Method for preparing P-xylene and propylene from methanol and/or dimethyl ether

Patent metadata

Field	Value
Publication number	US-9994496-B2
Application number	US-201415315768-A
Country	US
Kind code	B2
Filing date	Jun 4, 2014
Priority date	Jun 4, 2014
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

This invention relates to a method for preparing p-xylene and propylene from methanol and/or dimethyl ether. This method comprises coupling two reaction processes, an aromatization reaction of methanol and/or dimethyl ether and an alkylation reaction of ethylene with methanol and/or dimethyl ether. The method of this invention produces p-xylene and propylene with a high selectivity by returning an ethylene-enriched component in reaction byproducts from preparation of p-xylene from methanol and/or dimethyl ether to the reaction system for performing alkylation reaction with methanol and/or dimethyl ether in the presence of catalysts.

First claim

What is claimed is:

1. A method for preparing p-xylene and propylene from methanol and/or dimethyl ether in a reaction system comprising a first reaction zone and a second reaction zone, comprising the steps of:
a) passing a first portion of a raw material containing methanol and/or dimethyl ether through the first reaction zone to be in contact with a catalyst I to obtain an intermediate product stream,
b) passing the intermediate product stream and a second portion of the raw material containing methanol and/or dimethyl ether through the second reaction zone to be in contact with a catalyst II to obtain a final product stream comprising a C 6 + component, a C 4 -C 5 component, a C 3 component, an ethylene-enriched C 2 − component, and H 2 O;
c) passing the final product stream to a separation system to recover the C 6 + component, the C 4 -C 5 component, the C 3 component, the ethylene-enriched C 2 − component and H 2 O, respectively, and returning the ethylene-enriched C 2 − component to the second reaction zone;
d) further separating the recovered C 6 + component to obtain a product p-xylene; and
e) further separating the recovered C 3 component to obtain propylene;
wherein each of the catalyst I and the catalyst II independently comprises a modified zeolite molecular sieve catalyst obtained from ZSM-5 and/or ZSM-11 zeolite molecular sieve modified with a precious metal, a rare earth metal, and a siloxanyl compound.

2. The method according to claim 1 , wherein the first reaction zone and the second reaction zone are in the same reactor.

3. A method for preparing p-xylene and propylene from methanol and/or dimethyl ether in a reaction system comprising a first reaction zone and a second reaction zone, comprising the steps of:
a) passing a first portion of a raw material containing methanol and/or dimethyl ether through the first reaction zone to be in contact with a catalyst I for aromatization reaction to obtain a resultant A,
b) passing the resultant A to a separation system, and recovering and returning an ethylene-enriched C 2 − component to the second reaction zone,
c) passing a second portion of the raw material containing methanol and/or dimethyl ether through the second reaction zone to be in contact with a catalyst II to obtain a resultant B;
d) passing the resultant B to the separation system such that the resultant B is subjected to separation in the separation system along with the resultant A to recover a C 6 + component, a C 4 -C 5 component, a C 3 component, the ethylene-enriched C 2 − component, and H 2 O, respectively;
e) further separating the recovered C 6 + component to obtain a product p-xylene; and
f) further separating the recovered C 3 component to obtain a product propylene;
wherein each of the catalyst I and the catalyst II independently comprises a modified zeolite molecular sieve catalyst obtained from ZSM-5 and/or ZSM-11 zeolite molecular sieve modified with a precious metal, a rare earth metal, and a siloxanyl compound.

4. The method according to claims 1 or 3 , wherein, the catalyst I and the catalyst II contain the same or different modified zeolite molecular sieve catalysts(s).

5. The method according to claim 1 or 3 , wherein the siloxanyl compound used in the siloxanyl compound modification has a structural formula as shown below:

wherein R 1 , R 2 , R 3 , and R 4 are each independently a C 1-10 alkyl group.

6. The method according to claim 1 or 3 , wherein the reaction system comprises a plurality of reactors connected in series and/or in parallel.

7. The method according to claim 6 , wherein the plurality of reactors are selected from a fixed bed reactor, a fluidized bed reactor, and a moving bed reactor.

8. The method according to claim 3 , wherein the first reaction zone comprises a reactor or a plurality of reactors connected in series and/or in parallel; the second reaction zone comprises a reactor or a plurality of reactors connected in series and/or in parallel; and the first reaction zone and the second reaction zone are connected in parallel.

Assignees

• Dalian Inst Chem & Physics Cas

Inventors

• Liu Zhongmin
• Xu Lei

Classifications

• C07C1/20 Primary

  starting from organic compounds containing only oxygen atoms as heteroatoms · CPC title

• Y02P20/52

  using catalysts, e.g. selective catalysts · CPC title

• Y02P20/584

  Recycling of catalysts · CPC title

• C07C2529/44

  Noble metals · CPC title

• C07C2529/40

  of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11 · CPC title