Ethane oxidative dehydrogenation and acetic acid recovery

Patent metadata

Field	Value
Publication number	US-10427992-B2
Application number	US-201615770522-A
Country	US
Kind code	B2
Filing date	Oct 25, 2016
Priority date	Oct 26, 2015
Publication date	Oct 1, 2019
Grant date	Oct 1, 2019

Abstract

The invention concerns a process for oxidative dehydrogenation of ethane. In the process an ethane comprising stream is fed to a distillation column to remove propane. The purified ethane stream is subjected to oxidative dehydrogenation using a catalyst comprising Mo/V/Sb, or Mo/V/Nb and Te or Sb in the orthorhombic M1 crystalline phase. The reactor effluent comprises ethylene. The effluent is washed with water to remove acetic acid. The acetic acid is recovered from the aqueous stream by means of solvent extraction.

First claim

That which is claimed is:

1. A process for oxidative dehydrogenation of ethane, comprising the steps of:
(a) feeding a gas stream comprising ethane and propane to a distillation column to obtain a stream comprising propane and a stream comprising ethane;
(b) feeding at least a part of the gas stream comprising ethane obtained in step (a) to a reactor;
(c) contacting, in the reactor, oxygen and ethane and optionally ethylene with a catalyst comprising a mixed metal oxide;
(d) cooling the reactor effluent and, simultaneously and/or in a subsequent step, add water to the reactor effluent to obtain a liquid stream comprising water and acetic acid and a gas stream comprising ethylene;
(e) recovering the acetic acid from the liquid stream obtained in step (d) by means of solvent extraction;
wherein at least 50 wt % of the mixed metal oxide in the catalyst used in step (c) is in the orthorhombic M1 crystalline phase; and
wherein the mixed metal oxide in the catalyst used in step (c) comprises:
molybdenum, vanadium and antimony, or
molybdenum, vanadium, niobium and optionally tellurium or antimony.

2. The process according to claim 1 , wherein a gas stream in the reactor in step (c) comprises an amount of oxygen which is at least 6 vol. % and at most 40 vol. %.

3. The process according to claim 1 , wherein step (a) is performed at a pressure in the range of from 1 to 100 bara.

4. The process according to claim 1 , wherein step (c) is performed at a temperature in the range of from 250 to 450° C., and at a pressure in the range of from 1 to 10 bara.

5. The process according to claim 1 , wherein the mixed metal oxide in the catalyst used in step (c) comprises:
molybdenum, vanadium and antimony, or
molybdenum, vanadium, niobium and tellurium, or
molybdenum, vanadium, niobium and antimony.

6. The process according to claim 1 , wherein at least 60 wt %, of the mixed metal oxide in the catalyst used in step (c) is in the orthorhombic M1 crystalline phase.

7. The process according to claim 1 , wherein water is added to the reactor effluent in step (d) by means of a water-wash scrubber.

8. The process according to claim 1 , wherein the solvent used in the solvent extraction of step (e) comprises one or more of: butyl acetate, ethyl acetate, isopropyl acetate, n-propyl acetate, 2-pentanone (MPK), 4-methyl-2-pentanone (MIBK), cyclohexyl acetate, dimethyl phthalate, diethyl phthalate, 1-pentanol, ethylcyclohexane, isophorone and methyl tertiary butyl ether (MTBE).

9. The process according to claim 1 , wherein the solvent used in the solvent extraction of step (e) is ethyl acetate and/or methyl tertiary butyl ether (MTBE).

10. The process according to claim 9 , wherein ethyl acetate is used which is prepared from ethylene and acetic acid.

11. The process according to claim 1 , wherein step (e) is performed at a temperature in the range of from 5 to 50° C. at a pressure in the range of from 1 to 5 bar.

12. The process according to claim 1 , wherein in step (e) the acetic acid is recovered from the liquid stream obtained in step (d) by means of solvent extraction to obtain an aqueous stream and a stream comprising solvent and acetic acid, followed by distillation of the stream comprising solvent and acetic acid to obtain a stream comprising acetic acid and a stream comprising solvent.

13. The process according to claim 12 , wherein the solvent recovered by means of distillation is recycled to the solvent extraction of step (e).

14. The process according to claim 1 , wherein the gas stream comprising ethylene which is obtained in step (d) is subjected to distillation to obtain a stream comprising ethane and a stream comprising further purified ethylene.

15. The process according to claim 14 , wherein the stream comprising ethane which is recovered by means of distillation is recycled to the reactor used in step (c).

Assignees

• Shell Oil Co

Inventors

• Mitkidis Georgios
• San Roman Macia Maria
• Van Rossum Guus
• Schoonebeek Ronald Jan

Classifications

• C07C51/48

  by liquid-liquid treatment · CPC title

• C07C2523/18

  Arsenic, antimony or bismuth · CPC title

• C07C2523/28

  Molybdenum · CPC title

• C07C7/11

  by absorption, i.e. purification or separation of gaseous hydrocarbons with the aid of liquids · CPC title

• C07C51/215

  of saturated hydrocarbyl groups · CPC title