Description:FIELD OF THE INVENTION:
The present invention relates to petroleum refining catalysts. Particularly, the present invention relates to a Fluid Catalytic Cracking (FCC) catalyst composition for high severity FCC to produce light olefins. In particular, the present invention relates to the FCC catalyst and the method for preparation thereof wherein the FCC catalyst composition shows higher selectivity of propylene, and lower selectivity of dry gas and LCO (light cycle oil).

BACKGROUND OF THE INVENTION:
Fluid catalytic cracking (FCC), as an important process for petroleum refining, and is an important means to improve the economic benefits in a refinery plant. In the FCC process, heavy oils, with catalyst can be converted into such products as gasoline, diesel, ethylene, propylene, butylene, slurry, dry gas and coke, wherein gasoline, diesel, ethylene, propylene and butylene have high economic value, while dry gas, slurry and coke have lower economic value.
In Fluid catalytic cracking (FCC) process, a hydrocarbon feedstock is injected into the riser section of a FCC reactor, where the feedstock is cracked into lighter, more valuable products upon contacting hot catalyst circulated to the riser-reactor from a catalyst regenerator. A major breakthrough in FCC catalysts came in the early 1960s, with the introduction of molecular sieves or zeolites. These materials were incorporated into the matrix of amorphous and/or amorphous/kaolin materials constituting the FCC catalysts of that time. These new zeolitic catalysts, containing a crystalline aluminosilicate zeolite in an amorphous or amorphous/kaolin matrix of silica, alumina, silica-alumina, kaolin, clay or the like were at least 1,000-10,000 times more active for cracking hydrocarbons than the earlier amorphous or amorphous/kaolin containing silica-alumina catalysts. This introduction of zeolitic cracking catalysts revolutionized the fluid catalytic cracking process. New processes were developed to handle these high activities, such as riser cracking, shortened contact times, new regeneration processes, new improved zeolitic catalyst developments, and the like.
Low-carbon olefins including ethylene, propylene and butylene are petrochemical raw materials and their demand is increasing year by year. The lower olefin such as ethylene, propylene, butylene are an important raw material and can be used for synthesizing resin, fiber, and rubber. Propylene is an important raw material for manufacturing petrochemical products, and is mainly used for producing chemical products such as polypropylene, acrylonitrile and propylene oxide, Currently, major demand of propylene is met as a byproduct of ethylene production. However, the FCC process is the second most important source of low-carbon olefins, especially propylene and adding of low-carbon olefins additives to the cracking device is an important method for producing more low-carbon olefins.
The zeolites typically used in FCC are crystalline aluminosilicates which have a uniform crystal structure characterized by a large number of regular small cavities interconnected by a large number of even smaller channels. It was discovered that, by virtue of this structure consisting of a network of interconnected uniformly sized cavities and channels, crystalline zeolites are able to accept, for absorption, molecules having sizes below a certain well-defined value while rejecting molecules of larger sizes, and for this reason they have come to be known as “molecular sieves.” This characteristic structure also gives them catalytic properties, especially for certain types of hydrocarbon conversions. Also, since one of the benefits of using a zeolite catalyst is that the catalyst is shape selective and non-selective reactions on the surface of the zeolite are usually not desirable, zeolite catalysts used in hydrocarbon conversion processes have the capability of preventing or at least reducing unwanted reactions which may take place on the surface of the zeolite catalyst by selectively sieving molecules in the feed stream based on their size or shape. Thus, undesirable molecules present in the feed stream are prevented from entering the pores of the catalyst and reacting. In addition, the performance of a zeolite catalyst can sometimes be maximized if the catalyst selectively sieves desired molecules based on their size or shape in order to prevent the molecules from exiting the pores of the catalyst.
In current commercial practice, most FCC cracking catalysts used throughout the world are made of a catalytically active component large-pore zeolite. Conventional large-pore molecular sieves include REX; zeolite Y; Ultrastable Y (USY); Rare Earth exchanged Y (REY); Rare Earth exchanged USY (REUSY); Dealuminated Y (DeAl Y); Ultrahydrophobic Y (UHPY); and/or dealuminated silicon-enriched zeolites, e.g., LZ-210. ZSM-20, zeolite L and naturally occurring zeolites such as faujasite, mordenite and the like have also been used.
In addition to medium pore zeolites, the ZSM family of zeolites is well known, and their preparation and properties have been extensively described in the catalytic cracking of hydrocarbons. For example, one type of the ZSM family of zeolites is that known as ZSM-5.
US10894248B2 discloses a catalyst composition comprising rare earth exchanged USY zeolite (REUSY); pentasil zeolite; phosphorous compound; clay, silica, alumina, and spinel to enhance the catalytic activity and selectivity for light olefins in FCC operation conditions. The present invention also provides a process for the preparation of Light olefin enhancing catalyst composition with high propylene yield and coke selectivity.
US9227181B2 discloses discloses a catalyst composition resulting in increased propylene yields during fluid catalytic cracking processes comprises (i) Y zeolite, (ii) ZSM-5 zeolite, and (iii) Beta zeolite.
US20220219151A1 discloses a bifunctional additive for increasing low-carbon olefins and reducing slurry in cracking product, wherein the dry-basis components of said additive is as follows: 40˜55 wt % of phosphorus-containing MFI zeolite, 0˜10 wt % of large pore type Y and Beta zeolites, 3˜20 wt % of inorganic binder, 8˜22 wt % of inorganic matrix composed of alumina and amorphous silica-alumina and 15˜40 wt % of clay. The bifunctional additive is mainly used to facilitate production rate of cracked LPG and increase concentration of propylene in LPG and octane number of produced the gasoline, and at the same time reduce the yield of slurry in the cracking products. The invention also discloses its preparation method and application of said additive.
CN112473732A discloses a catalytic cracking catalyst for producing propylene, and a preparation method and an application method thereof. The catalyst comprises: natural mineral substances, zirconium-aluminum composite sol, other inorganic oxide binders, Y-type molecular sieves and MFI structure molecular sieves. The preparation method of the catalyst comprises the steps of mixing and pulping the MFI structure molecular sieve, the Y-type molecular sieve, natural minerals, zirconium-aluminum sol and other inorganic oxide binders, and spray drying.
US10844294B2 discloses an integrated process catalytically cracks whole light crude oil into light olefins, especially propylene and ethylene. The process is integrated with an adjacent conventional fluid catalytic cracking unit whereby the heavy liquid product mixture (light and heavy cycle oils) from whole crude oil cracking is mixed with vacuum gas oil (VGO) for further processing. The process comprises recycling total product fraction of light cracked naphtha (LCN) and mixing with fresh crude oil feed. High propylene and ethylene yields are obtained by cracking the whole light crude oil and LCN in an FCC configuration using a mixture of FCC catalyst and ZSM-5 additive at a temperature between, that of conventional FCC and steam cracking.
Light olefins (C2-C4 olefins) are important feedstocks for the petrochemical industry. Propylene, for example, a light olefin is an important chemical for use in the production of other useful materials, such as polypropylene. Polypropylene is one of the most common plastics found in use today and has a wide variety of uses for both as a fabrication material and as a material for packaging there is a need to develop catalyst for FCC process with higher selectivity for propylene that can cater to increasing demand.

OBJECTIVES OF THE INVENTION:
The main objective of the present invention is to provide an FCC catalyst composition that results in a significant increase in yield of light olefins.
Another, object of the present invention is to provide an FCC catalyst composition for enhancing selectivity of propylene.
It is also an object of the present invention to provide an FCC catalyst composition that has low selectivity for dry gases and light cycle oil (LCO) in fluid catalytic cracking (FCC) process.

SUMMARY OF THE INVENTION:
The present invention relates to a fluid catalytic cracking (FCC) catalyst composition, comprising: 10-20 wt % rare-earth metal modified ultra-stable Y zeolite (REUSY);10-30 wt % phosphorous modified zeolite (P-ZSM-5);15-30 wt % clay;10-25 wt % silica and15-25 wt % alumina, wherein the wt. % being based on total weight of the catalyst composition.
The rare earth metal modified ultra-stable Y zeolite comprises of 1 to 2 wt % of rare earth metal and the rare earth metal is selected from a group consisting of Lanthanum, cerium, praseodymium, samarium, europium, ytterbium, lutecium.
The rare earth metal modified ultra stable Y zeolite have pore size in a range of 6 to 8 Å and the phosphorous modified zeolite (P-ZSM-5) have pore size in a range of 5 to 6 Å.
The phosphorus modified zeolite (P-ZSM-5) has phosphorous content in a range of 0.2 to 1 wt.%.
The clay has density in a range of 0.3-0.4 g/cc and is selected from a group consisting of kaolin, attapulgite, bentonite, montmorillonite, diatomite clay.
The alumina is boehmite alumina having soda content in a range of 0.005 to 0.010 wt.%.
The catalyst composition has particle size in a range of 70-80 microns, average bulk density in a range of 0.8-0.85 g/cc and attrition in a range of 3-4 %.
The catalyst composition in Fluid catalytic cracking provides higher propylene to ethylene ratio, propylene yield in a range of 16-18 wt.%, lighter olefins yield in a range of 32-34 wt.% and Lower dry gas yield of at least 2 wt.%.
Further, the present invention provides a method for preparing a fluid catalytic cracking (FCC) catalyst composition comprising: milling of clay and alumina with water for time in the range of 2 to 3 hours to obtain a milled slurry; acidification of the milled slurry with a 20 to 98 % protic acid to obtain an acidified clay -alumina slurry; adding rare earth metal modified ultra-stable Y zeolite while stirring to the acidified clay alumina slurry of step (b) to obtain an acidified clay-alumina-zeolite slurry; adding the phosphorus modified ZSM-5 to the acidified clay-alumina- zeolite slurry of step (c); adding nanocrystals of colloidal silica in the acidified clay alumina and zeolite slurry of step (d) with continuous stirring for a time period in a range of 0.5 to 1 hour to obtain final slurry; spray-drying of the final slurry at temperature in the range of 320 to 420 ? as inlet temperature and temperature in the range of 110 to 130 ? as outlet temperature to obtain FCC catalyst composition; and calcination of a catalyst composition at temperature in a range of 450 to 550 ? for a time period in a range of 0.5 to 2 hours to obtain the fluid catalytic cracking (FCC) catalyst composition.
The clay is used in a range of 15 to 30 wt%, alumina is used in a range of 15 to 25 wt% protic acid is used in a range of 2 to 5 wt%, lanthanum modified ultra-stable Y zeolite is used in a range of 10 to 20 wt%, phosphorus modified zeolite (P-ZSM-5) is used in a range of 10 to 30 wt%,, nanocrystals of colloidal silica is used in a range of 10 to 25 wt%.
The phosphorous modified zeolite (P-ZSM-5) is modified by phosphorous acid.
The protic acid is selected from a group consisting of formic acid, hydrochloric acid, acetic acid and nitric acid.

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 present invention provides a fluid catalytic cracking (FCC) catalyst composition, comprising: 10-20 wt % rare-earth metal modified ultra-stable large pore zeolite (REUSY);10-30 wt % phosphorous modified medium pore zeolite (P-ZSM-5);15-30 wt % clay;10-25 wt % silica; and 15-25 wt % alumina and the wt. % being based on total weight of the catalyst composition.
Fluid catalytic cracking (FCC) is routinely used to convert heavy hydrocarbons to LPG, gasoline and distillate range molecules by using FCC catalyst. The catalyst composition mainly is rare-earth exchanged Y zeolite and matrix materials such as alumina, silica and clay. In addition, to increase the yield of light olefins mainly propylene in FCC process, ZSM-5 based additives to be used along with FCC catalyst. These two catalysts can be used together such that the reaction product of one catalyst is transported to and reacts on a catalyst site of the second catalyst. Hence, the product selectivity towards light olefins, mainly propylene will enhance.
Most of the reported catalyst systems are a combination of two/three catalysts. Also, the molecules used for these conversions are mainly Y zeolite, ultrastable Y Zeolite, rare-earth modified Y zeolite, alkali metal modified Y zeolite, ZSM-5, small sized ZSM-5, phosphorous modified ZSM-5, clay, alumina and silica.
In the present invention, a novel cost-effective synthesis methodology was developed for high propylene FCC catalyst preparation. The present invention discloses a method for the preparation of a single FCC catalyst for increasing light olefins (ethylene, propylene, butene). The catalyst consists of phosphorous modified nanosized medium pore zeolites, rare-earth modified large pore ultra-stable zeolites, nano sized particles of colloidal silica, low density clay and boehmite alumina. The prepared catalyst was made into micro spheroidal particles using spray dryer. This invention relates to petroleum refining catalyst for high severity FCC to produce light olefins. The prepared high propylene catalyst shows higher selectivity towards Propylene and lower dry gas and LCO selectivity in ACE-MAT evaluation.
In the present invention, Lanthanum (1 to 2 wt.%) modified ultra-stable Y zeolite and phosphorus modified nano sized ZSM-5 as active materials and low dense clay, boehmite alumina, small sized nanocrystals of colloidal silica as matrix material have been utilised. The catalyst is prepared by (i) milling of clay (15-30 wt.%) and boehmite alumina (15-25 wt.%) with appropriate amount of water (this milling stage will reduce the particle sizes from 10-15 microns to 1-2 micron); (ii) acidification of milled slurry with protic acid; (iii) addition of lanthanum modified ultrastable Y zeolite (10-20 wt. %) on the acidified clay alumina slurry; (iv) addition of phosphorous modified nano sized ZSM-5 (10-30 wt. %) on acidified clay alumina zeolite slurry; (v) addition of small sized nanocrystals of colloidal silica (10-25 %) in the mixture of P-ZSM-5 and acidified clay alumina zeolite slurry; (vi) spray-drying of the final slurry to obtain spherical particles; and subjecting the spherical particles to calcination at 550 ?.
In an aspect, the present invention provides a fluid catalytic cracking (FCC) catalyst composition, comprising:
a. 10-20 wt % rare-earth metal modified ultra-stable Y zeolite (REUSY);
b. 10-30 wt % phosphorous modified zeolite (P-ZSM-5);
c. 15-30 wt % clay;
d. 10-25 wt % silica; and
e. 15-25 wt % alumina,
wherein the wt. % being based on total weight of the catalyst composition.
In another aspect, the present invention provides a method for preparing a fluid catalytic cracking (FCC) catalyst composition, comprising:
a. milling clay and alumina with water for a time period in a range of 2 to 3 hours to obtain a milled slurry;
b. acidifying the milled slurry of step (a) with 20 to 98 % protic acid to obtain an acidified clay-alumina slurry;
c. adding rare earth metal modified ultrastable Y zeolite to the acidified clay alumina slurry of step (b) with continuous stirring to obtain an acidified clay-alumina-zeolite slurry;
d. adding phosphorus modified zeolite (P-ZSM-5) to the acidified clay-alumina-zeolite slurry of step (c) to obtain a mixture of P-ZSM-5 and the acidified clay alumina zeolite slurry;
e. adding nanocrystals of colloidal silica in the mixture of P-ZSM-5 and the acidified clay alumina zeolite slurry of step (d) with continuous stirring for a time period in a range of 0.5 to 1 hour to obtain a final slurry;
f. spray-drying of the final slurry at inlet temperature in a range of 320 to 420 0C and at outlet temperature in a range of 110 to 130 0C to obtain a catalyst composition; and
g. calcination of the catalyst composition at temperature in a range of 450 to 550 0C for a time period in a range of 0.5 to 2 hours to obtain the fluid catalytic cracking (FCC) catalyst composition.
In an embodiment of the present invention, the rare earth metal modified ultra-stable Y zeolite comprises of 1 to 2 wt % of rare earth metal and the rare earth metal is selected from a group consisting of Lanthanum, cerium, praseodymium, samarium, europium, ytterbium, lutecium.
In an embodiment of the present invention, the rare earth metal modified ultra stable Y zeolite have pore size in a range of 6 to 8 Å and the phosphorous modified zeolite (P-ZSM-5) have pore size in a range of 5 to 6 Å.
In an embodiment of the present invention, the phosphorus modified zeolite (P-ZSM-5) has phosphorous content in a range of 0.2 to 1 wt.%.
In an embodiment of the present invention, the clay has density in a range of 0.3-0.4 g/cc and is selected from a group consisting of kaolin, attapulgite, bentonite, montmorillonite, diatomite clay.
In another embodiment of the present invention, the alumina is boehmite alumina having soda content in a range of 50 ppm (0.005 wt%) to 100 ppm (0.010 wt%).
In another embodiment of the present invention, the catalyst composition has particle size in a range of 70-80 microns, average bulk density in a range of 0.8-0.85 g/cc and attrition in a range of 3-4 %.
In another embodiment of the present invention, the catalyst composition in Fluid catalytic cracking provides higher propylene to ethylene ratio, propylene yield in a range of 16-18 wt.%, lighter olefins yield in a range of 32-34 wt.% and Lower dry gas yield of at least 2 wt.%.
In an embodiment of the present invention, the clay is used in a range of 15 to 30 wt%, alumina is used in a range of 15 to 25 wt%,protic acid is used in a range of 2 to 5 wt%, lanthanum modified ultra-stable Y zeolite is used in a range of 10 to 20 wt%, phosphorus modified zeolite (P-ZSM-5) is used in a range of 10 to 30 wt%,, nanocrystals of colloidal silica is used in a range of 10 to 25 wt%,.
In an embodiment of the present invention, the phosphorous modified zeolite (P-ZSM-5) is modified by phosphorous acid.
In an embodiment of the present invention, the protic acid is selected from a group consisting of formic acid, hydrochloric acid, acetic acid and nitric acid.
The silica (SiO2) is in nano sized ammonium form of colloidal silica.
The catalyst composition is in a form of microspheres.
The prepared catalyst showed ABD of 0.8-0.85 g/cc and attrition was 3-4 %. Particle size is in a range of 70-80 microns. Performance evaluation of this catalyst shows higher LPG yields (35-39 wt.%) and propylene yield (16-17 wt. %).
Lower amount of lanthanum on ultrastable Y zeolite and phosphorous on nano ZSM-5 and its synergistic effects helps in increasing the yield of lighter olefins (C3 and C4) and decreasing the yield of dry gas.
In an embodiment of the present invention, the yield of Lower dry gas is (>2 wt.%).
EXAMPLES:
The disclosure will now be illustrated with working examples, which are intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar to or equivalent to those described herein can be used in the practice of the disclosed methods, the exemplary methods, devices and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may vary.
Example 1: Preparation of high propylene FCC catalyst composition.
The high propylene FCC catalyst is prepared by milling kaolin clay (352 grams) and boehmite alumina (275 grams) with water (1100 grams) for 3 hours. After milling the slurry was peptized by using 85 % formic acid (60 grams). To that, zeolite slurry (mixing of 136 grams of lanthanum modified ultra-stable Y zeolite with 200 grams of water) was added and continued the stirring for 10-20 minutes followed by addition of 179 grams of phosphorus acid modified ZSM-5 in 272 grams of water to make the homogeneous slurry. To that, nano sized colloidal silica slurry (735 grams) was added and continued stirring for another 1 hour. Total solid content in the finalized slurry was 27-28 %. Finally, the slurry was spray dried at 360 ? as inlet temperature and 120 0C as outlet temperature. The prepared catalyst was calcined at 550 ? for 2 hours.
Example 2: Preparation of high propylene FCC catalyst composition.
High propylene FCC catalyst was prepared by milling of kaolin clay (352 grams) and boehmite alumina (248 grams) with water (1070 grams) for 3 hours. After milling the slurry was peptized by using 85 % formic acid (60 grams). To that, zeolite slurry (mixing of 136 grams of lanthanum modified ultra-stable Y zeolite with 200 grams of water) was added and continued the stirring for 10-20 minutes followed by addition of 200 grams of phosphorus acid modified ZSM-5 in 304 grams of water to make the homogeneous slurry. To that, nano sized ammonium form of colloidal silica slurry (735 grams) was added and continued stirring for another 1 hour. Total solid content in the finalized slurry was 27-28 %. Finally, the slurry was spray dried at 360 ? as inlet temperature and 120 ? as outlet temperature. The prepared catalyst was calcined at 550 ? for 2 hours.
Example 3: Preparation of high propylene FCC catalyst composition using high rare earth loaded REUSY zeolite (Lanthanum content is 1-2 wt.% on microsphere).
High propylene FCC catalyst was prepared by milling of kaolin clay (352 grams) and boehmite alumina (248 grams) with water (1070 grams) for 3 hours. After milling the slurry was peptized by using 85 % formic acid (60 grams). To that, zeolite slurry (mixing of 136 grams of lanthanum modified ultra-stable Y zeolite with 200 grams of water) was added and continued the stirring for 10-20 minutes followed by addition of 200 grams of phosphorus acid modified ZSM-5 in 304 grams of water to make the homogeneous slurry. To that, nano sized ammonium form of colloidal silica slurry (735 grams) was added and continued stirring for another 1 hour. Total solid content in the finalized slurry was 27-28 %. Finally, the slurry was spray dried at 360 ? as inlet temperature and 120 ? as outlet temperature. The prepared catalyst was calcined at 550 ? for 2 hours.
Example 4: Preparation of high propylene FCC catalyst composition using high phosphorous loaded ZSM-5 (P2O5 content is 2-3 wt.% on microsphere).
High propylene FCC catalyst was prepared by milling of kaolin clay (352 grams) and boehmite alumina (248 grams) with water (1070 grams) for 3 hours. After milling the slurry was peptized by using 85 % formic acid (60 grams). To that, zeolite slurry (mixing of 136 grams of lanthanum modified ultra-stable Y zeolite with 200 grams of water) was added and continued the stirring for 10-20 minutes followed by addition of 200 grams of phosphorus acid modified ZSM-5 in 304 grams of water to make the homogeneous slurry. To that, nano sized ammonium form of colloidal silica slurry (735 grams) was added and continued stirring for another 1 hour. Total solid content in the finalized slurry was 27-28 %. Finally, the slurry was spray dried at 360 ? as inlet temperature and 120 ? as outlet temperature. The prepared catalyst was calcined at 550 ? for 2 hours.
Example 5: Preparation of high propylene FCC catalyst composition by changing phosphorous source (using diammonium hydrogen phosphate for ZSM-5 modification).
High propylene FCC catalyst was prepared by milling of kaolin clay (352 grams) and boehmite alumina (248 grams) with water (1070 grams) for 3 hours. After milling the slurry was peptized by using 85 % formic acid (60 grams). To that, zeolite slurry (mixing of 136 grams of lanthanum modified ultra-stable Y zeolite with 200 grams of water) was added and continued the stirring for 10-20 minutes followed by addition of 200 grams of diammonium hydrogen phosphate modified ZSM-5 in 304 grams of water to make the homogeneous slurry. To that, nano sized ammonium form of colloidal silica slurry (735 grams) was added and continued stirring for another 1 hour. Total solid content in the finalized slurry was 27-28 %. Finally, the slurry was spray dried at 360 ? as inlet temperature and 120 ? as outlet temperature. The prepared catalyst was calcined at 550 ? for 2 hours. The ABD of the prepared sample is 0.75 g/cc and attrition is very high and it is 13 %. This sample was not chosen for evaluation.
Example 6: Preparation of high propylene FCC catalyst composition by changing phosphorous source (using orthophosphoric acid for ZSM-5 modification).
High propylene FCC catalyst was prepared by milling of kaolin clay (352 grams) and boehmite alumina (248 grams) with water (1070 grams) for 3 hours. After milling the slurry was peptized by using 85 % formic acid (60 grams). To that, zeolite slurry (mixing of 136 grams of lanthanum modified ultra-stable Y zeolite with 200 grams of water) was added and continued the stirring for 10-20 minutes followed by addition of 200 grams of orthophosphoric acid modified ZSM-5 in 304 grams of water to make the homogeneous slurry. To that, nano sized ammonium form of colloidal silica slurry (735 grams) was added and continued stirring for another 1 hour. Total solid content in the finalized slurry was 27-28 %. Finally, the slurry was spray dried at 360 ? as inlet temperature and 120 ? as outlet temperature. The prepared catalyst was calcined at 550 ? for 2 hours.
Pre-treatment of high propylene FCC catalyst composition by Hydrothermal Deactivation Method.
In order to maintain the desired level of conversion (feed to useful products such as dry gas (DG), liquefied petroleum gas (LPG), light cracked naphtha, heavy cracked naphtha, light cycle oil, resid and coke) in the FCC unit. In FCC unit, catalyst gets hydrothermally deactivated due to high temperature and steam, so for simulating similar catalyst deactivation, all examples of high propylene FCC catalysts and reference catalysts are hydrothermally deactivated at 815 ? for 5 hours with 80 % steaming recipe in Metal Cyclic Deactivation unit before performance evaluation (table 1).
Table 1. Physico-chemical properties of high propylene FCC catalyst
Catalyst SiO2 (%) Al2O3 (%) P2O5 (%) RE (%) Surface area (m2/g Micropore SA (m2/g) External SA (m2/g) Pore volume (cc/g) Acidity (µmol/g)
Ref. Catalyst 51.8 43.4 3.31 0.34 230 135 95 0.23 764
Ref. Catalyst (Steamed) 54.3 40.5 2.85 0.33 157 67 90 0.2 96.5
Example 2
FCC Catalyst 52.3 45.2 0.48 0.15 225 107 118 0.21 623
Example 2
FCC Catalyst (Steamed) 53.+8 43.9 0.45 0.12 184 80 104 0.22 117
RE= Rare earth, SA= Surface area

Feedstock Characterization
The feed used in the present study is hydrotreated vacuum gas oil (VGO) and its properties are listed in below table 2.
Table 2: Feed Properties
Density at 15°C, gm/cc 0.90
Sulphur, wt% 105 ppm
CCR, wt% 0.08
Pour point, °C 39
Kinematic viscosity @100°C, cSt 6.93
ASTM-7169 Distillation, wt%
IBP 250.1
5 300
10 362.3
30 410
50 442.7
70 480.9
90 536.6
95 561.3
SARA, wt%
Saturates 51.6
Aromatics 42.1
Resin 6.3
Asphaltenes 0

Example 7: Performance evaluation results.
Advanced Cracking Evaluation (ACE) – R+MM unit (with micro-GC) was used to measure the micro activity of steam deactivated high propylene FCC catalyst and reference catalyst. The result shows that higher conversion and product yields are observed when compared to reference catalyst (table 3). It showed higher propylene (+?1.2 %) and lowers dry gas (-?2.6 %).
Table 3. Product yields
Catalyst Reference catalyst (blended catalyst) 75 % FCC-E-cat and 25 % ZSM-5 additive FCC catalyst Example 1 FCC catalyst
Example 2 FCC catalyst
Example 3 FCC catalyst
Example 4 FCC catalyst
Example 6
ABD 0.82 g/cc 0.84 g/cc 0.83 g/cc 0.80 g/cc 0.81 g/cc 0.79 g/cc
Attrition 5 3 3.2 4 3.5 4
Cat/oil 12 12 12 12 12 12
Recovery 99 96.8 99.3 97.21 98.75 97.4
Conversion 81.99 81.92 83.19 84.33 81.51 82.48
Coke 5.85 6.52 6.49 7.48 4.48 6.63
Dry Gas 8.78 6.11 5.46 5.73 5.02 5.96
LPG 35.87 37.48 39.01 36.48 38.48 36.79
Naphtha 31.48 31.8 34.23 34.64 33.53 33.08
LCO 10.4 10.51 8.9 9.66 11.09 9.64
Bottoms 7.6 7.55 5.91 6.01 7.40 7.87
Ethylene 6.05 3.72 2.79 3.18 2.98 3.562
Propylene 15.416 16.59 16.85 15.61 16.52 15.98
Butene 11.266 12.48 13.19 11.75 15.10 12.15
ABD= Average Bulk Density

Advantages of the Invention:
• The process of the present invention is cost-effective and does not require two different catalysts for enhancing light olefins yield.
• The catalyst composition of the present invention produces higher light olefins yield, mainly propylene and minimizes bottoms, LCO and dry gas in Fluid catalytic cracking unit in Refinery. , Claims:1. A fluid catalytic cracking (FCC) catalyst composition, comprising:
a. 10-20 wt % rare-earth metal modified ultra-stable Y zeolite (REUSY);
b. 10-30 wt % phosphorous modified zeolite (P-ZSM-5);
c. 15-30 wt % clay;
d. 10-25 wt % silica; and
e. 15-25 wt % alumina,
wherein the wt. % being based on total weight of the catalyst composition.
2. The composition as claimed in claim 1, wherein the rare earth metal modified ultra-stable Y zeolite comprises of 1 to 2 wt % of rare earth metal and the rare earth metal is selected from a group consisting of Lanthanum, cerium, praseodymium, samarium, europium, ytterbium, lutecium.
3. The composition as claimed in claim 1, wherein the rare earth metal modified ultra stable Y zeolite have pore size in a range of 6 to 8 Å and the phosphorous modified zeolite (P-ZSM-5) have pore size in a range of 5 to 6 Å.
4. The composition as claimed in claim 1, wherein the phosphorus modified zeolite (P-ZSM-5) has phosphorous content in a range of 0.2 to 1 wt.% and wherein the alumina is boehmite alumina having soda content in a range of 0.005 to 0.010 wt.%.
5. The composition as claimed in claim 1, wherein the clay has density in a range of 0.3-0.4 g/cc and is selected from a group consisting of kaolin, attapulgite, bentonite, montmorillonite, diatomite clay.
6. The composition as claimed in claim 1, wherein the catalyst composition has particle size in a range of 70-80 microns, average bulk density in a range of 0.8-0.85 g/cc and attrition in a range of 3-4 % and wherein the catalyst composition in Fluid catalytic cracking provides higher propylene to ethylene ratio, propylene yield in a range of 16-18 wt.%, lighter olefins yield in a range of 32-34 wt.% and Lower dry gas yield of at least 2 wt.%.
7. A method for preparing a fluid catalytic cracking (FCC) catalyst composition, comprising:
a. milling clay and alumina with water for a time period in a range of 2 to 3 hours to obtain a milled slurry;
b. acidifying the milled slurry of step (a) with 20 to 98 % protic acid to obtain an acidified clay-alumina slurry;
c. adding rare earth metal modified ultrastable Y zeolite to the acidified clay alumina slurry of step (b) with continuous stirring to obtain an acidified clay-alumina-zeolite slurry;
d. adding phosphorus modified zeolite (P-ZSM-5) to the acidified clay-alumina-zeolite slurry of step (c) to obtain a mixture of P-ZSM-5 and the acidified clay alumina zeolite slurry;
e. adding nanocrystals of colloidal silica in the mixture of P-ZSM-5 and the acidified clay alumina zeolite slurry of step (d) with continuous stirring for a time period in a range of 0.5 to 1 hour to obtain a final slurry;
f. spray-drying the final slurry at inlet temperature in a range of 320 to 420 0C and at outlet temperature in a range of 110 to 130 0C to obtain a catalyst composition; and
g. calcination of the catalyst composition at temperature in a range of 450 to 550 0C for a time period in a range of 0.5 to 2 hours to obtain the fluid catalytic cracking (FCC) catalyst composition.
8. The method as claimed in claim 7, wherein the clay is used in a range of 15 to 30 wt%, alumina is used in a range of 15 to 25 wt% protic acid is used in a range of 2 to 5 wt%, lanthanum modified ultra-stable Y zeolite is used in a range of 10 to 20 wt%, phosphorus modified zeolite (P-ZSM-5) is used in a range of 10 to 30 wt%,, nanocrystals of colloidal silica is used in a range of 10 to 25 wt%.
9. The method as claimed in claim 7, wherein the phosphorous modified zeolite (P-ZSM-5) is modified by phosphorous acid.
10. The method as claimed in claim 7, wherein the rare earth metal modified ultrastable Y zeolite comprises of 1 to 2 wt % of rare earth metal and the rare earth metal is selected from a group consisting of Lanthanum, cerium, praseodymium, samarium, europium, ytterbium, lutecium.
11. The method as claimed in claim 7, wherein the rare earth metal modified ultra stable Y zeolite have pore size in a range of 6 to 8 Å and the phosphorous modified zeolite (P-ZSM-5) have pore size in a range of 5 to 6 Å.
12. The method as claimed in claim 7, wherein the clay has density in a range of 0.3-0.4 g/cc and is selected from a group consisting of kaolin, attapulgite, bentonite, montmorillonite, diatomite clay.
13. The method as claimed in claim 7, wherein the phosphorus modified zeolite (P-ZSM-5) has phosphorous content in a range of 0.2 to 1 wt.% and wherein the alumina is selected from a group consisting of boehmite alumina having soda content in a range of 0.005 to 0.010 wt%.
14. The method as claimed in claim 7, wherein the protic acid is selected from a group consisting of formic acid, hydrochloric acid, acetic acid and nitric acid.
15. The method as claimed in claim 7, wherein the catalyst composition has particle size in a range of 70-80 microns, average bulk density in a range of 0.8-0.85 g/cc and attrition in a range of 3-4 %; and wherein the catalyst composition in Fluid catalytic cracking provides higher propylene to ethylene ratio, propylene yield in a range of 16-18 wt.%, lighter olefins yield in a range of 32-34 wt.% and Lower dry gas yield of at least 2 wt.%.