Oxygenate separation following oxidative dehydrogenation of a lower alkane

Patent metadata

Field	Value
Publication number	US-12577183-B2
Application number	US-202217953743-A
Country	US
Kind code	B2
Filing date	Sep 27, 2022
Priority date	Nov 19, 2018
Publication date	Mar 17, 2026
Grant date	Mar 17, 2026

Abstract

A process, a system, and an apparatus are provided for converting a lower alkane to an alkene. Oxygen and the lower alkane are provided to an ODH reactor to convert at least a portion of the lower alkane to an alkene. An ODH stream comprising the alkene, an oxygenate, steam, and a carbon-based oxide is produced. The bulk of the oxygenate is removed from the ODH outlet stream by non-dilutive cooling, with residual oxygenate being removed using dilutive quenching with a carbonate. Subsequently, separation of the carbon-based oxide from the alkene is achieved using a caustic tower, which also produces spent caustic in the form of a carbonate, which is then used as the carbonate for dilutive quenching. Dilutive quenching using a carbonate allows conversion of the oxygenate to an acetate, which can then be used to simplify separation of the oxygenate from water.

First claim

What is claimed is:

1 . A system comprising:
an oxidative dehydrogenation (ODH) reactor to convert a lower alkane to an alkene and discharge an ODH outlet stream comprising the alkene, an oxygenate, and a carbon-based oxide; a heat exchanger to cool the ODH outlet stream to condense oxygenate in the ODH outlet stream; a flash tower to receive the ODH outlet stream as cooled from the heat exchanger and discharge an alkene outlet stream comprising the alkene and the carbon-based oxide and discharge a first oxygenate outlet stream comprising oxygenate as condensed and water; a quench tower to contact the alkene outlet stream with a quenching agent comprising water and carbonate to remove oxygenate from the alkene and discharge a first quench outlet stream comprising the alkene and carbon-based oxide and a second quench outlet stream comprising acetate, water, and oxygenate; an extraction tower to receive the first oxygenate outlet stream and the second quench outlet stream to separate oxygenate from acetate and water and discharge an extraction outlet stream comprising acetate and water; and a recycle line to recycle to the extraction tower a portion of the extraction outlet stream as discharged.

2 . The system of claim 1 , wherein the recycle line is configured to recycle directly the portion of the extraction outlet stream to the extraction tower.

3 . The system of claim 1 , wherein the recycle line is coupled to an inlet of the extraction tower and coupled to an outlet line from the extraction tower conveying the extraction outlet stream as discharged from the extraction tower.

4 . The system of claim 1 , wherein the quench tower is configured to form acetate from the carbonate and the oxygenate, wherein forming the acetate reduces an amount of the oxygenate in the first quench outlet stream, wherein the oxygenate comprises acetic acid, and wherein a mole ratio of the carbonate in the quenching agent to the oxygenate in the alkene outlet stream is at least 0.8.

5 . The system of claim 1 , wherein the carbonate comprises at least one of sodium bicarbonate, potassium carbonate, or ammonium bicarbonate, and wherein the acetate comprises at least one of sodium acetate, potassium acetate, or ammonium acetate.

6 . The system of claim 1 , comprising a caustic wash tower to contact the first quench outlet stream with a hydroxide to discharge a caustic outlet stream comprising carbonate to the quench tower for the quenching agent.

7 . The system of claim 6 , wherein the hydroxide comprises at least one of sodium hydroxide, potassium hydroxide, or ammonium hydroxide.

8 . The system of claim 1 , wherein concentration of the oxygenate in the first oxygenate outlet stream is in a range of 0.5 mol % to 15 mol %, wherein the flash tower comprises a flash drum, and wherein the extraction tower comprises a liquid-liquid extractor.

9 . The system of claim 1 , wherein the first oxygenate outlet stream comprises water in a range of 80 mol % to 99.5 mol %.

10 . A system comprising:
an oxidative dehydrogenation (ODH) reactor to convert a lower alkane to an alkene in presence of oxygen and discharge an ODH outlet stream comprising the alkene, an oxygenate, and a carbon-based oxide; a heat exchanger to cool the ODH outlet stream to condense oxygenate in the ODH outlet stream; a flash tower to receive the ODH outlet stream as cooled from the heat exchanger and discharge an alkene outlet stream comprising the alkene and the carbon-based oxide and discharge a first oxygenate outlet stream comprising oxygenate as condensed and water; a quench tower to contact the alkene outlet stream with a quenching agent comprising water and carbonate to remove remaining oxygenate from the alkene and discharge a first quench outlet stream comprising the alkene and carbon-based oxide and a second quench outlet stream comprising acetate, water, and remaining oxygenate; an extraction tower to receive the first oxygenate outlet stream and the second quench outlet stream to separate oxygenate from acetate and water and discharge a first extraction outlet stream comprising oxygenate and a second extraction outlet stream comprising acetate and water; and a recycle line to recycle to the extraction tower a portion of the extraction outlet stream as discharged.

11 . The system of claim 10 , wherein the recycle line is configured to directly recycle the portion of the extraction outlet stream to the extraction tower.

12 . The system of claim 10 , wherein the lower alkane comprises ethane and the alkene comprises ethylene, or wherein the lower alkane comprises propane and the alkene comprises propylene, or a combination thereof.

13 . The system of claim 10 , wherein the ODH outlet stream further comprises at least one of water, an unreacted alkane, or oxygen.

14 . The system of claim 10 , wherein the extraction tower is configured to enhance separation of the oxygenate from the water in the extraction tower via presence of the acetate increasing an equilibrium of the oxygenate and water as separate species, and wherein the oxygenate comprises acetic acid.

15 . The system of claim 10 , wherein a mole ratio of the carbonate in the quenching agent to the oxygenate in the alkene outlet stream is in a range of 0.8 to 1.2.

16 . A system comprising:
an oxidative dehydrogenation (ODH) reactor to receive oxygen and an alkane, convert the lower alkane to an alkene, and discharge an ODH outlet stream comprising the alkene, an oxygenate, and a carbon-based oxide; a heat exchanger to cool the ODH outlet stream to condense oxygenate in the ODH outlet stream; a flash tower to receive the ODH outlet stream as cooled from the heat exchanger and discharge an alkene outlet stream comprising the alkene and the carbon-based oxide and discharge a first oxygenate outlet stream comprising oxygenate as condensed and water; a quench tower to contact the alkene outlet stream with a quenching agent comprising water and carbonate to separate remaining oxygenate from the alkene and convert remaining oxygenate by contact with carbonate into acetate and discharge a first quench outlet stream comprising the alkene and carbon-based oxide and a second quench outlet stream comprising acetate, water, and remaining oxygenate; an extraction tower to receive the first oxygenate outlet stream and the second quench outlet stream to separate oxygenate from acetate and water and discharge a first separation outlet stream as a second oxygenate outlet stream comprising oxygenate and a second separation outlet stream as an extraction outlet stream comprising acetate and water; and a recycle line to recycle directly to the extraction tower a portion of the extraction outlet stream as discharged.

17 . The system of claim 16 , wherein the carbon-based oxide comprises at least one of carbon monoxide or carbon dioxide, and wherein the oxygenate comprises at least one of acetic acid, acrylic acid, maleic acid, or maleic anhydride.

18 . The system of claim 16 , wherein the alkane comprises ethane and the alkene comprises ethylene, and wherein the acetate facilitates separation of the oxygenate from water in the extraction tower.

19 . The system of claim 16 , wherein concentration of oxygenate in the first oxygenate outlet stream is less than 15 mol %.

20 . The system of claim 16 , wherein the extraction tower comprises a liquid-liquid extractor that separates oxygenate from acetate and water via liquid-liquid extraction.

21 . The system of claim 16 ,

Assignees

• Nova Chemicals International Sa

Inventors

• Olayiwola Bolaji
• Simanzhenkov Vasily
• Goodarznia Shahin
• Serhal Kamal

Classifications

• B01J19/0013

  Controlling the temperature of the process · CPC title

• C07C7/09

  by fractional condensation · CPC title

• C07C11/06

  Propene · CPC title

• C07C51/41

  Preparation of salts of carboxylic acids ({C07C51/093 - C07C51/34 take precedence} preparation of soap C11D) · CPC title

• C07C7/11

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