Method for producing dimethyl ether from methane

Patent metadata

Field	Value
Publication number	US-9090543-B2
Application number	US-201314375891-A
Country	US
Kind code	B2
Filing date	Jan 15, 2013
Priority date	Jan 31, 2012
Publication date	Jul 28, 2015
Grant date	Jul 28, 2015

Abstract

The invention relates to processes for production of dimethyl ether from methane or natural gas comprising: a dry-reforming step, wherein methane and carbon dioxide are converted into carbon monoxide and hydrogen, and a DME synthesis step, wherein the carbon monoxide and hydrogen formed in the dry-reforming step are converted into dimethyl ether, wherein the dry-reforming step and the synthesis step are carried out at identical pressures or at pressures, which do not differ more than 3 bar, preferably not more than 1 bar.

First claim

The invention claimed is:

1. A process for production of dimethyl ether from methane ( 11 ) comprising:
a dry-reforming step ( 21 ), wherein methane ( 11 ) and carbon dioxide ( 12 ) are converted into carbon monoxide and hydrogen, and
a synthesis step ( 22 ), wherein the carbon monoxide and hydrogen formed in the dry-reforming step ( 21 ) are converted into a dimethyl ether ( 13 ) and carbon dioxide,
wherein the dry-reforming step ( 21 ) and the synthesis step ( 22 ) are carried out at pressures which do not differ by more than 3 bar.

2. A process according to claim 1 , wherein the process is carried out at a pressure of 20 bar to 50 bar.

3. A process according to claim 1 , wherein a product gas generated by the dry-reforming step ( 21 ) and containing said carbon monoxide and said hydrogen is fed directly to the synthesis step ( 22 ).

4. A process according to claim 1 , wherein the carbon monoxide and hydrogen formed in the dry-reforming step ( 21 ) are converted in the synthesis step ( 22 ) into dimethyl ether ( 13 ) and carbon dioxide until the dimethyl ether is present in a concentration amounting to not less than 60% of the equilibrium concentration of dimethyl ether.

5. A process according to claim 1 , wherein the product of synthesis step ( 22 ) is separated into a predominantly dimethyl ether-, methanol- and water-containing product phase ( 13 ) and a predominantly hydrogen-, carbon monoxide-, carbon dioxide- and methane-containing residual gas ( 14 ).

6. A process according to claim 5 , wherein the predominantly hydrogen-, carbon monoxide-, carbon dioxide- and methane-containing residual gas ( 14 ) is fed to the dry-reforming step ( 21 ).

7. A process according to claim 5 , wherein the predominantly hydrogen-, carbon monoxide-, carbon dioxide- and methane-containing residual gas ( 14 ) is used for providing thermal energy for the dry-reforming step ( 21 ).

8. A process according to claim 1 , wherein dimethyl ether is converted into a product containing olefins, wherein dimethyl ether is fed to a synthesis of olefins directly or only carbon dioxide is separated from the dimethyl ether before the dimethyl ether is fed to the synthesis of olefins.

9. A process according to claim 1 , wherein the dry-reforming step ( 21 ) and the synthesis step ( 22 ) are carried out at pressures which do not differ by more than 1 bar.

10. A process according to claim 1 , wherein the carbon monoxide and hydrogen formed in the dry-reforming step ( 21 ) are converted in the synthesis step ( 22 ) into dimethyl ether ( 13 ) and carbon dioxide until the dimethyl ether is present in a concentration amounting to not less than 70% of the equilibrium concentration of dimethyl ether.

11. A process according to claim 1 , wherein the carbon monoxide and hydrogen formed in the dry-reforming step ( 21 ) are converted in the synthesis step ( 22 ) into dimethyl ether ( 13 ) and carbon dioxide until the dimethyl ether is present in a concentration amounting to not less than 80% of the equilibrium concentration of dimethyl ether.

12. A process according to claim 1 , wherein the carbon monoxide and hydrogen formed in the dry-reforming step ( 21 ) are converted in the synthesis step ( 22 ) into dimethyl ether ( 13 ) and carbon dioxide until the dimethyl ether is present in a concentration amounting to not less than 90% of the equilibrium concentration of dimethyl ether.

13. A process according to claim 1 , wherein dimethyl ether is converted into a product containing ethylene and/or propylene, wherein dimethyl ether is fed to a synthesis of ethylene and/or propylene directly or only carbon dioxide is separated from the dimethyl ether before the dimethyl ether is fed to the synthesis of ethylene and/or propylene.

14. A process according to claim 1 , wherein the dry-reforming step ( 21 ) is carried out at a temperature of between 750° C. and 950° C.

15. A process according to claim 1 , wherein the molar ratio of water to carbon in the feed to the dry-reforming step ( 21 ) is less than 2:1.

16. A process according to claim 1 , wherein the dry-reforming step ( 21 ) and the synthesis step ( 22 ) are carried out at pressures which do not differ by more than 0.5 bar.

17. A process according to claim 1 , wherein the dry-reforming step ( 21 ) and the synthesis step ( 22 ) are carried out at pressures which do not differ by more 0.3 bar.

18. A process according to claim 1 , wherein the dry-reforming step ( 21 ) and the synthesis step ( 22 ) are carried out at pressures which do not differ by more than 0.2 bar.

19. A process according to claim 1 , wherein the dry-reforming step ( 21 ) and the synthesis step ( 22 ) are carried out at pressures which do not differ by more than 0.1 bar.

20. A process for production of dimethyl ether from methane ( 11 ) comprising:
a dry-reforming step ( 21 ), wherein methane ( 11 ) and carbon dioxide ( 12 ) are converted into carbon monoxide and hydrogen, and
a synthesis step ( 22 ), wherein the carbon monoxide and hydrogen formed in the dry-reforming step ( 21 ) are converted into a dimethyl ether ( 13 ) and carbon dioxide,
wherein no compression or expansion is performed between the dry-reforming step ( 21 ) and the synthesis step ( 22 ).

Assignees

• Linde Ag

Inventors

• Schoedel Nicole
• Haidegger Ernst
• Schmigalle Holger
• Behrens Axel
• Goeke Volker
• Thaller Christian
• Schmaderer Harald

Classifications

• C01B2203/0238

  the reforming step being a carbon dioxide reforming step · CPC title

• C07C41/01 Primary

  Preparation of ethers · CPC title

• C01B3/34

  by reaction of hydrocarbons with gasifying agents · CPC title

• C07C1/20

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

• C07C1/22

  by reduction · CPC title