FIELD OF THE INVENTION
[001] The present invention, in general, relates to adsorbent compositions for the
removal of sulphur from a hydrocarbon fluid stream containing sulfur, and in particular to a nano structured reactive adsorbent for removal of sulphur from diesel and gasoline like fuels and process for preparing the said adsorbent compositions.
BACKGROUND AND PRIOR ART
[002] Environmental regulations are becoming continually stringent worldwide, forcing
refiners to find novel and cost effective ways to produce cleaner fuels e.g. gasoline, kerosene, jet fuel, diesel fuel etc. The environmental regulations demand the reduction of sulphur in diesel and gasoline fuels to less than 10 ppm in most countries of the world.
[003] The present invention discloses a novel nano structured adsorbent composition
capable of removal of sulfur by reactive adsorption of most refractory sulfur species from diesel-and gasoline-like fuels to less than 5 ppm in a fixed-bed process under hydrogen environment. The adsorbent comprises of an active X-ray amorphous nano-sized mixed oxides of Ni, Zn, Al, Fe and Ti but having local crystalline characteristics in nano-scale as evidenced by TEM images. of the adsorbent, constituting 15-65 wt% as the active phase, 20-45 wt% NiO, 15-30 wt% ZnO, 5-15 wt% Al2O3, and 2-15 wt% clay. The adsorbent has a surface area of 50-200m /g, pore
volume of 0.1 to 0.6 cc/g and pore size ranging from 50-200 A°.
*
[004] Hernandez-Maldonado et. al. showed that for the production of less than 10-
ppm diesel, most refractory sulphur compounds e.g. 4 or 6-MDBT, 4,6-DMDBT, 2,4,6-TMDBT, 3,6-DMDBT, 2,3-DMDBT etc. are required to be removed. The removal of these most refractory sulfur compounds by hydrodesulfurization route requires severe operating pressure and temperature with higher consumption of hydrogen and/or larger reactor volumes. An estimate by Whitehurst et. al. showed that with conventional desulfurization catalyst systems reactor volume is to be increased by a factor of 7 to reduce the sulfur content of diesel from 500 to 10 ppmw. Other estimates by Avidan et. al., and Parkinson et. al. showed that in order to reduce the sulfur level in diesel from 300 to less than 10 ppmw, the reactor size to be increased by a factor 5 to 15 times on decreasing the operating pressure from 1000 psi to 600 psi.. This will

lead to tremendous increase of the operating cost. Hence novel materials and processes are
desired for removal of refractory sulphur compounds from various refinery streams to produce
ultra-low sulfur fuels.
[005] Song et. al. (US patent publication no. 2004/0007506) have made efforts to
design several adsorbents to physically adsorb the sulfur compounds selectively from various
hydrocarbon fuels e.g. gasoline, kerosene, jet fuel and diesel fuel etc. However, these adsorbents
also showed non selective adsorption of other compounds like aromatics and olefins etc.
Moreover, the adsorbent gets saturated with very low treated volume of the fuels. In the
regeneration process, the adsorbed compounds are removed by solvent washing. The sulfur
compounds are then recovered in concentrated forms by evaporation of the solvent. This
concentrated sulfur-containing stream is then treated in a small hydrotreater reactor and blended
with the product treated with adsorbent. The treating of this concentrated sulfur-containing
stream requires severe operating conditions and higher consumption of hydrogen. This process
may not be economically viable due to low selectivity, faster saturation of adsorbent, treating of
concentrated sulfur containing streams and low recovery of the fuel streams.
[006] US Patent Publication No. US2003/0032555 discloses an adsorbent prepared by
the conventional impregnation of a porous sorbent support comprising zinc oxide, expanded
perlite, and alumina with a promoter metal such as nickel, cobalt.
[007] US Patent Publication No. US2004/0063576 discloses a catalyst adsorbent^
comprised of nickel compound deposited on a silica carrier by using conventional precipitation
process. Alumina and alkaline earth compounds are used as promoters.
[008] US Patent No. 6,803,343 discloses a sorbent composition comprising, a support
system prepared by admixing zinc oxide with silica/alumina, and incorporating the support with
reduced valence noble metal.
[009] US Patent No. 6,683,024 discloses a sorbent composition, which contains a
support component and a promoter component with the promoter component being present as a
skin of the support. The sorbent is prepared by a process of impregnating a support component
with a promoter.
[010] US Patent No. 6,656,877 discloses an attrition resistant sorbent, prepared by the
impregnation of a sorbent support comprising zinc oxide, expanded perlite, and alumina with a

promoter such as nickel, nickel oxide or a precursor of nickel oxide followed by reduction of the valence of the promoter.
[011] US Patent No. 6,482,314 discloses a particulate sorbent compositions comprising
a mixture of zinc oxide, silica, alumina and a substantially reduced valence cobalt, prepared by
impregnation method, for the desulfurization of a feed stream of cracked-gasoline or diesel fuels.
[012] U.S Patent No. 6,429,170 discloses attrition resistant, sorbent compositions for
the removal of elemental sulfur and sulfur compounds, such as hydrogen sulfide and organic
sulfides, from cracked-gasoline and diesel fuels. The sorbents are prepared by the impregnation
of a sorbent support comprising zinc oxide, expanded perlite, and alumina with a promoter such
as nickel, nickel oxide or a precursor of nickel oxide followed by reduction of the valence of the
promoter metal in the resulting promoter metal sorbent support composition.
[013] US Patent No. 6,428,685 discloses particulate sorbent compositions which are
suitable for the removal of sulfur from streams of cracked-gasoline or diesel fuel. They have increased porosity and improved resistance to deactivation achieved through the addition of a calcium compound selected from the group comprising of calcium sulfate, calcium silicate, calcium phosphate or calcium aluminate to the support system comprising of zinc oxide, silica and alumina having thereon a promoter wherein the promoter is metal, metal oxide or metal oxide precursor.
[014] US Patent No. 6,346,190 discloses particulate sorbent compositions consisting
essentially of zinc ferrite, nickel and an inorganic binder, wherein the zinc ferrite and nickel, which are of reduced valence, are provided for the desulfurization of a feed stream of cracked-gasoline or diesel.
[015] US Patent No. 6,338,794 discloses particulate sorbent compositions comprising
zinc titanate support having thereon a substantially reduced valence promoter metal selected from the group of cobalt, nickel, iron, manganese, copper, molybdenum, tungsten, silver, tin and vanadium or mixtures thereof to provide a system for the desulfurization of a feed stream of cracked-gasolines or diesel fuels.
[016] US Patent No. 6,274,533 discloses a sorbent system prepared by impregnating a
particulate support which comprises zinc oxide and an inorganic or organic carrier with a bimetallic promoter formed from two or more metals selected from the group consisting of

nickel, cobalt, iron, manganese, copper, zinc molybdenum, tungsten, silver, tin, antimony and vanadium for the desulfurization of cracked-gasoline.
[017] US Patent Nos. 6,056,871 6,274,031 discloses a novel circulatable sorbent
material suitable for use in a transport desulfurization system for removing sulfur from a fluid stream containing sulfur and the use thereof in such a transport desulfurization system. The transport desulfurization process utilizes a circulatable particulate material containing alumina, silica, zinc oxide and a metal oxide, which is contacted with a fluid stream and thereafter separated and reused with a portion being regenerated.
[018] US Patent No. 6,271,173 discloses particulate sorbent compositions which are
suitable for the removal of sulfur from streams of cracked-gasoline or diesel fuel, and which have increased porosity, improved resistance to deactivation through the addition of a calcium compound selected from the group consisting of calcium sulfate, calcium silicate, calcium phosphate or calcium aluminate to the support system comprised of zinc oxide, silica and alumina having thereon a promoter wherein the promoter is metal, metal oxide or metal oxide precursor with the metal being selected from the group consisting of cobalt, nickel, iron, manganese, copper, molybdenum, tungsten, silver, tin and vanadium or mixtures thereof and wherein the valence of such promoter has been substantially reduced to 2 or less. Process for the preparation such sorbent systems as well as the use of same for the desulfurization of cracked-gasolines and diesel fuels are also provided.
[019] US Patent No. 6,254,766 discloses particulate sorbent compositions comprising a
mixture of zinc oxide, silica, alumina and a substantially reduced valence nickel for the desulfurization of a feed stream of cracked-gasoline or diesel fuels in a desulfurization zone by a process which comprises the contacting of such feed streams in a desulfurization zone followed by separation of the resulting low sulfur-containing stream and sulfurized-sorbent and thereafter regenerating and activating the separated sorbent before recycle of same to the desulfurization zone.
[020] US Patent No. 6,184,176 discloses a sorbent comprising a mixture of zinc oxide,
silica, alumina and substantially reduced valence cobalt provided for the desulfurization of a feed stream of cracked-gasoline or diesel fuels.

[021] US Patent no. 7897037 discloses a catalyst comprising nickel on a carrier, and a
process for desulphurisation of a hydrocarbon feedstock using such catalyst.
[022] US Patent no. 7682423 discloses zinc oxide-based sorbents, and a processes for
preparing and using them. The sorbents are preferably used to remove one or more reduced
sulfur species from gas streams.
[023] US Patent no. 7951740 discloses a method for regenerating desulfurization
sorbents that minimizes the in-situ formation of one or more silicates.
[024] US Patent no. 7956006 relates to zinc oxide-based sorbents, and processes for
preparing and using them.
[025] US Patent no. 7597798 discloses a process for removing relatively low levels of
high molecular weight organic sulfur from hydrocarbon streams, particularly from streams that"
have picked-up such sulfur while being transported through a pipeline.
[026] The adsorbents disclosed in the prior art and the patents cited above involve the
conventional impregnation approaches for loading the active metal components on the support
material. These approaches lead to the formation of crystalline mixed metal oxide phases,
particularly the spinel phase either as nickel aluminate, zincaluminate or nickelzincaluminate,
which are characterized by XRD patterns. The prior art does not disclose any adsorbent
composition with nano-structured phases having enhanced capability for removal of sulfur by
reactive adsorption of most refractory sulfur species of diesel- and gasoline-like fuels. The
selective desulfurization of refractory sulfur species from especially cracked gasoline with only
minimal octane loss, more specifically in the range of 1-2 units, has also not been addressed in
any of the prior art.
OBJECTS OF THE INVENTION
[027] An object of the invention is to provide a nano structured adsorbent composition
capable of removal of sulfur from most refractory sulfur species of diesel- and gasoline- like
fuels by reactive adsorption.
[028] Yet another object of the invention is to provide an adsorbent composition which
reduces the sulphur content of the treated fuel to less than 5 ppm having high adsorption
capacity.

[029] A further object of the invention is to provide an adsorbent which desulphurises
cracked gasoline with minimal octane loss which is within the range of 1-2 units.
[030] Another object of the invention is to provide a process for preparing the nano
structured adsorbent composition.
SUMMARY OF THE INVENTION
[031] In most countries of the world, the environmental regulations demand the
reduction of sulphur in diesel and gasoline fuels to less than 10 ppm. To achieve this goal, the
present invention discloses a novel nano structured adsorbent composition. This composition is
capable of removal of sulfur by reactive adsorption from most refractory sulfur species of diesel-
and gasoline- like fuels. The process of sulphur removal is carried out under hydrogen
environment. The sulphur content of the treated fuel comes down to less than 5 ppm.
[032] The adsorbent comprises of an active component having X-ray amorphous nano-
sized mixed oxides of Ni, Zn, Al, Fe and Ti having local crystalline order as evidenced by TEM as the active component, constituting 15-65 wt% as the active phase, 20-45 wt% NiO, 15-30 wt% ZnO, 5-15 wt% Al2O3, and 2-15 wt% clay. The adsorbent has a surface area of 50-200m2/g, pore volume of 0.1 to 0.6 cc/g and pore size ranging from 50-200 A°.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Fig. 1 shows Transmission Electro Micrograph of the adsorbent with nano structured crystalline phase of mixed metal oxides.
DETAILED DESCRIPTION OF THE INVENTION
[033] In the present invention, novel reactive adsorbents comprising active X-ray
amorphous nano- mixed oxides have been developed through solid-state reactions of the metal oxides to provide a porous structure for the adsorbent to accommodate most refractory high boiling range sulphur compounds. The adsorbent consist of an active X-ray amorphous nano-sized mixed oxides of Ni, Zn, Al, Fe and Ti oxide constituting 15-65 wt% active phases, 20-45 wt% NiO, 15-30 wt% ZnO, 5-15 wt% A1203, and 2-15 wt% clay. The Transmission Electro Micrograph of the adsorbent shown in Fig.l reveals nano structured crystalline phase of mixed

metal oxides. The adsorbent has a surface area of 50-200m2/g, pore volume of 0.1 to 0.6 cc/g and pore size ranging from 50-200 A°.
[034] The XRD analysis of different components, viz, nickel nitrate, zinc oxide and
pseudoboehmite of the adsorbent was performed on the fresh component employed in the preparation of the adsorbent under varying conditions (200 - 700°C) including the temperature conditions employed in the preparation of the adsorbent in the present invention to observe the change in the phases as well as size of crystallites are summarized in Table. 1.

XRD pattern of fresh Ni(NO3)2.6H2O indicated presence of Nickel Nitrate in the form of hydrate. At 200°C, decomposition of Ni(NO3)2.6H2O was observed with the removal of water molecules and no NiO phase was observed. At 300°C, formation of NiO phase was noticed along with Ni(NO3)2 phase. At 400°C, XRD showed the presence of NiO phase only and no change in peak width of NiO indicating no change in crystallite size. At 500, 600 and 700°C, XRD showed the presence of only NiO phase but the crystallite size was found to increase with temperature.
[035] The XRD pattern of fresh ZnO indicated presence of ZnO with zincite structure.
At 200, 300, 400 and 500°C, no change in the XRD pattern w.r.t peak position of Full Width at Half Maximum (FWHM) was observed indicating no change in the structure and crystallite size

of ZnO upon heating up to 500°C. At 600°C, no change in the structure of ZnO but the crystallite size of ZnO decreases as evident from the narrowing of FWHM of ZnO peaks.
[036] The XRD pattern of fresh alumina indicated presence of pseudobeohmite phase
only. At 200 and 300°C XRD pattern showed presence of pseudobeohmite phase only and no change in peak width indicating no change in crystallite size. At 400°C, the intensity of pseudobeohmite peaks decreases indicating some phase transformation to y-alumina. At 50°C, XRD studies confirmed the formation of y-alumina phase. At 600 and 700°C, XRD showed the presence of only y-alumina phase but the crystallite size was found to increase with temperature.
The XRD pattern of adsorbent showed the absence of initial phases like Ni(NO3)2.6H2O, ZnO and pseudobhomite alumina in the mixture indicated phase transformation to new phases at room temperature. Further change in the XRD pattern at 200°C indicated some phase transformation. with small amounts of ZnO and alumina. At 300 to 600°C, XRD showed the presence of NiO and ZnO as the only phases but in concentrations less than that of the staring composition indicating the formation of X-ray amorphous mixed oxide phases.
[037] In the present invention, commercial liquid hydrocarbon streams such as gasoline,
diesel fuel like streams containing refractory and most refractory sulphur compounds have been treated to reduce sulfur content below 10 ppm. The feed was treated with an adsorbent in a fixed bed pilot plant. The pilot plant comprised of two fixed bed reactors which are operated in swing mode of adsorption and regeneration. The adsorbent is activated under hydrogen flow and in a temperature range of 400-500°C. The adsorption experiments are carried out at liquid hourly space velocity (LHSV) from about 0.5 to 5.0 hr'1, temperature from about 250 to 400°C, pressure from about 10 to 30 bars, and hydrogen to hydrocarbon ratio from about 50 to 200. Hydrocarbon feed is introduced into the reactor in a down flow mode. The reactor effluent samples are collected from the reactor exit at regular intervals. The hydrocarbon feed and reactor effluent samples are analyzed for sulfur content by oxidative pyro-fluorescence technique using Antek 9000 Analyzer. The hydrocarbon feed sulfur is reduced from about 500-2000 ppm to less than 10-ppm sulfur. In case of cracked gasoline such as FCC, coker, visbreaker gasoline desulfurization, the octane loss is about 1-2 units. Adsorbent

[038] The adsorbents are specially designed to remove the most refractory sulfur
compounds even from high final boiling point (FBP) up to about 450°C. The adsorbent
comprises of an active component having X-ray amorphous nano-sized mixed oxide comprising
of of Ni, Zn, Al, Fe and Ti oxide at a concentration of 15-65 wt% as active phases, 20-45 wt%
NiO, 15-30 wt% ZnO, 5-15 wt% A1203, and 2-15 wt% clay and having local crystalline
characteristics as evidenced by TEM prepared through solid state reactions.
[039] The clay is of bentonite family, more specifically of polygorskite type, similar to
those found in the regions of state of Rajasfhan, India. The clay has a particle size in the range of 5-50um and more preferably in the range of 5-15nm. A combination of nickel sources or individual nickel compound from a group comprising of nickel nitrate, nickel carbonate and nickel hydroxide, and zinc oxide are subjected to sequential mix-mulling, preferably by high speed ball milling, and the mixture is further mix-mulled with alumina. This mix-mulling step too is most preferably done by high speed ball milling. In a typical case, the nickel source is a combination of nickel nitrate and nickel carbonate with a ratio ranges from 1:1 to 3:1, more preferably in the range 2:1, in terms of nickel content contributed by nickel nitrate and nickel carbonate respectively.
[040] The adsorbent has a surface area of 50-200m /g, pore volume of 0.1 to 0.6 cc/g
and pore size ranging from 50-200A0. The adsorbent according to the invention exhibits crystalline phases of unreacted NiO in the range of 20-35 wt% and of unreacted ZnO 10-25 wt%, as evidenced by XRD analysis.
[041] The components of adsorbent (nickel nitrate and/or nickel carbonate, zinc oxide
and alumina) were mix mulled in a Mix Muller for about 15-30 minutes followed by homogenization by mulling with solvent like water, acetone, and propanol, more preferably with acetone. The solvent from the mixture was evaporated either by continuous mulling or by drying at 40°C in about 2 hours. The mixture thus obtained was calcined in a furnace with the following steps and ramp rates:
i) From room temperature to 150°C @ 5°C/min and held there for 1 hr.
ii) From 150°C to 500°C @ 5°C/min and held there for 1 hrs.
iii) From 500°C to 600°C @ 5°C/min and held there for 4 hrs.
[042] The process of preparation of the adsorbent composition comprises mix-mulling
of nickel nitrate, zinc oxide and alumina preferably by high speed ball milling for 30-240

minutes, more preferably for a time of 30-90 minutes to obtain a particle size of < 200 micron and further mix mulling with ZnO, alumina and clay and homogenization in solvent like water, acetone, and propanol, more preferably with acetone to form a wet solid. The wet solid was then used in an extruder after peptizing with dilute acids like nitric acid, acetic acid, formic acid in a range of 0.25 to 5.0 w/w, and/or by the addition of extrusion-aiding agents selected from a group consisting of carbomethoxy cellulose, polyvinyl alcohols, polyethylene glycol, graphite and clay. The extrudates of the adsorbents were then dried overnight at room temperature.
The particle size of the dried mixture is less than 100 um, more preferably less than 50 um.
[043] The dry mixture so obtained is calcined in a furnace in a two-stage step involving
heating from room temperature to 450°C, more preferably in the range of 270-350°C, followed
by heating it to 700°C, more preferably in the range of 550-600°C for 3-5 hours.
[044] The mixture is mix mulled with ZnO, alumina and clay and homogenized by
addition of acetone followed by thorough homogenization. The acetone from the mixture is
evaporated either by continuous milling or by drying at 40-120°C in about 2 hours. The mixture
is peptized after adding a dilute acid and extruded after adding an extrusion aiding agent.
[045] The final adsorbents according to the present invention have surface area ranging
from 50 to 200 m /gm, pore volume ranging from 0.1 to 0.6 cc/gm and average pore size ranging
from 50 to 200 A°.
[046] The final adsorbent was then reduced in a temperature range from about 250 to
500°C under hydrogen flow.
[047] After reduction, the adsorbent was used for reducing sulfur content in
hydrocarbon fuels such as gasoline, diesel-like fractions. The adsorption process occurs in one or
more fixed bed reactors. The adsorption process was carried out in the temperature range of
150°C to 500°C, pressure range of 5 to 30 bar, hydrogen to hydrocarbon ratio in a range of 50-
200 v/v and liquid hourly space velocity in the range of 0.5 to 5 h"1'
[048] After reaching the breakthrough point, the adsorbents were regenerated in the
temperature range of about 200-500°C in a mixture of air and nitrogen.
[049] The adsorbent according to the present invention can reduce sulfur content in
straight run gasoil and cracked gasoil feed stocks from 1000-3000 ppm to less than 10 ppm under

hydrogen environment. The adsorbent desulfurizes cracked gasoline with an octane loss in the range of 1-2 units. Feed Stocks
[050] Diesel feed having boiling range 200- 450°C containing 1000-ppm residual sulfur
and coker gasoline having boiling range C5-210°C containing 2000 ppmsulfurhave been used.The diesel feed was generated by hydrotreating a high sulfur containing feed (1.0 to 1.5 wt%). The diesel feed contains high concentration of most refractory sulfur compounds such as 4 or 6-MDBT, 4,6-DMDBT, and other alkyl DBTs. Experimental Setup
[051] The experiments were conducted in a specially designed adsorption pilot plant
comprising two fixed bed reactors, which are operated in swing mode of adsorption and
regeneration. These reactors are equipped with separate electric furnaces, which can heat the
reactors up to 600°C. The furnace is divided into three different zones. The top zone is used for
preheating the feed stream before it enters the process zone. The middle zone is used for process
reactions and the bottom zone is used for heating to maintain temperature in the reaction zone.
Adjusting the corresponding skin temperatures controls the reactor internal temperatures.
[052] The feed was charged into a feed tank, which can preheat the feedstock up to
about 150°C. The feed was then pumped through a diaphragm pump to the reactor. Three mass flow controllers, one each for measurement of hydrogen, nitrogen and oxygen gases are provided at the inlet of the reactors. In the adsorption step, the liquid and gas streams join together and enter the reactors in the down flow mode. The isothermal temperature profile is maintained throughout the adsorption zone. The reactor effluent stream then enters the separator, where the gas and liquid streams were separated. The gas stream exits from the top of the separator and is vented. The liquid strean exits from the bottom of the separator and is collected in the product tank. The hydrocarbon feed and reactor effluent samples were analyzed for total sulfur content by oxidative pyro-fluorescence technique using Antek 9000 analyzer.
[053] After reaching the breakthrough of sulfur of about 10 ppm, the feed is diverted to
the second reactor, bypassing the first reactor. The first reactor adsorbent is now regenerated. The cycle time of the adsorption and regeneration steps depends upon the type of feed stock and its sulfur content. The cycle time typically varies from 4-10 days. During the regeneration,

reactor outlet stream is vented to atmosphere at a safe height after cooling. On-line CO, CO2 and
SO2 analyzer are provided, which ascertain the completion of regeneration step.
[054] The invention will be further described through examples.
Example-1
[055] 38 gms of bohemite alumina, 22 gms of diatomaceous earth, and 52 gms of zinc
oxide are homogenized and using a mix muller peptised using 1% nitric acid and extruded.The extruded material is calcined at 550°C for 3 hours.
[056] The extrudate was impregnated by incipient wetness method using 15% nickel (as
the metal) using nickel nitrate hexahydrate dissolved in 10% water to dissolve it. The nickel-
impregnated extrudate was again calcined at a temperature of 600°C for 3 hours.
[057] The calcined adsorbent composition containing 15% nickel was again re-
impregnated with 15% nickel using incipient wetness method. The resulting 30% nickel impregnated sorbent was then calcined at a temperature of 600°C for a period of 3 hour to provide a 30% (by weight) nickel-impregnated adsorbent.
Example-2
[058] 125g nickel nitrate powder is milled to l0um size in a pulverizer. To the-
pulverized nickel nitrate, 40 g of ZnO is added and mix-mulled for 30 minutes. 20 g of boehmite
powder is mixed further for 30 minutes. The mixture is homogenized by milling with 15 ml
acetone for 30 min and then the acetone is made to evaporate.The dried powder is further milled
by addition of 20 ml acetone and dried at 60°C for 1 hour and calcined at 600°C for 3 hours. The
calcined material is mixed with 10 gm alumina and peptized using 1% nitric acid and extruded.
The extruded material is calcined at 650°C for 3 hours.
Example-3
[059] 125g nickel nitrate powder is milled to lOum size in a pulverizer. To the
pulverized nickel nitrate, 40g of ZnO is added and mix-mulled for 30 min. 20g of boehmite
powder is mixed further for 30 minutes. The mixture is homogenized by milling with 15 ml
acetone for 30 min and the acetone evaporated. The dried powder is further milled by addition of
20 ml acetone and dried at 60°C for 1 hour and calcined at 600°C for 3 hours.
[060] The calcined material is homogenized and milled with 15 gms of clay obtained in
the region of State of Rajasthan in India for 30 min. To the milled mixture, 10 gm alumina is

further added and peptized using 1% nitric acid and extruded. The extruded material is calcined at 600°C for 3 hours.
Example-4
[061] 83g nickel nitrate powder is milled along with 38 gms nickel carbonate powder to
10 nm size in a pulverizer. To the pulverized nickel salt mixture, 40 g of ZnO is added and mix-mulled for 30 mins. 20 g of boehmite powder is mixed further for 30 minutes. The mixture is homogenized by milling with 15 ml acetone for 30 min and acetone evaporated. The dried powder is further milled by addition of 20 ml acetone and dried at 60°C for 1 hour and calcined at 600°C for 3 hours.
[062] The calcined material is homogenized and milled with 15 gms of clay (obtained in
the region of State of Rajasthan in India) for 30 mins. To the milled mixture, 10 gm alumina is further added and peptized using 1% nitric acid and extruded. The extruded material is calcined at 600°C for 3 hours.
Example-5
Treatment of Diesel Feed with adsorbent
[063] Adsorbent of examples 1 to 4 are evaluated in a fixed bed reactor that has an
internal diameter of 25 mm and length of 1100 mm. The adsorbent was activated under hydrogen environment at a temperature of 400°C and pressure of 1-2 barg for about one hour prior to evaluation. Diesel feed having boiling range 200-450°C containing 1000 ppm residual sulfur was passed through the reactor at LHSV of 1.0 h-1 in down flow mode at a temperature of 400°C and reactor pressure of 20 bar with H2/Hydrocarbon ratio of 100NL/L during the experiment. The treated reactor effluent samples were collected at regular intervals of 8 hours and analyzed for sulfur content by oxidative pyro-fluorescence technique using Antek 9000 Analyzer. The results obtained are shown in Table-2.



Treatment of Coker gasoline Feed with adsorbent
[064] Adsorbent of examples 1 to 4 are evaluated in a fixed bed reactor that has an
internal diameter of 25 mm and length of 1100 mm. The adsorbent was activated under hydrogen environment at 400°C and 1-2 barg for about one hour prior to evaluation. Coker gasoline having boiling range C5 - 210°C containing 2000 ppm sulfur was passed through the reactor at LHSV of 1.0 h"1 in down flow mode at a temperature of 300°C and reactor pressure of 15 bar with H2/Hydrocarbon ratio of 100 NL/L during the experiment. The treated reactor effluent samples were collected at regular intervals of 8 hours and analyzed for sulfur content by oxidative pyro-fluorescence technique using Antek 9000 analyzer. The results obtained are shown in Table-3. The loss in research octane number was observed in the range of 1-2 unit. Table-3

We Claim:
1. A nano structured adsorbent composition for removal of sulphur from diesel and gasoline
fuels comprising of an active component having X-ray amorphous nano-sized mixed
oxides of Ni, Zn, Al, Fe and Ti oxide constituting 15-65 wt% as active phases, 20-45
wt% NiO, 15-30 wt% ZnO, 5-15 wt% A1203, and 2-15 wt% clay having local crystalline
characteristics as evidenced by TEM as the active component,
characterised in that the adsorbent can reduce sulfur content in straight run gasoil and
cracked gasoil feed stocks from 1000-3000 ppm to less than 10 ppm under hydrogen
environment,
further characterized in that the adsorbent desulphurises cracked gasoline with an
octane loss which is in the range of 1-2 units.
2. The nano structured adsorbent composition as claimed in claim 1, wherein the nano-structured crystalline phases have a particle diameter in the range 5-100A.
3. The nano structured adsorbent composition as claimed in claim 1, wherein the adsorbent is activated under hydrogen flow and at a temperature in the range of 400-5 00°C.
4. The nano structured adsorbent composition as claimed in claim 1, wherein the active component constitutes 15-65 wt% as the active phase.
5. The nano structured adsorbent composition as claimed in claim 1, wherein the composition has a metal loading of 20-45 wt% NiO, 15-30 wt% ZnO, 5-15 wt% A1203, and rest 2-15 wt% clay.
6. The nano structured adsorbent composition as claimed in claim 1 and 5, wherein the clay is of bentonite family, more specifically of polygorskite type.

7. The nano structured adsorbent composition as claimed in claim 4, wherein the composition exhibits crystalline phases of unreacted NiO in the range of 20-35 wt% and unreacted ZnO 10-25 wt% in XRD analysis.
8. The nano structured adsorbent composition as claimed in claim 1, wherein the composition has a surface area of 50-200m2/g , pore volume of 0.1 to 0.6 cc/g and pore size ranging from 50-200A.
9. The nano structured adsorbent composition as claimed in claim 1, wherein the intermediate calcined powder has a particle size in the range of 5-50um and more preferably in the range of 5-15 um.
10. A process for preparation of a nano structured adsorbent for removal of sulphur from diesel and gasoline fuels comprising of:
mix-mulling of nickel nitrate, zinc oxide and alumina in high speed ball milling for 30-240 minutes, more preferably for 30-90 minutes;
sequential mix-mulling of a combination of nickel sources or individually comprising nickel nitrate, nickel carbonate, nickel hydroxide and zinc oxide in high speed ball mill;
further mix-mulling the mixture with alumina by high speed ball milling;
further mix mulling, alternatively ball milling said mix-mulled product or more preferably said ball milled product after addition of organic solvents;
evaporating the solvent from the mixture either by continuous mulling or by drying in temperature range of 40-120°C for about 4 hours more preferably at 40-60°C for 2 hours;

calcining the dried mixture obtained in a two stage step involving heating from room temperature to a temperature in the range of 270-3 5 0°C followed by heating it to a temperature in the range of 550-600°C for 2-6 hours, specifically for 3-5 hours;
further mix mulling the mixture so obtained with ZnO, alumina and clay and homogenized by addition of acetone followed by thorough homogenization;
evaporating the acetone from the mixture either peptizing with a dilute acid and extruding the mixture after adding an extrusion aiding agent to obtain the final adsorbent; and
reducing the final adsorbent in a temperature range of 250 to 500°C under hydrogen flow.
11. The process as claimed in claim 10, wherein the nickel source is a combination of nickel nitrate and nickel carbonate.
12. The process as claimed in claim 10, wherein the nickel content ratio ranges from 1:1 to 3:1, more preferable in the ratio 2:1 contributed by nickel nitrate and nickel carbonate respectively.
13. The process for preparation of nano structured adsorbent as claimed in claim 10, wherein the organic solvents are selected from the group consisting of acetone, methanol, ethanol and propanol, the most preferred solvent being either acetone or methanol.
14. The process as claimed in claim 10, wherein the size of dried mixture particle is less than 100 um, more preferable less than 50 um.
15. The process as claimed in claim 10, wherein the dilute acid is either nitric acid or acetic acid or formic acid in a concentration range of 0.25 to 5.0 w/w.

16. The process as claimed in claim 10, wherein the extrusion aiding agent is selected from the group consisting of carbomethoxy cellulose, polyvinyl alcohols, polyethylene glycol, graphite and clay.