Description:FIELD OF THE INVENTION
[0001] The present disclosure relates to an attrition resistant hydrocarbon cracking catalyst. The present disclosure also relates to a process for the production of an attrition resistant hydrocarbon cracking catalyst.

BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Catalyst manufacturers have been continuously improving FCC catalysts physical properties such as ABD and attrition resistance, which are related to hydrocarbon carryover and catalyst make up. In the late eighties, newer derivatives of faujasite zeolite like USY, REUSY, microporous USY as well as zeolite friendly binder for enhancing catalyst performance. These improved processes benefit refiners in reduction of cost of refining. Never the less, there are other improvements such as usage of FCC catalyst additives for enhancing propylene, octane number, reduction of sulfur in gasoline, and flue gas when, a conventional faujasite based FCC catalysts encountered limitations.
[0004] Numerous processes are available for manufacturing industry to raise solid content in the catalyst precursor slurry which reduce production cost. One approach which is not practiced is that, silica sol prepared as a batch or by inline mixing is not stable, as sol particles keep growing in size and pH too alters, which adversely affect binding efficiency. Secondly this acidic binder if mixed with a filler and zeolite component as a batch process gradually acidic environment around zeolite particles destroys it and longer it stays, higher will be the damage. Further, this damage is not only restricted to its presence in a fluidic state, but true in the solid form too. The efficacy of binding by silica sol is more effective under acidic environment, it’s size and uniformity of size. Thus, there is a challenge to develop more effective lower end nano size silica sol with uniform size, reduce contact time of zeolite in slurry as well of formed catalyst particles.
[0005] U.S. Pat. Nos. 3,425,956; 3,867,308; 3,957,689 disclose processes for the production of molecular sieve-type based, acidic silica sol bonded cracking catalysts. U.S. Pat. No. 3,425,956 refers to a process of employing CO2 for gelling sodium silicate, which is subsequently employed as a binder. U.S. Pat. No. 7,739,072 discloses a process for enhancing attrition resistance of cracking catalyst by employing acid/alkali stable surfactants Zonyl FSA and Zonyl TBS. The petroleum refining industry world-wide, has rapidly adopted the use of these catalysts in the early 1960's as these catalysts provided significant increases in gasoline yields and substantially reduced undesired products like coke and dry gas. This improvement is due to zeolites possess uniform pore in the range 6 to 13 A, high surface and hydrothermal stability, and even today these have been accepted as part and parcel of modern FCC catalyst formulation, no matter from what material they are bonded.
[0006] U S Pat. No. 7,456,123 refers to a process of producing FCC catalyst to reduce coke and dry gas, process comprises of reacting sodium silicate with urea and a source of phosphate as promoter.
[0007] FCC catalysts to be acceptable to the refining industry demanded product selective cracking with molecular sieves of a higher silica-alumina structure of "faujasite-type". The thermal, hydrothermal stability of these zeolites can be enhanced by the introduction of rare earth. Faujasite based catalysts do enhance octane number of gasoline, however application of medium pore zeolites having 10 member rings especially made from ZSM-5 series zeolite significantly increase octane number, where conventional faujasite FCC catalysts faced limitation.

OBJECTS OF THE INVENTION
[0008] An objective of the present invention is to provide an attrition resistant hydrocarbon cracking catalyst.
[0009] Another objective of the present invention is to provide a process for the production of an attrition resistant hydrocarbon cracking catalyst.

BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 showed graph of relative crystallinity v/s contact time between binder and zeolite.

SUMMARY OF THE INVENTION
[0010] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in Detailed Description section. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
[0011] The present disclosure discloses an attrition resistant hydrocarbon cracking catalyst comprising: 10 to 55% w/w of a zeolite; 10 to 35% w/w of a silica sol binder; 1 to 20% w/w of an alumina; 20 to 50% w/w of a clay; 0-5 % w/w of a water-soluble aluminium; and 0-2% w/w of polymeric inorganic and/or organic dispersant. The % w/w is based on the total weight of the catalyst.
[0012] The present disclosure also discloses a process for the production of an attrition resistant hydrocarbon cracking catalyst comprising: a) mixing of silica and mineral acid under stirring to produce a silica sol binder; b) adding 0-5 % w/w of a water soluble aluminium and 0-2% w/w of polymeric inorganic and/or organic dispersant to obtain a first slurry; c) mixing 1 to 20% w/w of an alumina to 20 to 50% w/w of clay and to obtain a second slurry; d) mixing 10 to 55% w/w of a zeolite in water to obtain a third slurry; e) introducing first, second and third slurry simultaneously in a homogeniser followed by spray drying to form a microsphere within 60 seconds; f) washing the microspheres with hot water to obtain a washed microspheres; g) exchanging ammonia of the washed microspheres to obtain an ammonia exchanged microspheres; h) exchanging rare earth content of the ammonia exchanged microspheres to obtain a rare earth content exchanged microspheres; and i) washing the rare earth content exchanged microspheres with hot water followed by drying to obtain an attrition resistant hydrocarbon fluid catalytic cracking catalyst.
[0013] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments.

DETAILED DESCRIPTION OF THE INVENTION
[0014] The following is a detailed description of embodiments of the disclosure. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0015] Unless the context requires otherwise, throughout the specification which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense that is as “including, but not limited to.”
[0016] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
[0017] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable.
[0018] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it is individually recited herein.
[0019] All processes described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0020] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.
[0021] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus, if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
[0022] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0023] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description that follows, and the embodiments described herein, is provided by way of illustration of an example, or examples, of particular embodiments of the principles and aspects of the present disclosure. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the disclosure.
[0024] It should also be appreciated that the present invention can be implemented in numerous ways, including as a system, a method or a device. In this specification, these implementations, or any other form that the invention may take, may be referred to as processes. In general, the order of the steps of the disclosed processes may be altered within the scope of the invention.
[0025] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0026] An embodiment of the present disclosure discloses an attrition resistant hydrocarbon cracking catalyst comprising: 10 to 55% w/w of a zeolite; 10 to 35% w/w of a silica sol binder; 1 to 20% w/w of an alumina; 20 to 50% w/w of a clay; 0-5 % w/w of a water-soluble aluminium; and 0-2% w/w of polymeric inorganic and/or organic dispersant. The % w/w is based on the total weight of the catalyst. The attrition resistant cracking catalyst has a particle size in the range of 20-150 microns.
[0027] An embodiment of the present disclosure discloses that the zeolite is selected from the group consisting of NaY, NaUSY, NH4Y, NaNH4Y, RENH4Y, USY, REUSY, X, NH4X, REX, mordenite, Zeolite beta, ZSM-5 and ZSM-11.
[0028] An embodiment of the present disclosure discloses that the silica sol binder is derived from mixing of silica with a mineral acid. The silica is selected from a group consisting of alkaline grade sodium silicate, neutral grade sodium silicate, colloidal silica and silicic acid. The mineral acid is selected from a group consisting of hydrochloric acid, nitric acid, sulphuric acid, formic acid, acetic acid and phosphoric acid. The silica sol binder has a particle size is the range 10 to 30 nm.
[0029] An embodiment of the present disclosure discloses that the alumina is selected from a group consisting of aluminum trihydrate, boehmite, pseudoboemite and gamma alumina.
[0030] An embodiment of the present disclosure discloses that the clay is selected from the group consisting of bentonite, montmorillonite, halloysite, attapulgite, kaolin, illite, vermiculite and smectite.
[0031] An embodiment of the present disclosure discloses that the aluminium is selected from a group consisting of aluminium sulphate, aluminium chloride and aluminum nitrate.
[0032] An embodiment of the present disclosure discloses that the polymeric inorganic and/or organic dispersant is selected from a group consisting of poly sodium acrylate, sodium polysilicate and sodium polyphosphate.
[0033] Another embodiment of the present disclosure discloses that the catalyst further comprises a residual sodium below 0.45 % w/w. The catalyst further comprises a rare earth content in the range of 0.1 to 4 % w/w. The rare earth content is selected from a group consisting of chlorides, sulphates, acetates and nitrates of lanthanum, cerium, neodymium, and praseodymium.
[0034] Another embodiment of the present disclosure discloses a process for the production of an attrition resistant hydrocarbon cracking catalyst comprising: a) mixing of silica and mineral acid under stirring to produce a silica sol binder; b) adding 0-5 % w/w of a water soluble aluminium and 0-2% w/w of polymeric inorganic and/or organic dispersant to obtain a first slurry; c) mixing 1 to 20% w/w of an alumina to 20 to 50% w/w of clay and to obtain a second slurry; d) mixing 10 to 55% w/w of a zeolite in water to obtain a third slurry; e) introducing first, second and third slurry simultaneously in a homogenizer followed by spray drying to form a microsphere within 60 seconds; f) washing the microspheres with hot water to obtain a washed microspheres; g) exchanging ammonia of the washed microspheres to obtain an ammonia exchanged microspheres; h) exchanging rare earth content of the ammonia exchanged microspheres to obtain a rare earth content exchanged microspheres; and i) washing the rare earth content exchanged microspheres with hot water followed by drying to obtain an attrition resistant hydrocarbon fluid catalytic cracking catalyst.
[0035] Another embodiment of the present disclosure discloses that the process includes i) the silica is mixed with mineral acid in step (a) at a temperature in the range of 10 to 30 °C. ii) the silica sol binder of step (a) is maintained at a pH below 3. iii) the final spray drying of slurry of step (e) has a pH in the range of 3 to 3.5. iv) the microspheres are washed with hot water having temperature above 80oC in step (f) within 120 seconds of their formation, to reduce pH of effluent below 7. v) the ammonia exchanged in step (g) is carried out with solid to liquid ratio 1:10 at a temperature in the range of 65 to 100 °C. vi) the rare earth exchanged in step (h) is carried out at a temperature in the range of 60 to 80 °C for a period of 20 to 40 minutes. vii) the drying in step (i) is carried out at a temperature in the range of 120 to 160 °C for a period of 8 to 14 hrs.
[0036] Another embodiment of the present disclosure discloses that present invention provides for a good attrition resistance to the catalyst particles, enhances yield of high value products like LPG and gasoline. The process enables reduction in the production cost, as the catalyst can be produced within 300 seconds. Further, process enables savings in raw material and intermediate product holding vessels, as the catalyst precursor slurry can be produced within a small volume, in a short time less than 300 seconds. The process enables, uninterrupted production of catalyst thus saving time, space, energy and cost.
[0037] Another embodiment of the present disclosure discloses that said catalyst composition comprises: (a) zeolite in the range of 10 wt % to 55 wt %; (b) silica binder in the range of 10 wt % to 35 wt %; (c) alumina in the range of 1 wt % to 20 wt %; (d) water soluble aluminium 0 to 5 wt%; and (e) clay in the range of 20 wt % to 50 wt %.
[0038] Another embodiment of the present disclosure discloses that the process comprises the steps of preparation of diluted silicate and acid in temperature range 10 °C to 30 °C, with or without aluminum salt. Simultaneous mixing of diluted silicate solution with a diluted acid. Maintaining the resulting silica sol pH below 3. To the silica sol stream, adding streams of alumina, clays and at the end adding a stream of zeolite slurry. Controlling the resulting catalyst precursor slurry pH in the range 3 to 3.3. Spray drying to produce microspheres. Hot water washing of dried particles as soon as they are produced within 120 seconds, to pH below 7. Ammonia exchanging the water washed catalyst. Rare earth exchanging of ammonia exchanged particles. Final hot water washing. Drying to produce the catalyst of present invention.
[0039] Another embodiment of the present disclosure discloses that clays are commonly used as major component of cracking catalysts as a filler, heat sink, heat carrier, density modifier. They are favored due to their low cost. Clays are used in finely divided form with a size below 3 microns. The most common varieties of clays used in cracking catalyst formulations are kaolinite and halloysite. Clays have a two-layer structure, consisting alternating sheets of silica in tetrahedral configuration and alumina in octahedral configuration. These sheets are separated with a gap of 7.13° A. Dry atmosphere equilibrated clay has moisture content of about 15 wt %. Clays are good sources for silica and alumina as they contain about 45 wt % of silica and about 38 wt % of alumina, impurities like sodium, titanium, iron, calcium all below 0.5 wt%.
[0040] Figure 1 shows impact of contact time between binder and Y zeolite on relative crystallinity of FCC catalyst.
Synthetic zeolite
[0041] Synthetic zeolites are sourced from faujasite, X, pentasil family products like mordenite, zeolite beta, ZSM-5, ZSM-11 as main hydrocarbon cracking material. They improve thermal stability, possess higher selectivity towards gasoline due to uniform pore size and high surface area. Faujasite also referred to, as Y zeolite is the most commonly used crystalline inorganic aluminosilicates, having pores in the range 6.5 to 13.5° A in its framework. These zeolites are synthesized with SiO2 to Al2O3 ratio in the range 4.5 to 6 and 12-13-wt %Na2O. To make them suitable for catalytic application, soda present inside for balancing electrovalence is required to be exchanged with a proton, via ammonium exchange followed by calcination. Higher silica to alumina ratio zeolite may be further prepared by modification of synthetic forms by steaming, chemical treatment or replacement of framework aluminum with silica. These modification steps enhance metal and steam stability.
Alumina
[0042] Bayerite alumina (Al(OH)3) is most suitable matrix material for FCC catalyst formulation. However, pseudoboehmite alumina, boehmite alumina, gamma alumina with soda, contentless than 0.1 wt %, are ideal matrix for different zeolite based catalysts as some of them can be converted to a glue by reacting with acids like nitric acid, formic acid or acetic acid. Alumina also acts as efficient heat carrier and metal passivator.
Cracking catalyst
[0043] In a preferred method for preparing cracking catalyst of present invention, (a) efficiently binding silica sol having uniform size in the range 20 to 30 nm are prepared by simultaneous mixing of a source of silica and a mineral/organic acid under vigorous stirring; (b) introducing matrix/fillers to the instant prepared silica sol binder; (c) followed by introducing finely milled source of zeolite, (d) spray drying, (e) hot water washing, ammonia exchanging, (f) rare earth exchanging, (g) further water washing and drying. Preparation of silica sol and further introduction of other components of cracking catalyst is carried out under vigorous stirring in a miniature vessel, fitted with a turbine stirrer and baffles to generate a catalyst precursor slurry with pH in the range, 3 to 3.3 to ensure uniform distribution of all the catalyst components; spray drying the slurry within 15 seconds to form hard microspheres; water washing of microspheres within 60 seconds of their formation, to reduce pH of effluent below 7; further ammonia exchange for atleast 4 times employing ammonium sulphate/ammonium nitrate, ammonium chloride solution with solid to liquid ratio 1:10, temperature 65 to 100 °C,; rare earth exchange for a period of 30 minutes at temperature 65 °C, to load 0.1 to 4 wt%, Re2O3; further hot water wash to eliminate anions; finally oven drying at a temperature of 150 °C, for 12 hours to generate catalyst of this invention.
[0044] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
EXAMPLES
[0045] The present invention is further explained in the form of following examples. However, it is to be understood that the following examples are merely illustrative and are not to be taken as limitations upon the scope of the invention.
Example 1: This example describes sensitivity of zeolite to the binder.
[0046] 500 gm of sodium silicate (Na2O 10%, SiO2 30%) was diluted with 500 gm of demineralized (DM) water. 15.6 gm of aluminium sulfate [Al2(SO4)3.16H2O] is dissolved in 261 gm of (33.33 %) sulfuric acid. 85 gm of aluminum trihydrate (ATH) (LOI 20.5 %) and 365 gm of kaolin clay (LOI 14.66) slurried in 750 gm of DM water and milled for 30 minutes in a wet ball mill. 243 gm of NaUSY (LOI 30%) is made into a paste by vigorous mixing with 243 gm of DM water. To the sulfuric acid – aluminum sulfate solution maintained at 20 °C, is added diluted sodium silicate (20 °C), in 30 minutes. At the end of silica sol preparation, resulting silica sol particle size measured to be in the range 20 nm to 150 nm. To the silica sol was added milled ATH, clay slurry followed by zeolite slurry under vigorous stirring. Final catalyst precursor slurry having composition 30% SiO2, 0.5% Al2O3, 5% ATH, 30% clay, 34% NaUSY and temperature 20 °C, pH of 3 was spray dried to produce micro- spheroidal particles with average size 80 microns. The spray dried product was washed 4 times with hot DM water (85 °C), each time employing fresh hot water, and dried in an air oven at 150 °C. X-ray crystallinity, attrition Index and ABD of the water washed, dried product measured respectively as 10, 9 and 0.8 gm/cc.
Example 2:
[0047] Example 1, experiment was repeated. However, under this experiment, spray dried product was collected at time interval 5 min, 15 min, 25 min and 35 min from the start of spray drying and named as example 2.1, example 2.2, example 2.3, example 2.4. Crystallinity of hot water washed and dried product measured as 20%, 15 %, 11 % and 10% while ABD for all the washed products remained in the range 0.83 to 0.85 gm/CC.
Example 3:
[0048] Under this example, 1000 gm of sodium silicate and 276.6 gm of dilute sulfuric acid alum mixture prepared in a typical example of 1, were added simultaneously to a stirred miniature tank, fitted with baffles, respectively @ 22.22 gm/min and 6.15 gm/min. The particle size of resulting silica sol was measured to be in the range 20-30 nm. Resulting silica sol having pH 1.8 was drained out from the bottom of mixing vessel employing a peristaltic pump at the rate 28.39 gm/minute and pumped to another mixing vessel fitted with baffle. To the silica sol was added 1886 gm of mixture of clay-ATH-zeolite slurry @41.91 gm/min under vigorous stirring. The clay-ATH-zeolite slurries were prepared with individual powders with a procedure explained under example 1. The resulting binder-matrix-zeolite mixture having pH 3.3 from the second stirred mixing vessel was drained employing a peristaltic pump at the rate 70.30 gm/min and spray dried in a spray drier to produce microspheres with average particle size 87 microns. At the end, spray dried microspheres lot was hot water washed, 4 times employing each time fresh DM water. Hot water washed catalyst was oven dried and calcined to 550 °C. The ABD and attrition index were measured respectively as 0.78 gm/cc and 3.0%. X-ray crystallinity of the calcined product was measured as 28%.
Example 4:
[0049] Hot water washed, oven dried product obtained under example 3 was ammonia exchanged 4 times employing 5% hot (90 °C) ammonium sulphate solution, maintaining solid to liquid ratio 1:10 for a duration 30 min, each time freshly prepared solution was employed. This was followed by loading of 2.5 % La2O3 by employing lanthanum chloride solution at temperature 75 °C, for 30 min. Rare earth exchanged product was once again hot water washed, oven dried and steam deactivated at 815 °C for 5hours.
Example 5:
[0050] Under this example, spray dried product under example 3, was instantaneously charged to a Buchner funnel, fitted with Whatman filter paper, and at the same time hot DM water was also charged to create a turbulence of catalyst in hot water, the resulting wash solution was continuously sucked from the bottom of Buchner funnel under vacuum. This addition of hot water and bottom suction was continued till the pH of filtrate was attained to a level 7.5 within 120 seconds. Hot water washed catalyst was oven dried, calcined and analyzed for physical properties. The X-ray crystallinity, ABD and AI were measured respectively as 25%, 0.85 g/cc, and 3%. Calcined catalyst was ammonia and lanthanum exchanged sequentially, adopting a procedure that explained under Example 4. Final exchanged and water washed product dried, calcined and steam deactivated at 815 °C for 5 hours.
Example 6:
[0051] Under this example, 768 gm of sodium silicate, 535 gm of Y zeolite mother liquor and 276.6 gm of dilute sulfuric acid alum mixture prepared in a typical example of 1, were added simultaneously to a stirred miniature tank, fitted with baffles, respectively @ 22.22 gm/min and 6.15 gm/min. The particle size of resulting silica sol was measured to be in the range 20-30 nm. Resulting silica sol having pH 1.8 was drained out from the bottom of mixing vessel employing a peristaltic pump at the rate 28.39 gm/minute and pumped to another mixing vessel fitted with baffle. To the silica sol was added 1886 gm of mixture of clay-ATH-zeolite slurry @41.91 gm/min under vigorous stirring. The clay-ATH-zeolite slurries were prepared with individual powders with a procedure explained under example 1. The resulting binder-matrix-zeolite mixture having pH 3.3 from the second stirred mixing vessel was drained employing a peristaltic at the rate 70.30 gm/min, and spray dried in a spray drier to produce microspheres with average particle size 85 microns. At the end, spray dried microspheres lot was hot water washed, 4 times employing each time fresh DM water. Hot water washed catalyst was oven dried and calcined to 550 °C. The ABD and attrition index were measured respectively as 0.90 gm/CC and 2.8 %. X-ray crystallinity of the calcined product was measured as 20%.
Example 7:
[0052] Under this example, 768 gm of sodium silicate, 535 gm of Y zeolite mother liquor and 276.6 gm of dilute sulfuric acid alum mixture prepared in a typical example of 1, were added simultaneously to a stirred miniature tank, fitted with baffles, respectively @ 22.22 gm/min and 6.15 gm/min. The particle size of resulting silica sol was measured to be in the range 20-30 nm. Resulting silica sol having pH 1.8 was drained out from the bottom of mixing vessel employing a peristaltic pump at the rate 28.39 gm/minute and pumped to another mixing vessel fitted with baffle. Clay mixture is prepared by mixing 90% untreated clay and 10% sulphuric acid leached clay. To the silica sol was added 1886 gm of mixture of clay mixture-ATH-zeolite slurry @ 41.91 gm/min under vigorous stirring. The clay mixture-ATH-zeolite slurries were prepared with individual powders with a procedure explained under example 1. The resulting binder-matrix-zeolite mixture having pH 3.3 from the second stirred mixing vessel was drained employing a peristaltic at the rate 70.30 gm/min, and spray dried in a spray drier to produce microspheres with average particle size 83 microns. At the end, spray dried microspheres lot was hot water washed, 4 times employing each time fresh DM water. Hot water washed catalyst was oven dried and calcined to 550 °C. The ABD and attrition index were measured respectively as 0.87 gm/CC and 2.9 wt%. X-ray crystallinity of the calcined product was measured as 19%.
Example 8:
[0053] This example illustrates application of acid and alkali stable surfactants respectively with silica sol and clay slurry. Final product was collected and processed adopting a procedure explained under Example 4. The X-ray crystallinity of the processed product was measured as 12%.
Example 9:
[0054] 500 gm of sodium silicate (Na2O-10%, SiO2-30%) was diluted with 500 gm of DM water and kept under stirring in a vessel fitted with baffles. To the silicate was added a solution prepared by dissolving 2.5 gm of diammonium hydrogen phosphate and 40 gm of urea in 200 gm of DM water under stirring. 67 gm of aluminum trihydrate (ATH) (LOI 20.5 %) and 157 gm of kaolin clay (LOI 14.66) were wet milled with 350 gm of DM water for 30 minutes and slowly added to silicate-urea-DAHP solution prepared earlier. Finally, 220 gm of NaUSY (LOI 30%) made into a paste by vigorous mixing with 165 gm of DM water was added to silicate-urea-DAHP-ATH-clay slurry under stirring. The catalyst precursor slurry having pH 11.5 was spray dried to produce microspheres with average particle size 80 microns. The spray-dried product was hot water washed, exchanged and rare earth loaded employing procedure practiced under examples 3 and 4 and steam deactivated at 815 °C for 5 hours. The ABD, AI of oven dried product measured respectively as 0.86 gm/cc and 5.2 %.
[0055] Physical properties of the catalyst of the present invention are shown in below Table 1:

Table 1: Physical properties of catalysts
Examples Attrition Index Average particle size, micron ABD, g/cc Relative crystallinity, %
Example 1 9 80 0.8 10
Example 2.1 2.9 82 0.85 20
Example 2.2 2.9 81 0.84 15
Example 2.3 2.9 85 0.85 11
Example 2.4 2.9 82 0.83 10
Example 3 3.0 87 0.78 28
Example 6 2.8 85 0.90 20
Example 7 2.9 83 0.87 19
Example 8 3.5 89 0.9 12
Example 9 5.2 80 0.86 23

Example 10:
[0056] Catalytic cracking experiments were carried out in ACE R+MM unit with VGO feed (VGO feed properties are given in Table 2) at reaction conditions mentioned in Table 3. Catalyst prepared in Example 5 shows higher conversion, higher LPG yield compared to comparative example 1 catalyst. Higher activity of Example 5 catalyst is attributed to retention of Y zeolite crystallinity in FCC catalyst which is attained by simultaneous mixing of binder and Y zeolite. Catalyst prepared in Example 9 shows higher conversion, higher LPG, higher ethylene, propylene and butylene yields compared to comparative example 1 catalyst.
Table 2: VGO feed properties
Properties Value
Density at 15°C, gm/cc 0.92
Sulphur, wt% 1.96
Conradson carbon residue, wt% 0.6
Boiling point distribution,
ASTM-7169 Distillation, wt%
IBP 283
5 345
10 365
30 404
50 429
70 457
90 506
95 529
SARA, wt%
Saturates 57.1
Aromatics 33.3
Resin 9.4
Asphaltene 0.2
Comparative example 1
[0057] In this example, Commercial FCC catalyst is used for comparison with FCC catalyst prepared in inventive examples (Table 3).

Table 3: ACE R+MM unit Cracking Experiment results
Catalyst name Comparative example 1 Example 5 Example 9
Feed VGO VGO VGO
Cat/Oil 6 6 6
Reaction temperature, 0C 529 529 529
Conversion, wt% 73.60 81.55 75.75
Yields, wt%
Coke 2.11 4.08 3.63
Dry Gas 2.57 2.54 3.04
LPG 17.65 23.46 30.54
Naphtha 51.27 51.47 38.55
LCO 15.56 11.07 12.6
Bottoms 10.84 7.38 11.65
Ethylene 0.63 0.83 1.61
Propylene 5.13 6.52 12.66
C4 Olefins 6.63 7.84 10.50

[0058] A skilled artisan will appreciate that the quantity and type of each ingredient can be used in different combinations or singly. All such variations and combinations would be falling within the scope of present disclosure.
The foregoing examples are merely illustrative and are not to be taken as limitations upon the scope of the invention. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the scope of the invention.
, Claims:1. An attrition resistant hydrocarbon cracking catalyst comprising:
10 to 55% w/w of a zeolite;
10 to 35% w/w of a silica sol binder;
1 to 20% w/w of an alumina;
20 to 50% w/w of a clay;
0-5 % w/w of a water-soluble aluminium; and
0-2% w/w of polymeric inorganic and/or organic dispersant,
wherein % w/w is based on the total weight of the catalyst.
2. The catalyst as claimed in claim 1, wherein the zeolite is selected from the group consisting of NaY, NaUSY, NH4Y, NaNH4Y, RENH4Y, USY, REUSY, X, NH4X, REX, mordenite, Zeolite beta, ZSM-5 and ZSM-11.
3. The catalyst as claimed in claim 1, wherein the silica sol binder is derived from mixing of silica with a mineral acid.
4. The catalyst as claimed in claim 3, wherein the silica is selected from a group consisting of alkaline grade sodium silicate, neutral grade sodium silicate, colloidal silica and silicic acid.
5. The catalyst as claimed in claim 3, wherein the mineral acid is selected from a group consisting of hydrochloric acid, nitric acid, sulphuric acid, formic acid, acetic acid and phosphoric acid.
6. The catalyst as claimed in claim 3, wherein the silica sol binder has a particle size is the range 10 to 30 nm.
7. The catalyst as claimed in claim 1, wherein the alumina is selected from a group consisting of aluminum trihydrate, boehmite, Pseudoboehmite and gamma alumina.
8. The catalyst as claimed in claim 1, wherein the clay is selected from the group consisting of bentonite, montmorillonite, halloysite, attapulgite, kaolin, illite, vermiculite and smectite.
9. The catalyst as claimed in claim 1, wherein the aluminium is selected from a group consisting of aluminium sulphate, aluminium chloride and aluminum nitrate.
10. The catalyst as claimed in claim 1, where the polymeric inorganic and/or organic dispersant is selected from a group consisting of poly sodium acrylate, sodium polysilicate and sodium polyphosphate.
11. The catalyst as claimed in claim 1, wherein the catalyst further comprises a residual sodium below 0.45 % w/w.
12. The catalyst as claimed in claim 1, wherein the catalyst further comprises a rare earth content in the range of 0.1 to 4 % w/w.
13. The catalyst as claimed in claim 1, wherein the attrition resistant cracking catalyst has a particle size in the range of 20-150 microns.
14. A process for the production of an attrition resistant hydrocarbon cracking catalyst comprising:
a) mixing of silica and mineral acid under stirring to produce a silica sol binder;
b) adding 0-5 % w/w of a water soluble aluminium and 0-2% w/w of polymeric inorganic and/or organic dispersant to obtain a first slurry;
c) mixing 1 to 20% w/w of an alumina to 20 to 50% w/w of clay and to obtain a second slurry;
d) mixing 10 to 55% w/w of a zeolite in water to obtain a third slurry;
e) introducing first, second and third slurry simultaneously in a homogeniser followed by spray drying to form a microsphere within 60 seconds;
f) washing the microspheres with hot water to obtain washed microspheres;
g) exchanging ammonia of the washed microspheres to obtain an ammonia exchanged microspheres;
h) exchanging rare earth content of the ammonia exchanged microspheres to obtain a rare earth content exchanged microspheres; and
i) washing the rare earth content exchanged microspheres with hot water followed by drying to obtain an attrition resistant hydrocarbon fluid catalytic cracking catalyst.
15. The process as claimed in claim 14, wherein the process includes
i) the silica is mixed with mineral acid in step (a) at a temperature in the range of 10 to 30 °C.
ii) the silica sol binder of step (a) is maintained at a pH below 3.
iii) the final spray drying of slurry of step (e) has a pH in the range of 3 to 3.5.
iv) the microspheres are washed with hot water having temperature above 80oC in step (f) within 120 seconds of their formation, to reduce pH of effluent below 7.
v) the ammonia exchanged in step (g) is carried out with solid to liquid ratio 1:10 at a temperature in the range of 65 to 100 °C.
vi) the rare earth exchanged in step (h) is carried out at a temperature in the range of 60 to 80 °C for a period of 20 to 40 minutes.
vii) the drying in step (i) is carried out at a temperature in the range of 120 to 160 °C for a period of 8 to 14 hrs.