Process for the conversion of methane into propanal

Patent metadata

Field	Value
Publication number	US-10519087-B2
Application number	US-201716304469-A
Country	US
Kind code	B2
Filing date	Jun 13, 2017
Priority date	Jun 30, 2016
Publication date	Dec 31, 2019
Grant date	Dec 31, 2019

Abstract

The present invention provides methods for making propanal in a reaction comprising the oxidative coupling of methane (OCM) and oxygen as a reactant stream in a gas phase reaction, preferably in the presence of water or steam, to form ethylene, ethane, carbon dioxide (CO2), water and syngas (CO and H2) in a first reactor as an ethylene stream, and then forming propanal in a second reactor by feeding to the second reactor the ethylene stream with the syngas from the first reactor in the gas phase and hydroformylating in the presence of a catalyst for a water shift reaction. In the method, the ratio of H2 to CO in the syngas is maintained by either co-feeding steam into the first reactor or the second reactor to generate additional H2 in the syngas, or by forming CO in the second reactor from the water shift reaction by feeding the CO2 from the ethylene stream into the second reactor.

First claim

We claim:

1. A method for making propanal in a reaction comprising the oxidative coupling of methane (OCM reaction) and oxygen as a reactant stream in a gas phase reaction to form ethylene, ethane, carbon dioxide (CO 2 ), water and syngas (CO and H 2 ) as an ethylene stream in a first reactor containing an OCM zone and a downstream thermal cracking zone to form ethylene from ethane, and then forming propanal in a second reactor by feeding to the second reactor the ethylene stream from the first reactor in the gas phase and hydroformylating the ethylene stream to form a propanal containing product stream in the presence of a catalyst for a water gas shift reaction in which water and carbon monoxide (CO) form carbon dioxide and hydrogen gas (H 2 ) and for the hydroformylating, wherein the molar ratio of the syngas to the total amount of ethylene and ethane in the ethylene stream before the downstream thermal cracking zone ranges from 2:1 to 10:1, and, further wherein, the molar ratio of total CO 2 and CO to total ethylene and ethane in the ethylene stream before the downstream thermal cracking zone ranges from 0.97:1 to 5:1.

2. The method as claimed in claim 1 , further comprising adjusting the molar ratio of H 2 to CO in the syngas in the ethylene stream by co-feeding steam into the second reactor and/or into the first reactor to generate additional H 2 in the syngas in any case wherein the molar ratio of the H 2 to CO in the syngas in the ethylene stream leaving the downstream thermal cracking zone of the first reactor is below 1:1 or, alternatively, by reacting the CO 2 and H 2 from the ethylene stream of the first reactor in the second reactor to generate additional CO in the syngas in the presence of a catalyst for a water gas shift reaction.

3. The method as claimed in claim 2 , wherein the steam is generated by compressing the ethylene stream output from the first reactor, to form a compressed OCM fluid stream containing water, removing water from the compressed OCM fluid stream and reheating the water therein to form steam.

4. The method as claimed in claim 3 , wherein the reheating the water to form steam comprises using the water as a heat exchanger to compress the output from the first reactor.

5. The method as claimed in claim 1 , wherein the catalyst for a water gas shift and for the hydroformylating is a sulfide catalyst.

6. The method as claimed in claim 1 , wherein the first reactor comprises an upstream zone and a downstream thermal cracking zone in which ethylene formation comprises dehydrogenating any ethane formed in the upstream zone to form ethylene in the downstream thermal cracking zone using the heat from the first reactor to drive the dehydrogenating.

7. The method as claimed in claim 1 , wherein after the hydroformylating, the propanal containing product stream, including propanal, methane, ethane, propanol, carbon dioxide, water vapor and syngas are fed to a separator.

8. The method as claimed in claim 7 , wherein the methane is recycled to the first reactor and ethane is recycled to a downstream thermal cracking zone in the first reactor.

9. The method as claimed in claim 1 , further comprising continuously adding H 2 S in the ethylene feed stream into the second reactor, in the amount of from 0.1 and 1 vol. %, based on the total volume of the ethylene feed stream.

10. The method as claimed in claim 1 , wherein the first reactor, the second reactor and all streams leading directly or indirectly from the first reactor to the second reactor are in an enclosed or sealed system.

Assignees

• Dow Global Technologies Llc

Inventors

• Corthals Steven L F
• Davidian Thomas
• Budroni Gerolamo
• Groenendijk Peter E

Classifications

• C07C2/82 Primary

  oxidative coupling · CPC title

• C01B2203/06

  Integration with other chemical processes · CPC title

• C01B3/16

  using catalysts · CPC title

• C07C45/50 Primary

  by oxo-reactions · CPC title

• C01B2203/0283

  containing a CO-shift step, i.e. a water gas shift step · CPC title