Description:FIELD OF THE INVENTION:
The present invention relates to an isodewaxing catalyst comprising non-noble metals impregnated on an extruded 2D zeolite support and its process for preparation thereof. It further relates to the use of the said catalyst in a hydroisomerisation method for the preparation of winter diesel with improved flow properties.

BACKGROUND OF THE INVENTION:
Diesel fuel is produced in petroleum industry by the distillation of crude oils and contains paraffin, aromatics, naphthene, and in small concentration of olefins. The presence of large number of n-paraffin’s leads to the increase of pour point (PP), cloud point (CP), cold filter plugging point (CFPP) values of diesel which makes diesel fuel ineffective in cold/arctic regions. PP in diesel refers to the temperature at which the diesel stops to flow in the motor vehicle. CP in diesel refers to the temperature at which the formation of crystals occurs in the diesel which leads to the low performance of the diesel fuel. CFPP refers to the temperature at which fuel will freely flow in the engines of the motor vehicle. According to GOST R 55475-2013, diesel can be regarded as winter diesel if its PP, & CP is less than -38 ?.

Intensive development of the Arctic/ cold region raises the demand of providing consumers with high quality diesel fuel with improved cold flow properties such as low PP, CP, and CFPP. This can be done by various techniques such as adjusting the fractionation in process units, blending with kerosene, and addition of cold flow depressants as additives into diesel fuel. These techniques may lead to higher costs of production in refinery units.

To address this challenge, isodewaxing process is often employed to produce diesel with improved cold flow properties (PP, CP, CFPP) and high diesel yield as it leads to reduction of n- paraffin's in the diesel fuel by minor hydrocracking and hydro isomerizing of n- paraffin's to iso-paraffins’s resulting in minimum loss of yield associated with n- paraffin removal by cracking or dewaxing exchange. The isodewaxing process allows higher yield of target fractions, i.e. it reduces the generation of low-molecular products gas and gasoline fraction. Another advantage of the process is it reduces the consumption of H2 gas.

For the above mentioned process, a suitable catalyst is required for selective isomerization of n-paraffin’s to iso-paraffins’s. Bifunctional catalysts such as zeolites combined with hydrogenating elements are suitable compounds to perform selective isomerization of n- paraffin's through HP HYDISOM method. Among zeolites, 2D zeolites act as a better catalyst compared to its other counterparts due to high external surface area, exposure of active sites externally, and contribution of large number of acidic sites. These properties make them as good support for any catalytic activity, especially in Hydroisomerisation reactions. Non-noble elements are preferred over noble elements as hydrogenating elements due to their low cost, and easy availability. Some of the prior arts mentioned here in below disclose catalyst and method for the hydrodeoxygenation, hydroisomerisation of various paraffin’s.

WO2022170338 discloses a catalyst for hydrodeoxygenation and hydroisomerization of paraffin’s having higher activity. The catalyst contains a molecular sieve, such as SAPO-11, a metal component such as platinum and/or palladium or nickel tungsten sulphide or nickel molybdenum sulphide and a binder such as gamma alumina. The catalyst exhibits a high proportion of weak acid sites and a relatively equal distribution of the metal component on the molecular sieve and the binder.

CN1098335C discloses a molecular sieve-based catalyst and its application for selective hydroisomerisation of long linear and/or branched paraffins are claimed. It consists of a matrix comprising of 5 wt.% of a hydro-dehydrogenating element chosen from a group composing of non-precious metals of group VIII, metals of group VIB, niobium and a molecular sieve containing a mono or a bi-dimensional porous network such that the pores openings accessible are limited by 10 oxygen atoms and the distance between the pores being less than 0.70 nm. The zeolite is the catalyst comprising of the zeolite and 0.5 wt.% of platinum, when subjected to the standard isomerisation test of n-heptadecane yields a selectivity of 70% of isomerised products for a conversion of 95%.

US11865527B2 discloses a hydroisomerization catalyst comprising a molecular sieve belonging to the ZSM-48 family of zeolites; an inorganic oxide support; one or more first modifiers selected from Groups 8 to 10; and one or more second modifiers selected from the group consisting of calcium (Ca), chromium (Cr), magnesium (Mg), lanthanum (La), barium (Ba), praseodymium (Pr), strontium (Sr), potassium (K) and neodymium (Nd). The molecular sieve comprises: a silicon oxide to aluminum oxide mole ratio of about 40 to about 220; at least about 70% polytype 6 of the total ZSM-48-type material present in the product; and an additional EUO-type molecular sieve phase in an amount of between about 0 and about 7.0 percent by weight of the total product. The molecular sieve has a morphology characterized as polycrystalline aggregates comprising crystallites collectively having an average aspect ratio of between about 1 and about 8.

However, the prior arts mentioned hereinabove discloses uses of solvent exchange method and use of additives for improving cold flow properties of the diesel, these methods are complex and also involves higher cost due to use of solvents and promoters. Also, the prior art processes are cost ineffective due to the use of catalyst in the metallic form. The prior disclosed catalyst also lacks long term stability and uses promoters. Thus, there is a need to develop a catalyst that provides improved cold flow properties without using additives, doesn’t use promoters and provides catalyst with long term stability at the same time cost effectively.

OBJECTIVES OF THE INVENTION:
It is the primary objective of the present invention to provide a suitable catalyst composition that can be used for isodewaxing of diesel feed for improving cold flow properties such as PP, CP, & CFPP.

Another objective of the present invention is to provide a process for the preparation of the catalyst composition by optimizing various parameters for using the developed catalyst to its full effect.

Yet another objective of the present invention is to provide a method for isodewaxing of diesel feed using the developed catalyst composition.

SUMMARY OF THE INVENTION:
The present invention discloses an isodewaxing catalyst, for use in Hydroisomerisation method on the diesel feed for improving cold flow properties of the winter diesel.

The present invention provides an isodewaxing catalyst for hydroisomerisation of diesel feed wherein the catalyst comprises:1% w/w to 6% w/w of non-noble metal; 50% w/w to 75% w/w of zeolite, wherein the zeolite is a 2D zeolite; and 24% w/w to 40% w/w of a binder.

The hydrogenating element impregnated on the support is non noble and contains transition elements from group VIB (Cr or Mo or W), or/ and group VIII (Fe or Co or Ni).

The non-noble metal is selected from metals Cr, Mo, W, Fe, Co and Ni or a combination thereof.

The catalyst which is used for isodewaxing of the diesel consists of a single support which is a zeolite from a group of MCM-22, MCM-41, ZSM-11, ZSM-22, ZSM-23, ZSM-48.

The zeolite is selected from the group consisting of MCM-22, MCM-41, ZSM-11, ZSM-22, ZSM-23, and ZSM-48 or a combination thereof.

The binder is selected from the group consisting of alumina, kaolin, PB-250, and PB-950.

Zeolite has BET surface area in a range of 600 to 900 m2/g; average pore diameter in a range of 6 to10 nm; and total acidic sites in a range of 200 to 1000 µmol/g.

The present invention provides a process for the preparation of an isodewaxing catalyst, comprising, mixing zeolite powder and a binder; homogenizing the mixture with a peptizing agent, wherein the peptizing agent is selected from CH3COOH and HNO3; extruding the homogenized mixture to obtain extrudes; drying the extrudes overnight and calcining at temperature in a range of 500 to 600 ? to obtain extruded zeolite support; impregnating metals on the extruded zeolite support using wet or dry impregnation method using aqueous solution of the salts of transition elements; and drying overnight and calcining at temperature in a range of 500 to 600 ? to obtain the isodewaxing catalyst.

The binder is selected from the group consisting of alumina, kaolin, PB-250, and PB-950.

The zeolite is selected from the group consisting of MCM-22, MCM-41, ZSM-11, ZSM-22, ZSM-23, and ZSM-48 or a combination thereof.

The present invention provides a method for hydroisomeration using the isodewaxing, wherein the method comprises: drying the isodewaxing catalyst under a nitrogen atmosphere at 130 to 175? for 2 to 4 hours at a pressure in a range of 2 to 4 bar; in situ sulphidation of the dried catalyst using a sulphiding agent under a hydrogen atmosphere at a temperature in a range of 275 to 325 ? and pressure in a range of 25 to 35 bar; and reacting diesel feed and sulphided catalyst in a fixed bed reactor at temperature in a range of 300 to 350 ?, pressure in a range of 25 to 40 bar, WHSV in a range of 2 to 4 h-1, and a ratio of H2/feed in a range of 750 to 1350 nm/m3 to obtain the isodewaxed diesel.

PP and CP is found to be <-51 ? while CFPP is found to be <-18 ?.

The isodewaxed diesel has yield in a range of 94 to 95 %, Cetane index value in a range of 47 to 52, sulphur concentration of 3 to 6 ppm, CP and PP value obtained is -51 to -55 ?, and CFPP value obtained is -18 to -23?.

The sulphiding agent is selected from the group consisting of Dimethyl sulphide (DMS), dimethyl disulphide (DMDS), methyl mercaptant and dimethyl sulphoxide (DMSO); preferably Dimethyl disulphide.

The experiments have been performed in fixed bed mode without use of promoters.

DETAILED DESCRIPTION OF THE INVENTION:
For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are delineated here. These definitions should be read in light of the remainder of the disclosure and understood as by a person of skill in the art.

The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below. The articles “a”, “an” and “the” are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.

The terms “comprise” and “comprising” are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as “consists of only”. The term "at least one" is used to mean one or more and thus includes individual components as well as mixtures/combinations. Throughout this specification, unless the context requires otherwise the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated element or step or group of element or steps but not the exclusion of any other element or step or group of element or steps. The term “including” is used to mean “including but not limited to”. “including” and “including but not limited to” are used interchangeably.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods and materials are now described.

The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally equivalent products, compositions, and methods are clearly within the scope of the disclosure, as described herein.

The diesel feed was subjected to Hydroisomerisation method for converting n-paraffin’s to iso-paraffins’s which helped in decreasing PP, CP, & CFPP of the winter diesel.

In an aspect, the present invention provides an isodewaxing catalyst for hydroisomerisation of diesel feed wherein the catalyst comprises:
a. 1% w/w to 6% w/w of non-noble metal;
b. 50% w/w to 75% w/w of zeolite, wherein the zeolite is a 2D zeolite; and
c. 24% w/w to 40% w/w of a binder.

In an embodiment of the present invention, the non-noble metal is selected from metals Cr, Mo, W, Fe, Co and Ni or a combination thereof.

In an embodiment of the present invention, the zeolite is selected from the group consisting of MCM-22, MCM-41, ZSM-11, ZSM-22, ZSM-23, and ZSM-48 or a combination thereof.
In an embodiment of the present invention, the binder is selected from the group consisting of alumina, kaolin, PB-250, and PB-950.

In an embodiment of the present invention, zeolite has BET surface area in a range of 600 to 900 m2/g; average pore diameter in a range of 6 to 10 nm; and total acidic sites in a range of 200 to 1000 µmol/g.

In another aspect, the present invention provides a process for the preparation of an isodewaxing catalyst, comprising,
a. mixing zeolite powder and a binder;
b. homogenizing the mixture with a peptizing agent, wherein the peptizing agent is selected from CH3COOH and HNO3;
c. extruding the homogenized mixture to obtain extrudes;
d. drying the extrudes overnight and calcining at temperature in a range of 500 to 600? to obtain extruded zeolite support;
e. impregnating metals on the extruded zeolite support using wet or dry impregnation method using aqueous solution of the salts of transition elements; and
f. drying overnight and calcining at temperature in a range of 500 to 600? to obtain the isodewaxing catalyst.

In an embodiment of the present invention, the binder is selected from the group consisting of alumina, kaolin, PB-250, and PB-950.

In an embodiment of the present invention, the zeolite is selected from the group consisting of MCM-22, MCM-41, ZSM-11, ZSM-22, ZSM-23, and ZSM-48 or a combination thereof.

In a yet another aspect, the present invention provides a method for hydroisomeration using the isodewaxing, wherein the method comprises:
a. drying the isodewaxing catalyst under a nitrogen atmosphere at 130 to 175? for 2 to 4 hours at a pressure in a range of 2 to 4 bar;
b. in situ sulphidation of the dried catalyst using a sulphiding agent under a hydrogen atmosphere at a temperature in a range of 275 to 325 ? and pressure in a range of 25 to 35 bar; and
c. reacting diesel feed and sulphided catalyst in a fixed bed reactor at temperature in a range of 300 to 350 ?, pressure in a range of 25 to 40 bar, WHSV in a range of 2 to 4 h-1, and a ratio of H2/feed in a range of 750 to 1350 nm/m3 to obtain the isodewaxed diesel.

In an embodiment of the present invention, the isodewaxed diesel has yield in a range of 94 to 95 %, Cetane index value in a range of 47 to 52, sulphur concentration of 3 to 6 ppm, CP and PP value obtained is in a range of -51 to -55 ?, and CFPP value obtained is in a range of -18 to -23?.

In an embodiment of the present invention, the sulphiding agent is selected from the group consisting of Dimethyl sulphide (DMS), dimethyl disulphide (DMDS), methyl mercaptant and dimethyl sulphoxide (DMSO), preferably Dimethyl disulphide.

The catalyst used in the process consists of single zeolite support whose BET surface area lies in between 600 to 900 m2/g, average pore diameter of the support is 6 to 10 nm while total acidic sites were found to be in the range of 200 to 1000 µmol/g.

The support was shaped in the form of extrudes by mixing with a binder from a group of either alumina, kaolin, PB-250, or PB-950 and using a peptizing agent such as 0.1 M CH3COOH or 0.1 M HNO3.

2D zeolites act as a better catalyst compared to its other counterparts due to high external surface area, exposure of active sites externally, and contribution of large number of acidic sites.

The hydrogenating elements used in the catalysts are non-noble elements and one / two elements from a group (Cr or Mo or W or Fe or Co or Ni) are impregnated.

The amount of zeolite used is 50 to 75 % weight of the catalyst, the non-noble metals impregnated lies in the range of 1 to 6 weight % of the catalyst, and rest of the amount of catalyst consist of binder.

The catalyst can be used in metallic or sulphide form. Both forms have advantages and disadvantages. For using a catalyst in metallic form, reduction of the catalyst has to be performed under hydrogen atmosphere for longer time and at elevated temperature greater than 400 ?. Furthermore, presence of non-noble metal elements in the catalyst deactivates the catalyst quickly in the presence of even minute amount of sulphur (10 ppm) in the diesel feed. To overcome this issue, catalyst in the form of sulphide is preferred at industrial scale to achieve stability of the catalyst. To convert a catalyst in the sulphide form, sulphiding agents such as dimethyl sulphide, dimethyl disulphide, methyl mercaptant, dimethyl sulphoxide, etc can be used. The sulphide form is obtained after treating the catalyst using sulphiding agent in the presence of hydrogen atmosphere at a temperature not more than 300 ?.

In the present invention, selective Hydroisomerisation with minimum loss of yield is performed by optimizing the catalyst’s physical parameters such as surface area, pore size, acidity, structure, and forms of catalyst. The process was further optimized by varying temperature, pressure, ratio of H2/ feed, and WHSV of the feed.

EXAMPLES:
Example 1: Catalyst synthesis.
In house synthesized zeolite powder was used as support material for the development of catalyst for the process. The extrudes of the synthesized powder were formed using a binder from a group consisting of alumina, kaolin, PB-250, or PB-950. The homogenization of binder to zeolite material was done using 0.1 M CH3COOH or 0.1 M HNO3. After making extrudes it was dried overnight and then calcined at temperature > 500 ? for 4 to 6 hours. In a preferred embodiment the temperature is in a range of 500 to 600 ?. After the supports got ready, transition elements were wet /dry impregnated using aqueous solution of the salts of transition elements. The impregnated zeolite was dried overnight and then calcined at temperature > 500 ? for suitable time. In a preferred embodiment the temperature is in a range of 500 to 600 ?.

Example 2: Fixed bed studies.
For isodewaxing of diesel using Hydroisomerisation method, fixed bed experiments were performed. After loading 2 to 4 g of catalyst, the catalyst was dried under nitrogen atmosphere at 150 ? for 3 hours in ambient pressure. After drying, in situ sulphidation of the catalyst was done using a sulphiding agent in the presence of hydrogen atmosphere at a temperature of 275 to 325 ? and pressure of 25 to 35 bar. After sulphidation completed, diesel feed was introduced and reaction was performed in the temperature range of 300 to 350 ?, pressure = 25 to 40 bar, WHSV = 2 to 4 h-1, and ratio of H2/feed = 750 to 1350 nm/m3 (Table 1).

Table. 1: Diesel feed before and after isomerization has following properties
Feed Property Method Isodewaxing process result #Standard BS VI specifications/
*GOST R 55475-2013

Pour Point (°C) D97 < -51 * (For winter diesel) <-38
Cloud Point (°C) D97 < -51 * (For winter diesel) <-38
Density (g/cc) D4052 0.8225 # 0.82-0.86
Kinematic Viscosity @ 40 ? (mm2/s) D445 2.034 # 2-4.5
Sulfur (ppm) D4294 5.2 # Maximum 10
Cold Filter Plugging Point (°C) D6371 < -18 # For summer diesel, maximum 18
# For winter diesel, maximum 6
Flash Point (°C) IP170 > 100 # minimum 35
Water Content (ppm) D4928 25 # Maximum 200
Cetane index D4737 49 # Minimum 46
Simulated distillation, ?, 95 % volume recovered D2887 383 # 370
Polycyclic Aromatic Hydrocarbon (PAH), max (%) mass HPLC-MS 3.27 # 11
Copper Strip Corrosion (3 hr. at
50°C) D 130 Class 1A # Class 1

The reaction was performed for more than 150 hours and CP, PP, & CFPP values were found to decrease drastically compared to reference feed i.e. <-51 ?, <-51 ?, & <-18 ?, respectively. In a preferred embodiment CP and PP lies between -51 to -55 ?, and CFPP lies between -18 to -23?.
The liquid yield of isodewaxed diesel after the experiment was found to be between 94-95 %. The product exhibits sulphur concentration of 3 to 6 ppm and Cetane index value in the range of 47 to 52.

Various experiments were performed by using the method of isodewaxing for straight run diesel to obtain cold flow properties matching with winter diesel.

Example 3: Isodewaxing of diesel feed using Catalyst sample 1.
The isodewaxing process is performed by using sample 1 as catalyst which contains zeolite ZSM-23 as support (60 % weight of catalyst), hydrogenating elements as nickel, and molybdenum (2% each by weight of catalyst), and alumina as binder (rest of the amount). The reaction parameters used are: temperature = 310 ?, pressure = 30 bar, WHSV = 2 h-1, ratio of H2/ feed = 900 nm/m3.

Example 4: Isodewaxing of diesel feed using Catalyst sample 2.
The isodewaxing process is performed by using sample 2 as catalyst which contains zeolite MCM-22 as support (65 % weight of catalyst), hydrogenating elements as cobalt, and molybdenum (2% each by weight of catalyst), and alumina as binder (rest of the amount). The reaction parameters used are: temperature = 325 ?, pressure = 30 bar, WHSV = 3 h-1, ratio of H2/ feed = 1100 nm/m3.

Example 5: Isodewaxing of diesel feed using Catalyst sample 3.
The isodewaxing process is performed by using sample 3 as catalyst which contains zeolite ZSM-11 as support (70 % weight of catalyst), hydrogenating elements as nickel, and tungsten (2% each by weight of catalyst), and PB-950 as binder (rest of the amount). Before experiment sulphidation of the catalyst was performed using DMDS as sulphiding agent. The reaction parameters used are: temperature = 350 ?, pressure = 30 bar, WHSV = 3 h-1, ratio of H2/ feed = 1000 nm/m3.

Example 6: Isodewaxing of diesel feed using Catalyst sample 4.
The isodewaxing process is performed by using sample 4 as catalyst which contains zeolite MCM-41 as support (55 % weight of catalyst), hydrogenating elements as iron (2% by weight of catalyst), and chromium (3% by weight of catalyst), and kaolin as binder (rest of the amount). The reaction parameters used are: temperature = 330 ?, pressure = 35 bar, WHSV = 2 h-1, ratio of H2/ feed = 1000 nm/m3.

Example 7: Isodewaxing of diesel feed using Catalyst sample 5.
The isodewaxing process is performed by using sample 5 as catalyst which contains zeolite ZSM-22 as support (72 % weight of catalyst), hydrogenating elements as cobalt and molybdenum (2% each by weight of catalyst), and PB-950 as binder (rest of the amount). The reaction parameters used are: temperature = 300 ?, pressure = 40 bar, WHSV = 4 h-1, ratio of H2/ feed = 800 nm/m3.

Example 8: Isodewaxing of diesel feed using Catalyst sample 6.
The isodewaxing process is performed by using sample 6 as catalyst which contains zeolite ZSM-48 as support (70 % weight of catalyst), hydrogenating elements as nickel (3% by weight of catalyst), and tungsten (3% by weight of catalyst), and kaolin as binder (rest of the amount). The reaction parameters used are: temperature = 320 ?, pressure = 40 bar, WHSV = 3 h-1, ratio of H2/ feed = 1200 nm/m3.

Advantages of the present invention:
1. Improvement of cold flow properties of winter diesel for using it in cold regions where temperature drops to below -10 ?.

2. The pour point and cloud point achieved is <-51 ? which showed that the diesel obtained can be considered as winter diesel.

3. The catalyst developed in the present invention contains non noble metals as hydrogenating elements which lowers the cost of catalyst. , Claims:1. An isodewaxing catalyst for hydroisomerisation of diesel feed wherein the catalyst comprises:
a. 1% w/w to 6% w/w of non-noble metal;
b. 50% w/w to 75% w/w of zeolite, wherein the zeolite is a 2D zeolite; and
c. 24% w/w to 40% w/w of a binder.

2. The isodewaxing catalyst as claimed in claim 1, wherein the non-noble metal is selected from metals Cr, Mo, W, Fe, Co and Ni or a combination thereof.

3. The isodewaxing catalyst as claimed in claim 1, wherein the zeolite is selected from the group consisting of MCM-22, MCM-41, ZSM-11, ZSM-22, ZSM-23, and ZSM-48 or a combination thereof.

4. The isodewaxing catalyst as claimed in claim 1, wherein the binder is selected from the group consisting of alumina, kaolin, PB-250, and PB-950.

5. The isodewaxing catalyst as claimed in claim 3, wherein the zeolite has BET surface area in a range of 600 to 900 m2/g; Average pore diameter in a range of 6 to 10 nm; total acidic sites in a range of 200 to 1000 µmol/g.

6. A process for the preparation of an isodewaxing catalyst as defined in claim 1, comprising,
a. mixing zeolite powder and a binder;
b. homogenizing the mixture with a peptizing agent, wherein the peptizing agent is selected from CH3COOH and HNO3;
c. extruding the homogenized mixture to obtain extrudes;
d. drying the extrudes overnight and calcining at 500 to 600 ? for 4 to 6 hours to obtain extruded zeolite support;
e. impregnating metals on the extruded zeolite support using wet or dry impregnation method using aqueous solution of the salts of transition elements; and
f. drying overnight and calcining at temperature in a range of 500 to 600 ? to obtain the isodewaxing catalyst.
7. The process as claimed in claim 6, wherein the binder is selected from the group consisting of alumina, kaolin, PB-250, and PB-950.

8. The process as claimed in claim 6, wherein the zeolite is selected from the group consisting of MCM-22, MCM-41, ZSM-11, ZSM-22, ZSM-23, and ZSM-48 or a combination thereof.

9. A method for hydroisomerisation using the isodewaxing catalyst as defined in claim 1, wherein the method comprises:
a. drying the isodewaxing catalyst under a nitrogen atmosphere at 130 to 175? for 2 to 4 hours at a pressure in a range of 2 to 4 bar.
b. in situ sulphidation of the dried catalyst using a sulphiding agent under a hydrogen atmosphere at a temperature in a range of 275 to 325 ? and pressure in a range of 25 to 35 bar; and
c. reacting diesel feed and sulphided catalyst in a fixed bed reactor at temperature in a range of 300 to 350 ?, pressure in a range of 25 to 40 bar, WHSV in a range of 2 to 4 h-1, and a ratio of H2/feed in a range of 750 to 1350 nm/m3 to obtain the isodewaxed diesel.

10. The method as claimed in claim 9, wherein the isodewaxed diesel has yield in a range of 94 to 95 %, Cetane index value in a range of 47 to 52, sulphur concentration of 3 to 6 ppm, CP and PP value obtained is in a range of -51 to -55 ?, and CFPP value obtained is in a range of -18 to -23?.

11. The method as claimed in claim 9, wherein the sulphiding agent is selected from the group consisting of Dimethyl sulphide (DMS), dimethyl disulphide (DMDS), methyl mercaptant and dimethyl sulphoxide (DMSO); preferably Dimethyl disulphide.