Butadiene extraction pre-absorber

Patent metadata

Field	Value
Publication number	US-10081581-B2
Application number	US-201615204167-A
Country	US
Kind code	B2
Filing date	Jul 7, 2016
Priority date	Sep 20, 2012
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

A process for recovering butadiene from a C 4 fraction is disclosed. The process may include: contacting a mixed C 4 stream comprising butane, butene, and butadiene, with a solvent comprising an organic solvent and water in a butadiene pre-absorber column to recover an overheads fraction comprising at least a portion of the butane, butene, and water, and a first bottoms fraction comprising the organic solvent, butadiene, and at least a portion of the butene; and feeding the first bottoms fraction to a butadiene extraction unit to recover a butene fraction, a crude butadiene fraction, and a solvent fraction.

First claim

What is claimed:

1. A process for retrofitting a butadiene extraction system for recovering butadiene from a mixed C4 stream comprising butane, butene, and butadiene, the system comprising a main wash column for contacting a gaseous mixed C4 stream with a solvent or solvent mixture to recover an overheads fraction comprising butane and butene and a bottoms fraction comprising butadiene and the solvent or solvent mixture, the process for retrofitting comprising:
installing a butadiene pre-absorber column and an associated fluid conduit for receiving and contacting the gaseous mixed C4 stream with the solvent or solvent mixture to recover a first overheads fraction comprising butane and butene and a first, liquid, bottoms fraction comprising butadiene, at least a portion of the butene, and the solvent or solvent mixture; and
fluidly connecting the butadiene pre-absorber column with the existing main wash column for contacting the first bottoms fraction with additional solvent to recover a second overheads fraction comprising the butene and a second bottoms fraction comprising the butadiene, the solvent, and the additional solvent.

2. The process of claim 1 , further comprising fluidly connecting the butadiene pre-absorber to an existing overhead system of the main wash column.

3. The process of claim 1 , further comprising installing a liquid distributor in the main wash column to distribute the bottoms fraction fed to the main wash column.

4. The process of claim 1 , further comprising adjusting a feed location of one or more streams being fed to the main wash column.

5. The process of claim 1 , further comprising installing one or both of a butadiene pre-absorber column overhead system and a pre-absorber column reboiler.

6. The process of claim 5 , wherein the pre-absorber column reboiler comprises a once-through reboiler.

7. The process of claim 5 , wherein the pre-absorber column reboiler comprises a suppressed vaporization reboiler.

8. The process of claim 5 , wherein the pre-absorber column overhead system comprises a condenser, an accumulator, and a feed line to provide reflux to the pre-absorber column.

9. The process of claim 1 , further comprising providing a control system for operating the butadiene pre-absorber column such that the concentration of butadiene relative to the total C4 hydrocarbons in the first bottoms fraction is at least 40 percent by weight.

10. A process for retrofitting a butadiene extraction system for recovering butadiene from a mixed C4 stream comprising butane, butene, and butadiene, the system comprising a main wash column for contacting a gaseous mixed C4 stream with a solvent or solvent mixture to recover an overheads fraction comprising butane and butene and a bottoms fraction comprising butadiene and the solvent or solvent mixture, the process for retrofitting comprising:
converting the main wash column to a butadiene pre-absorber column for contacting the gaseous mixed C4 stream with the solvent or solvent mixture to recover a first overheads fraction comprising butane and butene and a first bottoms fraction comprising butadiene, at least a portion of the butene, and the solvent or solvent mixture;
installing a new main wash column;
fluidly connecting the butadiene pre-absorber column with the new main wash column for contacting the first bottoms fraction with additional solvent to recover a second overheads fraction comprising the butene and a second bottoms fraction comprising the butadiene, the solvent, and the additional solvent.

11. The process of claim 10 , further comprising fluidly connecting the new main wash column to a rectifier/afterwash column for separating the butadiene from the organic solvent to recover the solvent fraction and the crude butadiene fraction.

12. The process of claim 10 , wherein the overhead system of the butadiene pre-absorber column is integrated with the overhead system of the new main wash column.

13. The process of claim 10 , further comprising providing a control system for operating the butadiene pre-absorber column such that the concentration of butadiene relative to the total C4 hydrocarbons in the first bottoms fraction is at least 40 percent by weight.

Assignees

• Lummus Technology Inc

Inventors

• Schwint Kevin John
• Brummer Robert John

Classifications

• C07C7/11 Primary

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

• C07C7/10 Primary

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

• C07C5/327

  Formation of non-aromatic carbon-to-carbon double bonds only · CPC title

• C07C5/48

  with oxygen as an acceptor · CPC title

• Y10T29/49716

  Converting · CPC title