CA1211425A

CA1211425A - Catalysts and catalyst supports

Info

Publication number: CA1211425A
Application number: CA000425572A
Authority: CA
Inventors: Roger J. Lussier
Original assignee: WR Grace and Co
Current assignee: WR Grace and Co
Priority date: 1982-04-12
Filing date: 1983-04-11
Publication date: 1986-09-16
Also published as: IT8320537A0; JPS58193732A; IT1164166B; AU1327283A; GB2118063A; GB8309852D0; NL8301268A; AU566582B2; DE3312639A1; FR2524817A1

Abstract

CATALYSTS AND CATALYST SUPPORTS
Abstract Catalysts and catalyst supports which comprise solid inorganic oxides, such as crystalline zeolites, clay and/or inorganic gels, combined with an acid reacted metakaolin binder. The compositions may be spray dried and calcined to obtain dense, attrition resistant fluid cracking catalysts or used in the preparation of formed catalyst supports.

Description

The present invention relates to the pLeparation of catalysts and supports therefor and more particularly to the preparation of dense, hard, particulate hydrocarbon conversion catalysts which comprise catalytically active components such as crystalline zeolites dispersed in an inorganic oxide matrix.
Hydrocarbon conversion catalysts such as fluid catalytic cracking catalysts (FCC) are typically manufactured by spray drying aqueous slurries, catalytically active zeolites and matrix forming components such as inorganic oxide gels and/or clays.
The resulting catalysts comprise small particles (microspheres) in which the zeolite crystals are dispersed throughout a matrix of relatively catalytically inactive gel or sol binder and clay.
While the inorganic oxide matrix generally has little catalytic activity, the matrix provides the physical strength, size and porosity characteristics which are required to obtain a commercially acceptable catalyst composition. Furthermore~ since FCC catalysts are produced and consumed in large quantities, the matrix components should be relatively inexpensive.
It has been found that clay, particularly kaolin, due to its reasonable price and availability, constitutes a particularly suitable FCC catalyst component. The prior art describes preparation of clay based hydrocarbon conversion catalysts that have been both thermally and chemically treated to obtain the desired characteristics.
U.S. 2,485,6~6 describes the preparation of clay based cracking catalyst wherein kaolin clay is heat treated, reacted with acid to remove part of the alumina component of the clay structure. Subsequently, the acid treated clay is washed free oE soluble ~.

com?onents, and finally formed into cat~lyst particles.
U.S. 3,4G6,1?4 describes a method for preparing catalysts which contain crystalline aluminosilicate zeolites dispersed in an inorganic oxide matrix. The matrix contains a clay component which is leached t~, remove a portion of the alumina of the clay structure as soluble aluminum saltsO Subsequently the aluminum salts are precipitated as aluminum hydroxide on the clay.
While th~ prior art describes ttle preparation of hydrocarbon conversion catalysts which may comprise or contain thermally/chemically treated clays, such as calcined/acid leached kaolin, the refining industry constantly requires low-cost catalysts which provide a high degree of activity and selectivity combined with substantial physical strength and attrition resistance.
It is therefore an object of the present invention to provide improved catalysts, catalyst supports and inorganic binders therefor.
It is another object to provide hydrocarbon conversion catalysts wnich are hard, dense and relatively inexpensive to manufacture.
It is yet another object to provide a zeolite containing FCC catalyst which contains substantial quantities of clay and/or clay derived matrix components~
These and still further objects of the present invention will become readily àpparent to one skilled in the art from the following detailed description and specific examples.
Broadly, my invention contemplates improved catalytic compositions (including catalysts, catalyst supports and inorganic binders) which contain an acid treated metakaolin that is obtained by heating .

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(calcining) kaolin and reactiny the resulting metakaolin with sufficient acid to react wîth up to about 25 mol percent of the alumina ~12O3) present in the kaolin.
More speciically, I have found that dense, hard, attrition resistant catalystic compositions may be prepared by combining particulate catalyst components with an acid treated metakaolin binder which is obtained by heating (calcining) Icaolin to a t_mperature of about 700 to 910C, and reacting the resulting - metakaolin with sufficient acid to react with less than I about 25 mol percent (and preferably for about 5 to 15 percent), of the structural alumina present in the metakaolin. The compositions are formed into particles which are then heat treated (calcined) at a te~perature of about 300-800C to obtain hard attrition resistant catalysts or catalyst supports.
While the process is particularly useful for tne manufacture of zeolite containing FCC catalysts, my invention also contemplates the preparation of catalyst ~I supports. These catalysts and supports comprise I inorganic oxide gels and hydrogels such as clay, alumina, silica, and silica-alumina dispersed in or combined with a binder which comprises the acid treated ! 25 metakaolin described above.
; The acid treated metakaolin binder is obtained by first thermally treating kaolin at a temperature of from about 700 to 310C and preferably 800 to 900 for a period of from about one-quarter to 8 hours, and preferably one-quarter to 2 hours. The thermal treatment or calcination step, which may be conducted in the presence of air~ converts the raw kaolin into a reactive form which is characterized as metakaolin.

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The metakaolin is then reacted with a quantity of acid, such as hydrochloric or nitric acid or an acid salt ~olution thereof such as aluminum chloride, aluminum nitrate, zirconyl chloride, etc.
The quantity of acid reacted with the metakaolin i5 suf~icient to react with from about 2 to 25 and preferably from 5 to 15 percent of the alumina (A12O3) present in the metakaolin. The reaction in the case of hydrochloric acid proceeds in accordance ~ 10 with the following overall reaction wherein metakaolin ; has the formula 2 SiO2.A12O3.

2 SiO .A1203 ~ 1 HCl~[2 Si2 (A123)o.g 0.6 3 To achieve the desired level o acid treatment, the quantity of acid used is equal to or less than about 1.5 mols of acid per mol of alumina present in the clay. I have ound that as little as 0.25 mols of acid per mol of alumina is sufficient to provide the desired acid reacted metakaolin product in less than about 24 hours. The most preferred level of acid is about 0.50 to 1.0 mol of acid per mol alumina in the metakaolin.
The desired quantity of acid is combined with sufficient water to provide from about 2.0 to 20 parts by weight acid solution per part by weight metakaolin~
The reaction with acid is conducted at a temperature of from about 60 to 100C for a period of from about 1 to 24 hours. The resulting acid/métakaolin reaction product contains from about 5 to 50 percent by weigh~
clay solids admixed with a liquid phase w~lich comprises an aqueous solution of a complex acid/aluminum reaction product which has a p~ from about 2.0 to 4Ø This acidic aluminum reaction product solution together witb ,i 2~;

the acid leached metakaolin solids comprises the binder or intermediate which is used in the preparation of the catalysts and catalyst supports contemplated Aerein.
The ratio of the acid leached clay solid to complex acidic aluminum solution i5 from about 8/1 to 9.8/l, preferably 9/1 to 9.5/l parts by weight.
- To ob-tain a cracking catalyst which contains the acid-metakaolin reaction product described above, the acid-metakaolin reaction mixture is admixed with ~he desired quantity oE catalytic components and/or gelled with a base and formed into catalyst particles. The added components typically comprise crystalline zeolites such as type X, type Y (synthetic faujasite), ZSM zeolite and/or other desired catalyst components such as clay, alumina and silica-alumina hydrogels.
Subsequent to mixing the acid reacted metakaolin binder slurry with the catalyst components, the soluble aluminum components of the binder may be precipitated as alumina by the addition of a base such as am~onium hydroxide, or sodium hydroxide. It is also contemplated that the acid reacted metakaolin reaction product may be geiled without added catalyst ingredients. In the alumina precipitating step, sufficient base is added to raise the pH of the reaction mixture to a level of about 5.0 to 9Ø
zeolite components may be initially mixed with the acid-metakaolin binder slurry in the sodium form, or the zeolites may be pre-exchanged with hydrogen and/or stabilizing ions such as rare earth ions. Typical exchanged/thermally treated zeolites comprise the calcined rare earth exchanged type X and Y zeolites (CREX and CREY) described inU.S. Re 28,629. In addition, the zeolite component may comprise an lz~ s ultrastable type zeolite such a~ described in U.S.

3,293,192 and 3,449,070. It is also contemplated that other catalytically active zeolites s~ch as ZSM 5, 11 and mordenite may be utilized alone or as blends with the previously mentioned zeolites.
It is generally found that the fluid cracking catalysts (F~C) prepared herein will comprise from about 5.0 to 20 parts by weight acid meta-kaolin binder (dry basis) and from about 9S to 80 parts by weight solid components such as zeolite, alumina and clays, (including the base gelled acid leached metakaolin described herein). The binder is thoroughly admixed with the solid components to obtain a spray drier feed slurry which contains from about 20 to 60 percent by weight solids. ~he ælurry is then spray dried using conventional techniques to obtain microspheroidal FCC
catalyst particles which are then calcined at a temperature of from about 300 to 800C. These calcined particles may then be ion exchanged and/or washed to remove undesirable soluble salts. Typically, the spray dried product is contacted with solutions of ammonium sulfate and/or rare earth chloxide ions.
In the event the acid treated metakaolin binders contemplated herein are utilized to prepare suppor~s, such as used in the preparation of hydroprocessing catalysts, the acid meta~aolin reaction mixture described above is gelled and/or admixed with the desired solid components which typically comprise zeolites, clay and inorganic oxide gels such as alumina, silica and silica alumina ~including the base gelled acid reacted metakaolin described herein)~ The mixtures which comprise from about S to 40 parts acid ; treated kaolin binder and 95 to 60 parts inoryanic ~ ~7~

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solids may be optionally reacted with a base to precipitate alumina. The mixtures are then formed into catalyst particles having the desired shape and size.
Typical forming techniques such as pilling, extruding ; 5 and granulating may be utilized. The resultant formed particles are then subjected to calcination and a temperature of from about 300 to 800C to o~tain hard attrition resistant particles. The resulting calcined particles may then be combined with catalytically active metals such as selected from group VI and group VIII of the Periodic Table to obtain catalysts useEul for hydrocracking and hydrodesulfurization, demetallization and so forth. In particular, it is found that from about 1 to 20 weight percent non-noble metals, such as cobalt, molybdenum, chromium and nickel may be impregnated or placed upon the catalyst supports contemplated herein using conventional techniques. In ; addition it is found that from about 0.1 to 2 weight percent noble metals such as platinum, palladium and rhodium may be combined with the supports to obtain useful, catalytically active products.
Having described the basic aspects of the present invention, the following examples are given to illustrate the specific embodiments thereof.

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A sample of kaolin clay having a particle size less than 2.0 microns which possessed the initial chemical composition 51.8 weight percent sio2, 42.2 percent A12O3 was calcined for one half hour at 900C~ A
300 g sample of the calcined clay was then added to 3 liters of a solution which contained 102 ml of 37 percent HCl. The resulting slurry was refluxed at a ~2~

temperature of 100C for 4 hoursO The reaction mixture was then combined with 500 g o calcined, rare earth exchanged type Y æeolite (CREY) which contained U.79 percent Na2O, and 2323 g (dry basis) raw kaolin. The slurry was homogenized and subsequently spray dried.
The physical properties of the resulting catalyst product are summarized in the Table.

~xample 2 9000 g sample o~ metakaolin, which was obtained by calcining raw kaolin for one-half hour at 900C, was admixed with 60 1 of an acid solution which contained 3042 ml of 37~ HCl. This mixture was then boiled under reflux fGr seven and one-half hours. The slurry p~ was adjusted to about 6.n by the addi~ion of 30 percent ammonium hydroxide. The gelled reaction mixture was then filtered, washed twice with 10 g~l of hot deionized water, and reslurried in approximately 25 gal of hot deionized water and recovered by filtration.
450 g D.B. (2074 9 as is) of this filter cake was dispersed in a blender along with a slurry which comprised 500 9 o the CREY described in Example 1 and 2175 g (dry basis), 2529 g as is of raw kaolin, and approximately 8tO00 g of water. The mixture was homogenized by recirculation through a centrifugal pump and subsequently spray dried. The physical properties of the catalyst obtained in this example are set forth in the Table.

F. ample 3 A 1400 9 sample of the me~akaolin described in Example 2 was combined with 4.2 1 of a solution which contained 472.6 ml of 37% HCl dissolved in water. ThiS
mixture was boiled under reflux for 2 hour~. The .

~.Z~1~425 reaction mixture was then combined in the blender with 559.4 g CREY and 2120 g (dry basis) kaolin. The slurry was then thoroughly mixed and spray dried to obtain microspheroidal particles. The catalyst particles were then calcined 2 hours at 540C. This sample had the physical properties described in the Table.

Example 4 ~ 6750 g sample of the metakaolin described in Example 2 was added to 80 1 oE the solution which contained 2286 ml of 37~ HCl. This mixture was then boiled under reflux for 7 hours. 6 1 of the resulting slurry was combined with a 2175 g (dry basis) sample of raw kaolin and 434 g (dry basis) CREY. The slurry was then mixed thoroughly, spray dried and calcined 2 hours at 54~C. The physical propexties of the catalyst obtained in this example is summariæed in the Table.

Example 5 i This example shows that a portion of the acid leached clay slurry can be used to bind an ammonium hydroxide gelled acid leached clay of the type described in Example 2. 600 g of kaolin was calcined one-half hour at 900C was added to 6.~ 1 solution containing 204 ml 37.0% HCl and boiled under reflux for approximately 4 hours. A blended slurry of 18Q g as is CREY (0~79% Na2Oj and 2,215 g dry basis (10,889 g as is) washed am~onium hydroxide gelled acid leached clay obtained by the procedure set forth in Example 2 was added. The slurry was thoroughly mixed and spray dried. The properties of this catalyst sample are set forth in the Table.

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Example_6 A 5,200 g dry basis sample of the washed ammonium hydroxide ~elled acid leached metakaolin of Example 2 was slurried in a total of about 30,000 g of water and spray dried. The properties are set forth in the Table.

~xample 7 450 9 of the calcined clay described in Example 1 was added to 4.5 1 solution containing 153.0 ml conc.
Hcl and boiled 4 hours under reflux. To this slurry 500 g of CREY and 2,529 g (raw) kaolin clay were added, the slurry briefly homogenized and spray dried. ThiS
sample, of composition 15 percent acid treated clay, 12.5 percent C~EY, 72.5 percent kaolin clay, had the proper~ies indicated in the Table.

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Ln o 12~425 (1) ~ttrition Resistance measured after calcination for 2 hours at looooF as determined by the method set forth in U.S. 4,247,420.

(2) Microactivity volume ~ con~ersion as determined by S use o~ the test as described by Henderson et al at 900F, 16 ~HSV, 3 c/o after an 8 hour, 1350F, 100 steam deactivation.

*ABD - Apparent Bulk Density (g/cc) **CD - Compacted Density (g/cc) The above Bxamples clearly indicate that valuable catalyst compositions may be obtained usin~ the teachings Oe my invention.

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Claims

I CLAIM:

1. A particulate catalytic composition comprising:
(a) a solid, inorganic oxide, and (b) an acid reacted metakaolin binder in which up to 25 mol percent of the alumina thereof has been reacted with an inorganic acid at a temperature of from about 60 to 100°C. for a period of from about 1 to 24 hours.

2. The composition of claim 1 wherein the solid inorganic oxide component is selected from the group consisting of crystalline zeolites, silica, alumina, silica-alumina, hydrogels and hydrosols, clays and mixtures thereof.

3. The composition of claim 1 wherein said binder comprises kaolin which is calcined at a temperature of 700 to 910°C for a period of about one-quarter to 2 hours and subsequently reacted with an acid selected from the group consisting of hydrochloric, nitric acids, salts and mixtures thereof.

4. The composition of claim 1 wherein said binder is reacted with sufficient base to precipitate soluble aluminum components.

5. The composition of claim 2 wherein said composition comprises a fluid cracking catalyst composition that contains up to 50 percent by weight of a crystalline zeolite.

6. The composition of claim 5 wherein said zeolite is rare earth exchanged type Y zeolite.

7. The composition of claim 6 wherein said composition includes up to 80 percent by weight raw kaolin.

8. The composition of claim 3 wherein from about 5 to 15 mol percent of the alumina in the calcined kaolin is reacted with acid.

9. A composition comprising an acid reacted metakaolin wherein said metakaolin is obtained by calcining kaolin at a temperature of 700 to 910°C for a period of one-quarter to 2 hours, and reacting at a temperature of from about 60 to about 100°C for a period of about 1 to 24 hours said metakaolin with sufficient acid to react with about 5 to 10 mol percent of the alumina present in said kaolin.

10. The composition of claim 9 which contains 2 to 20 parts by weight water per part by weight metakaolin.

11. The composition of claim 9 which is reacted with sufficient base to precipitate soluble alumina.

12. The composition of claim 11 which is washed and spray dried.

13. A method for preparing a catalytic composition which comprises: `
(a) calcining kaolin at a temperature of 700 to 910°C. for one-quarter to 2 hours;
(b) reacting at a temperature of from about 60 to about 100°C for a period of about 1 to 24 hours said calcined kaolin with sufficient acid to react with up to 25 mol percent of the alumina present;
(c) mixing said acid treated calcined kaolin with a particulate inorganic solid;
(d) forming the mixture into particles; and (e) calcining said particles at a temperature of 300 to 800°C.

14. The method of claim 13 wherein the particulate inorganic solid is selected from the group consisting of crystalline zeolites, silica, alumina, silica-alumina hydrogels, clays and mixtures thereof.

15. The method of claim 13 wherein the mixture obtained in step (c) is reacted with a base to precipitate soluble alumina components prior to step (d).

16. The method of claim 13 wherein said acid is selected from the group consisting of hydrochloric, nitric acids and salts thereof.

17. The method of claim 13 wherein up to about 20 parts by weight solid inorganic oxide is mixed per part by weight of the acid-kaolin reaction product obtained in step (a).

18. The method of claim 13 wherein said mixture is formed by spray drying, extruding, pilling or granulating.

19. The method of claim 13 wherein the particulate inorganic solid comprises an acid leached metakaolin which is reacted with a base to precipitate soluble alumina.

20. The method of claim 19 where the kaolin is calcined at a temperature of about 700 to 910°C for one-quarter to 2 hours.

21. The method of claim 20 wherein the calcined kaolin is reacted with sufficient acid to remove from about 5 to 15 mol percent of the alumina present in said kaolin.