Modified Y-zeolite/ZSM-5 catalyst for increased propylene production
Provided is a Fluid Catalytic Cracking catalyst composition having increased propylene production with respect to other Fluid Catalytic Cracking catalysts (measured at constant conversion). The catalyst composition comprises a particulate which comprises (a) non-rare earth metal exchanged Y-zeolite in an amount in the range of about 5 to about 50 wt %, based upon the weight of the particulate; and (b) ZSM-5 zeolite in an amount in the range of about 2 to about 50 wt %, based upon the weight of the particulate.
1. An FCC catalyst composition comprising a particulate, said particulate comprising
catalytic components (a) and (b), wherein component (a) comprises a non-rare earth metal exchanged Y-zeolite in an amount in the range of about 5 to about 50 wt %, based upon the weight of the particulate; and component (b) consists of ZSM-5 zeolite in an amount in the range of about 2 to about 50 wt %, based upon the weight of the particulate, wherein (a) and (b) are present in the same particle, wherein the Y-zeolite:ZSM-5 weight ratio is in the range of about 1:2.5 to about 1:6, and wherein the non-rare earth metal is magnesium, calcium, or strontium.
2. An FCC catalyst composition as in claim 1 wherein said non-rare earth metal comprises magnesium.
3. An FCC catalyst composition as in claim 1 wherein the FCC catalyst composition comprises a total non-rare earth metal content in the range of about 0.2 to about 3 wt % percent.
4. An FCC catalyst composition as in claim 2 wherein said FCC catalyst composition is prepared by a process comprising magnesium/hydrogen ion exchange with an unexchanged Y-zeolite.
5. A process for producing propylene from a hydrocarbon feedstock, said process comprising the steps of:
a) providing an FCC catalyst composition comprising:
a particulate, said particulate comprising catalytic components (a) and (b), wherein component (a) comprises a non-rare earth metal exchanged Y-zeolite in an amount in the range of about 5 to about 50 wt %, based upon the weight of the particulate; and component (b) consists of ZSM-5 zeolite in an amount in the range of about 2 to about 50 wt %, based upon the weight of the particulate, wherein (a) and (b) are present in the same particle, and wherein the Y-zeolite:ZSM-5 weight ratio is in the range of about 1:2.5 to about 1:6, and wherein the non-rare earth metal is magnesium, calcium, or strontium;
b) contacting the FCC particulate catalyst composition with the hydrocarbon feedstock, at one or more temperatures in the range of about 400 to about 650° C., with a dwell time in the range of about 0.5 to about 12 seconds.
6. A process as in claim 5 wherein contacting in b) takes place in a fluidized bed reactor.
7. A process as in claim 5 wherein the non-rare earth metal comprises magnesium.
8. A process as in claim 5 , wherein the resulting yield of propylene is greater, as compared with the resulting yield of propylene of the same process but modified to use an unexchanged Y-zeolite instead of said non-rare earth metal exchanged Y-zeolite on a weight-for-weight basis, the comparison being made at a feedstock conversion in the range of about 40 to about 90 weight percent conversion.
9. A process as in claim 5 wherein the ZSM-5 is in the range of about 5 to about 35 wt %, based upon the weight of the particles in which ZSM-5 and non-rare earth metal exchanged Y-zeolite are present.
10. A process as in claim 5 wherein the non-rare earth metal exchanged Y-zeolite is in the range of about 5 to about 30 wt %, based upon the weight of the particles in which ZSM-5 and non-rare earth metal exchanged Y-zeolite are present.
11. A process as in claim 5 , wherein the FCC catalyst composition further comprises an amount of alumina in the range of 0 to about 35 wt %, an amount of silica sol in the range of 0 to about 25 wt %, and the remaining balance being clay.
12. An FCC catalyst composition as in claim 2 wherein the magnesium is in an amount measured as magnesium oxide in the range of about 0.25 to about 3.0 wt % percent.
13. An FCC catalyst composition as in claim 1 wherein the Y zeolite is an ultrastabilized faujasite Y zeolite.
14. A process as in claim 5 wherein:
the Y zeolite is an ultrastabilized faujasite Y zeolite;
and/or
propylene is formed with a conversion efficiency in the range of about 4 to about 20 wt %, based upon the weight of the hydrocarbon feedstock.
15. A process as in claim 7 wherein the FCC catalyst composition comprises a magnesium salt in an amount measured as magnesium oxide in the range of from 0.25 to 3.0 wt %.