e) are subjected to an offgas treatment. It will be found to be advantageous in particular in the realm of the present invention for the polymeric organic starting material to be used to be in particu- lar ion exchanger resins and their precursors, for ex- ample sulphonated ion exchanger resins and also their unsulphonated precursors and/or divinylbenzene- crosslinked polystyrenes, for example styrene-divinyl- benzene copolymers, in sulphonated or unsulphonated form, preferably having a divinylbenzene content of for example 1% to 10% by weight of divinylbenzene, based on the copolymer. The offgas treatment generally comprises at least one thermal afterburning stage. It will be found advantageous in the realm of the pre- sent invention when the offgases from the carbonizing and the offgases from the activating are each subjected to an offgas treatment. The offgases from the carbonizing and the offgases from the activating are preferably each subjected to a sepa- rate offgas treatment since they have different compo- sitions and therefore the requirements for their treat- ment are different; for example, the offgases from the carbonizing have to be freed of sulphur oxides. In general, the carbonizing is conducted in at least one rotary tube, in particular in at least one rotary tube oven. It will further be found advantageous in the realm of the present invention when the carbonizing is conducted in a closed system and/or the carbonizing is conducted under inert conditions. According to the pre- sent invention, the carbonizing may be operated con- tinuously or quasi-continuously and/or the temperature during the carbonizing may be closed and/or open loop controlled continuously or steppedly. In one preferred embodiment of the present invention, the temperature during the carbonizing is closed and/or open loop con- trolled such that the carbonizing is conducted in two or more, in particular in at least two, preferably in four to eight, temperature zones having temperatures which each differ from the others, preferably having the temperature of the individual temperature stages each rising in the upstream direction. Alternatively, in the realm of the present invention, the carbonizing may be conducted in a temperature gradient, preferably having a rising temperature profile in the upstream di- rection . The temperature during the carbonizing can vary within wide limits. In general, the temperature during the carbonizing is closed and/or open loop controlled in the range from 20°C to 1200°C, in particular 30°C to 1100°C, preferably 50°C to 1000°C. Nonetheless, for a particular application or on a one-off basis, it is possible to depart from the aforementioned values with- out thereby going outside the scope of the present in- vention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. It may be contemplated in the realm of the present in- vention that a first temperature zone, preferably situ- ated at the inlet or in the process flow direction at the upstream end of the carbonizing (means) , is ad- justed in the range from 50°C to 500°C, in particular 200°C to 450°C. It may further be contemplated that a further temperature zone, preferably situated at the outlet or downstream end of the carbonizing (means), is adjusted in the range from 800°C to 1200°C, in particu- lar 850°C to 950°C. In these cases too the recited val- ues only mark the customary ranges hitherto preferred. However, for a particular application or on a one-off basis, it is readily possible to depart from the afore- mentioned values without thereby going outside the scope of the present invention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. The carbonizing is generally subdivided into at least two part-steps. It may be contemplated that a first, preferably upstream, part-step is conducted in a heated vibrating chute and a second part-step, preferably con- ducted downstream of the first section, is conducted in a rotary tube, preferably in a rotary tube oven, in particular having a rising temperature profile or tem- perature gradient in the process flow direction. According to the present invention, the first part-step may be conducted with a constant temperature or with a temperature profile or temperature gradient rising in the process flow direction and/or the second part-step may be conducted with a temperature profile or tempera- ture gradient rising in the process flow direction. Furthermore, in the realm of the present invention, the temperature in the first carbonizing part-step in the process flow direction may be closed loop controlled continuously or steppedly. The temperatures in the first carbonizing part-step in the process flow direc- tion may vary within wide limits. In general, the tem- perature in the first carbonizing part-step in the process flow direction is closed loop controlled con- tinuously or steppedly in the range from 50°C to 500°C, preferably 200°C to 450°C. Nonetheless, for a particu- lar application or on a one-off basis, it is possible to depart from the aforementioned values without thereby going outside the scope of the present inven- tion. A decision to do so is within the ability or dis- cretion of a person skilled in this field to decide. Furthermore, in the realm of the present invention, the temperature in the second carbonizing part-step in the process flow direction may be closed loop controlled to be rising, in particular steppedly or steplessly, in particular in two or more temperature zones or with a temperature gradient, in the process flow direction. The temperature in the second carbonizing part-step in the process flow direction may vary within wide limits. In general, the temperature in the second carbonizing part-step in the process flow direction is closed loop controlled to rise in the process flow direction in the range from 300°C to 1200°C, preferably from 350°C to 950°C. Nonetheless, for a particular application or on a one-off basis, it is possible to depart from the aforementioned values without thereby going outside the scope of the present invention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. In one particular embodiment of the present invention, water vapour, in particular in the form of a water va- pour-inert gas mixture, is injected by spraying or jet- ting during the carbonizing, preferably at the inlet or in the process flow direction at the upstream end of the carbonizing (means), in particular at the inlet or in the process flow direction at the upstream end of the second section of the carbonizing means. The pro- portion of water vapour in the water vapour-inert gas mixture can vary within wide limits. Generally, the proportion of water vapour in the water vapour-inert gas mixture is adjusted in the range from 1% to 30% by volume, in particular 2% to 20% by volume, preferably 5% to 15% by volume. Nonetheless, for a particular ap- plication or on a one-off basis, it is possible to de- part from the aforementioned values without thereby go- ing outside the scope of the present invention. A deci- sion to do so is within the ability or discretion of a person skilled in this field to decide. It will further be found advantageous in the realm of the present invention when oxygen, in particular in the form of an oxygen mixture with at least one further gas, preferably in the form of air, is introduced or injected during the carbonizing, preferably at the out- let or in the process flow direction at the downstream end of the carbonizing (means) . The introduced or in- jected volume stream of oxygen or of an oxygen mixture can vary within wide limits. In general, the introduced or injected volume stream of oxygen, in particular in the form of an oxygen mixture with at least one further gas, preferably in the form of air, is adjusted in the range from 10 to 500 l/min, in particular 25 to 250 l/min, preferably 50 to 100 l/min. Nonetheless, for a particular application or on a one-off basis, it is possible to depart from the aforementioned values with- out thereby going outside the scope of the present in- vention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. In general, the carbonizing is followed by treating the offgases formed in the carbonizing. It may be contem- plated here that the offgas treatment comprises at least one thermal afterburning stage. In a particularly preferred embodiment of the present invention, the offgas treatment is followed, in particular at a point upstream of the thermal afterburning stage, by the offgases resulting from the thermal afterburning stage being cooled, in particular by means of a heat ex- changer. Optionally, the cooling of the offgases is followed by drying of the cooled offgases. In turn, the drying of the offgases may optionally be followed by heating of the dried offgases. In a particularly preferred embodiment of the present invention, the offgas treatment comprises an oxidation, preferably a catalytic oxidation, of the sulphur ox- ides, in particular sulphur dioxide, present in the offgases formed in the carbonizing, to form sulphur trioxide, preferably downstream of the thermal after- burning stage and the optional cooling, drying and/or heating. It may be contemplated that the oxidation is conducted by means and/or in the presence of at least one oxidation catalyst, preferably vanadium and/or platinum based. It may be further contemplated that the sulphur trioxide generated in the oxidation is returned into the sulphonation and/or peptization. Optionally the sulphur trioxide generated in the oxidation is re- turned into the sulphonation and/or peptization after an interposed process step for producing the sulphonat- ing agent. It will further prove particularly advantageous in the realm of the present invention when the sulphur triox- ide generated in the oxidation is separated from the other constituents of the offgases, in particular car- bon oxides and/or water vapour and/or nitrogen oxides. It may be contemplated here that the separating is op- tionally followed by washing of the separated-off other constituents of the offgases. The carbonizing is then followed, optionally after an interposed classifying step for the carbonizate, by ac- tivating the previously produced carbonizate. In gen- eral, the activating is conducted batchwise. It will further be found to be advantageous according to the present invention when the activating is con- ducted in a closed system and/or when the activating is conducted under inert conditions, in particular at the start of the activating and/or at the start of the heating-up phase. The temperature during activating can vary within wide limits. In general, the temperature during activating is set in the range from 300°C to 1800°C, in particular 400°C to 1500°C, preferably 500°C to 1250°C. Nonethe- less, for a particular application or on a one-off ba- sis, it is possible to depart from the aforementioned values without thereby going outside the scope of the present invention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. It may be contemplated in this connection that the tem- perature during activating is set steplessly and/or continuously, preferably by means of a heating means, in particular an electrically operated heating system. In a particularly preferred embodiment of the present invention, the activating comprises introducing, in particular by jetting and/or blowing, at least one ac- tivating gas, in particular water vapour and/or carbon dioxide and/or oxygen and/or ammonia. It may be contemplated in the realm of the present in- vention that the activating gas introduced into the ac- tivating step is heated to a defined temperature. When two or more different activating gases are used, these may be introduced into the activating step at the same time or at different times, in which case intro- ducing at different times is preferable in the realm of the present invention. Similarly, the activating gases can be introduced at like or different temperatures. According to the present invention, the activating com- prises introducing, in particular by jetting, spraying and blowing, at least water vapour, in particular in the form of a water vapour-inert gas mixture, as acti- vating gas. The proportion of water vapour in the water vapour- inert gas mixture can vary within wide limits. In gen- eral, the proportion of water vapour in the water va- pour-inert gas mixture is set in the range from 5% to 70% by volume, in particular 10% to 50% by volume, preferably 15% to 40% by volume. Nonetheless, for a particular application or on a one-off basis, it is possible to depart from the aforementioned values with- out thereby going outside the scope of the present in- vention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. It may be contemplated in this connection that the wa- ter vapour is introduced at temperatures from 500°C by jetting, spraying and/or blowing during the activating. It will likewise prove advantageous in the realm of the present invention when the activating comprises intro- ducing carbon dioxide, particularly in the form of a carbon dioxide-inert gas mixture, as an activating gas, in particular in addition to water vapour being used as activating gas, in particular by jetting, spraying and/or blowing. It may be contemplated that the carbon dioxide is introduced at temperatures from 800°C by jetting, spraying and/or blowing. As already noted in the observations concerning the ap- paratus of the present invention, the temperatures and the carbon dioxide content during the activating influ- ence the burn-out behaviour of the material to be acti- vated and thus the material properties of the resulting activated carbon. In one particular embodiment of the present invention, the at least one activating gas is fed into the acti- vating step from a stockkeeping receptacle via a feed- ing means. In general, the activating is followed by a treatment being conducted on the offgases formed in the activat- ing. It may be contemplated in this connection that the offgas treatment comprises at least one thermal after- burning stage. According to the present invention, the thermal after- burning stage may be followed by a wash being conducted of the offgases from the thermal afterburning stage. After passing through the washer, the offgases which, owing to the thermal afterburning, consist overwhelm- ingly of carbon dioxide and water vapour, are emitted. However, only excess offgases are routed to the wash directly, the overwhelming portion being utilized as an energy supplier in the various operations of activated carbon manufacture. In a particularly preferred embodiment of the present invention, the offgases coming from the offgas treat- ment (i.e. offgas treatment of the offgases coming from the activating), in particular from the thermal after- burning, are used for indirect, in particular, heating for the activating (means) and/or for heating the at least one activating gas and/or for drying, in particu- lar for creating a fluidized bed. For further details concerning using the offgases from the activating, in particular after passing through the thermal afterburn- ing, reference can be made to the above elucidations concerning the apparatus of the present invention. As observed above, a drying step (a) is conducted in the case of undried/moist starting materials before the actual production of activated carbon. According to the present invention, the drying can be conducted in a fluidized bed; preferably, the drying, in particular the fluidized bed thereof, can be operated by means of offgases coming from the offgas treatment (i.e. the offgas treatment of the offgases from the activating), in particular from the thermal afterburning. In par- ticular, in the realm of the present invention, the drying can be operated batchwise. The temperatures in relation to the drying step can vary within wide lim- its. In general, the drying is operated at temperatures in the range from 100°C to 400°C, in particular 100°C to 200°C. Nonetheless, for a particular application or on a one-off basis, it is possible to depart from the aforementioned values without thereby going outside the scope of the present invention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. As observed above, a process step of sulphonating and/or peptizing is conducted before the carbonizing in the case of unsulphonated starting materials. This process step of sulphonating and/or peptizing comprises the actual sulphonation (i.e. the introduction of sul- phonic acid groups) and also, optionally, the peptiza- tion (i.e. the dissolving out of monomeric, dimeric and oligomeric units remaining in the starting material and the deposition of said units on the outer surface of the particles of the starting material). In particular, in the realm of the present invention, the sulphonating and/or peptizing can be operated batchwise. The sulphonating/peptizing temperature can vary within wide limits. In general, the sulphonating/peptizing is operated at temperatures in the range from 25°C to 400°C, in particular 50°C to 300°C. Nonetheless, for a particular application or on a one-off basis, it is possible to depart from the aforementioned values with- out thereby going outside the scope of the present in- vention. A decision to do so is within the ability or discretion of a person skilled in this field to decide. In a particularly preferred embodiment of the present invention, a process step of classifying the carboni- zate coming from the carbonizing can also be conducted between the carbonizing step and the activating step. For further details concerning the process of the pre- sent invention, reference can be made to the above ob- servations concerning the apparatus of the present in- vention, which hold mutatis mutandis in relation to the process of the present invention. The apparatus of the present invention and also the process of the present invention have a number of ad- vantages over the prior art: The oxidation of the sulphur-containing compounds to sulphur trioxide and the sulphur trioxide being re- turned into the sulphonation substantially avoids the emission of sulphur-containing offgases which would otherwise have to be inconveniently and cost- intensively cleaned/purified. A large proportion of the sulphonating agent used can be recovered, so that only a small proportion of the sulphonating agent is actually consumed and has to be replaced. Recovering the sulphonating agent also dramatically re- duces the total amount of all offgases generated, in particular the corrosive acidic offgases. Thermal afterburning of the offgases formed in the car- bonizing/activating ensures that the offgases, after removal of the sulphur-containing compounds, consist almost exclusively of the innocuous combustion residues carbon dioxide and water vapour. Afterburning generates heat whereby the energy require- ments of the activated carbon production process can be distinctly reduced; for instance, the energy require- ments of the activating step can be reduced by at least 10% to 20% by the thermal afterburning of the offgases formed. Hot offgases from the thermal afterburning, moreover, can also be used for heating the activating gases and/or for drying the starting materials used for the activated carbon production. Classifying the crude activated carbon before activa- tion makes it possible to separate or else to specifi- cally mix the individual classes, so that the resulting activated carbon can be optimally conformed to the in- tended end-use. The apparatus of the present invention and the process of the present invention make it possible to maintain the SO2 emission during carbonization at such a constant level as to allow a sulphur trioxide production process to be carried out and hence for the sulphonating agent to be recovered. The sole figure is a schematic and exemplary depiction of a typical, preferred embodiment of the inventive ap- paratus _1 and of the inventive process sequence: As the figure shows, when nondried/moist starting mate- rial is used, a drying operation, preferably in a flu- idized bed, is optionally initially carried out in 2, which in the case of unsulphonated starting materials is then followed optionally at 3 by a sulphonation and/or peptization. The dried and sulphonated/peptized starting material, for example based on sulphonated styrene-divinylbenzene polymers, for example in the form of so-called sulphonated ion exchanger resins of the gel type or of the macroporous type, is then subse- quently subjected to carbonization at 4, whereafter the carbonizate resulting from this stage is subjected to activation at 5, resulting in the desired end product (i.e. activated carbon). As the figure further shows, the acidic, in particular, offgases, coming from the carbonization 4 are initially subjected, at 4A, to thermal afterburning (TAB) and thereafter - optionally after cooling, drying and renewed heating of these gases - at 4B to a catalytic oxidation, in particular in the presence of vanadium pentoxide as oxidation catalyst, so that sulphur dioxide SO2 present in the offgas is converted to sulphur trioxide SO3, which can be returned, via 4C, back into the sulphonation 3, in particular in the form of concentrated sulphuric acid/oleum. The remaining offgases from the catalytic oxidation 4B, however, are then emitted, optionally af- ter a further downstream wash 4D, these offgases com- prising essentially carbon dioxide CO2, water vapour H2O and only very minor amounts of nitrogen oxides NOX and sulphur oxides SOX. The offgases from the activation 5, in particular hy- drogen H2 and carbon monoxide CO, are similarly sub- jected to thermal afterburning (TAB) 5C, and the still hot offgases coming from the thermal afterburning can be used firstly to co-heat the activating means 5, sec- ondly to heat up the activating gases, or the relevant receptacle for the activating gases, in particular wa- ter vapour, at 5B, in which case the heated activating gases, in particular water vapour, are then supplied to the activating step via 5A, and finally also to supply the requisite heat and the fluidized bed for the drying stage 2. Any unused offgases from thermal afterburning (TAB) 5C can then be emitted, optionally after a washer 5D, as offgases, in particular consisting mainly of carbon dioxide CO2 and water vapour H2O etc. In a typical embodiment of the present invention, the apparatus of the present invention or the process of the present invention can be executed as follows: The starting material, for example styrene-divinyl- benzene copolymers, in particular ion exchangers of the gel type or of the macroporous type, are - if present in nondried/moist form - subjected to drying in a first stage, said drying of the starting material being pref- erably effected in a fluidized bed, preferably by util- izing rejected heat from the activating step. The dry- ing is typically carried out batchwise/discontinuously (for example 1 m3 of starting material per batch). Unsulphonated starting materials are subjected in a second stage, downstream of the drying stage, to a sul- phonation/peptization. For this purpose, the starting polymers or to be more precise ion exchangers are con- tacted with a suitable sulphonating agent, in particu- lar concentrated sulphuric acid/oleum (for example 15% oleum), in particular at temperatures of 100°C to 400°C, preferably 150 to 250°C. Depending on the de- sired pore system, different quantitative ratios of sulphonating agent can be used and, for example, re- acted according to a temperature characteristic, se- lectable by a person skilled in the art, until the starting material has been sulphonated and is present in free-flowing form. This stage provides not just a sulphonation but generally also a so-called peptiza- tion, i.e. monomer, dimer and oligomer residues are dissolved out of the starting materials and subse- quently redeposited on the surface of the particles, these redepositions resulting in the course of the sub- sequent carbonization in a very hard and hence abra- sion-resistant pseudographite layer being formed on the surface of the particles. A subsequent, third, stage of the process then involves the dry and sulphonated starting material being carbon- ized/pyrolyzed, preferably continuously or quasi- continuously, in particular in a closed system. Car- bonization is typically carried out under inert reac- tion conditions. The material can typically be dis- charged onto a heatable vibrating chute, customarily under inert gas atmosphere, in which case the material can be heated to 350°C, for example, in the course of 60 minutes for example. This vibrating chute then feeds into a likewise continuously or quasi-continuously op- erated rotary tube oven having a temperature of typi- cally 400°C at the inlet side. In the course of trans- port in the rotary tube, the material is then typically heated to, for example, 900°C via six to eight heating zones. Preference is given to the simultaneous addition of water vapour, preferably of a corresponding nitro- gen-water vapour mixture (for example 10% to 30% by volume of water vapour) , from the oven inlet side and the addition of air/oxygen (for example 50 to 100 l/min) from the oven outlet side in order that the combustion of resulting pyrolysis gases in the reaction tube may be made possible. This can be used to achieve several positive effects. First, condensing of pyroly- sis gases in the base pore system of the starting mate- rial is substantially prevented, and secondly the com- bustion in the reaction tube can be used to utilize the heat content and the input of electric power into the oven-heating system can be minimized. After carboniza- tion/pyrolysis is concluded, the material is typically accessible and has an internal surface area (BET) of for example 400 to 800 m2/g. It is preferable when the particle shape is spherical, in accordance with the starting materials. A downstream, fourth stage then involves the initially produced carbonizate being activated. In the activating step, the material, preferably after prior classifica- tion, is filled in narrow particle size fractions into a rotary tube oven having internals and is heated under an inert atmosphere to about 960°C for example, while the atmosphere can have water vapour added to it (for example 20% to 30% by volume) , preferably in the form of a nitrogen/water vapour mixture, from about 600°C for example. Depending on the degree of activation de- sired and depending on the pore system desired, the at- mosphere can be admixed with carbon dioxide CO2 from about 900°C for example, and/or the temperature can be varied, for example to influence the burn-out behav- iour. The gases, in particular hydrogen H2 and carbon monoxide CO, formed in the activating step can advanta- geously be used for indirect heating of the activating pipe. As a result, about 20% of the total energy re- quirements of the apparatus can be coupled out of the process. As far as the offgas treatment is concerned, the offgases coming from the carbonization/pyrolysis can initially be afterburned in a thermal afterburning stage (TAB), in particular via excess air, to oxidize all organic constituents; subsequently, the SC>2-rich offgas is advantageously directed into a heat exchanger and cooled, in order that it may be dehumidified in a gas-drying stage, by means of sulphuric acid, and after subsequent heating, for example to temperatures of about 480°C, the gas can be led via a plurality of stages to an oxidation catalyst (for example vanadium- based oxidation catalyst, for example vanadium pentox- ide) until the sulphur dioxide SO2 has been oxidized to sulphur trioxide SO3. After all the SO2 has been oxi- dized to SO3, the SO3-containing offgas is typically cooled again and the SO3 is washed out by means of con- centrated sulphuric acid, so that the SO3 can be re- turned into the sulphonating step. Thus, a complete re- cycling circuit is provided for sulphonating agents and there is no need for costly and inconvenient disposal. In order that the design may be economically and ecol- ogically realizable, it is of advantage when the quan- tities of offgas generated are relatively constant, which can be achieved by the SO2-relevant process steps, in particular the carbonization/pyrolysis, being made continuous/quasicontinuous and the SO2 emission being maintained approximately constant, i.e. without spikes in the SO2 emission. The treatment of the offgases from the activating step can be carried out in the manner previously described (i.e. thermal afterburning and use of the offgases com- ing from the thermal afterburning for heating the acti- vating gas, in particular water vapour, and/or for in- direct heating of the activating oven and/or for use in fluidized bed drying). The present invention finally also provides - in accor- dance with a third aspect of the present invention - for the use of the apparatus of the present invention, as previously described, for producing activated car- bon. As previously described, the production of acti- vated carbon in the course of the use according to the present invention is effected by carbonization and sub- sequent activation of polymeric organic, preferably sulphonated, starting materials. For further details concerning the use according to the present invention, reference can be made to the above observations con- cerning the apparatus of the present invention and the process of the present invention, which apply mutatis mutandis to the use according to the present invention. Further refinements, modifications, variations and also advantages of the present invention will become readily apparent to and realizable by the ordinarily skilled after reading the description without their having to depart from the realm of the present invention. WE CLAIM 1. Apparatus (1) for producing activated carbon, in particular by carbonization and subsequent activa- tion of polymeric organic sulphonated starting ma- terials, the apparatus including - optionally a drying means (2) for drying the starting materials, - optionally a sulphonating means (3) for sulpho-* nating and/or peptizing the optionally previ- ously dried starting materials downstream of the optional drying means (2), - a carbonizing means (4) for carbonizing the op- tionally previously dried and/or sulphonated and/or peptized starting materials downstream of the optional drying means (2) and/or the op- tional sulphonating means (3), wherein the tem- perature of the carbonizing means (4) is ad- justable in operation such that at least two temperature zones having the temperature of the individual temperature stages each rising in the upstream direction are present or else a temperature gradient having a rising tempera- ture profile in the upstream direction is pre- sent, - downstream of the carbonizing means (4), an ac- tivating means (5) for activating the starting materials previously carbonized in the carbon- izing means (4), wherein the apparatus (1) also comprises at least one offgas-treating means (4A, 4B, 4D) for treating the offgases formed in operation in the carbonizing means (4) and at least one of fgas-treating means (5C, 5D) for treating the offgases formed in opera- tion in the activating means (5) , wherein the car- bonizing means (4) has an offgas-treating means (4A, 4B, 4D) for treating the offgases formed in operation in the carbonizing means (4) connected to and/or positioned downstream of it, wherein the offgas-treating means (4A, 4B, 4D) comprises at least one thermal afterburning stage (4A), and wherein the activating means (5) has an offgas- treating means (5C, 5D) for treating the offgases formed in operation in the activating means (5) connected to and/or positioned downstream of it, wherein the offgas-treating means (5C, 5D) com- prises at least one thermal afterburning stage (5C), and wherein the offgases coming from the of fgas-treating means (5C, 5D) are used for heating of the activating means (5) and/or via a supply line (5E) for heating a stockkeeping receptacle (5B) containing at least one activating gas or at least one activating gas and/or for heating the op- tional drying means (2). 2. Apparatus according to Claim 1, wherein the carbon- izing means (4) comprises at least one rotary tube or at least one rotary tube oven and is operable under inert conditions continuously or quasi- continuously. 3. Apparatus according to Claim 1 or 2, wherein the carbonizing means (4) is subdivided into at least two sections, wherein a first section, preferably disposed upstream, is formed by a heatable vibrat- ing chute and a second section, preferably disposed downstream of the first section, is formed by a ro- tary tube, preferably a rotary tube oven, having a rising temperature profile or temperature gradient in the process flow direction in the operating state. 4. Apparatus according to any preceding claim, wherein the offgas-treating means (4A, 4B, 4D) in- cludes, in particular upstream of the thermal af- terburning stage (4A), at least one heat exchanger for cooling the offgases resulting from thermal af- terburning, optionally followed by a drying means for drying the cooled offgases and optionally in turn followed by a heating means for heating the dried offgases, and/or wherein the offgas-treating means (4A, 4B, 4D) com- prises an oxidizing means (4B) for preferably cata- lytically oxidizing the sulphur oxides, in particu- lar sulphur dioxide, present in the offgases formed in operation in the carbonizing means (4), to form sulphur trioxide, preferably downstream of the thermal afterburning stage (4A) and the bptional heat exchanger, drying means and/or heating means 5. Apparatus according to any preceding claim, wherein the activating means (5) is operable batchwise and forms a closed system and wherein the activating means (5) is operable under inert conditions and is variable in operation in the range from 300°C to 1800°C. 6. Process for producing activated carbon, in particu- lar by carbonization and subsequent activation of polymeric organic preferably sulphonated starting materials, the process comprising the following process steps: (a) providing polymeric organic starting materials; then (b) drying the starting materials if appropriate; then (c) sulphonating and/or peptizing the possibly pre- viously dried starting materials if appropri- ate; then (d) carbonizing the possibly previously dried and/or sulphonated and/or peptized starting ma- terials, wherein the temperature during the carbonizing is closed and/or open loop con- trolled such that the carbonizing is conducted in at least two temperature zones having tem- peratures which each differ from the others, having the temperature of the individual tem- perature stages each rising in the upstream di-, rection, or else in a temperature gradient hav- ing a rising temperature profile in the up- stream direction; then (e) activating the previously carbonized starting materials; wherein the offgases from both the carbonizing (d) and from the activating (e) are each subjected to an offgas treatment, wherein the carbonizing is followed by treating the offgases formed in the carbonizing, wherein the offgas treatment comprises at least one thermal afterburning stage, and where- in the activating is followed by a treatment being conducted on the offgases formed in the activating, wherein the offgas treatment comprises at least one thermal afterburning stage, and wherein the offgas- es which come from the offgas treatment of the off- gases formed in the activating are used for heating for the activating (means) and/or for heating at least one activating gas and/or for drying. The invention relates to an apparatus or installation for producing active carbon, in particular by carbonization and subsequent activation of polymeric, organic, preferably sulphonated, starting materials, wherein the apparatus or installation comprises optionally a drying device for drying the starting materials, optionally a sulphonating device, arranged downstream of the optionally present drying device, for sulphonating and/or peptizing the optionally previously dried starting materials, a carbonizing device, arranged downstream of the optionally present drying device and/or the optionally present sulphonating device, for carbonizing the optionally previously dried and/or sulphonated and/or peptized starting materials, as well as an activating device, arranged downstream of the carbonizing device, for activating the starting materials previously carbonized in the carbonizing device, wherein the apparatus or installation also comprises at least one exhaust-gas treatment device for treating the exhaust gases formed in the carbonizing device and/or in the activating device during operation.

Full Text

INSTALLATION AND METHOD FOR PRODUCING ACTIVE CARBON
The present invention relates to the technical field of
producing activated carbon.
The present invention relates more particularly to an
apparatus and also a process for producing activated
carbon, in particular by carbonization and subsequent
activation of suitable polymeric starting materials,
such as sulphonated polymers.
Activated carbon has highly non-specific adsorption
properties and for this reason is the most widely used
adsorbant. Statutory requirements as well increasing
environmental awareness are leading to an increasing
demand for activated carbon.
Activated carbon is generally produced by carbonization
and subsequent activation of suitable carbonaceous
starting materials. Starting materials which lead to
economically viable yields are generally preferred,
since the weight losses caused by detachment of vola-
tile constituents during carbonization and by burn-out
during activation are appreciable. For further details
concerning the production of activated carbon, see for
example H. v. Kienle and E. Bader, Aktivkohle und ihre
industrielle Anwendung, Enke Verlag Stuttgart, 1980.
Carbonization, also known as pyrolysis, describes the
conversion of the carbonaceous starting material into
carbon. The process of carbonizing the aforementioned
polymeric, in particular sulphonated, organic starting
materials has the effect of detaching volatile con-
stituents such as SO2 in particular to destroy the func-
tional chemical groups, sulphonic acid groups in par-
ticular, to form free radicals which effect the pro-
nounced crosslinking without which there would be no
pyrolysis residue (= carbon).
Carbonization is followed by activation. The basic
principle of activation consists in some of the carbon
generated by carbonization being selectively and delib-
erately broken down under suitable conditions. This
gives rise to a large number of pores, cracks and fis-
sures, and the surface area per unit mass increases ap-
preciably. Activation thus involves a deliberate burn-
out of the previously carbonized material. Since carbon
is broken down during activation, this operation leads
to a loss of substance which is appreciable in some in-
stances and which under optimum conditions equates to
an increase in the porosity and an increase in the in-
ternal surface area and of the pore volume. Activation
is therefore effected under selective/controlled, gen-
erally oxidizing, conditions.
The condition or constitution of the activated carbon
produced - finely or coarsely porous, firm or brittle -
is also dependent on the starting material. Customary
starting materials are coconut shells, wood wastes,
peat, bituminous coal, pitches, but also particular
plastics, which play a certain part in the production
of woven activated carbon fabrics inter alia.
Various forms of activated carbon are used: carbon pow-
der, splint coal, granulocarbon, moulded carbon and
also, since the end of the 1970s, activated carbon in
spherical form ("spherocarbon"). Spherical activated
carbon has a number of advantages over other forms of
activated carbon such as carbon powder, splint coal,
granulocarbon and the like, making it valuable or even
indispensable for certain applications: it is free-
flowing, hugely abrasion-resistant (i.e. dustless) and
very hard. Owing to its high price, however, its use is
essentially limited to protective suits and high-
performance filters for noxiants in air streams.
Spherocarbon is in great demand on account of its spe-
cific shape, but also on account of its extremely high
abrasion resistance for particular fields of use for
example, examples being sheet filters for protective
suits against chemical poisons and filters for low
noxiant concentrations in large volumes of air. For in-
stance, when reticulated, large-cell polyurethane foams
are loaded with activated carbon as described in
DE 38 13 563 Al, only a very free-flowing carbon can be
used if optimal coverage of the inner layers of the
foam material as well as the outer layers is to be
achieved. The manufacture of protective suits against
chemical poisons on the lines of DE 33 04 349 C3 for
example can likewise utilize only a highly abrasion-
resistant carbon, and only spherocarbon fits this de-
scription.
Spherocarbon is currently still being mostly produced
by multistage processes which are very costly and in-
convenient. The best-known process consists in spher-
ules being produced from coal tar pitch and suitable
asphaltic residues from the petrochemical industry and
oxidized (to render them unmeltable), carbonized and
activated. For example, spherocarbon can be produced
from bitumen in a multistage process. These multistage
processes are very cost-intensive and the associated
high price of this spherocarbon prevents many applica-
tions wherein spherocarbon ought to be preferable by
virtue of its properties.
There have consequently been various attempts to pro-
duce high-grade spherocarbon in some other way. It is
prior art to produce spherocarbon by carbonization and
subsequent activation of new or used ion exchangers
containing sulphonic acid groups, or by carbonizing ion
exchanger precursors in the presence of sulphuric acid
and subsequent activation, wherein the sulphonic acid
groups and the sulphuric acid respectively have the
function of a crosslinker, and the yields obtained,
which do not depend on whether ready-produced cation
exchangers or unsulphonated ion exchanger precursors
are used as starting materials, being about 30% to 50%,
based on organic/polymeric starting material. Such
processes are described for example in DE 43 28 219 Al
and in DE 43 04 026 Al and also in DE 196 00 237 Al,
including the German patent-of-addition application DE
196 25 069 Al. But these processes are disadvantageous
and problematic particularly because of the large
amounts of sulphur dioxide released (about 1 kg of SO2
per kg of end product) and also because of the (partly)
associated corrosion problems in the manufacturing
equipment. When used ion exchanger resins, in particu-
lar used cation exchanger resins, are used as starting
materials, there is also the problem that these, al-
though they have been washed with acid, are contami-
nated with cations which then accumulate in the end
product, so that the production of major amounts of
spherocarbon in consistent quality is consequently very
difficult. When ion exchanger precursors, i.e. polymer
spherules without exchanger groups like sulphonic acid
groups, are used, it is additionally necessary to use
large amounts of sulphuric acid and/or oleum for the
crosslinking during the carbonization.
WO 98/07655 Al describes a process for producing spher-
ules of activated carbon wherein a mixture comprising a
distillation residue from diisocyanate production and a
carbonaceous processing assistant with or without one
or more further added substances is processed into
free-flowing spherules which are subsequently carbon-
ized and then activated. This process likewise re-
leases, in the course of the carbonizing step, large
pulses of decomposition products, which is associated
with the problems described above.
Commonly assigned WO 01/83368 Al relates to an improved
process for producing activated carbon wherein the req-
uisite process steps of carbonization on the one hand
and activation on the other are carried out separately
from each other in that the carbonization is carried
out as a continuous operation while the postcarboniza-
tion and activation is carried out as a batch opera-
tion. This process is mainly based on the separation of
the corrosive phase (i.e. precarbonization, associated
with SO2 emissions) from the high-temperature phase (ac-
tivation) . This is because precarbonized starting mate-
rial is no longer corrosive; i.e. corrosive materi-
als/gases are no longer formed when the temperature is
raised any further.
Furthermore, the commonly assigned printed publications
DE 10 2004 036 109 Al, DE 10 2005 036 607 Al and also
WO 2005/016819 Al disclose apparatuses for producing
activated carbon.
However, the processes and apparatuses for producing
activated carbon which are known from the prior art are
usually concerned with improving partial aspects only
and do not provide a holistic approach which takes ac-
count of all problems arising in activated carbon pro-
duction, particularly the high energy requirements, the
use of cost-intensive starting materials and chemicals,
the emission of offgases, the loss of energy in the in-
dividual processing stages, and the like.
The problem underlying the present invention therefore
consists in providing a novel apparatus and process for
producing activated carbon wherein the previously de-
scribed disadvantages associated with the prior art
shall be at least partly avoided or at least amelio-
rated.
The apparatus and process shall make it possible to
produce activated carbon in a less inconvenient, ide-
ally less cost-intensive and also ecologically as well
as economically improved or more efficient manner.
To solve the problem described above, the present in-
vention therefore proposes an apparatus for producing
activated carbon as per Claim 1, a process for produc-
ing activated carbon as per Claim 33 and the use of the
inventive apparatus as per Claim 65; further, advanta-
geous developments each form subject matter of respec-
tive subclaims.
It will be readily understood that particular develop-
ments and embodiments which have been described only in
connection with one aspect of the present invention
also apply mutatis mutandis in relation to the other
aspects of the present invention without this being ex-
pressly stated.
As for the rest, a person skilled in the art may, for a
particular application or on a one-off basis, depart
from the hereinbelow recited numbers, values and ranges
without thereby going outside the scope of the present
invention.
The present invention accordingly provides - in accor-
dance with a first aspect of the present invention - an
apparatus for producing activated carbon, in particular
by carbonization and subsequent activation of polymeric
organic, preferably sulphonated, starting materials,
the apparatus including
- optionally a drying means for drying the starting
materials,
- optionally a sulphonating means for sulphonating
and/or peptizing the optionally previously dried
starting materials, in particular downstream of
the optional drying means,
- a carbonizing means for carbonizing the optionally
previously dried and/or sulphonated and/or pep-
tized starting materials, in particular downstream
of the optional drying means and/or the optional
sulphonating means,
- downstream of the carbonizing means, an activating
means for activating the starting materials previ-
ously carbonized in the carbonizing means,
wherein the apparatus also comprises at least one
offgas-treating means for treating the offgases formed
in operation in the carbonizing means and/or in the ac-
tivating means.
In general, the offgas-treating means comprises at
least one thermal afterburning (TAB) stage.
Thermal afterburning (TAB) herein is to be understood
as referring to an operation wherein the offgases
formed in the carbonization and/or activation are
burned at temperatures above 900°C. This operation con-
verts gases in the offgases, in particular hydrocar-
bons, carbon monoxide and elemental hydrogen, into wa-
ter and carbon dioxide generally and essentially com-
pletely. The remaining offgases are thus less inconven-
iently and consequently less costly to clean/purify and
the resulting heat can be fed back to the carbonization
and/or activation process, saving energy.
In a preferred embodiment of the present invention, the
apparatus of the present invention comprises at least
one offgas-treating means for treating the offgases
formed in operation in the carbonizing means on the one
hand and at least one offgas-treating means for treat-
ing the offgases formed in operation in the activating
means, on the other.
The carbonizing means in the apparatus of the present
invention can customarily be constructed as follows:
In general, the carbonizing means comprises at least
one rotary tube, in particular at least one rotary tube
oven.
It will be found advantageous for the carbonizing means
to form a closed system and/or be operable under inert
conditions.
A closed system for the purposes of the present inven-
tion is, in particular, a system which exchanges very
little energy with the environment. Similarly, an ex-
change of matter with the environment, except for the
supplied process gases (for example water vapour, car-
bon dioxide, etc.) and the removed offgases, shall ide-
ally be avoided or at least minimized; thus, any ex-
change of matter only takes place under precisely de-
fined and policed conditions.
By "inert conditions" herein it is meant, in particu-
lar, that the apparatus of the present invention is op-
erated with an inert gas atmosphere and that the proc-
ess of the present invention is conducted under an in-
ert gas atmosphere, said inert gas atmosphere prefera-
bly comprising a noble gas and/or nitrogen atmosphere,
more preferably a nitrogen atmosphere. The inert gas
atmosphere prevents any unintended excessive oxidation
or a burn-out of the material used.
According to the present invention, the carbonizing
means may be operable continuously or quasi-
continuously. Furthermore, the temperature of the car-
bonizing means may be continuously or steppedly vari-
able in operation.
In a preferred embodiment of the present invention, the
temperature of the carbonizing means is adjustable in
operation such that two or more, in particular at least
two, preferably four to eight, temperature zones having
temperatures which each differ from the others, pref-
erably having the temperature of the individual tem-
perature stages each rising in the upstream direction,
are present. Alternatively, however, a temperature gra-
dient may also be present, preferably having a tempera-
ture profile which rises in the upstream direction.
A temperature zone for the purposes of the present in-
vention is a heating zone or a region of at least es-
sentially constant temperature. The rise in temperature
in the process flow direction via two or more tempera-
ture zones occasions a relatively constant emission of
sulphur oxides SOX from the starting material to be car-
bonized. More particularly, no spikes in sulphur oxide
emission, in particular in sulphur dioxide emission,
are obtained, so that the means for capturing and
treating the offgases can be made smaller than would be
possible in the event of spikes occurring in the emis-
sion of sulphur oxides. In addition, it is only the
continuous and constant release of sulphur oxides, in
particular sulphur dioxide, that permits a hereinbelow
recycling operation for the sulphur oxides, which would
otherwise be impossible to carry out.
The temperature of the carbonizing means in operation
can vary between wide limits in the realm of the pre-
sent invention. The range in which the temperature of
the carbonizing means is variable is generally from
20°C to 1200°C, in particular from 30°C to 1100°C,
preferably 50°C to 1000°C. It will be found particu-
larly advantageous when a first temperature zone, pref-
erably situated at the inlet or in the process flow di-
rection at the upstream end of the carbonizing means is
adjustable in operation in the range from 50°C to
500°C, in particular 200°C to 450°C. It may addition-
ally be contemplated that a further temperature zone,
preferably situated at the outlet or downstream end of
the carbonizing means, be adjustable in operation in
the range from 800°C to 1200°C, in particular 850°C to
950°C. However, for a particular application or on a
one-off basis, it is possible to depart from the afore-
mentioned values without thereby going outside the
scope of the present invention. A decision to do so is
within the ability or discretion of a person skilled in
this field to decide.
In a particularly preferred embodiment of the present
invention, the carbonizing means is subdivided into at
least two sections. A first section, preferably dis-
posed upstream, may be formed by a heatable vibrating
chute and a second section, preferably disposed down-
stream of the first section, may be formed by a rotary
tube, preferably a rotary tube oven, in particular hav-
ing a rising temperature profile or temperature gradi-
ent in the process flow direction in the operating
state.
Vibrating chute herein is to be understood as meaning a
chute or some other conveying means, such as a conveyor
belt for example, which ensures good commixing and uni-
form heating of the material to be carbonized, by sys-
tematic vibration.
In one particular embodiment of the present invention,
the first section of the carbonizing means may be con-
structed to be settable to a constant temperature or
may be constructed to be adjustable to a rising tem-
perature profile or temperature gradient in the process
flow direction, while the second section may be con-
structed to be adjustable to a rising temperature pro-
file or temperature gradient in the process flow direc-
tion. It will be found advantageous in the realm of the
present invention for the temperature in the first sec-
tion of the carbonizing means in the process flow di-
rection to be continuously or steppedly adjustable.
The temperature in the first section of the carbonizing
means in the process flow direction may vary within
wide limits. The range in which the temperature in the
first section of the carbonizing means in the process
flow direction is variable generally extends from 50°C
to 500°C, preferably from 200°C to 450°C. Nonetheless,
for a particular application or on a one-off basis, it
is possible to depart from the aforementioned values
without thereby going outside the scope of the present
invention. A decision to do so is within the ability or
discretion of a person skilled in this field to decide.
In an embodiment which is preferred according to the
present invention, the temperature in the second sec-
tion of the carbonizing means in the process flow di-
rection is adjustable to rise, in particular steppedly
or steplessly, in the process flow direction. More par-
ticularly, the temperature in the second section of the
carbonizing means in the process flow direction is ad-
justable to rise in two or more temperature zones or
with a temperature gradient in the process flow direc-
tion. The temperature in the second section of the car-
bonizing means in the process flow direction may vary
within wide limits. In general, the temperature in the
second section of the carbonizing means in the process
flow direction is settable to rise in the range from
300°C to 1200°C, preferably from 350°C to 950°C, in the
process flow direction. Nonetheless, for a particular
application or on a one-off basis, it is possible to
depart from the aforementioned values without thereby
going outside the scope of the present invention. A de-
cision to do so is within the ability or discretion of
a person skilled in this field to decide.
In an again particularly preferred embodiment of the
present invention, the carbonizing means includes,
preferably at the inlet or in the process flow direc-
tion at the upstream end of the carbonizing means, in
particular at the inlet or in the process flow direc-
tion at the upstream end of the second section of the
carbonizing means, an injective spraying or jetting
means for injective spraying or jetting of water va-
pour, in particular in the form of a water vapour-inert
gas mixture. The proportion of water vapour in the wa-
ter vapour-inert gas mixture may vary within wide lim-
its. In general, the proportion of water vapour in the
water vapour-inert gas mixture is adjustable in the
range from 1% to 30% by volume, in particular 2% to 20%
by volume, preferably 5% to 15% by volume. Nonetheless,
for a particular application or on a one-off basis, it
is possible to depart from the aforementioned values
without thereby going outside the scope of the present
invention. A decision to do so is within the ability or
discretion of a person skilled in this field to decide.
It is preferable in the realm of the present invention
when the injective spraying or jetting means for injec-
tive spraying or jetting of water vapour, in particular
in the form of a water vapour-inert gas mixture, is
situated in the first third, preferably in the first
quarter, of the carbonizing means.
It will further be found to be advantageous in the
realm of the present invention when the carbonizing
means includes, preferably at the outlet or in the
process flow direction at the downstream end of the
carbonizing means, an injective jetting means for in-
troducing oxygen, in particular in the form of an oxy-
gen mixture with at least one further gas, preferably
in the form of air. The volume stream of the introduced
oxygen into the carbonizing means may vary within wide
limits. In general, the injected volume stream of oxy-
gen, in particular in the form of an oxygen mixture
with at least one further gas, preferably in the form
of air, is adjustable in the range from 10 to 500
l/min, in particular 25 to 250 l/min, preferably 50 to
100 l/min. Nonetheless, for a particular application or
on a one-off basis, it is possible to depart from the
aforementioned values without thereby going outside the
scope of the present invention. A decision to do so is
within the ability or discretion of a person skilled in
this field to decide. It will be found to be particu-
larly advantageous when the injective jetting means for
introducing oxygen is situated in the last third, pref-
erably in the last quarter of the reaction sector in
the carbonizing means.
The injective jetting or spraying of water vapour
and/or oxygen substantially prevents, by oxida-
tion/burning of the pyrolysis gases, any condensing of
pyrolysis gases in the base pore system of the acti-
vated carbon being formed; secondly, the heat released
can be used for heating the carbonizing means, saving
the corresponding amount of heating energy. However,
when adding oxygen or an oxygen mixture, care must be
taken to ensure that it comes into contact with the py-
rolysis gases only and not with the carbonizate in or-
der to prevent burn-out thereof.
In general, the carbonizing means has an offgas-
treating means for treating the offgases formed in op-
eration in the carbonizing means connected
to/positioned downstream of it.
It may be contemplated here in particular that the
offgas-treating means comprises at least one thermal
afterburning stage.
In a particularly preferred embodiment of the present
invention, the offgas-treating means includes, in par-
ticular upstream of the thermal afterburning stage, at
least one heat exchanger for cooling the offgases re-
sulting from thermal afterburning.
The heat released can be used either for heating the
carbonizing means and/or for heating the hereinbelow
described oxidizing means for sulphur oxides.
Optionally, a drying means for drying the cooled
offgases is positioned downstream of the thermal after-
burning stage and the heat exchanger. The drying means
in turn has a heating means for heating the dried
offgases optionally positioned downstream of it. The
drying of the cooled offgases can be effected either
physically, for example by adsorption, or chemically,
for example by reaction with concentrated sulphuric
acid or phosphorous pentoxide, in which case drying the
offgases chemically is preferred in the realm of the
present invention.
It will be found particularly advantageous in the realm
of the present invention when the offgas-treating means
comprises an oxidizing means for preferably catalyti-
cally oxidizing the sulphur oxides, in particular sul-
phur dioxide, present in the offgases formed in opera-
tion in the carbonizing means, to form sulphur triox-
ide, preferably downstream of the thermal afterburning
stage and the optional heat exchanger, drying means
and/or heating means. It may be contemplated that the
oxidizing means includes at least one oxidation cata-
lyst, preferably vanadium and/or platinum based. It may
further be contemplated that the oxidizing means in-
cludes a returning means for returning the sulphur tri-
oxide into the sulphonating means. The returning of the
sulphur trioxide into the sulphonating means is option-
ally effected via an interposed producing means for the
sulphonating agent.
The sulphur trioxide formed can therefore be returned
into the sulphonating means either directly or indi-
rectly. Directly here is to be understood as meaning
that gaseous sulphur trioxide is returned into the sul-
phonating means without intervening space or time. In-
directly in relation to the mode of returning the sul-
phur trioxide into the sulphonating means, however, is
to be understood as meaning that the sulphur trioxide
is first washed out of the gas stream, in particular
with water or concentrated sulphuric acid in an inter-
posed means, and that the sulphur trioxide is therefore
returned into the sulphonating means in the form of
thus generated concentrated sulphuric acid or oleum.
In one particular embodiment of the present invention,
the oxidizing means includes a separating means for
separating the sulphur trioxide from the other con-
stituents of the offgases, in particular carbon oxides
and/or water vapour and/or nitrogen oxides.
It may be contemplated here that downstream of the
separating means for separating the sulphur trioxide
from the other constituents of the offgases there is
optionally provided a washer for washing the separated-
off other constituents of the offgases.
The activating means downstream of the carbonization
may generally be constructed as follows:
In general, the activating means is operable batchwise.
In a preferred embodiment of the present invention, the
activating means forms a closed system; more particu-
larly, the activating means is operable under inert
conditions, in particular at the start of the activat-
ing and/or the start of the heating-up phase. Concern-
ing the terms "closed system" and "inert conditions",
reference can be made to the above observations.
The temperature of the activating means in operation
can vary within wide limits. In general, the tempera-
ture of the activating means is variable in operation
in the range from 300°C to 1800°C, in particular 400°C
to 1500°C, preferably 500°C to 1250°C. Nonetheless, for
a particular application or on a one-off basis, it is
possible to depart from the aforementioned values with-
out thereby going outside the scope of the present in-
vention. A decision to do so is within the ability or
discretion of a person skilled in this field to decide.
More particularly, the temperature of the activating
means in operation is steplessly and/or continuously
variable. It may be contemplated that the activating
means includes at least one heating means, in particu-
lar an electrically operated heating system.
In general, the activating means includes at least one
feeding means for introducing, in particular by jetting
and/or blowing, at least one activating gas, in par-
ticular water vapour and/or carbon dioxide and/or oxy-
gen and/or ammonia. It may be contemplated in the con-
text of the present invention that the feeding means
includes at least one temperature control means for ad-
justing the activating gas (for example water vapour)
to be introduced into the activating means.
In one preferred embodiment of the present invention,
the feeding means includes at least one feeding means
for introducing, in particular by jetting, spraying
and/or blowing, water vapour, in particular in the form
of a water vapour-inert gas mixture. The proportion of
water vapour in the water vapour-inert gas mixture can
vary within wide limits. In general, the proportion of
water vapour in the water vapour-inert gas mixture is
adjustable in the range from 5% to 70% by volume, in
particular 10% to 50% by volume, preferably 15% to 40%
by volume. Inert gases for the purposes of the present
invention comprise gases or gaseous mixtures which have
little if any reactivity under the conditions prevail-
ing in the activating step, and/or the reactions of
which have no or at least no negative influence on the
processes taking place in activated carbon production;
the inert gases used for the purposes of the present
invention comprise in particular nitrogen and/or noble
gases (for example argon), preferably nitrogen. None-
theless, for a particular application or on a one-off
basis, it is possible to depart from the aforementioned
values without thereby going outside the scope of the
present invention. A decision to do so is within the
ability or discretion of a person skilled in this field
to decide. It may be contemplated that the water vapour
is introducible at temperatures of from 500°C by jet-
ting, spraying and/or blowing.
In a particularly preferred embodiment of the present
invention, the feeding means includes at least one
feeding means for introducing, in particular by jet-
ting, spraying and/or blowing, carbon dioxide, in par-
ticular in the form of a carbon dioxide-inert gas mix-
ture. With regard to the inert gases used, reference
can be made to the above observations. It may be con-
templated in this case that the carbon dioxide is in-
troducible at temperatures of from 800°C by jetting,
spraying and/or blowing.
The burn-out behaviour of the crude activated carbon
and thus its later porosity is chiefly influenced by
the temperature during the activating step and, where
appropriate, the CO2 content in the activating means
during the activating step.
In another particularly preferred embodiment of the
present invention, the feeding means for introducing
the activating gases is supplied by and/or connected to
at least one stockkeeping receptacle which contains the
at least one activating gas.
In general, the activating means has an offgas-treating
means for treating the offgases formed in operation in
the activating means connected to and/or positioned
downstream of it. It will prove to be particularly ad-
vantageous when the offgas-treating means comprises at
least one thermal afterburning stage. The offgases from
the activating means vary with the activating gases
used and comprise in general and at least essentially
hydrogen and carbon oxides, in particular carbon monox-
ide .
It may be provided according to the present invention
that the offgas-treating means includes, in particular
upstream of the thermal afterburning stage, at least
one washer for washing the offgases coming from the
thermal afterburning stage.
After passing through the optional washer, the offgases
which, owing to the thermal afterburning, consist over-
whelmingly of carbon dioxide and water vapour are emit-
ted. However, any excess offgases are supplied to the
washer, i.e. offgases which cannot be further utilized
in the operation. The overwhelming proportion of the
offgases from the activating step is - as described
hereinbelow - utilized as energy supplier in the indi-
vidual operating stages of activated carbon manufac-
ture.
In a very particularly preferred embodiment of the pre-
sent invention, the offgases coming from the offgas-
treating means, in particular from the thermal after-
burning stage, downstream of the activating means are
used for indirect, in particular, heating of the acti-
vating means and/or via a supply line for heating the
stockkeeping receptacle containing the at least one ac-
tivating gas, or the at least one activating gas and/or
for heating the drying means, in particular for creat-
ing a fluidized bed.
For this purpose, the apparatus can be designed in par-
ticular such that the hot offgases at about 1000°C com-
ing from the thermal afterburning (TAB) of the offgases
from the activating means are led on the outside along
the activating means and heat the latter indirectly, so
that at least about 10% to 20% of the activation energy
requirements can be covered in this way. The hot
offgases, which are then still at about 800°C, can sub-
sequently be used for heating the activating gases, in
particular the water vapour. Alternatively, the
offgases of the thermal afterburning stage can also be
used directly, i.e. without prior conducting along the
activating means, for heating the activating gases. It
is particularly preferred according to the present in-
vention when the offgases, optionally after passing
through the stockkeeping receptacle for the activating
gases and/or the heating of the activating gases, are
used for drying the starting materials needed for acti-
vated carbon production, in particular for creating a
fluidized bed, in particular after they have been
cooled down to about 150°C by dilution with air. The
cooled-down offgas can then be emitted via a washer, in
which case - as already indicated above - excess, un-
used offgas can at any time be removed via a washer and
subsequently emitted.
The drying stage upstream of the optional sulphonating
means can be embodied in particular as follows:
In general, the drying means is operable in a fluidized
bed. In particular, the drying means, in particular the
fluidized bed thereof, is operable and/or heatable by
means of offgases from the offgas-treating means, in
particular from the thermal afterburning stage, in par-
ticular by means of offgases from the offgas-treating
means for the activating means.
It can be contemplated in the realm of the present in-
vention that the drying means is operable batchwise.
The temperatures at which the drying means is operable
can vary within wide limits. In general, the drying
means is operable at temperatures in the range from
100°C to 400°C, in particular 100°C to 200°C. Nonethe-
less, for a particular application or on a one-off ba-
sis, it is possible to depart from the aforementioned
values without thereby going outside the scope of the
present invention. A decision to do so is within the
ability or discretion of a person skilled in this field
to decide.
The sulphonating means placed downstream of the op-
tional drying means can be constructed in particular as
follows:
It can be contemplated in the realm of the present in-
vention in particular that the optional sulphonating
means is operable batchwise.
The temperatures at which the sulphonating means is op-
erable can vary within wide limits. In general, the
sulphonating means is operable at temperatures in the
range from 25°C to 400°C, in particular 50°C to 300°C.
Nonetheless, for a particular application or on a one-
off basis, it is possible to depart from the aforemen-
tioned values without thereby going outside the scope
of the present invention. A decision to do so is within
the ability or discretion of a person skilled in this
field to decide.
It will prove advantageous in the realm of the present
invention when a classifying means for classifying the
carbonizate coming from the carbonizing means is pro-
vided between the carbonizing means and the activating
means. This permits classification of the resulting ac-
tivated carbon according to particle size and hence ac-
cording to use properties. Subsequent, purposive mixing
of the individual classes can be used to conform the
resulting activated carbon specifically to the require-
ments needed. This ensures that only carbonizate which
is desired with regard to its particle size passes into
the activating step.
The present invention further provides - in accordance
with a second aspect of the present invention - a proc-
ess for producing activated carbon, in particular by
carbonization and subsequent activation of polymeric
organic, preferably sulphonated, starting materials,
the process comprising the following process steps:
(a) providing polymeric organic starting materials;
then
(b) drying the starting materials if appropriate (i.e.
in the case of undried or moist starting materi-
als) ; then
(c) sulphonating and/or peptizing the possibly previ-
ously dried starting materials if appropriate
(i.e. in the case of unsulphonated starting mate-
rials) ; then
(d) carbonizing the possibly previously dried and/or
sulphonated and/or peptized starting materials;
then
(e) activating the previously carbonized starting ma-
terials;
wherein the offgases from the carbonizing (d) and/or
from the activating (e) are subjected to an offgas
treatment.
It will be found to be advantageous in particular in
the realm of the present invention for the polymeric
organic starting material to be used to be in particu-
lar ion exchanger resins and their precursors, for ex-
ample sulphonated ion exchanger resins and also their
unsulphonated precursors and/or divinylbenzene-
crosslinked polystyrenes, for example styrene-divinyl-
benzene copolymers, in sulphonated or unsulphonated
form, preferably having a divinylbenzene content of for
example 1% to 10% by weight of divinylbenzene, based on
the copolymer.
The offgas treatment generally comprises at least one
thermal afterburning stage.
It will be found advantageous in the realm of the pre-
sent invention when the offgases from the carbonizing
and the offgases from the activating are each subjected
to an offgas treatment.
The offgases from the carbonizing and the offgases from
the activating are preferably each subjected to a sepa-
rate offgas treatment since they have different compo-
sitions and therefore the requirements for their treat-
ment are different; for example, the offgases from the
carbonizing have to be freed of sulphur oxides.
In general, the carbonizing is conducted in at least
one rotary tube, in particular in at least one rotary
tube oven. It will further be found advantageous in the
realm of the present invention when the carbonizing is
conducted in a closed system and/or the carbonizing is
conducted under inert conditions. According to the pre-
sent invention, the carbonizing may be operated con-
tinuously or quasi-continuously and/or the temperature
during the carbonizing may be closed and/or open loop
controlled continuously or steppedly. In one preferred
embodiment of the present invention, the temperature
during the carbonizing is closed and/or open loop con-
trolled such that the carbonizing is conducted in two
or more, in particular in at least two, preferably in
four to eight, temperature zones having temperatures
which each differ from the others, preferably having
the temperature of the individual temperature stages
each rising in the upstream direction. Alternatively,
in the realm of the present invention, the carbonizing
may be conducted in a temperature gradient, preferably
having a rising temperature profile in the upstream di-
rection .
The temperature during the carbonizing can vary within
wide limits. In general, the temperature during the
carbonizing is closed and/or open loop controlled in
the range from 20°C to 1200°C, in particular 30°C to
1100°C, preferably 50°C to 1000°C. Nonetheless, for a
particular application or on a one-off basis, it is
possible to depart from the aforementioned values with-
out thereby going outside the scope of the present in-
vention. A decision to do so is within the ability or
discretion of a person skilled in this field to decide.
It may be contemplated in the realm of the present in-
vention that a first temperature zone, preferably situ-
ated at the inlet or in the process flow direction at
the upstream end of the carbonizing (means) , is ad-
justed in the range from 50°C to 500°C, in particular
200°C to 450°C. It may further be contemplated that a
further temperature zone, preferably situated at the
outlet or downstream end of the carbonizing (means), is
adjusted in the range from 800°C to 1200°C, in particu-
lar 850°C to 950°C. In these cases too the recited val-
ues only mark the customary ranges hitherto preferred.
However, for a particular application or on a one-off
basis, it is readily possible to depart from the afore-
mentioned values without thereby going outside the
scope of the present invention. A decision to do so is
within the ability or discretion of a person skilled in
this field to decide.
The carbonizing is generally subdivided into at least
two part-steps. It may be contemplated that a first,
preferably upstream, part-step is conducted in a heated
vibrating chute and a second part-step, preferably con-
ducted downstream of the first section, is conducted in
a rotary tube, preferably in a rotary tube oven, in
particular having a rising temperature profile or tem-
perature gradient in the process flow direction.
According to the present invention, the first part-step
may be conducted with a constant temperature or with a
temperature profile or temperature gradient rising in
the process flow direction and/or the second part-step
may be conducted with a temperature profile or tempera-
ture gradient rising in the process flow direction.
Furthermore, in the realm of the present invention, the
temperature in the first carbonizing part-step in the
process flow direction may be closed loop controlled
continuously or steppedly. The temperatures in the
first carbonizing part-step in the process flow direc-
tion may vary within wide limits. In general, the tem-
perature in the first carbonizing part-step in the
process flow direction is closed loop controlled con-
tinuously or steppedly in the range from 50°C to 500°C,
preferably 200°C to 450°C. Nonetheless, for a particu-
lar application or on a one-off basis, it is possible
to depart from the aforementioned values without
thereby going outside the scope of the present inven-
tion. A decision to do so is within the ability or dis-
cretion of a person skilled in this field to decide.
Furthermore, in the realm of the present invention, the
temperature in the second carbonizing part-step in the
process flow direction may be closed loop controlled to
be rising, in particular steppedly or steplessly, in
particular in two or more temperature zones or with a
temperature gradient, in the process flow direction.
The temperature in the second carbonizing part-step in
the process flow direction may vary within wide limits.
In general, the temperature in the second carbonizing
part-step in the process flow direction is closed loop
controlled to rise in the process flow direction in the
range from 300°C to 1200°C, preferably from 350°C to
950°C. Nonetheless, for a particular application or on
a one-off basis, it is possible to depart from the
aforementioned values without thereby going outside the
scope of the present invention. A decision to do so is
within the ability or discretion of a person skilled in
this field to decide.
In one particular embodiment of the present invention,
water vapour, in particular in the form of a water va-
pour-inert gas mixture, is injected by spraying or jet-
ting during the carbonizing, preferably at the inlet or
in the process flow direction at the upstream end of
the carbonizing (means), in particular at the inlet or
in the process flow direction at the upstream end of
the second section of the carbonizing means. The pro-
portion of water vapour in the water vapour-inert gas
mixture can vary within wide limits. Generally, the
proportion of water vapour in the water vapour-inert
gas mixture is adjusted in the range from 1% to 30% by
volume, in particular 2% to 20% by volume, preferably
5% to 15% by volume. Nonetheless, for a particular ap-
plication or on a one-off basis, it is possible to de-
part from the aforementioned values without thereby go-
ing outside the scope of the present invention. A deci-
sion to do so is within the ability or discretion of a
person skilled in this field to decide.
It will further be found advantageous in the realm of
the present invention when oxygen, in particular in the
form of an oxygen mixture with at least one further
gas, preferably in the form of air, is introduced or
injected during the carbonizing, preferably at the out-
let or in the process flow direction at the downstream
end of the carbonizing (means) . The introduced or in-
jected volume stream of oxygen or of an oxygen mixture
can vary within wide limits. In general, the introduced
or injected volume stream of oxygen, in particular in
the form of an oxygen mixture with at least one further
gas, preferably in the form of air, is adjusted in the
range from 10 to 500 l/min, in particular 25 to
250 l/min, preferably 50 to 100 l/min. Nonetheless, for
a particular application or on a one-off basis, it is
possible to depart from the aforementioned values with-
out thereby going outside the scope of the present in-
vention. A decision to do so is within the ability or
discretion of a person skilled in this field to decide.
In general, the carbonizing is followed by treating the
offgases formed in the carbonizing. It may be contem-
plated here that the offgas treatment comprises at
least one thermal afterburning stage. In a particularly
preferred embodiment of the present invention, the
offgas treatment is followed, in particular at a point
upstream of the thermal afterburning stage, by the
offgases resulting from the thermal afterburning stage
being cooled, in particular by means of a heat ex-
changer. Optionally, the cooling of the offgases is
followed by drying of the cooled offgases. In turn, the
drying of the offgases may optionally be followed by
heating of the dried offgases.
In a particularly preferred embodiment of the present
invention, the offgas treatment comprises an oxidation,
preferably a catalytic oxidation, of the sulphur ox-
ides, in particular sulphur dioxide, present in the
offgases formed in the carbonizing, to form sulphur
trioxide, preferably downstream of the thermal after-
burning stage and the optional cooling, drying and/or
heating. It may be contemplated that the oxidation is
conducted by means and/or in the presence of at least
one oxidation catalyst, preferably vanadium and/or
platinum based. It may be further contemplated that the
sulphur trioxide generated in the oxidation is returned
into the sulphonation and/or peptization. Optionally
the sulphur trioxide generated in the oxidation is re-
turned into the sulphonation and/or peptization after
an interposed process step for producing the sulphonat-
ing agent.
It will further prove particularly advantageous in the
realm of the present invention when the sulphur triox-
ide generated in the oxidation is separated from the
other constituents of the offgases, in particular car-
bon oxides and/or water vapour and/or nitrogen oxides.
It may be contemplated here that the separating is op-
tionally followed by washing of the separated-off other
constituents of the offgases.
The carbonizing is then followed, optionally after an
interposed classifying step for the carbonizate, by ac-
tivating the previously produced carbonizate. In gen-
eral, the activating is conducted batchwise.
It will further be found to be advantageous according
to the present invention when the activating is con-
ducted in a closed system and/or when the activating is
conducted under inert conditions, in particular at the
start of the activating and/or at the start of the
heating-up phase.
The temperature during activating can vary within wide
limits. In general, the temperature during activating
is set in the range from 300°C to 1800°C, in particular
400°C to 1500°C, preferably 500°C to 1250°C. Nonethe-
less, for a particular application or on a one-off ba-
sis, it is possible to depart from the aforementioned
values without thereby going outside the scope of the
present invention. A decision to do so is within the
ability or discretion of a person skilled in this field
to decide.
It may be contemplated in this connection that the tem-
perature during activating is set steplessly and/or
continuously, preferably by means of a heating means,
in particular an electrically operated heating system.
In a particularly preferred embodiment of the present
invention, the activating comprises introducing, in
particular by jetting and/or blowing, at least one ac-
tivating gas, in particular water vapour and/or carbon
dioxide and/or oxygen and/or ammonia.
It may be contemplated in the realm of the present in-
vention that the activating gas introduced into the ac-
tivating step is heated to a defined temperature.
When two or more different activating gases are used,
these may be introduced into the activating step at the
same time or at different times, in which case intro-
ducing at different times is preferable in the realm of
the present invention. Similarly, the activating gases
can be introduced at like or different temperatures.
According to the present invention, the activating com-
prises introducing, in particular by jetting, spraying
and blowing, at least water vapour, in particular in
the form of a water vapour-inert gas mixture, as acti-
vating gas.
The proportion of water vapour in the water vapour-
inert gas mixture can vary within wide limits. In gen-
eral, the proportion of water vapour in the water va-
pour-inert gas mixture is set in the range from 5% to
70% by volume, in particular 10% to 50% by volume,
preferably 15% to 40% by volume. Nonetheless, for a
particular application or on a one-off basis, it is
possible to depart from the aforementioned values with-
out thereby going outside the scope of the present in-
vention. A decision to do so is within the ability or
discretion of a person skilled in this field to decide.
It may be contemplated in this connection that the wa-
ter vapour is introduced at temperatures from 500°C by
jetting, spraying and/or blowing during the activating.
It will likewise prove advantageous in the realm of the
present invention when the activating comprises intro-
ducing carbon dioxide, particularly in the form of a
carbon dioxide-inert gas mixture, as an activating gas,
in particular in addition to water vapour being used as
activating gas, in particular by jetting, spraying
and/or blowing. It may be contemplated that the carbon
dioxide is introduced at temperatures from 800°C by
jetting, spraying and/or blowing.
As already noted in the observations concerning the ap-
paratus of the present invention, the temperatures and
the carbon dioxide content during the activating influ-
ence the burn-out behaviour of the material to be acti-
vated and thus the material properties of the resulting
activated carbon.
In one particular embodiment of the present invention,
the at least one activating gas is fed into the acti-
vating step from a stockkeeping receptacle via a feed-
ing means.
In general, the activating is followed by a treatment
being conducted on the offgases formed in the activat-
ing. It may be contemplated in this connection that the
offgas treatment comprises at least one thermal after-
burning stage.
According to the present invention, the thermal after-
burning stage may be followed by a wash being conducted
of the offgases from the thermal afterburning stage.
After passing through the washer, the offgases which,
owing to the thermal afterburning, consist overwhelm-
ingly of carbon dioxide and water vapour, are emitted.
However, only excess offgases are routed to the wash
directly, the overwhelming portion being utilized as an
energy supplier in the various operations of activated
carbon manufacture.
In a particularly preferred embodiment of the present
invention, the offgases coming from the offgas treat-
ment (i.e. offgas treatment of the offgases coming from
the activating), in particular from the thermal after-
burning, are used for indirect, in particular, heating
for the activating (means) and/or for heating the at
least one activating gas and/or for drying, in particu-
lar for creating a fluidized bed. For further details
concerning using the offgases from the activating, in
particular after passing through the thermal afterburn-
ing, reference can be made to the above elucidations
concerning the apparatus of the present invention.
As observed above, a drying step (a) is conducted in
the case of undried/moist starting materials before the
actual production of activated carbon. According to the
present invention, the drying can be conducted in a
fluidized bed; preferably, the drying, in particular
the fluidized bed thereof, can be operated by means of
offgases coming from the offgas treatment (i.e. the
offgas treatment of the offgases from the activating),
in particular from the thermal afterburning. In par-
ticular, in the realm of the present invention, the
drying can be operated batchwise. The temperatures in
relation to the drying step can vary within wide lim-
its. In general, the drying is operated at temperatures
in the range from 100°C to 400°C, in particular 100°C
to 200°C. Nonetheless, for a particular application or
on a one-off basis, it is possible to depart from the
aforementioned values without thereby going outside the
scope of the present invention. A decision to do so is
within the ability or discretion of a person skilled in
this field to decide.
As observed above, a process step of sulphonating
and/or peptizing is conducted before the carbonizing in
the case of unsulphonated starting materials. This
process step of sulphonating and/or peptizing comprises
the actual sulphonation (i.e. the introduction of sul-
phonic acid groups) and also, optionally, the peptiza-
tion (i.e. the dissolving out of monomeric, dimeric and
oligomeric units remaining in the starting material and
the deposition of said units on the outer surface of
the particles of the starting material). In particular,
in the realm of the present invention, the sulphonating
and/or peptizing can be operated batchwise.
The sulphonating/peptizing temperature can vary within
wide limits. In general, the sulphonating/peptizing is
operated at temperatures in the range from 25°C to
400°C, in particular 50°C to 300°C. Nonetheless, for a
particular application or on a one-off basis, it is
possible to depart from the aforementioned values with-
out thereby going outside the scope of the present in-
vention. A decision to do so is within the ability or
discretion of a person skilled in this field to decide.
In a particularly preferred embodiment of the present
invention, a process step of classifying the carboni-
zate coming from the carbonizing can also be conducted
between the carbonizing step and the activating step.
For further details concerning the process of the pre-
sent invention, reference can be made to the above ob-
servations concerning the apparatus of the present in-
vention, which hold mutatis mutandis in relation to the
process of the present invention.
The apparatus of the present invention and also the
process of the present invention have a number of ad-
vantages over the prior art:
The oxidation of the sulphur-containing compounds to
sulphur trioxide and the sulphur trioxide being re-
turned into the sulphonation substantially avoids the
emission of sulphur-containing offgases which would
otherwise have to be inconveniently and cost-
intensively cleaned/purified.
A large proportion of the sulphonating agent used can
be recovered, so that only a small proportion of the
sulphonating agent is actually consumed and has to be
replaced.
Recovering the sulphonating agent also dramatically re-
duces the total amount of all offgases generated, in
particular the corrosive acidic offgases.
Thermal afterburning of the offgases formed in the car-
bonizing/activating ensures that the offgases, after
removal of the sulphur-containing compounds, consist
almost exclusively of the innocuous combustion residues
carbon dioxide and water vapour.
Afterburning generates heat whereby the energy require-
ments of the activated carbon production process can be
distinctly reduced; for instance, the energy require-
ments of the activating step can be reduced by at least
10% to 20% by the thermal afterburning of the offgases
formed.
Hot offgases from the thermal afterburning, moreover,
can also be used for heating the activating gases
and/or for drying the starting materials used for the
activated carbon production.
Classifying the crude activated carbon before activa-
tion makes it possible to separate or else to specifi-
cally mix the individual classes, so that the resulting
activated carbon can be optimally conformed to the in-
tended end-use.
The apparatus of the present invention and the process
of the present invention make it possible to maintain
the SO2 emission during carbonization at such a constant
level as to allow a sulphur trioxide production process
to be carried out and hence for the sulphonating agent
to be recovered.
The sole figure is a schematic and exemplary depiction
of a typical, preferred embodiment of the inventive ap-
paratus _1 and of the inventive process sequence:
As the figure shows, when nondried/moist starting mate-
rial is used, a drying operation, preferably in a flu-
idized bed, is optionally initially carried out in 2,
which in the case of unsulphonated starting materials
is then followed optionally at 3 by a sulphonation
and/or peptization. The dried and sulphonated/peptized
starting material, for example based on sulphonated
styrene-divinylbenzene polymers, for example in the
form of so-called sulphonated ion exchanger resins of
the gel type or of the macroporous type, is then subse-
quently subjected to carbonization at 4, whereafter the
carbonizate resulting from this stage is subjected to
activation at 5, resulting in the desired end product
(i.e. activated carbon). As the figure further shows,
the acidic, in particular, offgases, coming from the
carbonization 4 are initially subjected, at 4A, to
thermal afterburning (TAB) and thereafter - optionally
after cooling, drying and renewed heating of these
gases - at 4B to a catalytic oxidation, in particular
in the presence of vanadium pentoxide as oxidation
catalyst, so that sulphur dioxide SO2 present in the
offgas is converted to sulphur trioxide SO3, which can
be returned, via 4C, back into the sulphonation 3, in
particular in the form of concentrated sulphuric
acid/oleum. The remaining offgases from the catalytic
oxidation 4B, however, are then emitted, optionally af-
ter a further downstream wash 4D, these offgases com-
prising essentially carbon dioxide CO2, water vapour H2O
and only very minor amounts of nitrogen oxides NOX and
sulphur oxides SOX.
The offgases from the activation 5, in particular hy-
drogen H2 and carbon monoxide CO, are similarly sub-
jected to thermal afterburning (TAB) 5C, and the still
hot offgases coming from the thermal afterburning can
be used firstly to co-heat the activating means 5, sec-
ondly to heat up the activating gases, or the relevant
receptacle for the activating gases, in particular wa-
ter vapour, at 5B, in which case the heated activating
gases, in particular water vapour, are then supplied to
the activating step via 5A, and finally also to supply
the requisite heat and the fluidized bed for the drying
stage 2. Any unused offgases from thermal afterburning
(TAB) 5C can then be emitted, optionally after a washer
5D, as offgases, in particular consisting mainly of
carbon dioxide CO2 and water vapour H2O etc.
In a typical embodiment of the present invention, the
apparatus of the present invention or the process of
the present invention can be executed as follows:
The starting material, for example styrene-divinyl-
benzene copolymers, in particular ion exchangers of the
gel type or of the macroporous type, are - if present
in nondried/moist form - subjected to drying in a first
stage, said drying of the starting material being pref-
erably effected in a fluidized bed, preferably by util-
izing rejected heat from the activating step. The dry-
ing is typically carried out batchwise/discontinuously
(for example 1 m3 of starting material per batch).
Unsulphonated starting materials are subjected in a
second stage, downstream of the drying stage, to a sul-
phonation/peptization. For this purpose, the starting
polymers or to be more precise ion exchangers are con-
tacted with a suitable sulphonating agent, in particu-
lar concentrated sulphuric acid/oleum (for example 15%
oleum), in particular at temperatures of 100°C to
400°C, preferably 150 to 250°C. Depending on the de-
sired pore system, different quantitative ratios of
sulphonating agent can be used and, for example, re-
acted according to a temperature characteristic, se-
lectable by a person skilled in the art, until the
starting material has been sulphonated and is present
in free-flowing form. This stage provides not just a
sulphonation but generally also a so-called peptiza-
tion, i.e. monomer, dimer and oligomer residues are
dissolved out of the starting materials and subse-
quently redeposited on the surface of the particles,
these redepositions resulting in the course of the sub-
sequent carbonization in a very hard and hence abra-
sion-resistant pseudographite layer being formed on the
surface of the particles.
A subsequent, third, stage of the process then involves
the dry and sulphonated starting material being carbon-
ized/pyrolyzed, preferably continuously or quasi-
continuously, in particular in a closed system. Car-
bonization is typically carried out under inert reac-
tion conditions. The material can typically be dis-
charged onto a heatable vibrating chute, customarily
under inert gas atmosphere, in which case the material
can be heated to 350°C, for example, in the course of
60 minutes for example. This vibrating chute then feeds
into a likewise continuously or quasi-continuously op-
erated rotary tube oven having a temperature of typi-
cally 400°C at the inlet side. In the course of trans-
port in the rotary tube, the material is then typically
heated to, for example, 900°C via six to eight heating
zones. Preference is given to the simultaneous addition
of water vapour, preferably of a corresponding nitro-
gen-water vapour mixture (for example 10% to 30% by
volume of water vapour) , from the oven inlet side and
the addition of air/oxygen (for example 50 to
100 l/min) from the oven outlet side in order that the
combustion of resulting pyrolysis gases in the reaction
tube may be made possible. This can be used to achieve
several positive effects. First, condensing of pyroly-
sis gases in the base pore system of the starting mate-
rial is substantially prevented, and secondly the com-
bustion in the reaction tube can be used to utilize the
heat content and the input of electric power into the
oven-heating system can be minimized. After carboniza-
tion/pyrolysis is concluded, the material is typically
accessible and has an internal surface area (BET) of
for example 400 to 800 m2/g. It is preferable when the
particle shape is spherical, in accordance with the
starting materials.
A downstream, fourth stage then involves the initially
produced carbonizate being activated. In the activating
step, the material, preferably after prior classifica-
tion, is filled in narrow particle size fractions into
a rotary tube oven having internals and is heated under
an inert atmosphere to about 960°C for example, while
the atmosphere can have water vapour added to it (for
example 20% to 30% by volume) , preferably in the form
of a nitrogen/water vapour mixture, from about 600°C
for example. Depending on the degree of activation de-
sired and depending on the pore system desired, the at-
mosphere can be admixed with carbon dioxide CO2 from
about 900°C for example, and/or the temperature can be
varied, for example to influence the burn-out behav-
iour. The gases, in particular hydrogen H2 and carbon
monoxide CO, formed in the activating step can advanta-
geously be used for indirect heating of the activating
pipe. As a result, about 20% of the total energy re-
quirements of the apparatus can be coupled out of the
process.
As far as the offgas treatment is concerned, the
offgases coming from the carbonization/pyrolysis can
initially be afterburned in a thermal afterburning
stage (TAB), in particular via excess air, to oxidize
all organic constituents; subsequently, the SC>2-rich
offgas is advantageously directed into a heat exchanger
and cooled, in order that it may be dehumidified in a
gas-drying stage, by means of sulphuric acid, and after
subsequent heating, for example to temperatures of
about 480°C, the gas can be led via a plurality of
stages to an oxidation catalyst (for example vanadium-
based oxidation catalyst, for example vanadium pentox-
ide) until the sulphur dioxide SO2 has been oxidized to
sulphur trioxide SO3. After all the SO2 has been oxi-
dized to SO3, the SO3-containing offgas is typically
cooled again and the SO3 is washed out by means of con-
centrated sulphuric acid, so that the SO3 can be re-
turned into the sulphonating step. Thus, a complete re-
cycling circuit is provided for sulphonating agents and
there is no need for costly and inconvenient disposal.
In order that the design may be economically and ecol-
ogically realizable, it is of advantage when the quan-
tities of offgas generated are relatively constant,
which can be achieved by the SO2-relevant process steps,
in particular the carbonization/pyrolysis, being made
continuous/quasicontinuous and the SO2 emission being
maintained approximately constant, i.e. without spikes
in the SO2 emission.
The treatment of the offgases from the activating step
can be carried out in the manner previously described
(i.e. thermal afterburning and use of the offgases com-
ing from the thermal afterburning for heating the acti-
vating gas, in particular water vapour, and/or for in-
direct heating of the activating oven and/or for use in
fluidized bed drying).
The present invention finally also provides - in accor-
dance with a third aspect of the present invention -
for the use of the apparatus of the present invention,
as previously described, for producing activated car-
bon. As previously described, the production of acti-
vated carbon in the course of the use according to the
present invention is effected by carbonization and sub-
sequent activation of polymeric organic, preferably
sulphonated, starting materials. For further details
concerning the use according to the present invention,
reference can be made to the above observations con-
cerning the apparatus of the present invention and the
process of the present invention, which apply mutatis
mutandis to the use according to the present invention.
Further refinements, modifications, variations and also
advantages of the present invention will become readily
apparent to and realizable by the ordinarily skilled
after reading the description without their having to
depart from the realm of the present invention.
WE CLAIM
1. Apparatus (1) for producing activated carbon, in
particular by carbonization and subsequent activa-
tion of polymeric organic sulphonated starting ma-
terials, the apparatus including
- optionally a drying means (2) for drying the
starting materials,
- optionally a sulphonating means (3) for sulpho-*
nating and/or peptizing the optionally previ-
ously dried starting materials downstream of
the optional drying means (2),
- a carbonizing means (4) for carbonizing the op-
tionally previously dried and/or sulphonated
and/or peptized starting materials downstream
of the optional drying means (2) and/or the op-
tional sulphonating means (3), wherein the tem-
perature of the carbonizing means (4) is ad-
justable in operation such that at least two
temperature zones having the temperature of the
individual temperature stages each rising in
the upstream direction are present or else a
temperature gradient having a rising tempera-
ture profile in the upstream direction is pre-
sent,
- downstream of the carbonizing means (4), an ac-
tivating means (5) for activating the starting
materials previously carbonized in the carbon-
izing means (4),
wherein the apparatus (1) also comprises at least
one offgas-treating means (4A, 4B, 4D) for treating
the offgases formed in operation in the carbonizing
means (4) and at least one of fgas-treating means
(5C, 5D) for treating the offgases formed in opera-
tion in the activating means (5) , wherein the car-
bonizing means (4) has an offgas-treating means
(4A, 4B, 4D) for treating the offgases formed in
operation in the carbonizing means (4) connected to
and/or positioned downstream of it, wherein the
offgas-treating means (4A, 4B, 4D) comprises at
least one thermal afterburning stage (4A), and
wherein the activating means (5) has an offgas-
treating means (5C, 5D) for treating the offgases
formed in operation in the activating means (5)
connected to and/or positioned downstream of it,
wherein the offgas-treating means (5C, 5D) com-
prises at least one thermal afterburning stage
(5C), and wherein the offgases coming from the
of fgas-treating means (5C, 5D) are used for heating
of the activating means (5) and/or via a supply
line (5E) for heating a stockkeeping receptacle
(5B) containing at least one activating gas or at
least one activating gas and/or for heating the op-
tional drying means (2).
2. Apparatus according to Claim 1, wherein the carbon-
izing means (4) comprises at least one rotary tube
or at least one rotary tube oven and is operable
under inert conditions continuously or quasi-
continuously.
3. Apparatus according to Claim 1 or 2, wherein the
carbonizing means (4) is subdivided into at least
two sections, wherein a first section, preferably
disposed upstream, is formed by a heatable vibrat-
ing chute and a second section, preferably disposed
downstream of the first section, is formed by a ro-
tary tube, preferably a rotary tube oven, having a
rising temperature profile or temperature gradient
in the process flow direction in the operating
state.
4. Apparatus according to any preceding claim,
wherein the offgas-treating means (4A, 4B, 4D) in-
cludes, in particular upstream of the thermal af-
terburning stage (4A), at least one heat exchanger
for cooling the offgases resulting from thermal af-
terburning, optionally followed by a drying means
for drying the cooled offgases and optionally in
turn followed by a heating means for heating the
dried offgases, and/or
wherein the offgas-treating means (4A, 4B, 4D) com-
prises an oxidizing means (4B) for preferably cata-
lytically oxidizing the sulphur oxides, in particu-
lar sulphur dioxide, present in the offgases formed
in operation in the carbonizing means (4), to form
sulphur trioxide, preferably downstream of the
thermal afterburning stage (4A) and the bptional
heat exchanger, drying means and/or heating means
5. Apparatus according to any preceding claim, wherein
the activating means (5) is operable batchwise and
forms a closed system and wherein the activating
means (5) is operable under inert conditions and is
variable in operation in the range from 300°C to
1800°C.
6. Process for producing activated carbon, in particu-
lar by carbonization and subsequent activation of
polymeric organic preferably sulphonated starting
materials, the process comprising the following
process steps:
(a) providing polymeric organic starting materials;
then
(b) drying the starting materials if appropriate;
then
(c) sulphonating and/or peptizing the possibly pre-
viously dried starting materials if appropri-
ate; then
(d) carbonizing the possibly previously dried
and/or sulphonated and/or peptized starting ma-
terials, wherein the temperature during the
carbonizing is closed and/or open loop con-
trolled such that the carbonizing is conducted
in at least two temperature zones having tem-
peratures which each differ from the others,
having the temperature of the individual tem-
perature stages each rising in the upstream di-,
rection, or else in a temperature gradient hav-
ing a rising temperature profile in the up-
stream direction; then
(e) activating the previously carbonized starting
materials;
wherein the offgases from both the carbonizing (d)
and from the activating (e) are each subjected to
an offgas treatment, wherein the carbonizing is
followed by treating the offgases formed in the
carbonizing, wherein the offgas treatment comprises
at least one thermal afterburning stage, and where-
in the activating is followed by a treatment being
conducted on the offgases formed in the activating,
wherein the offgas treatment comprises at least one
thermal afterburning stage, and wherein the offgas-
es which come from the offgas treatment of the off-
gases formed in the activating are used for heating
for the activating (means) and/or for heating at
least one activating gas and/or for drying.

The invention relates to an apparatus or installation for producing active
carbon, in particular by carbonization and subsequent activation of
polymeric, organic, preferably sulphonated, starting materials, wherein the
apparatus or installation comprises optionally a drying device for drying the
starting materials, optionally a sulphonating device, arranged downstream of
the optionally present drying device, for sulphonating and/or peptizing the
optionally previously dried starting materials, a carbonizing device, arranged
downstream of the optionally present drying device and/or the optionally
present sulphonating device, for carbonizing the optionally previously dried
and/or sulphonated and/or peptized starting materials, as well as an
activating device, arranged downstream of the carbonizing device, for
activating the starting materials previously carbonized in the carbonizing
device, wherein the apparatus or installation also comprises at least one
exhaust-gas treatment device for treating the exhaust gases formed in the
carbonizing device and/or in the activating device during operation.

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Patent Number

278371

Indian Patent Application Number

4/KOLNP/2012

PG Journal Number

53/2016

Publication Date

23-Dec-2016

Grant Date

21-Dec-2016

Date of Filing

02-Jan-2012

Name of Patentee

BLÜCHER GMBH

Applicant Address

METTMANNER STRASSE 25, D-40699 ERKRATH, GERMANY

Inventors:

#	Inventor's Name	Inventor's Address
1	VON BLÜCHER, HASSO	PARKSTRASSE 10 D-40699 ERKRATH, GERMANY
2	SCHÖNFELD, RAIK	AM FORSTKAMP 24B D-30629 HANNOVER, GERMANY

PCT International Classification Number

C01B 31/08

PCT International Application Number

PCT/EP2009/007172

PCT International Filing date

2009-10-06

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	102009032810.6	2009-07-10	Germany