[0001]The present disclosure relates generally to the field of hydrotreating of hydrocarbon feedstock. Particularly, the present disclosure provides a method for effecting hydrodesulphurisation of a sulphur-containing hydrocarbon feedstock. Aspects of the present disclosure also provide catalyst for hydrodesulphurisation of a sulphur-containing hydrocarbon feedstock and method of preparation of the catalyst that can find advantageous utility in hydrodesulphurisation of a sulphur-containing hydrocarbon feedstock.
BACKGROUND
[0002] Hydrotreating refers to a variety of catalytic hydrogenation processes that saturate the unsaturated hydrocarbons and remove S, N, O and metals from different petroleum steams in a refinery. These processes represent some of the most important catalytic processes with annual sales of such hydrotreating catalysts close to 10% of the total world market for catalysts. Now-a-days hydrotreating is used extensively both for conversion of heavy feed stocks and for improving the quality of final products. Hydrotreating also plays an essential role in pre-treating streams for the other refinery processes such as catalytic reforming, fluid catalytic cracking etc. Historically hydrotreating processes introduced in 1930's. Depending upon the specific aim of the treatment, various names are used to describe the processes like hydrodesulfurization (HDS), Hydorgenation (HYD), Hydrodenitrogenation (HDN), hydrodeoxygenation (HDO) and hydrodemetallation (HDM) (H. Topsoe, B.S Clausen and F.E. Massoth "Hydrotreating catalysis science and technology" Springer Verlag Berlin, 1996.)
[0003] Clean fuels research has become an important subject of environmental catalysis studies worldwide. US Environmental Protection Agency (EPA), and government regulations in many countries call for the production and use of more environmentally friendly transportation fuels with lower contents of sulfur and aromatics. The demand for transportation fuels has been increasing in most countries for the past two decades. Essentially, all of these liquid fuels are produced from petroleum except in South Africa (where a coal-based gasification system produces the synthesis gas which is then converted to

liquid fuels). More attention is being paid, worldwide, to chemistry of diesel fuels processing. This heightened interest is related to both the thermal efficiency and the environmental aspects, which include both the pollutants and greenhouse gas emissions. According to a recent analysis, diesel fuel demand is expected to increase significantly in the early part of the 21st century and both the US and Europe will be increasingly short of this product. Sulfur content in diesel fuel is an environmental concern because upon combustion, sulfur is converted to SOx during combustion, which not only contributes to acid rain, but also poisons the catalytic converter for exhaust emission treatment. Worldwide, now people are focusing on 10 ppm diesel production and usage. The problem of deep removal of sulfur has become more serious due to the lower and lower limit of sulfur content in finished fuel products by regulatory specifications, and the higher and higher sulfur contents in the crude oils. A survey of the data on crude oil sulfur content and API gravity for the past two decades reveals a trend that US refining crude slates continue towards higher sulfur contents and heavier feeds. The average sulfur contents of crude oils refined in the five regions of the US increased from 0.89 wt.% in 1981 to 1.25 wt.% in 1997, while the corresponding API gravity decreased from 33.74° in 1981 to 31.07° in 1997 (C. Song, X. Ma Applied Catalysis B: Environmental 41 (2003) 207-238).
[0004] US Patent 5,223,472 describes hydroprocessing catalyst preparation based on alumina impregnated with a Group VIII metal and a Group VIB metal. The catalyst has narrow pore size distribution and containing from 0.1 to 5.0 weight percent of a Group VIII metal and from 2.0 to 10.0 weight percent of a Group VIB metal. However, it fails to disclose incorporation or modification of support by additives like P or B. US Patent 5,686,375 describes hydroprocessing catalysts preparation that contains Group VIII metal and group VI B metals and their introduction on the support by impregnation or comulling. However, it fails to characterize the support or disclose modification of supports used for hydrotreating catalysts preparation. US patent 7446075 describes preparation of hydrotreating catalyst that comprises nickel phosphide and promoter metal, preferably Mo. Alumina is used as support. However, it fails to disclose usage of additives like Boron or Phosphorus or modification of alumina support.
[0005] US patent 7544632 describes preparation of novel bulk tri-metallic catalysts like Ni-Mo-W for use in the hydroprocessing of hydrocarbon feeds, as well as a method for preparing such catalysts. The catalysts are prepared from a catalyst precursor containing an

organic agent. However, it fails to disclose preparation of bi-metallic catalysts like CoMo or Ni Mo and/or modification of support with additives like P or B.
[0006] US patent 7538066 describes preparation of hydrotreating catalysts that consists group VIII as well as group VI metals and an organic agent selected from the group consisting of an amino alcohol and amino acids. However, it fails to disclose usage of additives like P or B and/or non organic routes for the synthesis of hydrotreating catalysts. [0007] US Patent 4,888,316 describes a hydrotreating catalyst made from spent hydrotreating catalyst that comprises molybdenum and/or tungsten and/or nickel and/or cobalt. The spent catalyst is subjected to a grinding step whereby it is ground to a suitable particle size. The ground spent hydrotreating catalyst is mixed with alumina material and formed into shaped particles that are calcined to give the hydrotreating catalyst. [0008] WO publication 02/32570 describes a hydroprocessing catalyst made by mixing alumina with fines produced by crushing a commercial hydroprocessing catalyst that contains a Group VIB metal and a Group VIII metal. Final catalyst contains Group VIB metal in the finished catalyst from 0.5 to 10 wt% of the catalyst and VIIB metal in the range of 2-6 wt%. [0009] US patent 7,842,181 B2 describes a composition and process for the removal of sulfur from middle distillate fuels. This patent mainly teaches a method which is based on adsorption which requires two reactors, one is exclusively used for adsorbent regeneration. [0010] US patent 7605107 describes the use of multi-metallic catalysts as well as the method of preparation. The catalysts prepared consists one group VIII metal and one group VI metal and an organic agent selected from the group consisting of amino alcohol and amino acids.
[0011] US patent 7824541 describes a catalyst and process for HDS of distillate feed. The catalyst comprises a calcined mixture of inorganic oxide material, a high concentration of molybdenum and a high concentration of a Group VIII metal. The mixture that is calcined to form the calcined mixture comprises molybdenum trioxide, a Group VIII metal compound, and an inorganic oxide material. The catalyst is made by mixing the starting materials and forming agglomerate and is calcined to yield the final catalyst.
[0012] US patent 7842181 describes a catalyst composition and process for the removal sulfur from middle distillate petroleum hydrocarbon fuels. The composition includes an alumina component and a carbon component. The composition is present in an amount effective to adsorb sulfur compounds from the fuel. The composition can also further include

at least one compound having a Group VI or Group VIII metal from the periodic table. However, it fails to disclose use of non-carbon based formulations for the desulphurization. [0013] While such catalysts have proven to be superior to more conventional hydrotreating catalysts, there still remains a need in the art for ever-more reactive and effective catalysts for removing heteroatoms, mainly sulfur from hydrocarbon streams. Need is also felt of an improved process for hydrodesulphunsation of a sulphur-containing hydrocarbon feedstock.
OBJECTS OF THE INVENTION
[0014] An object of the present disclosure is to provide a process for effecting
hydrodesulphunsation of a sulphur-containing hydrocarbon feedstock.
[0015] Another object of the present disclosure is to provide a catalyst for
hydrodesulphunsation of a sulphur-containing hydrocarbon feedstock.
[0016] Another object of the present disclosure is to provide a method of preparation of
a catalyst for hydrodesulphunsation of a sulphur-containing hydrocarbon feedstock.
SUMMARY
[0017] The present disclosure relates generally to the field of hydrotreating of hydrocarbon feedstock. Particularly, the present disclosure provides a method for effecting hydrodesulphunsation of a sulphur-containing hydrocarbon feedstock. Aspects of the present disclosure also provide catalyst for hydrodesulphunsation of a sulphur-containing hydrocarbon feedstock and method of preparation of the catalyst that can find advantageous utility in hydrodesulphunsation of a sulphur-containing hydrocarbon feedstock. [0018] An aspect of the present disclosure provides a hydrodesulphunsation process for effecting hydrodesulphunsation of a sulphur-containing hydrocarbon feedstock, the process comprising the steps of: (a) providing one or a plurality of hydrodesulphunsation zones, each containing a bed of a sulphided hydrodesulphunsation catalyst, wherein said sulphided hydrodesulphunsation catalyst comprises: (i) a porous support comprising at least one inorganic oxide; (ii) at least 10% by weight of at least one Group VIB metal; (iii) at least 2% by weight of at least one Group VIIIB metal; and (iv) at least 0.1% by weight of at least one metal of Group IIIA or Group VA; (b) maintaining temperature and pressure conditions in each of said one or a plurality of hydrodesulphunsation zone, effective for

hydrodesulphurisation of said sulphur-containing hydrocarbon feedstock; (c) supplying said
sulphur-containing hydrocarbon feedstock to a first hydrodesulphurisation zone of said one or
a plurality of hydrodesulphurisation zones; (d) passing said sulphur-containing hydrocarbon
feedstock through said one or a plurality of hydrodesulphurisation zones; (e) passing a
hydrogen-containing gas through said one or a plurality of hydrodesulphurisation zones; and
(f) contacting said sulphur-containing hydrocarbon feedstock with said hydrogen-containing
gas in each of said one or a plurality of hydrodesulphurisation zones in presence of said
hydrodesulphurisation catalyst to effect the hydrodesulphurisation of the sulphur-containing
hydrocarbon feedstock.
[0019] In an embodiment, the porous support comprises porous alumina extrudates. In an
embodiment, the porous alumina extrudates exhibit surface area ranging from 200 to 250
m2/g and pore volume ranging from 0.5 to 1 cc/g. In an embodiment, the porous alumina
extrudates exhibit average pore diameter ranging from 1 to 1.5 mm and length ranging from 4
to 7 mm. In an embodiment, the porous support exhibits unimodal pore size distribution
having majority of the pores in the range of 20 to 250 Å. In an embodiment, the porous
support exhibits Apparent bulk density (ABD) of about 0.85 g/cc and BCS of about 1 MPa.
In an embodiment, the porous support comprises alumina mixed with any or a combination of
discarded refinery catalyst and at least one mesoporus material. In an embodiment, the at
least one Group VIB metal comprises Molybdenum is in its elemental form. In an
embodiment, the at least one Group VIIIB metal comprises any or a combination of Cobalt or
Nickel. In an embodiment, the at least one metal of Group IIIA comprises Boron. In an
embodiment, the at least one metal of Group VA comprises Phosphorous. In an embodiment,
the at least one mesoporus material comprises any or a combination of HMS and alumina. In
an embodiment, the HMS exhibits surface area of about 1000 m2/g, pore volume of about 1
cc/gram and average pore size ranging from 40 to 80 Å. In an embodiment, the discarded
refinery catalyst exhibits surface area ranging from 120 to 160 m2/g, pore volume of about
0.2 cc/g, Apparent bulk density (ABD) of about 0.8 g/cc, and particle size distribution of
about 75 micron. In an embodiment, the sulphided hydrodesulphurisation catalyst comprises:
(i) a porous support ranging from 1 to 90% by weight, wherein said porous support comprises
alumininum oxide; (ii) at least one Group VIB metal ranging from 10 to 20% by weight; (iii)
at least one Group VIIIB metal ranging from 2 to 6% by weight; and (iv) at least one metal of
Group IIIA or Group VA ranging from 0.1 to 5% by weight.
6

[0020] In an embodiment, the step of maintaining temperature and pressure conditions in
each of said one or a plurality of hydrodesulphurisation zone comprises maintaining a temperature ranging from 300°C to 400°C and a hydrogen pressure ranging from 10 to 70 bar. In an embodiment, the step of maintaining temperature and pressure conditions in each of said one or a plurality of hydrodesulphurisation zone comprises maintaining a temperature ranging from 320°C to 370°C and a hydrogen pressure ranging from 30 to 50 bar. In an embodiment, the step of passing said sulphur-containing hydrocarbon feedstock through said one or a plurality of hydrodesulphurisation zones is effected such that Weight Hourly Space Velocity (WHSV) ranges from 1.0 hr-1 to 1.7 hr-1.
[0021] Various objects, features, aspects and advantages of the inventive subject matter
will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The accompanying drawings are included to provide a further understanding of
the present disclosure, and are incorporated in and constitute a part of this specification. The
drawings illustrate exemplary embodiments of the present disclosure and, together with the
description, serve to explain the principles of the present disclosure.
[0023] FIG. 1 illustrates an exemplary graph depicting fresh gamma alumina support pore
size distribution, in accordance with embodiments of the present disclosure.
[0024] FIG. 2 illustrates an exemplary sulfidation scheme, in accordance with
embodiments of the present disclosure.
[0025] FIG. 3 illustrates an exemplary catalyst loading pattern, in accordance with
embodiments of the present disclosure.
[0026] FIG. 4 illustrates an exemplary plot depicting amount of sulphur present in the
HDS treated feedstock over the period of time, in accordance with embodiments of the
present disclosure.
DETAILED DESCRIPTION
[0027] The following is a detailed description of embodiments of the disclosure depicted
in the accompanying drawings. The embodiments are in such detail as to clearly
7

communicate the disclosure. However, the amount of detail offered is not intended to limit
the anticipated variations of embodiments; on the contrary, the intention is to cover all
modifications, equivalents, and alternatives falling within the spirit and scope of the present
disclosure as defined by the appended claims.
[0028] Each of the appended claims defines a separate invention, which for infringement
purposes is recognized as including equivalents to the various elements or limitations
specified in the claims. Depending on the context, all references below to the “invention”
may in some cases refer to certain specific embodiments only. In other cases it will be
recognized that references to the “invention” will refer to subject matter recited in one or
more, but not necessarily all, of the claims.
[0029] As used in the description herein and throughout the claims that follow, the
meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates
otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on”
unless the context clearly dictates otherwise.
[0030] All methods described herein can be performed in any suitable order unless
otherwise indicated herein or otherwise clearly contradicted by context. The use of any and
all examples, or exemplary language (e.g. “such as”) provided with respect to certain
embodiments herein is intended merely to better illuminate the invention and does not pose a
limitation on the scope of the invention otherwise claimed. No language in the specification
should be construed as indicating any non-claimed element essential to the practice of the
invention.
[0031] Various terms as used herein are shown below. To the extent a term used in a
claim is not defined below, it should be given the broadest definition persons in the pertinent
art have given that term as reflected in printed publications and issued patents at the time of
filing.
[0032] The present disclosure relates generally to the field of hydrotreating of
hydrocarbon feedstock. Particularly, the present disclosure provides a method for effecting
hydrodesulphurisation of a sulphur-containing hydrocarbon feedstock. Aspects of the present
disclosure also provide catalyst for hydrodesulphurisation of a sulphur-containing
hydrocarbon feedstock and method of preparation of the catalyst that can find advantageous
utility in hydrodesulphurisation of a sulphur-containing hydrocarbon feedstock.
8

[0033] An aspect of the present disclosure provides a hydrodesulphurisation process for
effecting hydrodesulphurisation of a sulphur-containing hydrocarbon feedstock, the process
comprising the steps of: (a) providing one or a plurality of hydrodesulphurisation zones, each
containing a bed of a sulphided hydrodesulphurisation catalyst, wherein said sulphided
hydrodesulphurisation catalyst comprises: (i) a porous support comprising at least one
inorganic oxide; (ii) at least 10% by weight of at least one Group VIB metal; (iii) at least 2%
by weight of at least one Group VIIIB metal; and (iv) at least 0.1% by weight of at least one
metal of Group IIIA or Group VA; (b) maintaining temperature and pressure conditions in
each of said one or a plurality of hydrodesulphurisation zone, effective for
hydrodesulphurisation of said sulphur-containing hydrocarbon feedstock; (c) supplying said
sulphur-containing hydrocarbon feedstock to a first hydrodesulphurisation zone of said one or
a plurality of hydrodesulphurisation zones; (d) passing said sulphur-containing hydrocarbon
feedstock through said one or a plurality of hydrodesulphurisation zones; (e) passing a
hydrogen-containing gas through said one or a plurality of hydrodesulphurisation zones; and
(f) contacting said sulphur-containing hydrocarbon feedstock with said hydrogen-containing
gas in each of said one or a plurality of hydrodesulphurisation zones in presence of said
hydrodesulphurisation catalyst to effect the hydrodesulphurisation of the sulphur-containing
hydrocarbon feedstock.
[0034] In an embodiment, the porous support comprises porous alumina extrudates. In an
embodiment, the porous alumina extrudates exhibit surface area ranging from 200 to 250
m2/g and pore volume ranging from 0.5 to 1 cc/g. In an embodiment, the porous alumina
extrudates exhibit average pore diameter ranging from 1 to 1.5 mm and length ranging from 4
to 7 mm. In an embodiment, the porous support exhibits unimodal pore size distribution
having majority of the pores in the range of 20 to 250 Å. In an embodiment, the porous
support exhibits ABD of about 0.85 g/cc and BCS of about 1 MPa. In an embodiment, the
porous support comprises alumina mixed with any or a combination of discarded refinery
catalyst and at least one mesoporus material. In an embodiment, the at least one Group VIB
metal comprises Molybdenum is in its elemental form. In an embodiment, the at least one
Group VIIIB metal comprises any or a combination of Cobalt or Nickel. In an embodiment,
the at least one metal of Group IIIA comprises Boron. In an embodiment, the at least one
metal of Group VA comprises Phosphorous. In an embodiment, the at least one mesoporus
material comprises any or a combination of HMS and alumina. In an embodiment, the HMS
9

exhibits surface area of about 1000 m2/g, pore volume of about 1 cc/gram and average pore size ranging from 40 to 80 Å. In an embodiment, the discarded refinery catalyst exhibits surface area ranging from 120 to 160 m2/g, pore volume of about 0.2 cc/g, ABD of about 0.8 g/cc, and particle size distribution of about 75 micron.
[0035] In an embodiment, the sulphided hydrodesulphurisation catalyst comprises: (i) a
porous support ranging from 1 to 90% by weight, wherein said porous support comprises alumininum oxide; (ii) at least one Group VIB metal ranging from 10 to 20% by weight; (iii) at least one Group VIIIB metal ranging from 2 to 6% by weight; and (iv) at least one metal of Group IIIA or Group VA ranging from 0.1 to 5% by weight.
[0036] In an embodiment, the step of maintaining temperature and pressure conditions in
each of said one or a plurality of hydrodesulphurisation zone comprises maintaining a temperature ranging from 300°C to 400°C and a hydrogen pressure ranging from 10 to 70 bar. In an embodiment, the step of maintaining temperature and pressure conditions in each of said one or a plurality of hydrodesulphurisation zone comprises maintaining a temperature ranging from 320°C to 370°C and a hydrogen pressure ranging from 30 to 50 bar. In an embodiment, the step of passing said sulphur-containing hydrocarbon feedstock through said one or a plurality of hydrodesulphurisation zones is effected such that Weight Hourly Space Velocity (WHSV) ranges from 1.0 hr-1 to 1.7 hr-1.
[0037] The hydrotreating catalyst is versatile; it can be simultaneously applied to clean up
S, N and O impurities imbedded in the organic molecules comprising hydrocarbon oil. Although there are some technical variations in the processes by which the hetero-atoms are removed, the fundamental principles appear to be the same. Depending upon the function these reactions are termed as - Hydrodesulfurization (HDS), Hydrogenenation (HYD), Hydrodeoxygenation (HDO) and Hydrodemetallation (HDM).
[0038] The present disclosure mainly deals with hydrodesulphurization. In the HDS
reaction, sulfur impurities embedded in carbon molecules are removed by trickling diesel oil fraction and gaseous hydrogen through a catalyst bed at an elevated temperature and pressure. Sulfur heteroatom is reduced by the hydrogen gas and released from the organic molecule as gaseous H2S. Other than active metals, support is considered as vital for HDS catalyst preparation. The role of the robust and highly porous carrier material is primarily considered to support the active nano-particles on a large surface area and thereby ensure good contact
with the reactants. On the smallest scale, the active phase of the basic catalyst consists of
10

MoS2 particles promoted with small amounts of Ni or Co, and is referred to as CoMoS structures. These nanostructures are the ones of principal interest in the quest for a better insight into the catalyst.
[0039] Technologically, the preparation of the HDS catalyst is a major issue, and the
actual technique has decisive influence on the ultimate performance (D. D. Whitehurst, T.
Isoda, and I. Mochida, “Present State of the Art and Future Challenges in the
Hydrodesulfurization of Polyaromatic Sulfur Compounds”, Advances in Catalysis 42, 345
(1998), J. W. Gosselink, “Sulfide catalysts in refineries”, Cattech 4, 127 (1998). The feed
which is to be hydrotreated is normally very inhomogeneous and this puts large demands on
the performance and versatility of the catalyst to ensure a homogenous output. Depending on
the geographical origin of the crude oil, the feed contains varying amounts of sulfur in terms
of weight percent. The diversity of the molecules entering the HDS reaction is large, ranging
from simple organosulfur molecules like thiols (R-SH) or thiophenes to more complex
molecules with the heteroatom deeply imbedded inside a molecular carbon surrounding.
[0040] Typical operating conditions of the HDS process are at temperatures in the range
between 300◦C to 400◦C and a hydrogen pressure between 10 to 70 bar, but the precise operating conditions are dictated by the composition of the specific oil fraction. Especially heavier oil fractions, which generally contain more complicated molecules, have a lower reactivity and need forced HDS conditions. These deep HDS capabilities of the catalyst currently receive much attention, due to the persistent demand to reduce the S content in heavy oil fractions. At present, the legal requirements regarding fuel specifications can in principle be fulfilled, but only at considerable economic expense. The limit it set by the hydrogen consumption, which is a rather expensive resource. At elevated temperatures unwanted side reactions (reduced selectivity) may be initiated resulting in a more rapid aging due to sintering or coking. In order to optimize a large-scale industrial process like hydrodesulfurization according to future demands and to achieve economically feasible operation, it is evident that improvements have to carry out with respect to process and mainly catalyst.
[0041] The catalysts of the present disclosure contain at least one Group VIIIB metal and
at least one Group VIB metal. The preferred Group VIIIB metal is selected from the non-noble metals, cobalt or nickel. The Group VIB metal is molybdenum. The Group VIIIB metal, in terms of its metal form, is typically present in an amount ranging from about 2 to 20
11

wt %, preferably from about 4 to 10%. The Group VIB metal, also in terms of its metal form, is typically present in an amount ranging from about 1 to 50 wt%, preferably from about 5 to 20 wt%, and more preferably from about 10 to 15 wt%. All weight percents are based on the total weight of the catalyst composition.
[0042] Suitable support materials for the catalysts of the present disclosure include
inorganic refractory materials such as alumina, alumina-crystalline silica-alumina and alumina-HMS, or mixture thereof. The more preferred support material for purpose of the present disclosure is alumina. The catalytic metals may be loaded onto the support by any suitable conventional techniques known in the art. Such techniques include, but not limited to, impregnation by incipient wetness, by adsorption from excess impregnating medium, and by ion exchange. Preferred is incipient wetness. The metal-bearing catalysts of the present disclosure are typically dried, calcined, and sulfided.
[0043] Accordingly, an aspect of the present disclosure provides a hydrotreating catalyst
composition, the composition comprising (i) an inorganic oxide; (ii) at least 10% of group VI B metal (iii) at least 2% by weight of a group VIIIB metal; (iv) at least 0.01 % by weight of a metal of Group IIIA or VA.
[0044] The present disclosure also provides a catalyst composition for
hydrodesulphurisation of a sulphur-containing hydrocarbon feedstock, the composition comprising (i) an inorganic oxide; (ii) at least 10% of group VIB metal (iii) at least 2% by weight of a group VIIIB metal; (iv) at least 0.01 % by weight of a metal of Group IIIA or VA.
[0045] In an embodiment, the support in the catalyst composition is a fresh support or
combination of fresh and spent refinery catalyst. In an embodiment, the fresh support is porous in nature with surface area in the range of 200-250 m2/g and pore volume in the range of 0.5 to 1 cc/g. In an embodiment, fresh alumina is in extrudate form with an average diameter in the range of 1 to 1.5 mm and length in the range of 4-7 mm. In an embodiment, the support material exhibits unimodal pore size distribution having majority of the pores in the range of 20-250 Å. In an embodiment, the fresh support is commercial catapal alumina that has surface area in the range of 250-350 m2/g and pore volume in the range of 0.5 to 1 cc/g and pore size in the range of 50-200 A. In an embodiment, fresh alumina is in powder form. In an embodiment, extrudes are made by using acetic acid as peptizing agent.
12

[0046] In an embodiment, a composite support is made with alumina and the discarded
refinery catalyst, which exhibits total surface area of around 200 m2/g and pore volume of 0.6 cc/g. In an embodiment, alumina and spent catalyst are premixed using diluted acetic acid (10%) as a peptizing agent before effecting extrusion thereof. In an embodiment, group VIB metal is Molybdenum in the range of 0.001 % to 20% by weight in of the catalyst composition. In an embodiment, Molybdenum is present in its elemental form uniformly distributed within the catalyst composition.
[0047] In an embodiment, Group VIIIB metal is Cobalt or Nickel, present in the range of
0.01 % to 6% by weight of the catalyst composition; Group IIIA metal is B, present in the range of 0.01 to 5% by weight of the catalyst composition; Group VA metal is phosphorous, present in the range of 1 to 5% by weight of the catalyst composition; and alumina is present in the range of 1 to 90% by weight of the catalyst composition.
[0048] Another aspect of the present disclosure provides a process for preparation of a
hydrotreating catalyst composition for effecting removal of sulfur in HDS process, the process comprising the steps of i) drying the support by heating ii) incorporating one or more metals into the dried support; iii) drying the support with one or more metals incorporated therein; and iv) calcination of the catalyst. In an embodiment, the step of drying the support by heating comprises heating the support in a glass reactor at about 500°C in air for 4 Hrs. In an embodiment, the support is modified with group IIIA or VA metals viz. B or P by equilibrium adsorption or wet impregnation method either at room temperature or at a temperature slightly above the room temperature, preferably up to 40°C. In an embodiment, the step of drying the support with one or more metals incorporated therein is conducted at a temperature ranging from 110°C to 120°C and for a time period ranging from eight to sixteen hours. In an embodiment, other metals like Mo and Ni/Co are also added and dried as per the procedure described hereinabove. In an embodiment, the catalyst is calcined at 450°C to 550°C for three to four hours.
[0049] While the foregoing describes various embodiments of the invention, other and
further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
13

EXAMPLES
[0050] Hydrotreating catalyst formulations for sulfur reduction were prepared by using a
commercially available porous γ-alumina extrudates as a fresh support which has high surface area in the range of 200-250 m2/g and pore volume in the range of 0.5 to 1 cc/g. Fresh alumina utilized herein was in extrudate form with an average pore diameter in the range of 1 to 1.5 mm and length in the range of 4-7 mm. The support material was found to include uni-modal pore size distribution having majority of the pores in the range of 20-250Å. The ABD of the material was found to be around 0.85 g/cc and BCS was found to be around 1 MPa. FIG. 1 illustrates an exemplary graph depicting fresh gamma alumina support pore size distribution.
[0051] The support was dried by heating in glass reactor at 500°C in air for 4 hrs, before
incorporating Metals. HDS catalysts were prepared by firstly depositing the dried support with desired amount of Phosphorous (P) or Boran (B) using orthophosphoric acid or boric acid and drying at room temperature for about one hour. Subsequently, molybdenum (Mo) was impregnated by using ammonium hepta molybdate salt and dried for about 10-14 hours. Cobalt (Co) or Nickel (Ni) was impregnated (using nitrate salt of Ni or Co as precursor) on Mo and P or B impregnated support. After impregnation the samples were dried at 110°C for about 10-14 hrs and calcined at about 540°C for 4 hrs. These samples are referred as catalysts 1 through 12, composition of which are provided in Table 1 hereinbelow, wherein SA = Surface area, ABD= Apparent bulk density, and PV = Total pore volume. Each of these catalysts was subjected to sulfidation using sulfiding mixture in accordance with the sulfidation scheme as depicted in FIG. 2.
Table 1: Composition and Characteristics of Catalysts

SA (m2/g) ABD (g/cc) PV (cc/g)
Support 240 0.84 0.6

Metals Mo% Co% Ni% B2O3% P2O5%
Catalyst 1 (CAT 1) 14 - 3 - 1
14

Catalyst 2 (CAT 2) 14 3 - 1 -
Catalyst 3 14 3 - - -
Catalyst 4 14 3 1
Catalyst 5 14 3 3
Catalyst 6 14 3 5
Catalyst 7 14 3 3
Catalyst 8 14 3 5
Catalyst 9 14 3 3
Catalyst 10 14 3 5
Catalyst 11 14 3 1
Catalyst 12 14 3 3
Catalyst 13 14 3 5
[0052] Hydrotreating catalyst formulations for sulfur reduction were prepared by using
another commercially available porous alumina powder (catapal alumina) as a fresh support which has high surface area in the range of 250-350 m2/g and pore volume in the range of 0.5 to 1 cc/g and pore size in the range of 50-200 A. Fresh alumina was in powder form and extrudates were made by using acetic acid as peptizing agent. The support was dried by heating in glass reactor at 500°C in air for 4 hrs, before incorporating Metals. Different catalysts were prepared using the procedure as set-out in details hereinabove. These samples are referred as catalysts 14 through 17, composition of which are provided in Table 2 hereinbelow, wherein SA = Surface area, ABD= Apparent bulk density, and PV = Total pore volume. Each of these catalysts was subjected to sulfidation using sulfiding mixture in accordance with the sulfidation scheme as depicted in FIG. 2.
Table 2: Composition of Catalysts

SA (m2/g) ABD (g/cc) PV (cc/g)
Support 332 0.80 0.8
15

Metals Mo% Co% Ni% B2O3% P2O5%
Catalyst 14 14 3 - - 3
Catalyst 15 14 3 3
Catalyst 16 14 3 3
Catalyst 17 14 3 3
[0053] Hydrotreating catalyst formulations for sulfur reduction were prepared by using
gamma alumina and spent FCC catalyst which has high surface area in the range of 200-240 m2/g and pore volume in the range of 0.5 to 1 cc/g and pore size in the range of 50-300 Å. Fresh alumina and spent FCC catalyst were mixed in the ratio of 90:10 and extrudes were made by using acetic acid as peptizing agent. The support is dried by heating in glass reactor at 500°C in air for 4 hrs, before incorporating Metals. Different catalysts were prepared using the procedure as set-out in details hereinabove. These samples are referred as catalysts 18 and 19, composition of which are provided in Table 3 hereinbelow, wherein SA = Surface area, ABD= Apparent bulk density, and PV = Total pore volume. Each of these catalysts was subjected to sulfidation using sulfiding mixture in accordance with the sulfidation scheme as depicted in FIG. 2.
Table 3: Composition of Catalysts

SA (m2/g) ABD (g/cc) PV (cc/g)
Support 350 0.80 0.8

Metals Mo% Co% Ni% B2O3% P2O5%
Catalyst 18 14 3 - - 3
Catalyst 19 14 3 3
[0054] EXAMPLE 1 - CATALYST EVALUATION STUDY IN SMALL-SCALE
(MICRO SCALE) TRICKLE BED REACTOR
[0055] In trickle bed reactors, vapor (mostly hydrogen) and liquid (oil) pass concurrently
down over a bed of catalyst particles. Flow dynamics, heat transfer and mass transfer
16

influence the performance of the reactor to a much greater degree than in other reactors. In trickle bed reactors the liquid flows over the catalyst particles in films and rivulets; the vapor flows through the remaining voids. In trickle flow, at low liquid and gas mass velocities the gas phase is continuous and the liquid falls in rivulets from one particle to the next. These conditions may result in incomplete catalyst wetting, axial dispersion and restricted interphase mass transfer with correspondingly poor catalyst utilization. Therefore, the data generated in such a reactor may give misleading information for scale-up and scale-down activities. It was demonstrated in the previous reports that use of proper size of fine diluent can overcome the limitations of laboratory trickle bed reactors, and hence, meaningful data can be generated in such reactors using dilution technique. Accordingly, for testing the catalysts in micro scale reactor, each of the catalysts were taken in its original size and shape and diluted with 0.18 mm silicon carbide diluent to minimize the wall effect, deviation from plug flow and incomplete wetting effects.
[0056] A high pressure, high temperature micro scale catalyst testing unit designed and
supplied by M/s Hi-tech Engineering was used for performing the evaluation studies of commercial as well as DHDS catalysts of the present disclosure. The unit was designed for 100 bars pressure and 850°C temperatures. The unit was equipped with mass flow controllers, HPLC pump, feed and product weigh scales and wet gas flow meter. The unit was a PC-PLC controlled with history information and trending facility of all process parameters. The unit includes two fixed bed reactors. At a time only one reactor can be taken on stream and in the second reactor regeneration of catalyst can be done or the second reactor can be loaded with another catalyst and tested for leak. Once the run for the catalyst in the first reactor was over, second reactor can be directly taken on-stream. The reactor was tubular. The inner diameter of the reactor was 13 mm and length of the reactor was 48 cm. A thermo well of outer diameter 3.14 mm was located centrally in the reactor. Thus, free space available for packing the catalyst in radial direction was 9.86 mm. A thermocouple was placed inside the thermo well such that it measures the temperature at the middle of the catalyst bed. The reactor was located inside a single zone split furnace. Isothermal catalyst bed temperatures were achieved using reactor furnace temperature control.
[0057] Reactor catalyst loading:
17

[0058] Commercial as well as catalysts of the present disclosure (CAT 1 and CAT 2)
were trilobe extrudates having a diameter about 1.5 mm and length from 3-5 mm. In order to avoid channeling of flow and also to achieve good packing, catalyst particles were diluted with 180 microns silicon carbide particles (inert), to provide a uniform flow. Before loading, the reactor was thoroughly cleaned, dried and bolted at one end. Dip measurement was taken for the empty reactor. The catalyst was loaded as per the loading pattern detailed in FIG. 3. Thermocouple was inserted in place to measure the catalyst bed temperature at the middle of the bed. The reactor end bolts were tightened to give a leak tight joint and the reactor was installed inside the split zone furnace.
[0059] Reactor pressure test for leak:
[0060] In order to ensure a leak-proof system, the reactor was pressure tested with
Nitrogen at a pressure of 45 bar (i.e. 5 bar above the operating pressure). Once no leaks were detected, the reactor was purged and pressurized to 45 bars with Hydrogen. The pressure drop at ambient temperature over a period of ~16 hours was recorded. The pressure test was successful if the pressure drop in this period was found to be below 2 bars. For all the catalysts, the pressure drop observed over a period of ~16 hours was less than 2 bar with Hydrogen.
[0061] Catalyst Dry-out and Sulfidation
[0062] The catalyst was dried in order to ensure complete moisture removal prior to
sulfidation at 1200 C for 16 hrs. Sulfiding feed was made by mixing Sulfurzol-54 (SZ-54) in Iso-octane. SZ-54, upon reaction with Hydrogen releases Hydrogen Sulphide, H2S, in the reactor, which was used to convert the oxides of Co, Ni and Mo in the catalyst into their respective sulphides. At 1800 C, sulphiding feed was injected. Total sulfur passed through the catalyst bed during sulphiding hours was ~15% of catalyst weight. Catalyst sulphidation was done in accordance with the sulfidation scheme as depicted in FIG. 2.
[0063] Catalyst activity test and product characterization
[0064] Unit was standardized with commercial catalyst. Activity for each of the
commercial as well as catalysts of the present disclosure were tested at 1.5 hr-1 WHSV, 3500C catalyst bed temperature, 40 bar pressure and H2/Oil ratio of 485. Feed used was NRL Light Gas Oil (LGO). After Feed cut in, a stabilization time of 24 hours was provided and diesel from the product tank was discarded. Final product diesel was collected continuously for a period of 90 hours at intervals of 8 and 16 hours respectively and used for product analysis.
18

Sulphur analysis was done by ThermoFisher Scientific Total Sulfur/Nitrogen Analyzer using ASTM D5453 method. Operating conditions are presented in Table 4 hereinbelow. Product was characterized for Density, Viscosity, Pour point and D86 Distillation profile and the results are presented in Table-5 hereinbelow.
Table 4: Operating Conditions

PARAMETER (Units) VALUE
Catalyst quantity (gms) 8
Catalyst length (mm) 3-5
Catalyst Shape Trilobe
Temperature (⁰C) 350
Pressure (bar) 40
WHSV (hr-1) 1.5
H2/Oil ratio 485
SiC/Cat ratio 2
SiC size (µm) 180
Table 5: Feed and Product Characterization

Properties (units) NRL LGO (Feed) Commercial Catalyst CAT-2
Sulphur (mg/L) 980 70 80
Density (gm/cc) 0.8758 0.8673 0.8660
Viscosity at 40 °C (mm2/s) 3.1135 3.0787 3.0523
Pour Point (0C) IBP - 21 -18 -21

197 183.9 182.2
D86, (0C) 10 252 245.3 238.3

50 274 269.2 268.9

90 302 299.6 299.4

FBP 322 316.7 318.1
[0065] EXAMPLE 2 - PILOT SCALE TESTING
19

[0066] In order to achieve the target of bringing down the product Sulphur to less than 10
ppm, the formulations of catalysts (catalyst 1 and 2 exemplified hereinabove) were prepared
in quantities of 200 gms and were tested in high pressure, high temperature bench scale
testing unit (supplied by M/s ITS Corp.) designed to test 50 gms of catalyst compared to
earlier 8 gms of catalyst. The reactor diameter was 1 inch compared to 1.3 cms in the
previous case. The studies on various operating parameters such as temperature, pressure and
WHSV were also carried out in a phased manner where the LGO feed was tested at several
operating conditions starting from low severity and gradually shifting to high severity.
[0067] The catalyst loading procedure, pressure tests and leak tests as well as sulphiding
procedures were maintained unchanged (as provided in Example 1 hereinabove). The catalyst evaluation activity was carried out by continuous operation of the bench scale testing unit for more than 1500 hrs with the actual feed (i.e. NRL LGO) and simultaneous evaluation of collected product samples was done on regular basis. The details of the experimental work carried out, data obtained and analysis of the results are presented in Table 6 through 8 hereinbelow:
Table 6: Operating Conditions Evaluated for Catalyst Performance (Catalyst 1/CAT 1)

Catalyst Condition No Pressure (bar) Temp (oC) WHSV (hr-1)
CAT 1 1 40 320 1.5
CAT 1 2 40 320 1.2
CAT 1 3 40 335 1.5
CAT 1 4 40 335 1.2
CAT 1 5 40 350 1.5
CAT 1 6 40 350 1.2
Table 7: Operating Conditions Evaluated for Catalyst Performance (Catalyst 2/CAT 2)

Catalyst Condition No Pressure (bar) Temp (oC) WHSV (hr-1)
CAT 2 1 40 320 1.5
CAT 2 2 40 320 1.2
CAT 2 3 40 335 1.5
CAT 2 4 40 335 1.2
CAT 2 5 40 350 1.5
CAT 2 6 40 350 1.2
20

Table 8: Comparison of Catalyst Performance (Catalyst 1 vs. Catalyst 2)

Condition No Pressure (kg/cm2) Temperature (oC) WHSV (hr-1) Feed
Sulphur
(PPM) Average Product Sulphur (PPM)

CAT-1 CAT-2
Cond - 1 40 320 1.5 980 36.7 13.6
Cond - 2 40 320 1.2 980 38.4 10.5
Cond - 3 40 335 1.5 980 23.5 9.8
Cond - 4 40 335 1.2 980 12.3 4.5
Cond - 5 40 350 1.5 980 10.2 2.6
Cond - 6 40 350 1.2 980 10.1 1.4
[0068] From the detailed experimentation, it could be observed that an operating pressure
of 40 bars is optimum for hydrodesulphurization of streams with relatively lower sulphur content like that of NRL-LGO (Light Gas Oil). Leaving operating pressure, the two main parameters that were considered for studying the effect upon the catalytic activity were Operating Temperature and Weight Hourly Space Velocity (WHSV). Based on preliminary studies, catalyst activity was further tested at various conditions with operating temperature varying from 320°C to 350°C and the WHSV varying from 1.5 hr-1 to 1.2 hr-1. The entire range of operating conditions was thus divided into different sets of parameters and activity studies were carried out whose results are tabulated in Table 6 hereinabove.
[0069] At constant WHSV (in-fact for both the WHSVs), it could be observed that the
product Sulphur continuously decreased with increasing temperature for both the CAT-1 as well as CAT-2. The study of the effect of temperature on the product Sulphur was carried out in incremental steps of 15°C starting from 320°C to 335°C and finally 350°C. It was observed that: (a) For WHSV of 1.5 hr-1 and first step increase of the temperature from 320°C to 335°C, the product sulphur got reduced by around 13 PPM [equivalent to 35.9 % decrease from base value of 36.7 ppm at 320 °C to 23.5 ppm at 335 °C] and 3.8 PPM [equivalent to 27.9 % decrease from base value of 13.6 ppm at 320 °C to 9.8 ppm at 335°C ] for CAT-1 and CAT-2 respectively; (b) For WHSV of 1.5 hr-1 and subsequent step increase of the temperature from 335°C to 350°C, the product Sulphur got reduced by about 13.3 PPM [equivalent to 56.6% decrease from base value of 23.5 ppm at 335 °C to 10.2 ppm at 350 °C] and 7.2 PPM [equivalent to 73.5% decrease from base value of 9.8 ppm at 335 °C to 2.6 ppm
21

at 350 °C] for CAT-1 and CAT-2 respectively; (c) For WHSV of 1.2 hr -1 and first step increase of the temperature from 320 °C to 335 °C , the product sulphur got reduced by around 26.1 PPM [equivalent to 67.9% decrease from base value of 38.4 ppm at 320 °C to 12.3 ppm at 335 °C ] and 6 PPM [equivalent to 57.1 % decrease from base value of 10.5 ppm at 320 °C to 4.5 ppm at 335 °C ] for CAT-1 and CAT-2 respectively; (d) For WHSV of 1.2 hr-1 and subsequent step increase of the temperature from 335°C to 350°C , the product Sulphur got reduced by about 2.2 PPM [equivalent to 17.8% decrease from base value of 12.3 ppm at 335°C to 10.1 ppm at 350 °C ] and 3.1 PPM [equivalent to 68.9% decrease from base value of 4.5 ppm at 335 °C to 1.4 ppm at 350 °C] for CAT-1 and CAT-2 respectively; (e) It could also be observed that for almost the entire temperature range operated, CAT-2 exhibits superior activity and performance compared to CAT-1 and commercial catalyst in terms of desulphurization.
[0070] The study of the effect of Weight Hourly Space Velocity (WHSV) on the product
Sulphur was carried out by varying it from 1.5 hr-1 to 1.2 hr-1. It could be observed that – (a) as WHSV was decreased from 1.5 hr-1 to 1.2 hr-1, the product Sulphur also continuously decreased accordingly; (b) for almost all the conditions of the experiment, the product Sulphur when operated at 1.2 hr-1 was always found to be less than that when operated at 1.5 hr-1 for both the catalysts; (c) for both the WHSVs operated, CAT-2 exhibits superior activity and performance compared to CAT-1 as well as commercial catalyst in terms of desulphurization. The catalysts of the present disclosure (specifically, catalyst 1 and 2 denoted herein as CAT-1 and CAT-2) exhibits superior activity and stability as compared to conventional catalysts. FIG. 4 illustrates an exemplary plot depicting amount of sulphur present in the HDS treated feedstock over the period of time.
[0071] Although the subject matter has been described herein with reference to certain
preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein. Furthermore, precise and systematic details on all above aspects are currently being made. Work is still underway on this invention. It will be obvious to those skilled in the art to make various changes, modifications and alterations to the invention described herein. To the extent that these various changes, modifications and alterations do not depart from the scope of the present invention, they are intended to be encompassed therein.
22

ADVANTAGES OF THE INVENTION
[0072] The present disclosure provides a process for effecting hydrodesulphurisation of
a sulphur-containing hydrocarbon feedstock.
[0073] The present disclosure provides a catalyst for hydrodesulphurisation of a
sulphur-containing hydrocarbon feedstock.
[0074] The present disclosure provides a method of preparation of a catalyst for
hydrodesulphurisation of a sulphur-containing hydrocarbon feedstock.

We Claim:

A hydrodesulphurisation process for effecting hydrodesulphurisation of a sulphur-containing hydrocarbon feedstock, the process comprising the steps of:
(a) providing one or a plurality of hydrodesulphurisation zones, each containing a
bed of a sulphided hydrodesulphurisation catalyst, wherein said sulphided
hydrodesulphurisation catalyst comprises:
(i) a porous support comprising at least one inorganic oxide;
(ii) at least 10% by weight of at least one Group VIB metal;
(iii)at least 2% by weight of at least one Group VIIIB metal; and
(iv)at least 0.1% by weight of at least one metal of Group IIIA or Group VA;
(b) maintaining temperature and pressure conditions in each of said one or a
plurality of hydrodesulphurisation zone, effective for hydrodesulphurisation of
said sulphur-containing hydrocarbon feedstock;
(c) supplying said sulphur-containing hydrocarbon feedstock to a first
hydrodesulphurisation zone of said one or a plurality of hydrodesulphurisation
zones;
(d) passing said sulphur-containing hydrocarbon feedstock through said one or a
plurality of hydrodesulphurisation zones;
(e) passing a hydrogen-containing gas through said one or a plurality of
hydrodesulphurisation zones; and
(f) contacting said sulphur-containing hydrocarbon feedstock with said hydrogen-
containing gas in each of said one or a plurality of hydrodesulphurisation zones in
presence of said hydrodesulphurisation catalyst to effect the
hydrodesulphurisation of the sulphur-containing hydrocarbon feedstock.
The hydrodesulphurisation process as claimed in claim 1, wherein said porous support comprises porous alumina extrudates, and wherein said porous alumina extrudates

exhibit surface area ranging from 200 to 250 m /g and pore volume ranging from 0.5 to 1 cc/g, further wherein said porous alumina extrudates exhibit average pore diameter ranging from 1 to 1.5 mm and length ranging from 4 to 7 mm.
The hydrodesulphurisation process as claimed in claim 1, wherein said porous support exhibits unimodal pore size distribution having majority of the pores in the range of 20 to 250 A, and wherein said porous support exhibits Apparent Bulk Density (ABD) of about 0.85 g/cc and BCS of about 1 MPa.
The hydrodesulphurisation process as claimed in claim 1, wherein said porous support comprises alumina mixed with any or a combination of discarded refinery catalyst and at least one mesoporus material.
The hydrodesulphurisation process as claimed in claim 1, wherein said at least one Group VIB metal comprises Molybdenum, and wherein Molybdenum is in its elemental form, further wherein said at least one Group VIIIB metal comprises any or a combination of Cobalt and Nickel.
The hydrodesulphurisation process as claimed in claim 1, wherein said at least one metal of Group IIIA comprises Boron, and wherein said at least one metal of Group VA comprises Phosphorous.
The hydrodesulphurisation process as claimed in claim 4, wherein said at least one mesoporus material comprises any or a combination of HMS and alumina, and wherein said HMS exhibits surface area of about 1000 m /g, pore volume of about 1 cc/gram and average pore size ranging from 40 to 80 A.
The hydrodesulphurisation process as claimed in claim 4, wherein said discarded refinery catalyst exhibits surface area ranging from 120 to 160 m2/g, pore volume of about 0.2 cc/g, Apparent Bulk Density (ABD) of about 0.8 g/cc, and particle size distribution of about 75 micron.
The hydrodesulphurisation process as claimed in claim 1, wherein said sulphided hydrodesulphurisation catalyst comprises:

(i) a porous support ranging from 1 to 90% by weight, wherein said porous support comprises alumininum oxide;
(ii) at least one Group VIB metal ranging from 10 to 20% by weight;
(iii)at least one Group VIIIB metal ranging from 2 to 6% by weight; and
(iv)at least one metal of Group IIIA or Group VA ranging from 0.1 to 5% by weight. The hydrodesulphunsation process as claimed in claim 1, wherein said step of maintaining temperature and pressure conditions in each of said one or a plurality of hydrodesulphunsation zone comprises maintaining a temperature ranging from 300°C to 400°C and a hydrogen pressure ranging from 10 to 70 bar.
The hydrodesulphunsation process as claimed in claim 1, wherein said step of maintaining temperature and pressure conditions in each of said one or a plurality of hydrodesulphunsation zone comprises maintaining a temperature ranging from 320°C to 370°C and a hydrogen pressure ranging from 30 to 50 bar.
The hydrodesulphunsation process as claimed in claim 1, wherein the step of passing said sulphur-containing hydrocarbon feedstock through said one or a plurality of hydrodesulphunsation zones is effected such that Weight Hourly Space Velocity (WHSV) ranges from 1.0 hr1 to 1.7 hr"1.