Monolith structure loaded with metal promoted nanozeolites for enhanced propylene selectivity in methanol conversion

Patent metadata

Field	Value
Publication number	US-9682367-B2
Application number	US-201414520978-A
Country	US
Kind code	B2
Filing date	Oct 22, 2014
Priority date	Oct 22, 2014
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

A catalyst system and a process for methanol to light olefin conversion with enhanced selectivity towards propylene. The catalyst system comprises a honeycomb monolith catalyst support coated with nanozeolite catalysts on the edges and inside the channels of the support structure. The nanozeolite catalysts have been pre-modified with metal. The catalyst system gives higher hydrothermal stability to the catalyst compared to randomly packed pellet catalyst and allows methanol to be converted to predominantly propylene at a low temperature, with decreased selectivity towards C 2 , higher olefins and paraffinic hydrocarbons.

First claim

The invention claimed is:

1. A catalyst system for the conversion of methanol into light olefins comprising:
zeolite nanoparticles in the form of crystals having an average particle diameter of 10-50 nm modified with at least one promoter transition metal selected from the group consisting of iron, nickel, and chromium in the form of nanoparticles with an average particle diameter of 1-10 nm adsorbed onto a surface of the zeolite nanoparticles; and
a honeycomb monolith support with 400-1200 cells per square inch coated with the zeolite nanoparticles on the edges and inside the channels of the honeycomb monolith support;
wherein the catalyst system comprises 5-15 wt % of the promoter transition metal relative to the total weight of the catalyst system; and
wherein the catalyst is capable of converting methanol to propylene with a selectivity towards propylene of at least 40% relative to a total mass of light olefin products and a selectivity towards propylene that is greater than a selectivity towards ethylene relative to a total mass of light olefin products and that is greater than a selectivity towards butylene relative to a total mass of light olefin products.

2. The catalyst system of claim 1 , wherein the zeolite nanoparticles comprise metalloaluminosilicates and metallosilicalites of at least one transition metal selected from the group consisting of iron, nickel and chromium and wherein a ratio of metalloaluminosilicates to metallosilicalites is in a range from 1:1 to 2:1.

3. The catalyst system of claim 1 , wherein the zeolite nanoparticles are microporous molecular sieves having an MFI framework type, which have a BET surface area of 100-1000 m 2 g −1 and which have a pore size distribution of 0.6-1.0 nm.

4. The catalyst system of claim 1 , wherein the promoter transition metal is iron.

5. The catalyst system of claim 1 , further comprising a binder.

6. The catalyst system of claim 1 , wherein the zeolite nanoparticles further comprise alkaline earth metal ions.

7. The catalyst system of claim 1 , wherein the selectivity of the conversion towards propylene is 40-80% of the total mass of light olefin products.

8. A process of converting methanol into light olefins, comprising:
contacting the methanol in a reactor with the catalyst system of claim 1 .

9. The process of claim 8 , wherein the methanol is in vapor phase.

10. The process of claim 8 , wherein the process is carried out at a pressure of 0 psig to 50 psig.

11. The process of claim 8 , wherein the process is carried out in the presence of an inert gas.

12. The process of claim 8 , wherein the reactor is selected from the group consisting of a fixed-bed reactor and a moving-bed reactor.

13. The process of claim 8 , wherein the zeolite nanoparticles comprise metalloaluminosilicates and metallosilicalites of at least one transition metal selected from the group consisting of iron, nickel and chromium.

14. The process of claim 8 , wherein the zeolite nanoparticles are microporous molecular sieves having an WI framework type.

15. The process of claim 8 , wherein the promoter transition metal is iron.

16. The process of claim 8 , wherein the catalyst system further comprises a binder.

17. The process of claim 8 , wherein the zeolite nanoparticles further comprise alkaline earth metal ions.

18. The process of claim 8 , wherein the selectivity of the conversion towards propylene is 40-80% of the total mass of light olefin products.

19. A method of preparing the catalyst system of claim 1 , comprising:
(a) modifying zeolite nanoparticles with at least one promoter transition metal selected from the group consisting of iron, nickel and chromium;
(b) optionally mixing the metal-modified zeolite nanoparticles with a binder;
(c) coating the honeycomb monolith with the metal-modified zeolite nanoparticles, and optionally a binder, on the edges and inside the channels of the honeycomb monolith; and
(d) calcining the coated honeycomb monolith;
wherein the zeolite nanoparticles are microporous molecular sieves having an WI framework type.

20. The method of claim 19 , wherein the zeolite nanoparticles comprise metalloaluminosilicates, metallosilicalites of at least one transition metal selected from the group consisting of iron, nickel and chromium.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Ali Mohammad Ashraf
• Ahmed Shakeel

Classifications

• B01J35/57

  Honeycombs · CPC title

• B01J29/76

  Iron group metals or copper · CPC title

• C07C2529/46

  Iron group metals or copper · CPC title

• B01J29/78 Primary

  containing arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium · CPC title

• B01J35/0006

  Operations & Transport · mapped topic