Title of Invention	AN IMPROVED PROCESS FOR THE MANUFACTURE OF CARBON BLACK BY FURNACE PROCESS AND AN IMPROVED HIGH VOLUME HIGH TEMPARETURE (HVHT) REACTOR FOR CARRYING OUT SAID METHOD
Abstract	The invention presents new geometry and design of throat section of the reaction zone, improved design of combustion zone and arrangement of feedstock nozzle for HVHT reactor to achieve excellent quality and efficient yield of carbon black. The invention provides stable flame in combustion chamber, flame being restricted to the combustion chamber only, leading to proper and complete combustion. A novel combination of positioning of nozzles and residence time in reaction zone ensures total and efficient combustion. Better coverage of hot gas produced is ensured to increase the refractory life. While emphasizing on the modification of the reaction zone, the invention offers innovations in the other related zones, vig. combustion zone, cooling zone and evaporation zone too to present a very much improved process.

Title of Invention

AN IMPROVED PROCESS FOR THE MANUFACTURE OF CARBON BLACK BY FURNACE PROCESS AND AN IMPROVED HIGH VOLUME HIGH TEMPARETURE (HVHT) REACTOR FOR CARRYING OUT SAID METHOD

Abstract

The invention presents new geometry and design of throat section of the reaction zone, improved design of combustion zone and arrangement of feedstock nozzle for HVHT reactor to achieve excellent quality and efficient yield of carbon black. The invention provides stable flame in combustion chamber, flame being restricted to the combustion chamber only, leading to proper and complete combustion. A novel combination of positioning of nozzles and residence time in reaction zone ensures total and efficient combustion. Better coverage of hot gas produced is ensured to increase the refractory life. While emphasizing on the modification of the reaction zone, the invention offers innovations in the other related zones, vig. combustion zone, cooling zone and evaporation zone too to present a very much improved process.

Full Text	The present invention relates to a process for the manufacture of carbon black by furnace process in High Volume High Temperature (HVHT) reactor and also said HVHT reactor. This invention, in general, relates to an apparatus and an improved method for producing carbon black and in particular to control the surface area, particle size distribution, as reflected by tinting strength and other colloidial properties. Additionally, the new process substantially increases the productivity and yield. HVHT reactor essentially consists of four zones e.g. : (a) Combustion zone (Head Section) (b) Reaction zone (Throat Section) (c) Cooling zone (Cooler Section and (d) Evaporating zone (Breeching Section) This invention suggests (1 ) an improved design of combustion zone, (2) reaction zone and (3) an arrangement for feedstock nozzle for High Volume High Temperature (HVHT) reactor. It has been found that the geometry and design of throat section of the reaction zone of HVHT plays an important role for achieving the desired result i.e. the excellent quality and efficient yield of carbon black. _ 2 — Carbon black is known to be finely divided high carbonaceous pigment which is produced by burning of gas or liquid hydrocarbon feedstock in a deficiency of air under carefully controlled conditions. It is an industrial product and is used in polymer industries and mainly in rubber industries as reinforcing, colourant and diluting agents for polymer/rubber to improve mechano-chemical and rheological properties for processing of raw compound and improving service of the cured product like tyre, conveyor belts, plastics, paints and inks etc. The classification of carbon black has tradionally been based on the method of its manufacture. There are three basic known methods which are as follows : (1) The Channel Process (2) The Thermal Process (3) The Furnace Process At present, the furnace process is extensively used for the production of carbon black mainly due to two reasons e.g. 1) The much improved production of economics of this process as against cost and availability of the raw materials for other processes of carbon black manufacture. 2) The technical advantage of oil furnace black of carbon black is characterised by following properties: - 3 - (A) Particle Size (B) Surface Area (C) Structure (D) Surface Activity and (E) pH Today the latest carbon black technology includes the production of carbon black in improved furnace process. Depending on the particle size and use, carbon black is divided into two broad categories, namely: i) Tread ii) Carcass Most of the manufacturers of the developed countries who are the world players in the field of carbon black, have developed High Volume High Temperature (HVHT) reactors either for carcass or for tread variety in their own way. All of the leading manufacturers in the above field have developed the advanced technology but all the known method of manufacturing carbon black have certain disadvantages through the common goal mostly lies in the economics and . To multigate the disadvantages of the prior art methods for manufacturing carbon black, the applicants have concentrated on high volume high temperature tread black reactor and therefore, the following description mainly refers to the tread reactor. _ 4 _ Also to remove some of the operational constraints or disadvantages of the existing HVHT reactor, the applicant has developed a new design of the constrict section in the combustion zone of the said reactor and the nozzle arrangement. It has been observed that some parameters like throughput (make oil flow rate) and quality like CTAB (Cetyl Trimethyl Ammonium Bromide), DBP (Di-Butyl Phathalate) and tint are mosly dependent on the following factors in addition to the spray condition of the feedstock. (a) Geometry of the Throat (b) Maximum coverage of flow area by oil spray (c) Spray nozzle and (d) Number of spray Among the above-mentioned four factors, the coverage of the flow area of the oil spray and the geometry of the throat are vital for controlling the quality, the throughput, yield and improvement of the refractory life of the HVHT reactor. To get maximum coverage of oil spray in the flow are vital for controlling the quality, the throughput, yield and improvement of the refractory life of the HVHT reactor. To get maximum coverage of oil spray in the flow area of the throat section, it was found by the applicant that the optimum number of oil sprays should be at least six. 5 An object of the present invention is to achieve the maximum coverage of the oil spray in the cross sectional area of the throat of HVHT reactor by the feedstock (conversion oil) into the flow of the hot combustion gas by introducing at least six numbers of sprays of the feedstock. Another object of the present invention is to minimize the flame length required during the pyrolysis using at least six hydrocarbons sprays and by keeping the flame well within the reaction chamber. A still further object of the present invention is to minimize the residence time or duration of the pyrolysing the feedstock in the reactor by using substantially all the hot gases produced in the combustion chamber and thereby eliminating any waste of the enthalpy. One more object of the present invention is the improvement of the service life of the throat section refractory as well as that beyond the throat section. Still one more object of the present invention is to provide a bi-fluid atomization nozzle with wide angle spray for the supporting feedstock to achieve the complete combustion in the combustion zone of the HVHT reactor. Yet another object of the present invention is to accomplish more efficiency in the operation of HVHT reactor. -6 - The above aspects are implemented by: (a) Increased Throughput (Production Rate) (b) Increased Yield (i.e. efficiency) and (c) Higher Tint along alongwith the following characteristics: i) CTAB ii) Nitrogen Surface Area iii) Iodine Number iv) 24M4 DBP (i.e. Compressed DBP) v) DBP as shown the Performance Analysis Thus according to the present invention there is provided an improved process for the manufacture of carbon black by furnace process in High Volume High Temperature (HVHT) reactor which comprises the following steps: burning completely liquid hydrocarbons supporting feedstock in a combustion zone to attain flame temperature between 1800 to 2000°C by passing axial air of 0.5 to 0.9 kg/cm2 (g) to achieve the continuous heat input of 75-88 BTU/SCFH; allowing the hot flue gas coming out of combustion zone containing 8 to 10% of excess oxygen into a reaction chamber; allowing the hot flue gas to pass through the said reaction zone of said reactor and injecting conversion oil in said reaction zone for pyrolysis reaction to take place; - 7 - allowing the pyrolysed smoke from the reaction zone to enter into a cooling zone for reducing the temperature suddenly by increasing the residence time to improve the colloidal property; allowing said smoke to enter a cooler to bring down the temperature thereof to 1200 + 100°C; passing said cool gas through an evaporating zone where said gas being further cooled with the help of water spray for lowering its temperature. allowing the sprayed water droplets to absorb heat to get evaporated; passing the water-quenched smoke into an air preheater to preheat the air to 700 to 900°C for utilizing in said combustion chamber. The present invention further provides an improved High Volume High Temperature (HVHT) reactor for carrying out the above method comprising a Combustion Zone, Reaction Zone, Cooling Zone and Evaporating Zone wherein improvement comprises in said reaction zone having multiple planes by adopting atleast six nozzles located in one or different planes of said reactor for spraying the combustion oil feedstock, said combustion zone being provided with a constrict section to enhance the speed of the air injected into said combustion zone to form a turbulant mixture with the - 8 - supporting feedstock, said combustion zone being connected to said reaction zone and said reaction zone being coupled to said cooling zone which is further connected to said evaporation zone to have a complete air tight assembly. The second generation reactors for the production of the carbon black are the HVHT which is basically an improved reactor for production of carbon black by furnace process. This invented arrangement causes much better and rapid distribution of the oil droplets in the gas stream and also efficiently cracks all the feedstock oil, under the same thermal condition. According to one embodiment of the present invention, we have adopted 'circular choke' with at least six burners in a plane. In comparison with the geometry of 10" I.D. standard design choke with 10" circular choke, there is a 5% advantage of spray area coverage than previous shape. We have found that circular chokes gave longer refractory life than standard shapes wake oil throughput (other conditions remaining same) increased but there was a marginal drop in tinting strength. According to another embodiment of the present invention, we have changed the choke design to a regular POLYGON with provision for using at least six burners in a plane. - 9 - According to a further embodiment of the present invention, the geometry of the newly designed throat being a 8-16 sided regular POLYGON having one oil spray port located in alternate sides having minimum provisions for at least six nos, of ports in each plane. According to a still further embodiment of the present invention, the brick lining with lap joints and coated with plasma in hot face for better stability and easy repairs/replacement. The carbon black is produced in a reactor which comprises the following four different sections: (1) Combustion zone (Head Section) (2) Reaction zone (Throat Section) (3) Cooling zone (Cooler Section) (4) Evaporation zone (Breeching Section) If any of these sections under performs, there will be a substantial loss in yield, productivity and will also lead to quality deficiency. These can be well judged by the volume/mass of production and also the quality. The quality should be such that it should consistently produce a narrow and uniform particle size distribution reflected by tint and other colloidal properties of the particular grade produced, which is tested in laboratory as per ASTM method. - 10 - Feedstock used in the process of the present invention is the liquid hydrocarbons of petroleum and of coal tar origin. The pyrolytic reaction is carried in high temperature resistant refractory lined reaction zone in the deficiency of air. As mentioned earlier, the oil furnace process for producing carbon black is well known, in which liquid hydrocarbon or the raw material (feed or make oil) is injected in a continuous stream of hot gas producesd by burning the gas or liquid hydrocarbon commonly known as Supporting Feedstock (SFS) in the combustion zone. This hot gas is controlled in such a way that it contains known amount of free oxygen. The basic purpose of this method is that the hot gas is to supply the required amount of heat for pyrolysis of feed oil to get converted into carbon black and the reaction is endothermic in nature. Excess oxygen is maintained to save the refractory which partially burns the feed oil, The pyrolysis and partial burning of feed oil takes place in the reaction chamber. The pyrolyzed hydrocarbon which gets converted into carbon black and gaseous products is quenched in the cooling zone of the reactor where reaction is stopped as per the requirement. Carbon black and combustion gas stream pass through the vaporizing section, air preheater, oil preheater and enter the bag filter, where carbon black is separated from gases and sent for further processing for packing and transport. - 11 - After leaving the combustion zone (as soon as combustion is completed), the high temperature flue gas with controlled amount of oxygen content enter in the mixing and reaction zone where the area is characterised by high stress factor which increases towards the throat, created by varying cross section and high turbulance due to very high flow and velocity. These are the two main characteristics for getting the desired properties (like surface area, structure etc.) of carbon black during pyrolysis reaction. At the same time, it is also required to achieve higher production rate and improved yield for lowering down the cost of production. Thus an optimisation is needed considering all the above factors. The reaction zone follows the mixing zone. The reaction zone design depends on the throughput and residence time required for complete carbon black formation. In the. process of optimisation, it has been established that a convergent nozzle with throat of polygonal shape with an equivalent diameter of 10 inch will give the desired result, also maximising the yield by minimising the side reaction by producing a short flame of exothermic reaction and pyrolysing the same by endothermic reaction. As soon as conversion oil droplet is released from the nozzle to the hot gas stream into a converging throat which is the reaction zone, it immediately absorbs energy from the surroundings to vaporise at the unbalanced conditions. Pyrolysis - 1 7 - reaction starts followed by combustion reaction and also at the same time, it is being struck by high velocity gas stream with a particular stress factor. The primary structure of the carbon black depends on stress factor. Lower the cross-section, higher the stress factor. The important properties like particle size, structure, surface area, surface activity and rubber properties like tensile strength, modulus etc. all primarily achieved in the first three sections of the reactor i.e. combustion zone, reaction zone and cooling zone by adjusting the process parameters and the residence time. After working in cylindrical and non-crylindrical reactor of earlier generation, it was felt that improvement in both quality and cost are required to survive in the competitive market. Extensive studies were made to improve upon the quality and yield with different combination of parameters. In the conventional design of the reaction chamber spray guns are adopted in various planes ranging from two to five and at each plane, normally two or four guns are used. As the number of planes are more in the conversional reaction chamber, likelihood of failure of refractory is too often. We have, on the contrary, adopted six to twelve guns at those planes of the reaction chamber selectively to get the best result and - 13 - also thereby avoiding the failure of the refactory as observed in the know reaction chambers. Moreover, we have adopted at least six numbers of spray guns at each plane which gave the optimum result as mentioned in the specification. Ultimately, it was decided by us that the first three sections of the reactor need total change in the design to - i) achieve total and efficient combustion of liquid hdyrocarbon supporting feedstock in head zone or combustion zone. ii) better coverage of hot gas produced in the combustion or head zone by the feed oil in the reaction zone, and iii) increase in the refractory life of reaction and cooling zone. iv) flexibility and ease of operation. Priority was given to the reaction zone. The design was changed and the performance was extensively studied. Although a substantial improvement was noticed but it was more in quality. Further studies were performed by the applicant and it was found that combustion section needs a proper design to achieve visibility of hot gas and nozzle tips of feed oil by total combustion of liquid hydrocarbon supporting feedstock before reaching the throat of the reactor. - 14 - Modification was also done in the cooling section at the same time, to increase the ease of operation, flexibility and refractory life and to adjust the residence time more effectively by utilising thermodynamic and aerodynamic characteristics of the high temperature gas stream. After the changes in design for above three zones, a very positive improvement both in quality and yield has been achieved. To overcome the limitations, we have developed the section called "Throat" with a design of regular polygon which is having provision of using at least six numbers of burners in a single plane. The provisions for three nos. of plane at proper distances (to obtain a required cross section, hence the velocity) are provided to attain the required residence time for different grades to achieve wide spectrum of properties. Another important aspect for better outcome of supporting feedstock which continuously supply the required amount of heat to facilitate the pyrolysis is endothermic in nature. This pre-pyrolysis activity, exothermic in nature, takes place on continuous basis in the combustion zone. The existing high volume high temperature tread reactor has various limitations for producing different grades of carbon black with wide spectrum of properties efficiently. Extensive studies have been made from different angles. In the first step of action plan, following changes were incorporated: - 15 - 1) Changing of original SFS (Supporting Feedstock) nozzle. 2) Selection of feedstock injection nozzle of predetermined angle. Though some improvements were noticed, but it was failed to achieve the target of quality and efficiency of the production of carbon black. Further studies were made in second step of action plane and the following conclusions were arrived: It was felt necessary to change the design of the throat section (reaction zone) , the combustion zone and SFS to improve upon- (a) Particle size distribution (PSD) as reflected in higher tinting strength of carbon black produced at identical process conditions compared to HVHT reactor of existing design. (b) The visibility of the feedstock nozzle for conversion oil spray is a necessity to get optimum output. (c) To have proper control of thermodynamic process and to eliminate the refractory failure, the heat input and the higher flame temperature required for endothermic pyrolysis for higher conversion and productivity by efficient and complete burning of SFS (Supporting Liquid Hydrocarbon Feedstock) within the combustion zone. With same refractory condition, it is also revealed from thermodynamic, enthalpy lading to higher yield and efficiency. - 16 - (d) The coverage of the cross-sectional area of combustion gas flow through the throet of the reactor by oil spray to utilise effectively the total heat generated by combustion of liquid hydrocarbon feedstock for efficient conversion of make oil. Disadvantages in 2nd Generation Reactor: 1) In combustion chamber, the flame is unstable. 2) The combustion chamber is invisible due to carry over of unburnt gas (oil vapour) conversion oil (Liquid Hydrocarbon). Nozzle tip position cannot be located. 3) The aerodynamic characteristics is such that the flame is extended upto reaction zone. 4) Incomplete combustion in the combustion zone leading heterogenity and PSD irregularities often resulting process inadequacy and loss of conversion efficiency resulting in loss of yield. 5) Unstable flame heating the refractory wall. Due to this, skin temperature in this zone remaining high, resulting in heat loss. To overcome all the above limitations, a new combustion zone has been designed by us. - 17 - Redesign parts includes two major activities e.g.: (A) Designing a suitable bi-fluid atomisation nozzle for supporting liquid hydrocarbon feedstock, so that it can produce convergent and stable flame. (B) Combustion should be completed within the combustion chamber. After studying various bi-fluid atomisation nozzle, it has been found by us that a nozzle with wide angle of having value of 90 degree and preferably between 120 and 180 degree when put into a high velocity zone, the stress that generated by high velocity air, reduce the angle of spray effectively to produce a convergent short flame. This results efficient mixing of air and oil and at the same time, total combustion is achieved within the combustion zone. The mathematical modelling has been done and it is found that velocity in the range of 100-150 m/sec and preferably 130 m/sec is required to generate the suitable stress factor to fulfil the above requirement. Therefore air quantity (13,000+1500 nm3/hr.) being heated upto 800-900 degree centigrade passed through (310+40) mm dia opening, the required velocity is achieved. - 18 - Keeping the above factors in mind, reactor (HVHT) has been modified and fruitful results are achieved. The achievement are as under: 1) Combustion reaction completed with the combustion chamber. 2) Combustion chamber is totally visible and nozzle tip conversion oil gun are easily positioned. 3) Short convergent flame produced. 4) Increase in conversion yield. drawings This invention is explained in detail with reference to the f accompanying the provisional specification, wherein Figure-1 shows the cross-section of the reaction chamber of the new reactor. Figure-2 shows the combustion zone of the new reactor. Figure-3 shows the fluid atomization nozzle of the invention. With reference to the drawings, hot gas is injected into the reactor through the hot gas inlet (10) which has a wide mouth (22) . The neck of the hot gas inlet is gradually reduced in - 19 - its diameter as shown at (20) in Fig.1 forming a tapered end at (24). At least six spray guns are positioned at different planes of the reaction chamber. Fig.1 illustrates guns located at two planes (30,32) having comparatively wide diameter while another set of spray guns are located at the narrowest section of the reaction chamber, namely (34). Spray guns are arranged at different planes of the reaction chamber for better circulation of the hot gas inside the reactor (40). With reference to Fig.2, gas inlet (50) is located at one end of the substantial cylinder combustion zone (45). The location of said inlet for liquid supporting feedstock is shown at (50) which is at right angle to the air inlet (52). As the mixture of liquid supporting feedstock and air gets through the combustion zone of the reactor it faces a rather wide neck (54) which is gradually narrowed down into a wider area (56) and ultimately into a still wider area (58) into the reaction zone (60). Finally, the mixture passes through the other end of the reaction zone (70) to enter into the reaction of the reactor as illustrated in Fig.1. Fig.3 illustrates a fluid atomization nozzle for the reactor. The said nozzle (70) is closed at one end (80) and is open at the other end (75) and is located at one end of the combustion zone which is away from the reaction chamber. Near to the closed end of the said nozzle, there is provided a plurality of holes along its periphery so that oil can be sprayed through said holes (90) along the periphery (95) into the combustion chamber at a much wider angle. - 20 - The following Tables-I, II, III & IV will depict the results obtained by using the newly designed throat of the reactor as compared to the existing one. - 21 - Calculation based on Make Oil (Conversion Oil) I) Analysis after changing the design of the Reaction Chamber (Throaty Yield is calculated as % of carbon black of make oil input Date Grade Air Rate Air Temp. Make Oil % Yield on % Yield on newly % Increase (NM /HR °C (kg/hr) existing design designed throat in Yield 9.6.97 N220 11750 775 3325 53.0 54.56 2.94 20.7.97 N220 12500 750 3700 53.0 54.18 2.22 2.7.97 N234 12516 789 3502 51.0 51.8 1.56 4.7.97 N330 12000 800 4450 59.0 60.53 2.59 17.6.97 N330 12000 788 4300 59.0 59.61 1.03 29.7.96 N375 12000 779 3850 55.0 55.7 1.27 29.7.96 N326 12000 760 4650 59.0 60.51 2.56 OIL BMCI = 128; SULPHUR CONTENT = 1.95% : EFFECTIVE BMCI = 125 II) Analysis after changing the design for both Reaction Chamber (Throat) & Combustion Chamber Yield is calculated as % of carbon black of make oil input Date Grade Air Rate Air Temp. Make Oil % Yield on % Yield on newly % Increase NM /HR °C (kg/hr) newly-designed designed throat throat & combustion chamber 13.8.98 N330 12000 788 4250 60.53 64.4 6.39 13.8.98 N330 11500 790 4100 60.53 64.5 6.55 16.8.98 N220 13000 785 3650 54.56 56.5 3.55 17.8.98 N220 13000 784 3675 54.56 56.5 3.55 III) Comparison between newly designed Reactor Throat & Combustion Chamber with existing standard design Reactor Yield is calculated as % of carbon black of make oil input Grade % Yield for existing % Yield for newly designed % Increase in standard design throat & combustion chamber Yield N220 53.0 56.5 6.6 N220 53.0 56.5 6.6 N330 59.0 64.4 9.15 N330 59.0 64.5 9.32 Thus it is established that PCBL designed Throat & Combustion Chamber gives better Yield Yield is calculated as % of carbon black of make oil input Reactor resutls are as follows :- Grade Reactor % Yield I2 Number DBP Tint CTAB N2SA N220 Unit-3 56.5 127.5 125.0 113.0 111.0 119.0 N330 -do- 64.4 83.0 113.0 101.0 81.0 82.0 TABLE-IV Remarks It must be noted that the data (Table I, II and III) studied have been taken from actual production data and the trial run carried out on commercial reactor under identical conditions by gas analysis through Orsat analysis apparatus. Table IV indicates the average yield obtained by actual physical measurement on prolonged commerical runs under identical conditions. The average yield as shown in Table - IV, though much higher than the old standard design high volume high temperature tread reactor are in some cases less than the result obtained from Orsat analysis data which are only indicative. Therefore, it is established that improvement is achieved by the newly designed combustion chamber and throat over the existing old standard designed throat. - 24 - Results and Discussions: Productivity: Throughput - In similar operating conditions the throughput is increased by approx. 10(%) (N330) over original reactors. Air Rate - 12000 NM3/hr. Air Temp. - 780 degree C (avg.) Ratio - 1:19 Conv, oil Rate - 4400 kg/hr., for POLYGON (12-16 sided) with at least 6 burners. But with existing reactor only 4000 kg/hr. Quality CTAB - Better control in polygon throat with at least six burners. Tint{Particle pore size distribution) - - do - DBF (agglomerate size distribution - do - Refractor life - Improved. -25 - The design and the performance of the Sections specially the Combustion and Reaction Zone are discussed next. Carbon Black Properties Primary Process Parameters Derived Process Parameters Iodine Number 1. Air Flow (Nm3 /hr.) 1. Fuel-Air Ratio -(mg/g) 2. Air Temperature (oC) 2. Air-Conv.oil Ratio(Nm1 /kg 3. Cooling Air Flow 3. Heat Input (BTU/SCFH) (Nm 3/hr.) DBP Absorption 4. Supporting Feedstock 4. Flame Temperature (°C) (ml/100g) Flow (Kg./hr.) 5. Conversion Oil 5. K'-Oil Ratio (PPM) 6. Reactor Pressure gauges 6. Air Velocity (kgt/m2) 7. Oil Pressure (Bar) 8. Cut Off Water Flow 9. Oil Temperature ((oC) Fixed Paramter : 1. Reactor Volume 2. Conv. Oil Nozzle Type : ANGLE Press. 3. Quench Water Nozzle Type ; ANGLE, Press 4. Conv. Oil Gum Position. Yield = function (f) = f(Air Temperature ; f(Heat Input). f{Air Rate). f(Supporting Feestock Flow). f(Flame Temperature), f(Oil Rate - Conv, Oil). f(Side Reaction), f(Area covered by oil droplet in the Chock Section). f(Residence time), f(Fuel/Air Ratio), f(Oxygen concn,), f(Oil press.) f(MMCl of oil, f(Reynolds Number). To maximise Yield ; Thermal decomposition to be maximised subject to the minimisation of Oxidation reaction (Side Reactions). - 26 - Again, the number of nucleation for formation of carbon black depends on the number of eddies formed. For this, a very high turbulent flow is required. At the same time, it is followed by prolysis reaction which is also followed by release of additional energy by combustion reaction with the desired short flame. For all the above, the situation demand a design of convergent nozzle where, for a given set of upstream condition, the linear velocity in the throat reaches that of sound in the gas at that location i.e. at throat it should be sonic velocity. The characteristics of carbon black product having desired properties are generally dependent on the following factors: 1) Turbulance during pyrolysis. 2) Type of spray pattern. 3} Type of liquid hydrocarbon feedstock. 4) Temperature of flue gas. 5) Temperature of the flame during pyrolysis. 6) Type/Geometry of the flame during pyrolysis. 7) Time required to accelerate the diffusion rate of the reactant constituents. 8) Type of nozzle (throat) through which the high gas stream passes. — 27 - The stress factor depends on the - 1) Velocity of gas 2) Velocity of oil droplets 3) Oil droplet size Thus in throat section Plane-III has got 70% lower cross-sectional area than Plane-I and hence, stress factor is higher in Plane-Ill. As per the requirement of structure level of carbon black, oil guns are shifted from Plane-I,II and III. DBP value also may be controlled by shifting conversion oil spray position. - 28 - We claim: 1 . An improved process for the manufacture of carbon black by furnace process in High Volume High Temperature (HVHT) reactor which comprises the following steps: burning completely liquid hydrocarbons supporting feedstock in a combustion zone to attain flame temperature between 1800 to 2000°C by passing axial air of 0.5 to 0.9 kg/cm2 (g) to achieve the continuous heat input of 75-88 BTU/SCFH; allowing the hot flue gas coming out of combustion zone containing 8 to 10% of excess oxygen into a reaction chamber; allowing the hot flue gas to pass through the said reaction zone of said reactor and injecting conversion oil in said reaction zone for pyrolysis reaction to take place; allowing the pyrolysed smoke from the reaction zone to enter into a cooling zone for reducing the temperature suddenly by increasing the residence time to improve the colloidal property; allowing said smoke to enter a cooler to bring down the temperature thereof to 1200+100°C - 29 - passing said cool gas through an evaporating zone where said gas being further cooled with the help of water spray for lowering its temperature; allowing the sprayed water droplets to absorb heat to get evaporated; passing the water quenched smoke into an air preheater to preheat the air to 700 to 900°C for utilizing in said combustion chamber. 2. An improved process as claimed in claim 1 wherein said conversion oil feedstock is selected from petroleum base raw material and also from coal tar origin. 3. An improved process as claimed in claim 1 wherein ratio between air and liquid hydrocarbon feedstock varies from 15:1 to 20:1 so as to have 1000 BTU per SCFH to 1000 BTU/20 SCFH of air. 4. An improved process as claimed in any one of claims 1 to 3 wherein in said reaction chamber conversion oil is injected through nozzles in the atomised form for the partial combustion and pyrolysis of conversion oil. - 30 - 5. An improved process as claimed in any one of the preceeding claims wherein water is sprayed co-currently or counter-currently or radially to the direction of the flow of said smoke. 6. An improved process as claimed in claim 1 wherein water in injected into the cooler in atomized form. 7. An improved process as claimed in claim 6 wherein water is sprayed through multiple nozzles located at same or different planes of said cooler. 8. An improved process as claimed claim 1 wherein in said evaporation zone quenching is done with water spray so that water droplets get evaporated quickly, 9. An improved process for the manufacture of carbon black by furnace process in HVHT reactor substantially as herein described. 10. An improved High Volume High Temperature (HVHT) reactor for carrying out the method as claimed in any of the preceeding claims comprising a Combustion Zone, Reaction Zone, Cooling Zone and Evaporating Zone wherein improvement comprises in said - 31 - reaction zone having multiple planes by adopting atleast six nozzles located in one or different planes of said reactor for spraying the combustion oil feedstock,said combustion zone being provided with a constrict section to enhance the speed of the air injected into said combustion zone to form a turbulant mixture with the supporting feedstock, said combustion zone being connected to said reaction zone and said reaction zone being coupled to said cooling zone which is further connected to said evaporation zone to have a complete air tight assembly. 11. An improved HVHT reactor as claimed in claim 10 wherein a sprayed gun assembly is adopted to spray the supporting feestock, said spray gun assembly is fitted with a nozzle provided with perforations along its peripheral line and is housed in said combustion zone . 12. An improved HVHT reactor as claimed in claim 9 or 10 wherein said reaction zone is substantially funnel shaped at its end connected with said cooling zone. 13. An improved HVHT reactor as claimed in claim 11 or 12 wherein said cylinderical cooler is connected to said evaporating zone having one or more breeching sections. —32 — 14. An improved HVHT reactor as claimed in claim 11 wherein the throat section is located in said reaction zone having a regular polygonal shape with 12 to 16 sides for spraying the conversion oil . 15. An improved HVHT reactor as claimed in claim 11 wherein said reaction zone is provided with at least six spray nozzles for the conversion of oil feedstock, said spray nozzles being located at one or more planes. 16. An improved HVHT reactor as claimed in claim 14 or 15 wherein said reaction zone is provided with spray nozzles located at three different planes and each of said planes having 3 to 18 nozzles. 17. An improved HVHT as claimed in any one of claims 10 to 16 wherein in said cooler or evaporation zones water spray gun assembly are positioned either in regular or irregular distances from each other. - 33 - 18. An improved High Volume High Temperature (HVHT) reaction substantially as herein described and as illustrated in the drawings accompanying the Provisional Specification. The invention presents new geometry and design of throat section of the reaction zone, improved design of combustion zone and arrangement of feedstock nozzle for HVHT reactor to achieve excellent quality and efficient yield of carbon black. The invention provides stable flame in combustion chamber, flame being restricted to the combustion chamber only, leading to proper and complete combustion. A novel combination of positioning of nozzles and residence time in reaction zone ensures total and efficient combustion. Better coverage of hot gas produced is ensured to increase the refractory life. While emphasizing on the modification of the reaction zone, the invention offers innovations in the other related zones, vig. combustion zone, cooling zone and evaporation zone too to present a very much improved process.

Full Text

The present invention relates to a process for the manufacture of carbon black by furnace process in High Volume High Temperature (HVHT) reactor and also said HVHT reactor.
This invention, in general, relates to an apparatus and an improved method for producing carbon black and in particular to control the surface area, particle size distribution, as reflected by tinting strength and other colloidial properties. Additionally, the new process substantially increases the productivity and yield.
HVHT reactor essentially consists of four zones e.g. :
(a) Combustion zone (Head Section)
(b) Reaction zone (Throat Section)
(c) Cooling zone (Cooler Section and
(d) Evaporating zone (Breeching Section)
This invention suggests (1 ) an improved design of combustion zone, (2) reaction zone and (3) an arrangement for feedstock nozzle for High Volume High Temperature (HVHT) reactor.
It has been found that the geometry and design of throat section of the reaction zone of HVHT plays an important role for achieving the desired result i.e. the excellent quality and efficient yield of carbon black.
_ 2 —

Carbon black is known to be finely divided high carbonaceous pigment which is produced by burning of gas or liquid hydrocarbon feedstock in a deficiency of air under carefully controlled conditions.
It is an industrial product and is used in polymer industries and mainly in rubber industries as reinforcing, colourant and diluting agents for polymer/rubber to improve mechano-chemical and rheological properties for processing of raw compound and improving service of the cured product like tyre, conveyor belts, plastics, paints and inks etc.
The classification of carbon black has tradionally been based on the method of its manufacture. There are three basic known methods which are as follows :
(1) The Channel Process
(2) The Thermal Process
(3) The Furnace Process
At present, the furnace process is extensively used for the production of carbon black mainly due to two reasons e.g.
1) The much improved production of economics of this process
as against cost and availability of the raw materials for other
processes of carbon black manufacture.
2) The technical advantage of oil furnace black of carbon black
is characterised by following properties:
- 3 -

(A) Particle Size
(B) Surface Area
(C) Structure
(D) Surface Activity and
(E) pH
Today the latest carbon black technology includes the production of carbon black in improved furnace process. Depending on the particle size and use, carbon black is divided into two broad categories, namely:
i) Tread ii) Carcass
Most of the manufacturers of the developed countries who are the world players in the field of carbon black, have developed High Volume High Temperature (HVHT) reactors either for carcass or for tread variety in their own way.
All of the leading manufacturers in the above field have developed the advanced technology but all the known method of manufacturing carbon black have certain disadvantages through the common goal mostly lies in the economics and .
To multigate the disadvantages of the prior art methods for manufacturing carbon black, the applicants have concentrated on high volume high temperature tread black reactor and therefore, the following description mainly refers to the tread reactor.
_ 4 _

Also to remove some of the operational constraints or disadvantages of the existing HVHT reactor, the applicant has developed a new design of the constrict section in the combustion zone of the said reactor and the nozzle arrangement.
It has been observed that some parameters like throughput (make oil flow rate) and quality like CTAB (Cetyl Trimethyl Ammonium Bromide), DBP (Di-Butyl Phathalate) and tint are mosly dependent on the following factors in addition to the spray condition of the feedstock.
(a) Geometry of the Throat
(b) Maximum coverage of flow area by oil spray
(c) Spray nozzle and
(d) Number of spray
Among the above-mentioned four factors, the coverage of the flow area of the oil spray and the geometry of the throat are vital for controlling the quality, the throughput, yield and improvement of the refractory life of the HVHT reactor. To get maximum coverage of oil spray in the flow are vital for controlling the quality, the throughput, yield and improvement of the refractory life of the HVHT reactor. To get maximum coverage of oil spray in the flow area of the throat section, it was found by the applicant that the optimum number of oil sprays should be at least six.
5

An object of the present invention is to achieve the maximum coverage of the oil spray in the cross sectional area of the throat of HVHT reactor by the feedstock (conversion oil) into the flow of the hot combustion gas by introducing at least six numbers of sprays of the feedstock.
Another object of the present invention is to minimize the flame length required during the pyrolysis using at least six hydrocarbons sprays and by keeping the flame well within the reaction chamber.
A still further object of the present invention is to minimize the residence time or duration of the pyrolysing the feedstock in the reactor by using substantially all the hot gases produced in the combustion chamber and thereby eliminating any waste of the enthalpy.
One more object of the present invention is the improvement of the service life of the throat section refractory as well as that beyond the throat section.
Still one more object of the present invention is to provide a bi-fluid atomization nozzle with wide angle spray for the supporting feedstock to achieve the complete combustion in the combustion zone of the HVHT reactor.
Yet another object of the present invention is to accomplish more efficiency in the operation of HVHT reactor.
-6 -

The above aspects are implemented by:
(a) Increased Throughput (Production Rate)
(b) Increased Yield (i.e. efficiency) and
(c) Higher Tint along alongwith the following characteristics:
i) CTAB
ii) Nitrogen Surface Area
iii) Iodine Number
iv) 24M4 DBP (i.e. Compressed DBP)
v) DBP as shown the Performance Analysis
Thus according to the present invention there is provided an improved process for the manufacture of carbon black by furnace process in High Volume High Temperature (HVHT) reactor which comprises the following steps:
burning completely liquid hydrocarbons supporting
feedstock in a combustion zone to attain flame temperature

between 1800 to 2000°C by passing axial air of 0.5 to 0.9 kg/cm2
(g) to achieve the continuous heat input of 75-88 BTU/SCFH;
allowing the hot flue gas coming out of combustion zone containing 8 to 10% of excess oxygen into a reaction chamber;
allowing the hot flue gas to pass through the said reaction zone of said reactor and injecting conversion oil in said reaction zone for pyrolysis reaction to take place;
- 7 -

allowing the pyrolysed smoke from the reaction zone to enter into a cooling zone for reducing the temperature suddenly by increasing the residence time to improve the colloidal property;
allowing said smoke to enter a cooler to bring down the temperature thereof to 1200 + 100°C;
passing said cool gas through an evaporating zone where said gas being further cooled with the help of water spray for lowering its temperature.
allowing the sprayed water droplets to absorb heat to get evaporated;
passing the water-quenched smoke into an air preheater to preheat the air to 700 to 900°C for utilizing in said combustion chamber.
The present invention further provides an improved High Volume High Temperature (HVHT) reactor for carrying out the above method comprising a Combustion Zone, Reaction Zone, Cooling Zone and Evaporating Zone wherein improvement comprises in said reaction zone having multiple planes by adopting atleast six nozzles located in one or different planes of said reactor for spraying the combustion oil feedstock, said combustion zone being provided with a constrict section to enhance the speed of the air injected into said combustion zone to form a turbulant mixture with the
- 8 -

supporting feedstock, said combustion zone being connected to said reaction zone and said reaction zone being coupled to said cooling zone which is further connected to said evaporation zone to have a complete air tight assembly.
The second generation reactors for the production of the carbon black are the HVHT which is basically an improved reactor for production of carbon black by furnace process.
This invented arrangement causes much better and rapid distribution of the oil droplets in the gas stream and also efficiently cracks all the feedstock oil, under the same thermal condition.
According to one embodiment of the present invention, we have adopted 'circular choke' with at least six burners in a plane. In comparison with the geometry of 10" I.D. standard design choke with 10" circular choke, there is a 5% advantage of spray area coverage than previous shape. We have found that circular chokes gave longer refractory life than standard shapes wake oil throughput (other conditions remaining same) increased but there was a marginal drop in tinting strength.
According to another embodiment of the present invention, we have changed the choke design to a regular POLYGON with provision for using at least six burners in a plane.
- 9 -

According to a further embodiment of the present invention, the geometry of the newly designed throat being a 8-16 sided regular POLYGON having one oil spray port located in alternate sides having minimum provisions for at least six nos, of ports in each plane.
According to a still further embodiment of the present invention, the brick lining with lap joints and coated with plasma in hot face for better stability and easy repairs/replacement.
The carbon black is produced in a reactor which comprises the following four different sections:
(1) Combustion zone (Head Section)
(2) Reaction zone (Throat Section)
(3) Cooling zone (Cooler Section)
(4) Evaporation zone (Breeching Section)
If any of these sections under performs, there will be a substantial loss in yield, productivity and will also lead to quality deficiency. These can be well judged by the volume/mass of production and also the quality. The quality should be such that it should consistently produce a narrow and uniform particle size distribution reflected by tint and other colloidal properties of the particular grade produced, which is tested in laboratory as per ASTM method.
- 10 -

Feedstock used in the process of the present invention is the liquid hydrocarbons of petroleum and of coal tar origin. The pyrolytic reaction is carried in high temperature resistant refractory lined reaction zone in the deficiency of air.
As mentioned earlier, the oil furnace process for producing carbon black is well known, in which liquid hydrocarbon or the raw material (feed or make oil) is injected in a continuous stream of hot gas producesd by burning the gas or liquid hydrocarbon commonly known as Supporting Feedstock (SFS) in the combustion zone. This hot gas is controlled in such a way that it contains known amount of free oxygen. The basic purpose of this method is that the hot gas is to supply the required amount of heat for pyrolysis of feed oil to get converted into carbon black and the reaction is endothermic in nature. Excess oxygen is maintained to save the refractory which partially burns the feed oil, The pyrolysis and partial burning of feed oil takes place in the reaction chamber.
The pyrolyzed hydrocarbon which gets converted into carbon black and gaseous products is quenched in the cooling zone of the reactor where reaction is stopped as per the requirement.
Carbon black and combustion gas stream pass through the vaporizing section, air preheater, oil preheater and enter the bag filter, where carbon black is separated from gases and sent for further processing for packing and transport.
- 11 -

After leaving the combustion zone (as soon as combustion is completed), the high temperature flue gas with controlled amount of oxygen content enter in the mixing and reaction zone where the area is characterised by high stress factor which increases towards the throat, created by varying cross section and high turbulance due to very high flow and velocity. These are the two main characteristics for getting the desired properties (like surface area, structure etc.) of carbon black during pyrolysis reaction. At the same time, it is also required to achieve higher production rate and improved yield for lowering down the cost of production. Thus an optimisation is needed considering all the above factors.
The reaction zone follows the mixing zone. The reaction zone design depends on the throughput and residence time required for complete carbon black formation. In the. process of optimisation, it has been established that a convergent nozzle with throat of polygonal shape with an equivalent diameter of 10 inch will give the desired result, also maximising the yield by minimising the side reaction by producing a short flame of exothermic reaction and pyrolysing the same by endothermic reaction.
As soon as conversion oil droplet is released from the nozzle to the hot gas stream into a converging throat which is the reaction zone, it immediately absorbs energy from the surroundings to vaporise at the unbalanced conditions. Pyrolysis
- 1 7 -

reaction starts followed by combustion reaction and also at the same time, it is being struck by high velocity gas stream with a particular stress factor. The primary structure of the carbon black depends on stress factor. Lower the cross-section, higher the stress factor.
The important properties like particle size, structure, surface area, surface activity and rubber properties like tensile strength, modulus etc. all primarily achieved in the first three sections of the reactor i.e. combustion zone, reaction zone and cooling zone by adjusting the process parameters and the residence time.
After working in cylindrical and non-crylindrical reactor of earlier generation, it was felt that improvement in both quality and cost are required to survive in the competitive market. Extensive studies were made to improve upon the quality and yield with different combination of parameters.
In the conventional design of the reaction chamber spray guns are adopted in various planes ranging from two to five and at each plane, normally two or four guns are used. As the number of planes are more in the conversional reaction chamber, likelihood of failure of refractory is too often. We have, on the contrary, adopted six to twelve guns at those planes of the reaction chamber selectively to get the best result and
- 13 -

also thereby avoiding the failure of the refactory as observed in the know reaction chambers. Moreover, we have adopted at least six numbers of spray guns at each plane which gave the optimum result as mentioned in the specification.
Ultimately, it was decided by us that the first three sections of the reactor need total change in the design to -
i) achieve total and efficient combustion of liquid hdyrocarbon supporting feedstock in head zone or combustion zone.
ii) better coverage of hot gas produced in the combustion or head zone by the feed oil in the reaction zone, and
iii) increase in the refractory life of reaction and cooling zone.
iv) flexibility and ease of operation.
Priority was given to the reaction zone. The design was changed and the performance was extensively studied. Although a substantial improvement was noticed but it was more in quality.
Further studies were performed by the applicant and it was found that combustion section needs a proper design to achieve visibility of hot gas and nozzle tips of feed oil by total combustion of liquid hydrocarbon supporting feedstock before reaching the throat of the reactor.
- 14 -

Modification was also done in the cooling section at the same time, to increase the ease of operation, flexibility and refractory life and to adjust the residence time more effectively by utilising thermodynamic and aerodynamic characteristics of the high temperature gas stream.
After the changes in design for above three zones, a very positive improvement both in quality and yield has been achieved.
To overcome the limitations, we have developed the section called "Throat" with a design of regular polygon which is having provision of using at least six numbers of burners in a single plane. The provisions for three nos. of plane at proper distances (to obtain a required cross section, hence the velocity) are provided to attain the required residence time for different grades to achieve wide spectrum of properties.
Another important aspect for better outcome of supporting feedstock which continuously supply the required amount of heat

to facilitate the pyrolysis is endothermic in nature.
This pre-pyrolysis activity, exothermic in nature, takes place on continuous basis in the combustion zone.
The existing high volume high temperature tread reactor has various limitations for producing different grades of carbon black with wide spectrum of properties efficiently. Extensive studies have been made from different angles. In the first step of action plan, following changes were incorporated:
- 15 -

1) Changing of original SFS (Supporting Feedstock) nozzle.
2) Selection of feedstock injection nozzle of predetermined
angle.
Though some improvements were noticed, but it was failed to achieve the target of quality and efficiency of the production of carbon black. Further studies were made in second step of action plane and the following conclusions were arrived:
It was felt necessary to change the design of the throat section (reaction zone) , the combustion zone and SFS to improve upon-
(a) Particle size distribution (PSD) as reflected in higher
tinting strength of carbon black produced at identical process
conditions compared to HVHT reactor of existing design.
(b) The visibility of the feedstock nozzle for conversion oil
spray is a necessity to get optimum output.
(c) To have proper control of thermodynamic process and to
eliminate the refractory failure, the heat input and the higher
flame temperature required for endothermic pyrolysis for higher
conversion and productivity by efficient and complete burning
of SFS (Supporting Liquid Hydrocarbon Feedstock) within the
combustion zone.
With same refractory condition, it is also revealed from thermodynamic, enthalpy lading to higher yield and efficiency.
- 16 -

(d) The coverage of the cross-sectional area of combustion gas flow through the throet of the reactor by oil spray to utilise effectively the total heat generated by combustion of liquid hydrocarbon feedstock for efficient conversion of make oil.
Disadvantages in 2nd Generation Reactor:
1) In combustion chamber, the flame is unstable.
2) The combustion chamber is invisible due to carry over of
unburnt gas (oil vapour) conversion oil (Liquid Hydrocarbon).
Nozzle tip position cannot be located.
3) The aerodynamic characteristics is such that the flame
is extended upto reaction zone.
4) Incomplete combustion in the combustion zone leading
heterogenity and PSD irregularities often resulting process
inadequacy and loss of conversion efficiency resulting in loss
of yield.
5) Unstable flame heating the refractory wall. Due to this,
skin temperature in this zone remaining high, resulting in heat
loss.
To overcome all the above limitations, a new combustion zone has been designed by us.
- 17 -

Redesign parts includes two major activities e.g.:
(A) Designing a suitable bi-fluid atomisation nozzle for
supporting liquid hydrocarbon feedstock, so that it can produce
convergent and stable flame.
(B) Combustion should be completed within the combustion
chamber.
After studying various bi-fluid atomisation nozzle, it has been found by us that a nozzle with wide angle of having value of 90 degree and preferably between 120 and 180 degree when put into a high velocity zone, the stress that generated by high velocity air, reduce the angle of spray effectively to produce a convergent short flame. This results efficient mixing of air and oil and at the same time, total combustion is achieved within the combustion zone.
The mathematical modelling has been done and it is found that velocity in the range of 100-150 m/sec and preferably 130 m/sec is required to generate the suitable stress factor to fulfil the above requirement.
Therefore air quantity (13,000+1500 nm3/hr.) being heated upto 800-900 degree centigrade passed through (310+40) mm dia opening, the required velocity is achieved.
- 18 -

Keeping the above factors in mind, reactor (HVHT)
has been modified and fruitful results are achieved. The
achievement are as under:
1) Combustion reaction completed with the combustion chamber.
2) Combustion chamber is totally visible and nozzle tip
conversion oil gun are easily positioned.
3) Short convergent flame produced.
4) Increase in conversion yield.
drawings This invention is explained in detail with reference to the f
accompanying the provisional specification, wherein
Figure-1 shows the cross-section of the reaction chamber of the new reactor.
Figure-2 shows the combustion zone of the new reactor.
Figure-3 shows the fluid atomization nozzle of the invention.
With reference to the drawings, hot gas is injected into the reactor through the hot gas inlet (10) which has a wide mouth (22) . The neck of the hot gas inlet is gradually reduced in
- 19 -

its diameter as shown at (20) in Fig.1 forming a tapered end at (24). At least six spray guns are positioned at different planes of the reaction chamber. Fig.1 illustrates guns located at two planes (30,32) having comparatively wide diameter while another set of spray guns are located at the narrowest section of the reaction chamber, namely (34). Spray guns are arranged at different planes of the reaction chamber for better circulation of the hot gas inside the reactor (40).
With reference to Fig.2, gas inlet (50) is located at one end of the substantial cylinder combustion zone (45). The location of said inlet for liquid supporting feedstock is shown at (50) which is at right angle to the air inlet (52). As the mixture of liquid supporting feedstock and air gets through the combustion zone of the reactor it faces a rather wide neck (54) which is gradually narrowed down into a wider area (56) and ultimately into a still wider area (58) into the reaction zone (60). Finally, the mixture passes through the other end of the reaction zone (70) to enter into the reaction of the reactor as illustrated in Fig.1.
Fig.3 illustrates a fluid atomization nozzle for the reactor. The said nozzle (70) is closed at one end (80) and is open at the other end (75) and is located at one end of the combustion zone which is away from the reaction chamber. Near to the closed end of the said nozzle, there is provided a plurality of holes along its periphery so that oil can be sprayed through said holes (90) along the periphery (95) into the combustion chamber at a much wider angle.
- 20 -

The following Tables-I, II, III & IV will depict the results obtained by using the newly designed throat of the reactor as compared to the existing one.
- 21 -

Calculation based on Make Oil (Conversion Oil)
I) Analysis after changing the design of the Reaction Chamber (Throaty Yield is calculated as % of carbon black of make oil input

Date Grade Air Rate Air Temp. Make Oil % Yield on % Yield on newly % Increase (NM /HR °C (kg/hr) existing design designed throat in Yield
9.6.97 N220 11750 775 3325 53.0 54.56 2.94 20.7.97 N220 12500 750 3700 53.0 54.18 2.22 2.7.97 N234 12516 789 3502 51.0 51.8 1.56 4.7.97 N330 12000 800 4450 59.0 60.53 2.59 17.6.97 N330 12000 788 4300 59.0 59.61 1.03 29.7.96 N375 12000 779 3850 55.0 55.7 1.27 29.7.96 N326 12000 760 4650 59.0 60.51 2.56
OIL BMCI = 128; SULPHUR CONTENT = 1.95% : EFFECTIVE BMCI = 125
II) Analysis after changing the design for both Reaction Chamber (Throat) & Combustion Chamber Yield is calculated as % of carbon black of make oil input

Date Grade Air Rate Air Temp. Make Oil % Yield on % Yield on newly % Increase
NM /HR °C (kg/hr) newly-designed designed throat throat & combustion chamber
13.8.98 N330 12000 788 4250 60.53 64.4 6.39 13.8.98 N330 11500 790 4100 60.53 64.5 6.55 16.8.98 N220 13000 785 3650 54.56 56.5 3.55 17.8.98 N220 13000 784 3675 54.56 56.5 3.55

III) Comparison between newly designed Reactor Throat & Combustion Chamber with existing standard design Reactor
Yield is calculated as % of carbon black of make oil input

Grade % Yield for existing % Yield for newly designed % Increase in standard design throat & combustion chamber Yield
N220 53.0 56.5 6.6 N220 53.0 56.5 6.6
N330 59.0 64.4 9.15 N330 59.0 64.5 9.32
Thus it is established that PCBL designed Throat & Combustion Chamber gives better Yield Yield is calculated as % of carbon black of make oil input
Reactor resutls are as follows :-

Grade Reactor % Yield I2 Number DBP Tint CTAB N2SA
N220 Unit-3 56.5 127.5 125.0 113.0 111.0 119.0 N330 -do- 64.4 83.0 113.0 101.0 81.0 82.0

TABLE-IV

Remarks
It must be noted that the data (Table I, II and III) studied have been taken from actual production data and the trial run carried out on commercial reactor under identical conditions by gas analysis through Orsat analysis apparatus.
Table IV indicates the average yield obtained by actual physical measurement on prolonged commerical runs under identical conditions.
The average yield as shown in Table - IV, though much higher than the old standard design high volume high temperature tread reactor are in some cases less than the result obtained from Orsat analysis data which are only indicative.
Therefore, it is established that improvement is achieved by the newly designed combustion chamber and throat over the existing old standard designed throat.
- 24 -

Results and Discussions: Productivity:
Throughput - In similar operating conditions the throughput
is increased by approx. 10(%) (N330) over original reactors.
Air Rate - 12000 NM3/hr.
Air Temp. - 780 degree C (avg.)
Ratio - 1:19
Conv, oil Rate - 4400 kg/hr., for POLYGON (12-16 sided) with
at least 6 burners. But with existing reactor only 4000 kg/hr.
Quality
CTAB - Better control in polygon throat with at
least six burners.
Tint{Particle
pore size
distribution) - - do -
DBF (agglomerate
size distribution - do -
Refractor life - Improved.
-25 -

The design and the performance of the Sections specially the Combustion and Reaction Zone are discussed next.
Carbon Black Properties Primary Process Parameters Derived Process Parameters
Iodine Number 1. Air Flow (Nm3 /hr.) 1. Fuel-Air Ratio
-(mg/g)
2. Air Temperature (oC) 2. Air-Conv.oil Ratio(Nm1 /kg
3. Cooling Air Flow 3. Heat Input (BTU/SCFH)
(Nm 3/hr.)
DBP Absorption 4. Supporting Feedstock 4. Flame Temperature (°C)
(ml/100g) Flow (Kg./hr.)
5. Conversion Oil 5. K'-Oil Ratio (PPM)
6. Reactor Pressure gauges 6. Air Velocity
(kgt/m2)
7. Oil Pressure (Bar)
8. Cut Off Water Flow
9. Oil Temperature ((oC)
Fixed Paramter :
1. Reactor Volume
2. Conv. Oil Nozzle Type : ANGLE Press.
3. Quench Water Nozzle Type ; ANGLE, Press
4. Conv. Oil Gum Position.
Yield = function (f) = f(Air Temperature ; f(Heat Input). f{Air Rate). f(Supporting Feestock Flow). f(Flame Temperature), f(Oil Rate - Conv, Oil).
f(Side Reaction), f(Area covered by oil droplet in the Chock Section).
f(Residence time),
f(Fuel/Air Ratio), f(Oxygen concn,),
f(Oil press.) f(MMCl of oil, f(Reynolds Number).
To maximise Yield ;
Thermal decomposition to be maximised subject to the minimisation of Oxidation reaction (Side Reactions).
- 26 -

Again, the number of nucleation for formation of carbon black depends on the number of eddies formed. For this, a very high turbulent flow is required. At the same time, it is followed by prolysis reaction which is also followed by release of additional energy by combustion reaction with the desired short flame.
For all the above, the situation demand a design of convergent nozzle where, for a given set of upstream condition, the linear velocity in the throat reaches that of sound in the gas at that location i.e. at throat it should be sonic velocity.
The characteristics of carbon black product having desired properties are generally dependent on the following factors:
1) Turbulance during pyrolysis.
2) Type of spray pattern.
3} Type of liquid hydrocarbon feedstock.
4) Temperature of flue gas.
5) Temperature of the flame during pyrolysis.
6) Type/Geometry of the flame during pyrolysis.
7) Time required to accelerate the diffusion rate of the
reactant constituents.
8) Type of nozzle (throat) through which the high gas stream
passes.
— 27 -

The stress factor depends on the -
1) Velocity of gas
2) Velocity of oil droplets
3) Oil droplet size
Thus in throat section Plane-III has got 70% lower cross-sectional area than Plane-I and hence, stress factor is higher in Plane-Ill. As per the requirement of structure level of carbon black, oil guns are shifted from Plane-I,II and III. DBP value also may be controlled by shifting conversion oil spray position.
- 28 -

We claim:
1 . An improved process for the manufacture of carbon black by furnace process in High Volume High Temperature (HVHT) reactor which comprises the following steps:
burning completely liquid hydrocarbons supporting feedstock in a combustion zone to attain flame temperature between 1800 to 2000°C by passing axial air of 0.5 to 0.9 kg/cm2 (g) to achieve the continuous heat input of 75-88 BTU/SCFH;
allowing the hot flue gas coming out of combustion zone containing 8 to 10% of excess oxygen into a reaction chamber;
allowing the hot flue gas to pass through the said reaction zone of said reactor and injecting conversion oil in said reaction zone for pyrolysis reaction to take place;
allowing the pyrolysed smoke from the reaction zone to enter into a cooling zone for reducing the temperature suddenly by increasing the residence time to improve the colloidal property;
allowing said smoke to enter a cooler to bring down the temperature thereof to 1200+100°C
- 29 -

passing said cool gas through an evaporating zone where said gas being further cooled with the help of water spray for lowering its temperature;
allowing the sprayed water droplets to absorb heat to get evaporated;
passing the water quenched smoke into an air preheater to preheat the air to 700 to 900°C for utilizing in said combustion chamber.
2. An improved process as claimed in claim 1 wherein said
conversion oil feedstock is selected from petroleum base raw
material and also from coal tar origin.
3. An improved process as claimed in claim 1 wherein ratio
between air and liquid hydrocarbon feedstock varies from 15:1
to 20:1 so as to have 1000 BTU per SCFH to 1000 BTU/20 SCFH
of air.
4. An improved process as claimed in any one of claims
1 to 3 wherein in said reaction chamber conversion oil is
injected through nozzles in the atomised form for the partial
combustion and pyrolysis of conversion oil.
- 30 -

5. An improved process as claimed in any one of the
preceeding claims wherein water is sprayed co-currently or
counter-currently or radially to the direction of the flow of
said smoke.
6. An improved process as claimed in claim 1 wherein water
in injected into the cooler in atomized form.
7. An improved process as claimed in claim 6 wherein water
is sprayed through multiple nozzles located at same or
different planes of said cooler.
8. An improved process as claimed claim 1 wherein in said
evaporation zone quenching is done with water spray so that
water droplets get evaporated quickly,
9. An improved process for the manufacture of carbon black
by furnace process in HVHT reactor substantially as herein
described.
10. An improved High Volume High Temperature (HVHT) reactor
for carrying out the method as claimed in any of the preceeding
claims comprising a Combustion Zone, Reaction Zone, Cooling
Zone and Evaporating Zone wherein improvement comprises in said
- 31 -

reaction zone having multiple planes by adopting atleast six nozzles located in one or different planes of said reactor for spraying the combustion oil feedstock,said combustion zone being provided with a constrict section to enhance the speed of the air injected into said combustion zone to form a turbulant mixture with the supporting feedstock, said combustion zone being connected to said reaction zone and said reaction zone being coupled to said cooling zone which is further connected to said evaporation zone to have a complete air tight assembly.
11. An improved HVHT reactor as claimed in claim 10 wherein
a sprayed gun assembly is adopted to spray the supporting
feestock, said spray gun assembly is fitted with a nozzle
provided with perforations along its peripheral line and is
housed in said combustion zone .
12. An improved HVHT reactor as claimed in claim 9 or 10
wherein said reaction zone is substantially funnel shaped at
its end connected with said cooling zone.
13. An improved HVHT reactor as claimed in claim 11 or 12
wherein said cylinderical cooler is connected to said evaporating
zone having one or more breeching sections.
—32 —

14. An improved HVHT reactor as claimed in claim 11 wherein
the throat section is located in said reaction zone having
a regular polygonal shape with 12 to 16 sides for spraying the conversion oil .
15. An improved HVHT reactor as claimed in claim 11 wherein
said reaction zone is provided with at least six spray nozzles
for the conversion of oil feedstock, said spray nozzles being
located at one or more planes.
16. An improved HVHT reactor as claimed in claim 14 or 15
wherein said reaction zone is provided with spray nozzles located
at three different planes and each of said planes having 3 to
18 nozzles.
17. An improved HVHT as claimed in any one of
claims 10 to 16 wherein in said cooler or evaporation zones
water spray gun assembly are positioned either in regular or
irregular distances from each other.
- 33 -

18. An improved High Volume High Temperature (HVHT) reaction substantially as herein described and as illustrated in the drawings accompanying the Provisional Specification.
The invention presents new geometry and design of throat section of the reaction zone, improved design of combustion zone and arrangement of feedstock nozzle for HVHT reactor to achieve excellent quality and efficient yield of carbon black.
The invention provides stable flame in combustion chamber, flame being restricted to the combustion chamber only, leading to proper and complete combustion.
A novel combination of positioning of nozzles and residence time in reaction zone ensures total and efficient combustion. Better coverage of hot gas produced is ensured to increase the refractory life.
While emphasizing on the modification of the reaction zone, the invention offers innovations in the other related zones, vig. combustion zone, cooling zone and evaporation zone too to present a very much improved process.

Documents:

01734-cal-1998-abstract.pdf

01734-cal-1998-claims.pdf

01734-cal-1998-correspondence.pdf

01734-cal-1998-description(complete).pdf

01734-cal-1998-drawings.pdf

01734-cal-1998-form-1.pdf

01734-cal-1998-form-2.pdf

01734-cal-1998-form-3.pdf

01734-cal-1998-form-5.pdf

01734-cal-1998-letters patent.pdf

01734-cal-1998-p.a.pdf

1734-CAL-1998-(23-01-2013)-FORM-27.pdf

1734-CAL-1998-CORRESPONDENCE 1.1.pdf

1734-CAL-1998-CORRESPONDENCE.pdf

1734-CAL-1998-FORM 27 1.1.pdf

1734-CAL-1998-FORM 27.pdf

1734-CAL-1998-FORM-27.pdf

1734-cal-1998-granted-abstract.pdf

1734-cal-1998-granted-claims.pdf

1734-cal-1998-granted-description (complete).pdf

1734-cal-1998-granted-drawings.pdf

1734-cal-1998-granted-form 2.pdf

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Patent Number

201453

Indian Patent Application Number

1734/CAL/1998

PG Journal Number

08/2007

Publication Date

23-Feb-2007

Grant Date

23-Feb-2007

Date of Filing

25-Sep-1998

Name of Patentee

PHILLIPS CARBON BLACK LTD.,

Applicant Address

R.N. MUKHERJEE ROAD,DURGAPUR-711 201, DIST.BURDWAN,

Inventors:

#	Inventor's Name	Inventor's Address
1	RABISHWAR ROYCHOWDHURY	PHILLIPS CARBON BLACK LTD. R.N. MUKHERJEE ROAD,DURGAPUR-711 201, DIST.BURDWAN,WEST BENGAL
2	BRAHMANANDA MUKHOPADHYAY	PHILLIPS CARBON BLACK LTD. R.N. MUKHERJEE ROAD,DURGAPUR-711 201, DIST.BURDWAN,WEST BENGAL

PCT International Classification Number

C 09C 1/50

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA