Title of Invention

A PROCESS FOR PRODUCING FCC ADDITIVE

Abstract

This invention relates to a process for producing FCC additive composite, effective as cracking catalyst. According to the process an aluminium phosphate mixture is prepared by mixing aqueous aluminium salt solution with phosphoric acid in amounts to obtain Al to PO4 ratio of 0.4 to 2.0. An aqueous slurry of crystalline zeolite component comprising non-templated (defect structure) Pentasil of silica to alumina ratio in the range of 20 to 150 ir order to get 10-25 wt. % of zeolite slurry concentration is prepared. Clay such as kaolin (acid treated) is added thereto in dry state under rigorous stirring. The aluminium phosphate mixture and aqueous slurry are mixed thoroughly under strong agitation at room temperature and is introduced into collodial mill. The pH of the resulting slurry having a value between 4.0-5.0 is adjusted. The slurry so obtained is held in the slurry tank at room temperature under constant stirring till it spray dried at inlet temperature of 450-490°C and outlet temperature between I50-2I0°C. Solid particles are calcinated in the temperature range between 530°C-IOOO°C for a period so as to produce attrition resistant FCC additive particles.

Full Text

FIELD OF THE INVENTIONi: This invention is related to an effective method for the preparation of attrition resistant binder matrix containing non-templated zeolites useful for fluid catalytic cracking (FCC) addtive composition specfically non-templated pentasii shape selective zeolites having fault structure as one of the active component dispersed in silica-alumina phosphate-clay matrix. The invention more specficaliy related to a method for the preparation of active FCC additive composite comprising crystalline non-templated pentasii zeolites, aluminium phosphate and clay components having improved thermal / hydrothermal stability with high degree of attrition resistance which are particularly effective in catalytic cracking of high molecular hydrocarbon feedstocks to produce more LPG (liquifled Petroleum Gas) with high C4 & C3 yield. Broadly, this invention contemplates a FCC additive which comprises a non-templated zeolite pentasii type with stacking disorders in Its framework structure, alumina phosphate and clay components formulated and spray dried and a specific heat treatment to get stabilized surface areaof about 50 m2./g which does not change on steaming and also retains the structure and texture of ts (addtive) constituents. BACKGROUND OF THE INVENTION: FCC additives containing zeolites are widely used In the petroleum refining Industries to Increase/enhanced gasoline octane and yelld light olefins. At present, various complexes of alumina, alumina-silicate compounds, silica, magnesia, chromia, zirconia, gallium, germinium etc., are the materials most widely employed as binders. Those skilled In the art also with appreciate that regardless of the specffic catalytic duties to which a given binder material Is put in a given fluid catatytic process, elutratin losses with occur when particles of different sizes, shapes and/or velocities undergo inter-particle impacts. Such impacts tend to shatter or otherwise damage the matrices of all such materials, Hence smaller and smaller fragments are constantly being formed and subsequently lost via cyclone elutration of the resulting smaller particles. Fragments having diameters of less than about 20 microns are especially susceptible to elutration losses. Other losses occur as a result of differences of two or more catalyst species used in the same fluid process, I.e. to say that many modern catalytic processes, It Is not at ail uncommon to have number of different kinds of catalyst species simultaneously circulating through a reaction system In order to carryout distinctly different catalytic functions. Consequently, classification and sequestration are often caused by action of mass of reaction vapors sweeping through and separating different kinds of catalyst particles according to their densfty differences. Consequently, use of the very same binder material to make different catalyst species is a widely employed practice since it tends to create like densities in different particle species. Synthetic zeolites comprise a large group of catalytic materials of great Interest to commercial operations. The pentasii group of zeolites are by far most important catalysts in petroleum cracking operations. In such operations, zeolites are generally combined with one or more amorphous catalyst or binder In the same particle. Pentasii class zeolites are typically medium pore (5.0-5.8 A pore dia) high silica, microporous crystalline materials. These are generally synthesized fol;owing (emplated as well as non-templated process methods. Generally, non-templated methods produce Intergrowths or stacking disorders generated during hydrothermal synthesis step. It Is well known that even small number of planar faults can have a dramatic effect on a zeolite's microscopic properties. The product distribution obtain from certain catalytic test reactions, such as hydrocracklng. also depend on the geometries of the pore spaces within which they occur. Cartain different reaction studies have been reported [(1) Acta Phys. Chem. 31, 487 1986 and (iO Zeolites 9, 423, 1989] and catalytic data also been related quantitatively to Intergrowth occurrence In the pentast family (Stud. Surf. Scl. Catal. No. 33,1987. Amsterdam: Elsevier). US Patent No. 63S5S91 diseases a process for the preparatton of fluid catalytic cracking catalyst additive composition comprising 4 to 20 wt % aiuminum phosphate composite, 1 to 40wt % crystalline molecular sieve zeolites and 40 to 90 wt % clay. The catalyst is prepared by the steps of reacting aiuminum metal powder withh phosphoric add to obtain aluminum phosphate; and the aluminum phosphate is then dried and calcined at a temperature of 538°C for 1 hour. The calcined aluminium phosphate thus obtained is mixed with a slurry containing clay and zeoltte slurry, under high sheer mixing to obtain a slurry, followed by spray drying, and calcining the same to obtain the catalyst micropores. Therefore, It uses aluminium powder to lead to the aluminium phosphate sol/gel which Is then dried, calcined and then used for further steps. Further, the ^uid sol fills up the mkcropores of the penfasil crystalline voids which reduces the efficiency of the Pentasil catalyst in reactions. OBJECTS OF THE INVENTION An object of this invention is to propose a process for the preparation of an improved zeolite based additives for increasing LPG yield during catalytic cracking of vacuum gas oil. Another object of this Invention Is to propose a process for the preparation of an Improved zeolite based additives for increasing LPG yield during catalytic craclcing of vacuum gas oil comprising defect structure Pentasil/.alumlna phosphate and clay which is resistant to attrition and selective for the production of LPG (liquid petroieum gas). DESCRIPTION OF THE INVENTION According to this Invention there Is provided a process for producing FCC additive catalyst composite, effective as cracking catalyst having a stolchlometric composttion range in terms of oxide mole ratios of the product as S 102(2.0-2.95) al2O3(1:0) :PO4(0.30-0.45):Na20 (0.03-0.06) :Fe203 (0.006-0.009) comprising the steps of, a) preparing an aluminum phosphate mixture by mixing an aqueous aluminum salt solution with phosphoric acid In amounts to obtain At to PO4 ratio of 0.4 to 2.0 b) preparing an aqueous slurry of crystaline zeolite component which comprises non-templated (defect structure ) Pentasii of silica to alumina ratio in (he range 20 to ISO in order to get 10-25 wt% of zeolite slurry concentration, adding clay such as Kaolin (acid treated) thereto in dry state under rigorous stirring, c) mixing (a) and (b) solutions thoroughly under strong agitation at room temperature and introducing A irito coilodial mill, the pH of the resisting slurry being maintained at a value between 4.0-5.0, d) holding the slurry obtained at (c) In slurry tank at room temperature under constant stirring and spray drying at inlet temperature of 460°--490°C and outlet temperature between 150°-210°C, e) calcining said solid particles in the temperature range between 530°C-1000°C for a period so as to produce attrition resistant FCC additive particles. This Invention generally Involves the use of i) large proportions (l.e.>20%, In many cases proportions upto 50% ) of naturally occurring clays (e.g, Bentonite, Kaolin or diatomite, commonly known as diatomaceous earth). 11) Various phosphate containing compounds. iii) Crystalline alumlnosllicate zeolite of Pentasil type-with fault planes in the structure. Iv) Selectlvely pH conditions and certain drying and calcination procedures In order to produce highly attrition-resistant binder formulations. Some particularly preferred embodiments of this invention involve the use of certain specific kinds of clays those which have been subjected to dealuminatlon and calcining procedures before they are used as ingredients in the herein described processes. Thus, the attrition resistant qualities produced by the hereinafter described processes, are the result of both chemical reactions and physical process, which when used In the ways described in this patent disclosure, produce FCC additive matnx material that have required qualities whk:h render the resuming particles attrition resistant. One of the major factor that accounts for the large Improvements In the performance of FCC additive catalyst made with phosphate -PentasU-clay matrix is that there is no liquid sol to nll the micropores of the Pentasil crystalline voids. This makes more of the surface ports of the Pentasil crystals accessible to reactants. Further more, the tortoislty produced due to fault planes In Pentasil structure enhanced LPQ yield during catalytic cracking. Moreover, phosphate containing compounds requires minimum washing or even no washings during preparative stage of the matrix. One of the important step being acid-.treated clays (pre-acidlfication) render to change the aluminium-oxygen bonds found in most of these clay materials to a catlonic form, i.e., A3+ which is capable of producing the desired phosphate complex units required to Impart good binding ability. In one of the embodiment of the present Invention series of FCC additive composite prepared using various silica: alumina oxide mole ratio of zeolite Pentasil powder as one of the ingredient component Mo the matrix. In addition to this the matrbx comprises aiumino-phosphates and clay to Impart highly attrition resistant property. A preferred method for preparing the FCC addtive composite comprises: 1. Combining an active source of phosphorus and aluminum salt solution in a desired proportion to yield aiumino-phosphate sol/gel In Ai: PO4 ratio within 0.4-2.0 and thereafter the formed Soi/gei of aiumino-phosphate Is made to pass through a colloidal mill, the pH value of soi/gel being kept less than 2. 2. .Combining the aqueous slurry source of Pentasil zeolite powder in a desired percent proportion with a previously acid treated source of clay powder. 3. Mixing the above (1) & (2) slurry together without further filtration/ washing and drying under stirring at room temperature and thereafter introducing the entire mix Mo colloidal mill, the pH value of the mix being kept about 4.0 to 5.0. 4. The resulting slurry to be held in a slurry tank under high shear constant stirring before being spray dried. 5. The slurry preferably comprsing appropriate percerrtage of solids which contains aiumino-phosphate, zeolte Penstasil and clay being spray dried at gas/ inlet/outlet temperatures of 450°C-476°C and 160°C-180°C respectively at pumping pressure of 4.0-7.0 Kg./cm2 to obtain particulate spray dried FCC catalyst particle in the range of 40-100 microns. 6. Calcining the obtained particulate FCC additive In air atmosphere at ismperatures ranging between 550°C to 750°C. 7. Steam treating the calcined particles at 750°C for 5-7 hrs. to yield higher conversion and LPG yield. Thus the preferred method in an embodiment for producing FCC additive of the present invention wherein an aluminium salt solution, preferably an aluminum nitrate solution containing SO to 65% AI(N03)3. 9H2O is combined with phosphoric acid solution preferably containing SO to 85 wt % H3PO4 to obtain aiumino-phosphate sot-gei having pH value preferably O.S to 1.5 and Al to PO4 mole ratio between 0.4 to 1.5. The aiumlno -phosphate sol-gel solution Is then combined with aqueous slurries of zeolite such as defect structure Penstasil and previously acid treated (mineral acid of 0.1 to 1.0 N strength) clay preferably Kaolin under high shear stirring and pass through coiioidal miH to obtain a spray drier feed slurry that contains 15-25% solids, which preferably comprises 8-30 wt % aiumino-phosphate, 10-30 wt % zeolite Pentasil and 35-80 wt % Kaolin (Preacidified). The FCC additive slurry Is held in a spray dryer storage tanit under mixing conditions until spray dried at a temperature of 450°C -4750°C. During the drying process the aiumino—phosphate sol-gel is converted into a binder and yields FCC additive particulates ranging between 40-100 micron size. Particles withh good attrition resistance could be made by applying air calcination to FCC additive particles at a temperatures between 550X to 750*>C, and subjecting them to cracl(ing process of hydrocarbon feedstock. Having described the basic aspects of the present invention the following specific examples are given to illustrate specific preferred embodiments. Example 1 This example describes the preparation of FCC additive containing synthetic zeolite Pentasll type modified power formed into an attrition resistant material using alumino phosphate/Clay binder. The synthetic zeolite Pentasll is our commercial product (NUZ005) having defect structure features and silica to alumina mole ratio of 50, BET surface area 415 m2/g and particle density 0.5 g/cc and the Kaolin clay (Cannary grade) was obtained from Thapar group company. India. 9.03 Kg. of aluminium-nitrate nonahydrate were dissolved & diluted with 15 Kg of deionised water to get about 60 weight percent AI(N03)3 solution. 14.6 Kg of the above diluted Al-nitrate solution were withdrawn and mixed with 4.01 Kg. of 85% orthophosphoric acid (H3P04) under high shear stirring. There was an immediate increase in the viscosity of the resulting aluminum—phosphate sol/gel slurry which was then aiiowed to pass through the colloidal mill for three times at 5,10 & 15 settings (Frigmairies/lndia). The pl-l of the resulting slurry (1) was 2.0 4.2 Kg of H- Penfasll zeoitte powder were added to 19.8 Kg of deionised wafer under stirring and to this slurry (11) 19.55 Kg of dry meta-Kaolln clay was added wittt constant stirring. Finally both the slurries i & 11 were mixed together and again allowed to pass through the colloidal mill and the pH of the slurry was 4.0. The slurry was spray dried (Alro(herm-india) to produce particles of approximately 60—65 micron size. The spray dried product (about 35 Kg) was calcined in air for one hour at 600°C The calcined FCC additive particles were then tested for their resistance to attrition and found to have an Attrition Index of 1.5 Particle density was found to be 0.65 g/cc. Example 2 In order to improve the particle density this example demonstrate the use of calcined dealuminated Kaolin Clay as one of the component/ingredient In FCC additive matrix. 20 Kg of Cannery grade Kaolin clay was treated with 0.1 N Hydrochloric acid at room temperature and then washed with sufficient deionised water till free of chioride ions and dried at 120°C for 5 hours. The acid treated Kaolin was calcined in air at 770°C for one hour. Example 3 FCC additive containing high silica: Alumina ratio (SiO2/AbO3=150) Pentasil zeolite with defective co-crystaliised phase. 11.0 kg of aluminum nitrate nonanhydrate were dissolved in 20.0 Kg of deionised water to yield about 55 wt % AI(N03)3 solution. 4.5 kg of 85% FbP04 was directly added to the above AI(N03)3 solution under strong stirring. The resulting highly viscous gel was allowed to aged to room temperature for 12 hours and then allowed to pass through the colloidal mill under the conditions described in example 1. The pH of the resuting slurry (I) was 1.9 6.0 kg of H-Pentasll (SAR 150) zeolte powder were slurried by adding 30 kg of delonlsed water under stirring and to this slurry (II) 25 kg of dry preacidified Kaolin clay was added with constant stirring. Both slurry (I) & (II) were mixed at room temperate and allowed to pass through the coliotdal mill and pH value of the resulting homogenised gel was adjusted to 4.8 ±0.23. The spray dried product of the above slurry was calcined at 650°C for 2 hours. The FCC additive formulated matrix particles were then tested for their resistance to attrition and found to have an index of 1.2 with particle denstly of 0.7 g/cc. Example 4 This example illustrates the preparation of FCC additive containing 15 wt % of ammonium exchanged form of Pentasli (SAR 80, NH3+ form) zeolite formed Ho a spray dried product using alumina phosphate and Kaolin. The procedure and composition for the formulation of FCC additive in this example was same a per example 1, except 15 wt % of NH3 Pentasli powder having silica: alumina mole ratio of 80 was used replacing H- Pentasli of ratio 50. The calcined spray dried particles of FCC additive had an attrition resistance Index of 1.8 having BET surface area of 47 m2/g. Example 5 256 g of about 60 wt % of AI(N03)3 9 H2O solution were added to 100 g of 42% of Orthophosphoric acid solution under stirring until mixed to yield homogenised ge!. The pH of me gel was less than 1.0 80 g of zeolite Pentasil (SiO:::Al203 40 ratio), 320 g of preacididfied Kaolin clay and 336 g of DM water were all together addded to previously made slurry of alumino-phosphate under high shear stirring. The pH of resulting slurry was adjusted to a value of 6.0+ 0.2 by adding 25% liquid ammonia The entire slurry was then passed through colloidat mill thrice as illustrated at example 1. The physico-chemical properties of spray dried and calcined FCC additive produced are presented in Table 1. Examples 6 to 10 These examples illustrates the effect of different composition of alumino-phosphate in terms of their At; PO4 ratios on the physico-Chemical properties of final FCC additive products obtained. The method of preparation was same as adopted at example 1. The relevant data is presented In Table 2. The data reveals that as the AI:P04 mole ratio in alumino-phosphate compcslticn increases i.e. to say moles of PO4 decreases then it weakens the binding ability during the formulation which in turn affects attrition a density properties of FCC additive composite. By optimizing the Al; PO4 ratio, it was possible to get the required attrition index and the density of the final product. Example 11 This example illustrates the use of FCC addltrve samples selected from example 9 along with FCC catalyst for cracking test procedure as per in accordance with ASTM D 3907-80. Cracking conditions were 485°C, 3:1 Caialyst:oil ratio, 5.0 gms of catalyst used, 1. 25 minute feed Injection followed by a 10 minute nitrogen purge. The feed was a gas oil having a bolting range 370°C -490°C at atmospheric pressure. Test results are summerized in Table 3. Table-3 MAT Conversion Data as per ASTM Procedure A-100% FCC- Catalyst (Commerical) and B-4% additive +96% FCC catalyst Feed -VGO (standard feed-IBP-250°C, FBR-170°C) Test data at Table 3 clearly show that the FCC additive has contributed in boosting LPG yield to the tune of 36.13 wt% as compared to 18.08 wt% from FCC catalyst without additive. ». WE CLAIM: 1. A process for producing FCC additive catalyst composite, effective as cracking catalyst having a stoichiometric composition range in terms of oxide mole ratios of (he product as 8iO2(2.0-2.95):Al2O3(1:0):PO4(0.30-0.46):Na2O(0.03-0.06):Fe2O3 (0.006-0.009) comprising the steps of, a) preparing an aluminum phosphate mixture by mixing an aqueous aluminum salt solution with phosphoric acid in amounts to obtain aluminum( Ai) to phosphate (PO4) ratio of 0.4 to 2.0 b) preparing an aqueous slurry of crystalline zeolite component which comprises non-tempfated (defect structure ) Pentasil of silica to alumina ratio hi the range 20 to 150 in order to get 10-25 wt% of zeolite slurry concentration, adding clay such as Kaolin (add treated) thereto In dry state under rigorous stirring, c) mixing (a) and (b) solutions thoroughly under strong agitation at room temperature and introducing it Mo coliodlai mlll, the ph of the resulting slurry being maintained at a value between 4.0-5.0, d) holding the slurry obtained at (c) in slurry tank at room temperature under constant stirring and spray drying at inlet temperature of 450°-90°C and outlet temperature between 150°-210°C, e) calcining said solid particles In the temperature range between 530°C 1000°C for a period of 2-5 hours so as to produce attrition resistant FCC additive particles. 2. The process as claimed in claim 1 wherein aluminum salt compound is selected from aluminum nitrate .AKNO3) 3 9H2O2 aluminum chloride AlCI3 6H3O or aluminum sulphate Ab(S04)3.16 H2O. 3. The process as claimed in claim 1 wherein the aluminum salt solution concentration is in the range of 50-65 weight percent. 4. The process as claimed in claim 1 wherein the phosphoric acid moles range between 0.01-0.05 while moles of aluminum are kept between 0.02-0.04, In order to get Aluminium;Phosphate ratio In the range 0.4-2.0 of aluminum phosphate. 5. The process as claimed in claim 1 wherein the pH of the aluminium phosphate slurry Is below 2.0. 6. The process as claimed in claim 1 wherein the homogenized alumino-phosphate slurry is passed through a colloidai mill. 7. The process as claimed in claim 1 wherein the aluminium salt solution contains a salt such as aluminium nitrate or chloride. 8. The process as clamed in claim 1 wherein the crystailne zeolite component Is selected from non-tempiated NH3- Pentasli or H-Pentasll having its defect structural framework silica to alumina oxide mole ratios in the range of 20 to 150 consisting of an average submicron range particle size between 0.4 (0 0.9 microns. 9. The process as claimed in claim 1 where non-tempiated pentasil zeolite concentration In slurry Is kept between 10-25 wt% on dry basis. 10. The process as claimed in claim 1 wherein a clay concentration in slurry is from about 20-60 weight percent and Is selected from Kaolin group having dealumlnated and ciaclned variety. 11. The process as claimed in claim 1 wherein water is added to concentrated phosphate-zeolite -clay/water slurry to being the slurry's solids concentration to about 12 to 25 weight percent. 12. The process as claimed In claims 1 and 11 wherein the drying of phosphate-zeolife-clay slurry is carried out till a particle size of approximately 50-80 microns is achieved. 13. The process as claimed in claim 1 wherein the step of calcination Is carried out for 2 to 4 hours at temperatures between 550°-760°C ( 14. The process as claimed in ciaim 15 wherein the product of FCC additive obtained is subjected to steam treatment during cracking operations. 15. The process for producing FCC additive composite substantially as herein described and illustrated In the example.

Documents:

844-mas-2000-abstract.pdf

844-mas-2000-assignement.pdf

844-mas-2000-claims filed.pdf

844-mas-2000-claims grand.pdf

844-mas-2000-correspondnece-others.pdf

844-mas-2000-correspondnece-po.pdf

844-mas-2000-description(complete) filed.pdf

844-mas-2000-description(complete) grand.pdf

844-mas-2000-form 1.pdf

844-mas-2000-form 19.pdf

844-mas-2000-form 26.pdf

844-mas-2000-form 3.pdf

844-mas-2000-form 4.pdf

844-mas-2000-form 5.pdf

844-mas-2000-form 6.pdf