Method of producing FCC catalysts with reduced attrition rates
FCC catalysts having improved attrition resistance are provided by mixing a cationic polyelectrolyte with either zeolite crystals or a zeolite-forming nutrient and/or a matrix material, prior to or during formation of a catalyst microsphere.
1. An FCC zeolite-containing catalyst microsphere, the microsphere comprising zeolite Y, the microsphere having been formed from a slurry comprising a matrix and at least one of a zeolite-forming nutrient or zeolite crystals, the slurry having been mixed with, prior to or during formation of the microsphere, a cationic polyelectrolyte in an amount from 0.005 to 0.5 wt. % relative to a total weight of the matrix and the zeolite-forming nutrient or the zeolite crystals in the slurry.
2. The catalyst of claim 1 , wherein the microsphere is 20-200 microns.
3. The catalyst of claim 1 , wherein the microsphere is formed from the zeolite-forming nutrient and the matrix, and wherein the zeolite Y is formed in situ.
4. The catalyst of claim 3 , wherein the zeolite-forming nutrient is metakaolin.
5. The catalyst of claim 4 , wherein the matrix is formed from kaolin that has been calcined through its exotherm.
6. The catalyst of claim 1 , wherein the cationic polyelectrolyte is a polyamine.
7. The catalyst of claim 4 , wherein the cationic polyelectrolyte is polyamine.
8. The catalyst of claim 6 , wherein the polyamine is mixed with the zeolite-forming nutrient and the matrix.
9. The catalyst of claim 6 , wherein the polyamine is mixed with the zeolite-forming nutrient and the matrix in an amount of from about 0.025 to 0.1 wt. %, relative to a total weight of the matrix and the zeolite-forming nutrient.
10. The catalyst of claim 1 , wherein the microsphere is formed from zeolite crystals and said matrix.
11. The method of claim 6 , wherein the polyamine has a molecular weight of between 10,000 and 1,000,000.
12. A method of producing an FCC catalyst microsphere, the method comprising:
forming a slurry comprising a matrix and zeolite Y crystals or kaolin;
mixing with the slurry a cationic polyelectrolyte such that the cationic polyelectrolyte is present in the slurry in an amount from 0.005 to 0.5 wt. % relative to a total weight of the matrix and the zeolite Y crystals or kaolin in the slurry; and
spray drying the slurry into microspheres.
13. The method of claim 12 , wherein the catalyst microspheres are 20-200 microns in diameter.
14. The method of claim 12 , wherein the matrix is kaolin calcined through the exotherm.
15. The method of claim 12 , wherein the cationic polyelectrolyte is a polyamine, and wherein the polyamine has a molecular weight of between 10,000 and 1,000,000.
16. The method of claim 12 , wherein the cationic polyelectrolyte is present in the slurry in an amount from 0.025 to 0.1 wt. % relative to a total weight of the matrix and the zeolite Y crystals or kaolin in the slurry.
17. The method of claim 12 , wherein the slurry contains hydrous kaolin and/or metakaolin, and the microspheres are reacted with a silicate to form zeolite Y crystals in situ.
18. The method of claim 17 , wherein said matrix is kaolin calcined through the exotherm and is formed from an ultrafine hydrous kaolin having at least 90 wt. % of the particles less than 2 microns.
19. The method of claim 12 , further comprising:
reacting the microspheres with a silicate to form catalyst microspheres containing zeolite Y crystals formed in situ.
20. The method of claim 12 , wherein the kaolin comprises one or more of hydrous kaolin or metakaolin.