|Title of Invention||
CATALYST COMPOSITE MATERIALS SUITABLE FOR DEEP DESULFURIZATION OF HYDROCARBON FEEDSTOCKS AND A PROCESS FOR THE PREPARATION THEREOF
|Abstract||The present invention relates to novel catalyst composite materials suitable for deep desulfurization of hydrocarbon feed stocks and a process for the preparation thereof. The catalysts according to the present invention are basically composed of the following: an alumina carrier substance, at least one organic derivative of a heteropoly anion formed by an organic compound having at least two oxygen atoms, one of which being part of an aldehyde (-CHO) group, and one EDTA complex of the active metal selected from the Gr. VIII metals in the periodic table. The alumina carrier is impregnated by a single step process with a homogeneous solution containing organic derivatives of group VI and VIII metal elements. The amount of the selected active metal element is 10 - 35 % and 2 - 10 % of the catalyst weight once converted to oxide weight, respectively for the group VI and group VIII metals. The phosphorous content in the catalyst can be increased by adding additional phosphorous as a phosphate salt or phosphoric acid to the mixture of the complexes of the metals. The invention also provides process for the preparation of composite material.|
|Full Text||FIELD OF THE INVENTION
The present invention relates to catalyst composite materials suitable for deep desulfiirization of hydrocarbon feedstocks and a process thereof. More specifically, it relates to catalyst composite materials useful for deep desulfiirization of hydrocarbon feedstocks and methods for their preparations.
BACKGROUND OF THE INVENTION
The sulfur content of hydrocarbon fuels typically from petroleum used for automotive purposes is being lowered all over the world in stages. In the case of diesel fuel, it is expected that it will be limited to 50 ppm or below by the year 2005 in most parts of the world. Many types of sulfur compounds are present in straight run and cracked distillates. The ease of hydrodesulfurization (HDS) of these molecules over conventional Co-Mo (or Ni-Mo) catalysts depends on their molecular structure. Among these S-compounds, 4,6-disubstituted dibenzothiophenes are the most difficult to desulflirize. For example, the relative rate of desulfiirization of (unsubstituted) dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) over a Co-Mo-HDS catalyst has been reported to be 6:1 (F. Bataille, J. Mijoin, J.L. Lemberton, G. Perot, G. Berhault, M. Lacroix, F. Mauge, S. Kasztelan and M. Breyesse, Stud. Surf. Sci. Catal., 130 (2000) 2831). Another study has reported the pseudo first order rate constants for HDS of DBT, 4-MDBT (4-methyldibenzothiophene) and 4,6-DMDBT on a Co-Mo catalyst to be 0.058, 0.018 and 0.006 min-1 respectively (X. Ma, K. Sakanishi and I. Mochida, Ind. Eng. Chem. Res., 33 (1994) 218). Therefore, due to the presence of these refractory 4,6-dialkyldibenzothiophene compounds, the desulfiirization of diesel to less than 50 ppm is difficult.
Work is in progress throughout the world on the development of new processes for deep desulfiirization of diesel. Some new catalyst technologies have been reported recently for deep HDS of diesel. Besides, research on biodesulfurization methods for S reduction in diesel is also in progress. US Patent 5,897,768 discloses that the incorporation of zeolitic and acidic components in these catalysts to isomerize or disproportionate the dialkyldibenzothiophene compounds leading to ease of their desufurization. However, due to the presence of acidic components, one would expect unwanted cracking of other components causing lower product yields, besides rapid deactivation due to fast coke deposition. The technological innovations for deep desulfurization include the introduction of multiple hydrogen injection and removal of H2S and NH3 from intermediate sections of the reactor. These improvements are rather expensive to implement in existing reactors and totally new reactor systems need to be constructed. In this context, it will be much more economical to design an active catalyst that can desulfurize diesel to the desired low sulfur specification. Such a catalyst can be loaded in existing HDS reactors without any additional expense.
Co-(Ni)-Mo catalysts are widely used in desulfurizing petroleum fractions. These
catalysts are active in the sulfided state converting the sulfur in sulfur compounds into
H2S in the presence of H2. Various types of species such as M0S2, Co-(Ni)-Mo-S and
Co (Ni) sulfides have been reported to be present on the surface of sulfided Co-Mo-
alumina catalyst. Of these, only the Co-Mo-S phase has been found to be mainly
responsible for HDS activity (H. Topsoe, B.S. Clausen and F.E. Massoth,
"Hydrotreating Catalysts", SpringerVerlag, Berlin, 1996). The structure of the Co-
Mo-S phase is now clearly established. This phase consists of microcrystallites of
M0S2, the edge sites of which are substituted by Co (P. Ratnasamy and S. Sivasanker,
Catal. Rev.-Sci. Eng., 22 (1980) 401). In the presence of H2 some S atoms are lost as
H2S creating anion vacancies. These vacancies (coordinately unsaturated site, CUS)
can arise on the basal plane and at the edges and corners of crystallites. The smaller
the crystallite, the larger is the proportion of edge and corner anion vacancies to
vacancies at the basal plane. The S-containing molecules adsorb at these vacancies on
the CUS and undergo desulfurization. The CUS at the basal surface, though may be
sufficiently active to desulfurize non-beta substituted dibenzothiophene compounds,
cannot easily desulfurise the di-beta substituted compounds due to steric hindrance.
These compounds can, however, undergo HDS at the edge (or preferably the corner)
CUS. Hence, the number and location of these sites determine the overall activity of
A large number of innovations in hydrodesulfurization catalysts has been published or patented over the years. A few relevant ones are described below.
US 5468709 describes a catalyst made from an alumina carrier substance, atleast one active metal element selected from Gr.VI metals in the periodic table, one active metal element chosen from Gr.VIII metals in the periodic table, phosphoric acid and an additive agent such as ethers of alcohols or alcohols (ethylene glycol, sugers as
additives) US 6239066 gives the process for forming high activity catalysts,
consisting of wetting the catalyst composition by contact with a chelating agent such
as EDTA, MEA etc in a carrier liquid, aging the so wetted substrate and drying and
calcining. EP 1041133 describes a catalyst with organic additives selected from a
group of compounds comprising at least two hydroxyl groups and 2-10 carbon atoms
and the polyethers of these compounds along with M0O3, NiO and P2O5. EP 1043069
A discloses the preparation of a sulfided hydrotreating catalyst as 50% alumina, one
hydrogenation metal component and an organic compound comprising at least one
covalently bonded nitrogen atom and atleast one carbonyl moiety. Thus a catalyst
containing 26% M0O3, 4.7% NiO, 6.7% P2 05 on gamma-alumina as carrier was
impregnated with diammonium salt of EDTA solution, aged for three days and dried
OBJECT OF THE INVENTION:
The main object of the present invention is to provide the novel catalyst composite
materials suitable for deep desulfurization of hydrocarbon feedstocks and a process
for the preparation thereof.
Another object of the present invention is to prepare the catalyst composite material
comprising impregnating an alumina support material with an aqueous solution of
composite mixture at a temperature ranging between room temperature to 40°c, drying
the impregnated alumina at room temperature, heating the impregnated alumina at
100 to 120°c for a period of 6 to 8 hrs. to obtain the catalyst composite material.
In Another object is to incorporate phosphoric acid component as a heteropoly acid of
a group VI metal.
In yet another object is to use two organic additives, one additive possessing at least
one aldehyde (-CHO) group and another additive possessing atleast two carboxylic
SUMMARY OF THE INVENTION:
The present invention provides for catalyst composite materials suitable for the deep desulfurization of petroleum oils; typically, the S-content of diesel fuels can be brought down to below 50 ppm. The invention also provides a process for the preparation of said catalyst composite materials.
The catalyst composite materials of the present invention consist of a porous support, typically alumina with a surface area in the range of 200 to 300 m2/g and a pore-volume of about 0.7 - 1.2 ml/g and Co (or Ni) and Mo (or W) loaded on to it as
two different miscible interacting complexes or organometallic derivatives. The catalyst composite material consisting of the support and the complexes are dried at low enough temperatures in the range of 80 - 120°C to prevent the decomposition of the organometallics. It is then sulfided externally prior to loading in the reactor or insitu after loading in the reactor. The catalyst so prepared and sulfided contain more number of active sites for desulfurization and are also more suited for the desulfurization of refractory S-compounds such as 4.6-dibenzothiophene. The preparation process also enables the incorporation of the promoter phosphorous into the catalyst without an additional impregnation step.
The hydrocarbon feedstock, typically belonging to the diesel fraction, is contacted with the catalyst composite materials in the presence of hydrogen at typical hydrotreating conditions of temperature and pressure to bring down its sulfur content to below 50 ppm. The use of this type of catalyst is expected to improve liquid yields due to minimal cracking and due to higher activity of the catalyst, be able to operate at lower temperatures than prior-art catalysts. DETAILED DESCRIPTION OF THE INVENTION
There are two main components in HDS catalysts, the support and the active component, the mixed metal sulfide crystallites. The support helps in the dispersion of the supported specie and may also affect its activity. The conventional method of making HDS catalysts say of the Co (Ni)-Mo-alumina type, involves the deposition of salts of Mo and Co from aqueous solutions by impregnation, drying and calcination to give a deposit of oxides of Co (Ni) and Mo. The catalyst is then sulfided at high temperatures, say 300 - 340°C, to convert the oxides into the sulfides. This method possess limitations. For example, due to the high calcination temperature (about 500°C) used in the preparation, the metals, especially Co (Ni), interact with the support (alumina) and a fraction of the impregnated metals is lost as a useful desulfurizing catalyst. Again, as the metal components are deposited separately as oxides, after sulfidation, a substantial amount of these active components end up as inactive individual sulfide phases. Further, due to the high temperatures of calcination, the oxides (especially Mo) agglomerate into large clusters, thereby leading to large sulfide particles after sulfidation; these sulfide particles" expose more the basal planes and are less active for desulfurizing the sterically hindered S-compounds. One more limitation of the prior-art method of preparing catalysts is that
the oxides of Co and Mo deposited on the surface of the support undergo sulfidation at different temperatures. The temperature required for sulfidation increases in the order, Ni > Mo > Co. As a result when a typical catalyst containing mixed oxides of Co (Ni) and Mo is sulfided, discrete phases of the individual phases are formed at different temperatures and the formation of the active mixed metal sulfide phase is less.
Further, a yet another limitation of the process of the prior-art is that due to the limited solubility of the Mo salts in water and the low pick up of the salts by alumina, the loading of Mo is small and multiple impregnation steps with intermediate calcinations are required for loading substantial quantities of the metals. The multiple calcination causes loss of the active centres by reaction with the support, besides causing growth of the metal oxide phase on the surface. Further due to the need to impregnate the Mo and Co (Ni) salts from solutions with different pH values, the impregnation of the two metals is carried out separately, generally, Mo being loaded first in multiple steps, depending on the loading required, and calcined before loading the next metal Co (Ni). This method not only increases the number of preparation steps, it also prevents the intimate mixing of the two metallic components.
The present invention provides for a catalyst composite material that does not possess the above limitations. Accordingly, the metal components Co (Ni) and Mo are incorporated on the surface of the support as miscible organometallic derivatives. The organometallic derivatives or complexes of the individualmetals are prepared by adding the organic complexing agents or organic additives to the metal salts, namely a heteropoly acid or a polyoxometallate in the case of the group VI metal and as a hydrated carbonate species in the case of the group VIII metal. The two solutions containing the metals and the complexing agents or additives are mixed. The mixture of complexes and additives containing the active metals is loaded on the support by a single impregnation step at a low temperature, say below 50°C and pre-dried at a similar low temperature. The water component present in the composite material made up of the complexes and the support is removed at a low enough temperature, say below 150°C, to prevent the decomposition of the complexes / additives. The catalyst composite comprising of the mixture of complexes / additives and the support is sulfided directly without any calcination and conversion of the metals into oxides as practiced in the prior-art. The sulfidation may be carried out insitu in the reactor or
externally before loading in the reactor. The advantages of this process are many. As the catalysts are not calcined, loss of the active metal through reaction with the support does not occur and bulk oxide phases are not formed on the surface. Besides, as the active metals are present as intimately mixed complexes, the possibility of forming a mixed Co(Ni)-Mo-S phase is greatly enhanced. The mixed sulfide phases are also expected to be smaller in size than those prepared from the oxide precursors due to the low temperature of drying and the absence of large bulk metal oxide phases. Small crystallites of the mixed metal phase will, as already explained, be-more effective in the desulfurization of the refractory hindered dialkyl-dibenzothiophene compounds.
The use of the complexes for impregnating the metals also enables the loading of substantially large quantities of the metals in a single step than hitherto possible.
Another embodiment of the invention provides for the inclusion of the promoter phosphorus into the catalyst during the preparation of the complex besides loading of phosphorous in any other form as practiced in the prior-art. The invention also provides for the exclusion of phosphorous from the catalyst, if necessary, by the use of a non-phosphorous containing group VI metal precursor.
The catalyst of the present invention is prepared from a heteropoly acid (HPA) containing phosphorous as the source of Mo (or W), hydrated Co (or Ni)-carbonate as the source of Co (or Ni), an aqueous solution of a complexing agent, such as glyoxylic acid to dissolve the HPA, hydrogen form of EDTA to solubilize the Co-carbonate, sufficient water to make a mixture of the desired composition to load the required amount of the metals. An important embodiment of the present invention is that the group VI and group VIII metals are incorporated along with different organic additives that are interchangeable with one another so that when the solution of the two organometallic compounds are mixed, a solution containing both the metals in a similar environment results.
As described above, the catalysts according to the present invention are basically composed of the following: an alumina carrier substance, at least one organic derivative of a heteropoly anion formed by an organic compound having at least two oxygen atoms, one of which being part of an aldehyde (-CHO) group, and one EDTA complex of the active metal selected from the Gr. VIII metals in the periodic table. The alumina carrier is impregnated by a single step process with a homogeneous solution containing organic derivatives of group VI and VIII metal elements. The amount of the selected active metal element is 10 - 35 % and 2 -10 % of the catalyst weight once converted to oxide weight, respectively for the group VI and group VIII metals. The phosphorous content in the catalyst can be increased by adding additional phosphorous as a phosphate salt or phosphoric acid to the mixture of the complexes of the metals.
In one embodiment of the process, the catalyst contains one or more elements selected from the group VI, and one or more elements chosen from the group VIII. The typical group VI elements are Mo and W while the typical group VIII elements are Ni and Co.
It is necessary that the alumina carrier substance possesses a large surface area, 150 to 300 m2/g and a pore-volume of about 0.7 - 1.2 ml/g and should possess sufficient mechanical strength. The alumina may preferably of the gamma or eta-form prepared by any method including precipitation from aluminum salts or aluminates or decomposition of alkoxides. The alumina carrier is formed preferably as extrudates of dimensions between 1mm to 2mm. The extrudates may be plain or of the structured type of different shapes containing lobes or crevices.
The glyoxylic acid complex of the HPA and EDTA complex of cobalt/nickel carbonates are prepared separately and mixed together with the required amount of water and the mixed organometallic species formed is used as the impregnating solution. The wet impregnated material is dried at a temperature between 80 - 120°C. The catalyst may be loaded in the reactor and presulfided as per the procedures in current practice and well known in the art. Experiments reveal that the complexing agents / additives break down easily during sulfidation and do not leave any carbonaceous residue that may be detrimental to the catalyst activity.
Accordingly, the present invention provides a catalyst composite material suitable for deep desulfurization of hydrocarbon feedstocks, the said composite material expressed as moles of oxides: (MO3)x (NO)Y (Al2O3)z (P2O5)n, comprising an impregnated porous alumina support material having a general (M03) represents oxides of group VI metals from Mo and W 10-35 %, (NO) represents oxides of group VIII metals from Co and Ni 2 to 10%, (A12O3) is aluminium oxide 49 to 87%, P2O5 is phosphorous oxide 1 to 6% and x has values between 4.0 and 26.0, y is between 2 and 15.0 and z is between 58.7 and 93.9, and n is between 0.1 and 0.3 such that x + y + z + n add to 100 moles.
The present invention also provides a process for the preparation of a catalyst composite material, comprising ; impregnating the alumina support material with components in a mixture comprising at least one active metal selected from group VI metals from Mo and W and at least one active metal selected from group VIII from Co and Ni, phosphoric acid salt, an additive containing at least one aldehyde group and an additive possessing at least two carboxylic acid groups, to form an impregnated substance, drying at a temperature 30- 50° C for a period of 14-18 hrs, drying further at a temperature between 100 to 150°C for a period of 6 to 10 hrs to obtain composite material.
In one of the embodiments of the present invention the composite mixture contains
atleast one active metal selected from each group VI and VIII of the p-eriodic table,
phosphoric acid salt, an additive containing atleast one aldehyde group and an
additive possessing at least two carboxylic acid groups.
In another embodiment the phosphoric acid component is incorporated principally as
a heteropoly acid of a group VI metal.
In yet another embodiment the group VI metals are Mo and W
In still another embodiment the group VIII metals are Co and Ni.
In another embodiment the group VI metals are used in an amount between 10 to 35
wt % as oxides.
In still another embodiment the group VIII metals are used in an amount between 2 to
10 wt % as oxides.
In yet another embodiment atleast two organic additives are used, one additive
possessing at least one aldehyde (-CHO) group and another additive possessing atleast
two carboxylic acid groups.
In still another embodiment the one additive is glyoxylic acid.
In another embodiment the other additive is ethylenediamine tetraacetic acid (EDTA).
In yet another embodiment the group VI metals are used as heteropoly acids
exemplified by phosphomolybdic acid.
Also described herein in the present invention is a process of deep desulfurization of
the hydrocarbon feedstock which comprises feeding the bed of impregnated alumina
of claim 1 by a sulfurization feed at room temperature and hydrogen atmosphere
having a pressure of at least 40 bars, gradually increasing the temperature to a
minimum temperature of 270°c in a period of atleast 6 hrs, maintaining the
temperature atleast 270°c for atleast 16 hrs, gradually raising the temperature to 320°c
for 4 hrs.and at 340°c, decreasing the sulfurization feed by half and continuing for a
further period of atleast 4 hrs, injecting the hydrocarbon feedstock to be desulfurised
in the system and separating the desulphurised feedstock by conventional methods by
conventional methods after atleast 24 hrs. to obtain the desulphurized hydrocarbon
In another embodiment the sulphurizing mixture consists of 1% sulfure solution of
dimethyl disulfide in a diesel oil fraction.
In yet another embodiment the hydrocarbon feedstock is injected at a lh"1 liquid space
The present invention is illustrated with following examples, which are only
illustrative in character and should not be construed to limit the scope of the present
invention in any manner.
This example illustrates the preparation of Co-Mo-alumina catalyst. An impregnating mixture of molybdenum and cobalt complexes was prepared as follows. Two solutions, Solution A and Solution B were prepared as described below.
Solution A: 31.2 g phosphomolybdic acid (equivalent to 29.5 g M0O3) was taken in a 250 ml beaker. 10 g of water was added to it followed by 7.5 g glyoxylic acid (50 %). The mixture was heated on a water bath to form a green coloured clear solution.
Solution B: In another beaker, 40 g wet, freshly made C0CO3 (equivalent to 6.2 g CoO) was weighed. 6 g of water and 10 g of H-EDTA were added to it and the mixture was stirred to get a pink coloured Co-EDTA complex.
The solutions A and B were mixed to get a clear blue homogeneous solution. This was impregnated on 50 g of freshly calcined, dry alumina extrudates. Thus a single step impregnation of cobalt-molybdenum with a high concentration of active species was achieved. The mixture was gently mixed for 2 h and the excess solution (if any) was drained. The impregnated extrudates were dried at room temperature for 16 h and further dried at 110°C for 8 h to obtain a blue coloured catalyst. This was stored in air-tight container under N2 immediately. The catalyst contained 31.5% of Mo and 6.8 % of Co as oxides (M0O3 and CoO) and 3 % of P as P205.
This example illustrates the preparation of Ni-Mo-alumina catalyst. An impregnating mixture of molybdenum and nickel complexes was prepared as follows. Two solutions. Solution A and Solution B were prepared as described below.
Solution A: 31.2 g phosphomolybdic acid (equivalent to 29.5 g M0O3) was taken in a 250 ml beaker. 10 g of water was added to it followed by 7.5 g glyoxylic acid (50 %). The mixture was heated on a water bath to form a green coloured clear solution.
Solution B: Freshly made wet NiC03 (30 g) equivalent to 6 g NiO was weighed in the beaker, 6 g water and 10 g H-EDTA were added to it. The mixture was stirred to get a clear solution .
Solutions A and B were mixed and impregnated on 50 g freshly calcined and dry alumina extrudates. The mixture was kept for 2 h with gentle mixing and the excess solution (if any) was drained. The impregnated extrudates were dried at room temperature for 16 h and further dried at 110°C for 8 h to obtain a light green catalyst. This was stored in an air-tight container under N2 immediately. The catalyst contained 29.6 % of Mo and 6.2 % of Ni as oxides (M0O3 and NiO) and 3 % of P as P205.
EXAMPLE 3 In this example, the presulfiding of the catalyst composite material of this invention is described.
Sixty grams the catalyst prepared according to Example 1 was loaded in a high pressure down-flow reactor (220 ml volume). The catalyst used contained 32, 6 and 2 % of Mo,
Co and P as M0O3, CoO and P2O5. The catalyst was diluted with half its volume of ceramic beads of similar size before loading. The drying of the catalyst was done at 100°C for two hours in a slow flow of nitrogen (6 litres per hour). The reactor was then pressurized to 40 bars with hydrogen and the sulfiding feed (a commercial diesel oil from a hydrocracker containing 45 ppm S (wt.) spiked with dimethyl disulfide to give a total S content of 1 wt %) was injected at a liquid hourly space velocity (LHSV) of 1 h"1. A hydrogen flow of 300 volumes to oil volume (was maintained. The temperature was slowly raised to 270°C in 6 hours and the sulfidation continued for 16 hours. The temperature was then raised to 320 and 340°C in steps holding for 4 hours at each temperature. The sulfidation feed was changed to one with 0.5% S and the sulfidation continued for 4 hours. The diesel required to be desulfurized (containing 2500 ppm S by wt.) was then injected to find out the activity of the catalyst keeping the temperature of the reactor at 340°C. PFPD (gas chromatograph. GC) analysis of the feed revealed that it contained essentially dibenzothiophene and its alkyl derivatives as S-compounds. The S content was analyzed by X-ray Flourescence analysis (XRF).
1. A catalyst composite material suitable for deep desulfurization of hydrocarbon feedstocks, the said composite material expressed as moles of oxides: (MO3)x (NO)Y (A12O3)Z (P2O5)n, comprising an impregnated porous alumina support material having a general (MO3) represents oxides of group VI metals from Mo and W 10-35 %, (NO) represents oxides of groupVIII metals from Co and Ni 2 to 10%, (A12O3) is aluminium oxide 49 to 87%, P2O5 is phosphorous oxide 1 to 6% and x has values between 4.0 and 26.0, y is between 2 and 15.0 and z is between 58.7 and 93.9, and n is between 0.1 and 0.3 such that x + y + z + n add to 100 moles.
2. A process for the preparation of a catalyst composite material as claimed in claim 1, comprising ; impregnating the alumina support material with components in a mixture comprising at least one active metal selected from group VI metals from Mo and W and at least one active metal selected from group VIII from Co and Ni , phosphoric acid salt, an additive containing at least one aldehyde group and an additive possessing at least two carboxylic acid groups, to form an impregnated substance, drying at a temperature 30- 50° C for a period of 14-18 hrs, drying further at a temperature between 100 to 150°C for a period of 6 to 10 hrs to obtain composite material.
3. A process as claimed in claims 2, wherein the phosphoric acid component is incorporated principally as a heteropoly acid of a group VI metal.
4. The process of claim 2-3, wherein the group VI metals are used in an amount between 10 to 35 wt% as oxides and the group VIII metals are used in an amount between 2 to 10 wt % as oxides.
5. The process as claimed in claims 2-4, wherein at least two organic additives are used, one additive possessing at least one aldehyde (-CHO) group and another additive possessing at least two carboxylic acid groups.
6. The process as claimed in claims 2-5, wherein the additive is glyoxylic acid.
7. The process as claimed in claims 2-6,wherein the additive is ethylenediamine tetraacetic acid (EDTA).
8. The process as claimed in claims 2-7, wherein the group VI metals are used as heteropoly acids or as polyoxometallates.
9. The process as claimed in claims 2-8, wherein the heteropoly acid is phosphomolybdic acid.
10. The process as claimed in claims 2-9, wherein water is removed from the
impregnated composite material in vacuum to prevent the decomposition or
evaporation of the organic additives or the metal complexes.
11. The process as claimed in claims 2-10, wherein water is removed from the
impregnated composite material by drying below 120°C.
12. A composite catalyst material suitable for deep hydrodesulfurization of hydrocarbon feedstocks substantially as herein describe with reference to examples accompanying this specification.
|Indian Patent Application Number||1795/DEL/2004|
|PG Journal Number||23/2011|
|Date of Filing||22-Sep-2004|
|Name of Patentee||COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH|
|Applicant Address||RAFI MARG, NEW DELHI-110 001, INDIA|
|PCT International Classification Number||B01J 21/02|
|PCT International Application Number||N/A|
|PCT International Filing date|