Catalyst additive composition for reduction of sulfur in gasoline

Abstract

The present invention relates to an improved CuAl.sub.2O.sub.4 spinel based catalyst additive composition having bi-modal pore size for improving gasoline sulfur removal activity by maintaining high gasoline selectivity and maintaining research octane number (RON) while cracking heavier hydrocarbon feedstocks in the fluid catalytic cracking unit. More particularly, present invention relates to a gasoline sulfur reduction (GSR) additive comprising copper aluminate spinel, acidic alumina matrix; and clay, wherein the additive having bimodal pore distribution. Present invention also relates to a process for preparing the gasoline sulfur reduction (GSR) additive.

Claims

1. A gasoline sulfur reduction (GSR) additive, the additive comprising: 10-30 wt. % of a copper aluminate spinel; 20-40 wt. % of an acidic alumina matrix; and 40-60 wt. % of a clay, and the wt. % being based on the total weight of the additive, wherein the additive has a bimodal pore distribution with 55-75% of total pores having a large pore diameter in the range of 200 to 400 and 25-45% of total pores having a mesoporous pore diameter in the range of 20-200 .

2. The additive as claimed in claim 1, wherein the copper aluminate spinel has a surface area in the range of 30-85 m.sup.2/gm and a total acidity in the range of 0.121-0.232 mmol/gm.

3. The additive as claimed in claim 1, wherein the acidic alumina matrix has a surface area in the range of 34-380 m.sup.2/gm, a total acidity in the range of 0.093-0.348 mmol/gm and a pore volume in the range of 0.19-0.82 cm.sup.3/gm.

4. The additive as claimed in claim 1, wherein the clay is selected from kaolinite, bentonite, illite, vermiculite, smectite, dolomite, or a combination thereof.

5. The additive as claimed in claim 1, wherein the additive has a total acidity in the range of 0.171-0.432 mmol/gm, a surface area in the range of 26 to 43 m.sup.2/gm, a pore volume in the range of 0.15 to 0.24 cm.sup.3/gm and an ABD in the range of 0.74 to 0.84 gm/cm.sup.3.

6. A process for preparing the gasoline sulfur reduction (GSR) additive as claimed in claim 1, the process comprising: i. milling 20-40 wt. % of alumina and 40-60 wt. % of the clay to obtain a clay-alumina slurry; ii. peptizing the clay-alumina slurry with an acid to obtain a peptized clay-alumina slurry; iii. adding 10-30 wt. % of the copper aluminate spinel to the peptized clay-alumina slurry and stirring the same for homogenization to obtain a final slurry; iv. spray drying the final slurry of step (iii) to obtain microspheres having a dimension in the range of 20-300 micron and an ABD greater than 0.74 gm/cm.sup.3; and v. calcining the microspheres to obtain the gasoline sulfur reduction (GSR) additive.

7. The process as claimed in claim 6, wherein the acid is selected from formic acid and nitric acid.

8. The process as claimed in claim 6, wherein the copper aluminate spinel of step (iii) is prepared by a co-precipitation method either by a sequential addition or a simultaneous addition.

9. The process as claimed in claim 6, wherein the final slurry of step (iii) has a pH in the range of 3-4.

10. The process as claimed in claim 6, wherein the spray drying of step (iv) is carried out with an inlet temperature of 300-400 C., and with an outlet temperature of 150-200 C. to obtain the microspheres having a dimension in the range of 45-300.

11. The process as claimed in claim 6, wherein the alumina has a pore size in the range of 20 to 400 .

12. The process as claimed in claim 6, wherein the copper aluminate spinel has a pore size in the range of 30 to 60 .

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates Pore size distribution of additive;

(2) FIG. 2 illustrates the gasoline yield vis--vis amount of sulfur with base catalyst and base catalyst with additive-1 (10 wt % concentration and 15 wt % concentration);

(3) FIG. 3 illustrates the gasoline yield vis--vis amount of sulfur with base catalyst and base catalyst with Additive 1, Additive 2 and Additive 3 (10 wt % concentration); and

(4) FIG. 4 XRD pattern of Copper aluminate calcined at 850 C. and 1000 C.

DETAILED DESCRIPTION OF THE INVENTION

(5) Accordingly, present invention provides a gasoline sulfur reduction (GSR) additive comprising:

(6) 10-30 wt. % of copper aluminate spinel;

(7) 20-40 wt. % of acidic alumina matrix; and

(8) 40-60 wt. % of clay, and the wt. % being based on the total weight of the additive,

(9) wherein the additive having bimodal pore distribution with 55-75% of total pore is large pore diameter in the range of >200 to 400 and 25-45% of total pore is mesoporous pore diameter in the range of 20-200 .

(10) In one of the feature of the present invention, the copper aluminate spinel is having surface area in the range of 30-85 m.sup.2/gm and total acidity in the range of 0.121-0.232 mmol/gm.

(11) In another feature of the present invention, the acidic alumina is having surface area in the range of 34-380 m.sup.2/gm, total acidity in the range of 0.093-0.348 mmol/gm and pore volume in the range of 0.19-0.82 cm.sup.3/gm.

(12) In yet another feature of the present invention, the clay is selected from kaolinite, bentonite, illite, vermiculite, smectite, dolomite, or combination thereof.

(13) In still another feature of the present invention, the additive is having total acidity in the range of 0.171-0.432 mmol/gm, surface area in the range of 26 to 43 m.sup.2/gm, pore volume in the range of 0.15 to 0.24 cm.sup.3/gm and ABD is in the range of 0.74 to 0.84 gm/cm.sup.3.

(14) In yet another feature of the present invention, the additive is used in a fluid catalytic cracking (FCC) unit at 10-25 wt % concentration and the remaining 90-75 wt % is a base catalyst.

(15) In yet another feature of the present invention, the additive gives gasoline product having RON in the range of 91.2-92.1 and gasoline produce sulphur reduction in the range of 24-33 wt %.

(16) Present invention also provides a process for preparing the gasoline sulfur reduction (GSR) additive comprising: i. milling 20-40 wt. % of alumina and 40-60 wt. % of clay to obtain a clay-alumina slurry; ii. peptizing the clay-alumina slurry with an acid to obtain a peptized clay-alumina slurry; iii. adding 10-30 wt. % of copper aluminate spinel to the peptized clay-alumina slurry and stirring the same for homogenization to obtain final slurry; iv. spray drying the final slurry of step (iii) to obtain microspheres having 20-300 micron particle with ABD>0.74 gm/cc; and v. calcining the obtained microsphere to obtain the gasoline sulfur reduction (GSR) additive.

(17) In one of the feature of the present invention, in the above process the acid is selected from formic acid and nitric acid.

(18) In another feature of the present invention, the copper aluminate spinel of step (iii) is prepared by co-precipitation method by sequential addition or simultaneous addition.

(19) In yet another feature of the present invention, the pH of the final slurry step (iii) is in the range of 3-4.

(20) In yet another feature of the present invention, the spray drying of step (iv) is carried out with inlet temperature 300-400 C., out let temperature 150-200 C., the microsphere having dimension of 45-300.

(21) In still another feature of the present invention, the alumina used in the above process is having pore size in the range of 20 to 400 .

(22) In yet another feature of the present invention, the copper aluminate spinel used in the above process is having pore size in the range of 30 to 60 .

(23) Feedstocks:

(24) Feed stock for the present invention includes a wide range of heavy as well as hydrocarbon fractions starting from fractions such as vacuum gas oil, hydro treated vacuum gas oil, once through hydro cracker unit bottom, short residue and their mixtures, etc. The preferred types of feed stocks used in this invention are the residual fractions having metals (Ni+V) up to a value of 28.43 ppm. Table 1 gives the properties of feed stock used in this invention.

(25) TABLE-US-00001 TABLE 1 Feed properties Feed-2 Feed-1 30% 80% VGO & OHCUB & 20% Short Attribute Units 70% HVGO Residue Density, @ 15 C. G/cc 0.8937 0.9391 Kin Viscosity @ 100 C. CST 22.4 @ 50 C. 12.69 CST Sulphur Wt % 0.5 3.59 CCR Wt % 0.2 4.06 Total N.sub.2 ppmw 1150 1294 Na ppmw <1 0.38 Fe ppmw <1 0.72 V ppmw <1 21.53 Ni ppmw <1 6.9 PNA, wt % Aromatics 45.2 Saturates 54.8 CA- % Aromatic Ring Carbons 23.02 CP- % Paraffinic Ring Carbons 58.34 CN- % Naphthenic Ring 18.64 Carbons

(26) Synthesis of Copper Aluminate Spinel (CuAl.sub.2O.sub.4):

(27) Additive system employed in this invention includes three types of components in varied quantity, namely, copper aluminate spinel, large pore acidic alumina matrix and clay. First the copper aluminate is prepared by co-precipitation method by sequential addition and simultaneous addition.

Example 1

(28) Batch 1:

(29) Copper aluminate spinel was synthesized by co-precipitation method using copper (II) nitrate hexahydrate as source of copper and sodium aluminate as source of aluminium. 241.6 g of copper (II) nitrate hexahydrate, 10 g of concentrate nitric acid (68%) and 5000 g of DM water were mixed uniformly (Solution-A). In another beaker, 185 g sodium aluminate and 2000 g of DM water were stirred thoroughly to obtain clear solution of B. The solution-B was added into solution-A at constant flow rate by employing peristaltic pump at half an hour of addition time. During the addition of solution B into solution A, pH of the slurry was monitored by using Metrohm digital pH meter. Final pH of the slurry was 11 and reaction temperature is 40 C. After the precipitation was completed, the stirring was continued for 1 hour to obtain uniform mixing and to complete the hydrolysis. After 1 h, entire slurry was filtered out and washed repeatedly with hot water to obtain the material without sodium ion as impurities. The material was dried at 120 C. for overnight, and calcined at 850 C. and 1000 C. for 2 h. The synthesized material is designated as copper aluminate CuAl.sub.2O.sub.4. The XRD pattern of the sample calcined at 850 C. shows mixed CuO and CuAl.sub.2O.sub.4 (41%) and the sample calcined at 1000 C. shows 90% CuAl.sub.2O.sub.4 spinel.

(30) Batch 2:

(31) Copper aluminate spinel was synthesized by co-precipitation method using copper (II) nitrate hexahydrate as source of copper and sodium aluminate as source of aluminium. 241.6 g of copper (II) nitrate hexahydrate, 10 g of concentrate nitric acid (68%) and 5000 g of DM water were mixed uniformly (Solution-A). In another beaker, 185 g sodium aluminate and 2000 g of DM water were stirred thoroughly to obtain clear solution of B. The solution-A and solution-B were simultaneously mixed at constant flow rate by employing peristaltic pump at half an hour of addition time. During the simultaneous addition, pH of the slurry was monitored by using Metrohm digital pH meter. Final pH of the slurry was 11 and reaction temperature is 40 C. After the precipitation was completed, the stirring was continued for 1 hour to obtain uniform mixing and to complete the hydrolysis. After 1 h, entire slurry was filtered out and washed repeatedly with hot water to obtain the material without sodium ion as impurities. The material was dried at 120 C. for overnight, and calcined at 850 C. and 1000 C. for 2 h. The synthesized material is designated as copper aluminate CuAl.sub.2O.sub.4. The XRD pattern (FIG. 4) of the sample calcined at 850 C. shows mixed CuO and CuAl.sub.2O.sub.4 (48%) and the sample calcined at 1000 C. shows 98% CuAl.sub.2O.sub.4 spinel.

(32) The XRD pattern of copper aluminate confirms the formation of copper aluminate along with copper oxide. Upon increasing calcination temperature, copper oxide present in the surface reacting with free available alumina and forming copper aluminate spinel. Hence, the formation of spinel lattice confirming increase of intensity at 31.3, 36.86, 44.8, 55.7, 59.4 and 62.2 degree (2) and decreasing the copper oxide peaks.

(33) Batch 3:

(34) Copper aluminate spinel was synthesized by co-precipitation method using copper (II) nitrate hexahydrate as source of copper and aluminium sulphate hexadecahydrate as source of aluminium. Sodium hydroxide is used as hydrolyzing agent. 241.6 g of copper (II) nitrate hexahydrate, 630 g of aluminium sulphate hexadecahydrate and 5000 g of DM water were mixed uniformly (Solution-A). In another beaker, 320 g of sodium hydroxide and 2000 g of DM water were stirred thoroughly to obtain clear solution of B. The solution-B and solution-A were simultaneously mixed at constant flow rate by employing peristaltic pump at half an hour of addition time. During the simultaneous addition, pH of the slurry was monitored by using Metrohm digital pH meter. Final pH of the slurry was 11 and reaction temperature is 40 C. After the precipitation was completed, the stirring was continued for 1 hour to obtain uniform mixing and to complete the hydrolysis. After 1 h, entire slurry was filtered out and washed repeatedly with hot water to obtain the material without sodium ion as impurities. The material was dried at 120 C. for overnight, and calcined at 850 C. and 1000 C. for 2 h. The synthesized material is designated as copper aluminate CuAl.sub.2O.sub.4. The XRD pattern of the sample calcined at 850 C. shows mixed CuO and CuAl.sub.2O.sub.4 (43%) and the sample calcined at 1000 C. shows 95% CuAl.sub.2O.sub.4 spinel.

(35) The prepared copper aluminate support shows surface area in the range of 30-85 m.sup.2/gm and total acidity in the range of 0.121-0.232 mmol/gm. The Batch 2 sample having high acidity (0.232 mmol/gm) and moderate surface area is used for preparing the gasoline sulfur reduction additive.

(36) Table 2 lists the preparation method and the properties of prepared copper aluminate spinel.

(37) TABLE-US-00002 TABLE 2 Synthesis of Copper Aluminate Spinel (CuAl.sub.2O.sub.4) and its properties: Total Calcination End XRD SA Acidity Batch Preparation temperature, C. pH (% of spinel phase) (m.sup.2/g) mmol/gm 1 Source: CuN + NaAl (+HNO.sub.3) 850 11 Mixed CuO and 85 0.166 Method: Precipitation method, CuAl.sub.2O.sub.4 (41%) Sequential, RT 40 C. 2 Source: CuN + NaAl (+HNO.sub.3) 850 11 Mixed CuO and 54 0.232 Method: Precipitation method, CuAl.sub.2O.sub.4 (48%) Simultaneous, RT 40 C. 3 Source: CuN + AlS + NaOH 850 11 Mixed CuO and 55 0.182 Method: Precipitation method CuAl.sub.2O.sub.4 (43%) Simultaneous, RT 40 C. 4 Source: CuN + NaAl (+HNO.sub.3) 1000 11 Mixed CuO and 30 0.121 Method: Precipitation method, CuAl.sub.2O.sub.4 (95%) Simultaneous, RT 40 C.

Example-2

(38) Additive Preparation:

(39) The Gasoline Sulfur Reduction (GSR) additives were prepared from Cu based spinel obtained from Batch 2 mentioned in example 1 as active support, different pore size alumina as matrix component and clay as filer/provides mechanical strength to catalyst. The additive composition was spinel (10-30%): Alumina (20-40%): Clay (40-60%). The additive was prepared by following steps:

(40) Step 1:

(41) The commercial alumina having different properties is employed in the additive preparation and the properties are shown in the Table 3.

(42) TABLE-US-00003 TABLE 3 Properties of alumina Surface Pore Pore size Total area volume distribution Acidity S. No. Description (m.sup.2/g) (m.sup.3/g) () mmol/gm 1. Alumina-1 350 0.44 82% <50 0.348 APD = 41 2. Alumina-2 275 0.84 4% (<50 ), 51% 0.291 (50-100 ), 22% (100-200 ), 23 (<200 ) APD = 93 3. Alumina-3 34 0.21 76% >200 0.093 APD = 165

(43) The acidic alumina having high acidity has APD of 41-165 is responsible for optimum interaction of free weak basic CuO (52%) to form the final additive having pore size more than 200 .

(44) Appropriate amount of alumina 1, alumina 2 and alumina 3 and clay were milled together for 2 hours. Obtained clay-alumina slurry was peptized with formic acid (85%). The slurry was mixed thoroughly for 1 h.

(45) Step 2:

(46) Required amount of spinel materials obtained from Experiments 1, 2 and 3 were added to clay-alumina slurry and stirred for homogenization for 30 minutes. pH of the final slurry is in the range of 3-4.

(47) Step 3:

(48) The final slurry was spray dried with inlet temperature 370 C., out let temperature 150 C., the microsphere having dimension of 45-300, was subjected to calcinations at 550 C. for 2 hr.

(49) Table 4 shows the composition of the gasoline sulfur reduction additive and its properties such as surface area, pore volume, apparent bulk density and pore diameter. The prepared additive has shown bi model pore in the range of 20 -200 and 201-400 (FIG. 1). Additive 1 has the highest percentage of pore in the range 20 -200 i.e. 41.7 and Additive 3 has the highest percentage of pore in the range of 201-400 i.e. 73.6.

(50) TABLE-US-00004 TABLE 4 Properties of Additive prepared: Preparation Alumina Spinel Clay Properties of additive Additive-1 Commercial Spinel-2 from 50% SA = 40 m.sup.2/gm Alumina-1 (20%) the Batch 2 of Pore Dia : SA = 380 m.sup.2/gm Example 1 20-200 = 41.7 Avg Pore Dia = 41 (30%) 201-400 = 58.3 PV = 0.3798 cm.sup.3/gm PV = 0.204 cm.sup.3/gm ABD = 0.84 gm/cc Total Acidity = 0.432 mmol/gm Additive-2 Commercial Spinel-2 from 50% SA = 43 m.sup.2/gm Alumina-2 (20%) the Batch 2 of Pore Dia : SA = 354.9 m.sup.2/gm Example 1 20-200 = 39.6 Avg Pore Dia = 93 (30%) 201-400 = 60.4 PV = 0.8239 cm.sup.3/gm PV = 0.236 cm.sup.3/gm ABD = 0.74 gm/cc Total Acidity = 0.332 mmol/gm Additive-3 Commercial Spinel-2 from 50% SA = 26 m.sup.2/gm Alumina-3 (20%) the Batch 2 of Pore Dia : SA = 47.72 m.sup.2/gm Example 1 20-200 = 26.4 Avg Pore Dia = 165 (30%) 201-400 = 73.6 PV = 0.197 cm.sup.3/gm PV = 0.149 cm.sup.3/gm ABD = 0.75 gm/cc Total Acidity = 0.171 mmol/gm

Example 3

(51) Commercial FCC and RFCC catalyst were used to check the performance of the spinel based GSR additive. Before the micro activity test experiment the catalysts and additive were pretreated to simulate the hydrothermal deactivation, which occurs in a commercial regenerator.

(52) Pretreatment of Fresh FCC and RFCC Catalyst and GSR Additives: (i) The FCC catalyst was hydrothermally deactivated at 850 C. for 5 hrs and the additives were hydrothermally deactivated at 750 C. for 3 hrs without metal. (ii) The RFCC catalyst and additive sample were impregnated with 2500 ppm nickel and 7000 ppm vanadium by Mitchell method as per the procedure mentioned in B. R. Mitchell, Ind. Eng. Chem. Prod. Res. Dev. 19 (1980) 209-213, Title: Metal Contamination of Cracking Catalysts. 1. Synthetic Metals Deposition on Fresh Catalysts. The RFCC catalyst and additive were impregnated with a required volume of the impregnation solution that was double the pore volume of the catalysts. The excess solvent was removed in a rotary evaporator at 80 C. The remaining organics were burned off with air at 150 C. for 3 h followed by calcinations for 550 C. for 1 h. Hydro thermal deactivation was carried out at 788 C. temperature for 3 hrs for catalyst and 750 C. temperature for 3 hrs for additive sample.

Example 4

(53) Simulated MAT Experiment and Product Characterization:

(54) The activity measurement for base catalyst and additive samples (10 wt % concentration) was done using advanced cracking evaluation resid (ACE R+) MAT unit supplied by M/s. Kayser technologies, USA. The experiments were carried out at the catalyst/oil ratio of 4.5, 6.0 and 7.5 by varying the amount of catalyst loading (with and without additive) at a constant feed rate and feed injection time. The feed injection time was such; it minimized the effect of time averaging on yields because of catalyst deactivation due to the formation of coke. Reactor operating temperature was maintained close to the riser outlet temperature in the commercial plant (i.e. 510 C.). After the completion of the reaction, the catalyst was stripped with nitrogen to remove adsorbed reaction products. Coke on the catalyst was determined by in-situ regeneration at about 650 C. by fluidizing with air. The gaseous sample was analyzed, online, by M/s. Agilent micro gas chromatography analyzer. The H.sub.2, C.sub.1, C.sub.2, C.sub.3, C.sub.4, and C.sub.5 lump were determined quantitatively. The liquid products were diluted in the CS.sub.2 solvent and analyzed in a simulated distillation analyzer (Make and ModelPerkin Elmer Clarus 500 gas chromatography). The percentage of the liquid products boiling in the range of gasoline (C5-150 C.), heavy naphtha (C150-216 C.), light cycle oil (C-216-370 C.) and clarified oil (370 C.+) were calculated. Carbon content of the catalyst was determined by online IR analyzer (Make and ModelServomex 1440).

(55) The collected product samples were analyzed for the presence of sulfur in Analytical Control's high-temperature carbon-nitrogen-sulfur simulated distillation (HT CNS SIMDIST) analyzer with Agilent 7890B gas chromatography. The paraffin, olefins, naphthenes, and aromatics (PONA) analysis and RON of the product samples were analyzed in Analytical Control's built-in custom paraffin, iso-paraffins, olefins, naphthenes and aromatics (PIONA) pre-fractionator M3 reformulyzer analyzer with Agilent's 7890 gas chromatography.

Example 4A

(56) The cracking experiment with base catalyst and base catalyst along with additive 1 (10 & 15 wt % concentration) and feedstock-1 at FCC condition is given in Table 5. The experiments were conducted at three different Cat/Oil. The yields and sulfur reduction of base catalyst and base catalyst along with additive were calculated at the constant conversion of 59.67 wt %. FIG. 2 indicates the gasoline yield vis--vis amount of sulfur with base catalyst and base catalyst with additive (10 wt % concentration and 15 wt % concentration).

(57) TABLE-US-00005 TABLE 5 Cracking experiment yields with feedstock-1 with additive 1 and Sulfur in product gasoline sample. Base + Base + Yields, wt % Base 10% Additive 1 15% Additive 1 Dry gas 1.42 1.45 1.6 LPG 16.72 15.86 16.45 Gasoline (C5 = 150 C.) 28.83 29.04 28.65 Heavy Naphtha (150-216 C.) 7.33 7.86 7.49 Light Cycle Oil (216-370 C.) 22.79 23.3 23.44 Clarified Oil (216-370 C.) 17.54 17.04 16.89 Coke 5.37 5.45 5.48 Conversion, wt % 59.67 59.66 59.67 Sulfur in gasoline, ppm 585 443 393 % Sulfur Reduction 24.36 32.76

(58) The additive A with Pore Diameter in the range of <20 -200 range has highest percentage 41.7%, which could able to remove sulfur in gasoline from 585 ppm to 443 ppm with 10 wt % additive concentration and from 585 ppm to 393 ppm with 15 wt % additive concentration. At 216 C. conversion of 59.67 wt % the selectivity of gasoline is high when the additive concentration is 10 wt %. Because of the large pore alumina matrix in the additive preparation could able to reduce the clarified yield from 17.54 wt % to 17.04 wt % and 16.89 wt %.

Example 4B

(59) The cracking experiment with base catalyst and base catalyst along with 10 wt % additive concentration (Additive 1, Additive 2 and Additive 3) and feedstock-1 at RFCC condition is given in Table 6.

(60) TABLE-US-00006 TABLE 6 Cracking experiment yields with feedstock 2 with Additive 1, Additive 2 and Additive 3 and Sulfur in product gasoline sample. Metal Level Nickel, ppm 2500 2500 2500 2500 Vanadium, ppm 7000 7000 7000 7000 Base + 10% Base + 10% Base + 10% Yields, wt % Base Additive 1 Additive 2 Additive 3 Drygas 2.52 2.53 2.53 2.47 LPG 15.71 15.11 15.01 14.91 Gasoline (C5 = 150 C.) 23.98 23.68 23.47 23.56 Heavy Naphtha (150-216 C.) 6.65 6.54 6.75 6.89 Light Cycle Oil (216-370 C.) 23.99 25.05 24.80 24.53 Clarified Oil (216-370 C.) 19.07 18.01 18.26 18.53 Coke 8.08 9.08 9.18 9.11 Conversion, wt % 56.94 56.94 56.94 56.94 Sulfur in gasoline, ppm 1397 688 1018 1183 % Sulfur Reduction 50.74 27.14 15.32 RON 91.2 92.1 91.7 91.9

(61) The additive having highest percentage in the 20 -200 pore diameter helped to reduce the sulfur in the gasoline range molecule. Additive 1 has produces lowest sulfur in gasoline i.e. 688 ppm. The gasoline selectivity is maintained in the same range for all the additives. Because of the large pore alumina matrix in the formulation helped to maintain the similar selectivities even after the main catalyst diluted with 10 wt % additive concentration. Further it also helped to reduce the clarified oil yield of base catalyst from 19.07 wt % to 18.01 wt % (Additive 1), 18.26 wt % (Additive 2) and 18.53 wt % (Additive 3).

(62) FIG. 3 indicates the gasoline yield vis--vis amount of sulfur with base catalyst and base catalyst with Additive 1, Additive 2 and Additive 3 (10 wt % concentration).

(63) Further it also helped to increase the octane number of base catalyst from 91.2 wt % to 92.1 wt % (Additive 1), 91.7 wt % (Additive 2) and 91.9 wt % (Additive 3).