Butadiene extraction process

Patent metadata

Field	Value
Publication number	US-9744475-B2
Application number	US-201615059771-A
Country	US
Kind code	B2
Filing date	Mar 3, 2016
Priority date	Oct 30, 2012
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

A process for recovering 1,3-butadiene from a C 4 fraction, where the butadiene extraction processes may be operated at an intermediate pressure using a liquid ring type compressor. The use of a liquid ring compressor, among other process options presented herein, may advantageously reduce capital and operating costs, similar to the compressorless option, while mitigating the risks associated with the higher operating temperatures and pressures associated with the compressorless option. Thus, the embodiments of the processes disclosed herein encompass the best features of the conventional design (low pressure, with a compressor) with the advantages of the compressorless design (low capital and operating cost), as well as other advantages unique to the systems disclosed herein.

First claim

What is claimed is:

1. A system for recovering 1,3-butadiene from a C 4 fraction, comprising:
a flow conduit for feeding a hydrocarbon fraction containing butanes, butenes, 1,2-butadiene, 1,3-butadiene, C 4 acetylenes, C 3 acetylenes, and C 5+ hydrocarbons to an extractive distillation system;
the extractive distillation system for contacting the hydrocarbon fraction with a solvent in the extractive distillation system to selectively dissolve a portion of the hydrocarbon fraction;
a flow conduit for recovering a vapor fraction comprising a first portion of the butanes and the butenes from the extractive distillation system;
a flow conduit for recovering an enriched solvent fraction comprising the 1,3-butadiene, the 1,2-butadiene, C 4 acetylenes, C 3 acetylenes, C 5+ hydrocarbons, and a second portion of the butanes and the butenes;
a flow conduit for feeding the enriched solvent fraction to a rectifier;
the rectifier for at least partially degassing the enriched solvent;
a flow conduit for recovering a second portion of the butanes and butenes from the rectifier as an overheads fraction;
a flow conduit for recovering the C 3 and C 4 acetylenes, 1,3-butadiene, 1,2-butadiene, and C 5+ hydrocarbons from the rectifier as a side draw fraction;
a flow conduit for recovering a partially degassed solvent comprising 1,2-butadiene and C 4 acetylenes from the rectifier as a bottoms fraction;
a flow conduit for feeding at least a portion of the partially degassed solvent to a degasser;
the degasser for further degassing the solvent;
a flow conduit for recovering an overheads fraction comprising at least one of C 4 acetylenes and 1,2-butadiene from the degasser;
a flow conduit for recovering a side draw fraction comprising the C 4 acetylenes from the degasser;
a flow conduit for recovering a bottoms fraction comprising degassed solvent from the degasser;
a liquid ring compressor for compressing the degasser overheads fraction; and
a flow conduit for recycling at least a portion of the compressed degasser overheads fraction to the rectifier.

2. The system of claim 1 , further comprising:
a separator for phase separating the compressed degasser overheads fraction to recover a condensate fraction; and
a flow conduit for recycling at least a portion of the condensate fraction to the liquid ring compressor.

3. The system of claim 1 , further comprising:
a heat exchanger for heating the partially degassed solvent via indirect heat exchange to vaporize at least a portion of the dissolved 1,2-butadiene and/or C 4 acetylenes;
a flow conduit for feeding the heated partially degassed solvent to a degasser feed drum;
the degasser feed drum for phase separating the vaporized portion of the 1,2-butadiene and/or C 4 acetylenes from the heated partially degassed solvent;
a flow conduit for recovering a vapor phase from the degasser feed drum comprising at least one of 1,2-butadiene and C4 acetylenes;
a flow conduit for recovering a liquid phase from the degasser feed drum and feeding of the liquid phase from the degasser feed drum to the degasser as the at least a portion of the partially degassed solvent.

4. The system of claim 3 , further comprising a mixing device for admixing the vapor phase recovered from the degasser feed drum and the at least a portion of the compressed degasser overheads and recycling the combined portion to the rectifier.

5. The system of claim 3 , wherein the heat exchanger for heating the partially degassed solvent via indirect heat exchange comprises at least one of:
a heat exchanger for contacting the partially degassed solvent with the degasser bottoms fraction via indirect heat exchange; and
a heat exchanger for contacting the partially degassed solvent with a heat exchange medium comprising at least one of oil, water, and steam.

6. The system of claim 5 , wherein the heat exchanger(s) for contacting the partially degassed solvent comprise a suppressed vaporization heater.

7. The system of claim 1 , further comprising a reboiler to supply heat to the rectifier via indirect heat exchange, wherein the reboiler comprises a single pass heat exchanger.

8. A system for recovering 1,3-butadiene from a C 4 fraction, comprising:
an extractive distillation system for contacting a hydrocarbon fraction containing butanes, butenes, 1,2-butadiene, 1,3-butadiene, C 4 acetylenes, C 3 acetylenes, and C 5+ hydrocarbons with a solvent to produce a vapor fraction and an enriched solvent fraction;
a rectifier for at least partially degassing the enriched solvent fraction and producing (i) a rectifier overheads fraction, (ii) a rectifier side draw fraction, and (iii) a rectifier bottoms fraction;
a degasser for further degassing the rectifier bottoms fraction and producing (i) a degasser overheads fraction, (ii) a degasser side draw fraction; and (iii) a degasser bottoms fraction;
a liquid ring compressor for compressing the degasser overheads fraction; and
a flow conduit for recycling at least a portion of the compressed degasser overheads fraction to the rectifier.

9. The system of claim 8 , wherein
the vapor fraction comprises a first portion of the butanes and the butenes;
the enriched solvent fraction comprises the 1,3-butadiene, the 1,2-butadiene, C 4 acetylenes, C 3 acetylenes, C 5+ hydrocarbons, and a second portion of the butanes and the butenes;
the rectifier overheads fraction comprises the second portion of the butanes and butenes
the rectifier side draw fraction comprises C 3 and C 4 acetylenes, 1,3-butadiene, 1,2-butadiene, and C 5+ hydrocarbons;
the rectifier bottoms fraction comprises a partially degassed solvent containing 1,2-butadiene and C 4 acetylenes
the degasser overheads fraction comprises 1,2-butadiene;
the degasser side draw fraction comprises C 4 acetylenes; and
the degasser bottoms fraction comprises degassed solvent.

10. The system of claim 8 , further comprising:
a separator for phase separating the compressed degasser overheads fraction to recover a condensate fraction; and
a flow conduit for recycling at least a portion of the condensate fraction to the liquid ring compressor.

11. The system of claim 8 , further comprising:
a heat exchanger for heating the rectifier bottoms fraction via indirect heat exchange;
a degasser feed drum for phase separating the heated rectifier bottoms fraction to produce a vapor phase and a liquid phase fed to the degasser.

12. The system of claim 11 , wherein the degasser feed drum and the degasser are integral.

13. The system of claim 11 , further comprising a heat exchanger for heating the liquid phase via indirect heat exchange upstream of the degasser.

14. The system of claim 11 , wherein the heat exchanger for heating the rectifier bottoms fraction via indirect heat exchange comprises a heat exchanger for contacting the partially degassed solvent with the degasser bottoms fraction via indirect heat exchange.

15. The system of claim 14 , wherein the heat exchanger for contacting the rectifier bottoms fraction comprises a suppressed vaporization heater.

16. The system of claim 8 , further comprising a reboiler to supply heat to the rectifier via indirect heat exchange, wherein the reboiler comprises a single pass heat exchanger.

17. The system of claim 8 , further comprising an afterwash column for separating solvent from the rectifier side draw and to recover a crude butadiene product stream.

18. The system of claim 7 , further comprising a methyl acetylene distillation column for separating the crude butadiene product str

Assignees

• Lummus Technology Inc

Inventors

• Schwint Kevin John
• Brummer Robert J

Classifications

• B01D3/40 Primary

  Extractive distillation · CPC title

• B01D19/0068

  General arrangements, e.g. flowsheets (B01D19/0063 takes precedence) · CPC title

• C07C11/167

  1, 3-Butadiene · CPC title

• C07C7/08 Primary

  by extractive distillation · CPC title

• B01D3/143

  by two or more of a fractionation, separation or rectification step · CPC title