Hydrocarbon gas treatment systems and methods

Patent metadata

Field	Value
Publication number	US-10837272-B2
Application number	US-201916436414-A
Country	US
Kind code	B2
Filing date	Jun 10, 2019
Priority date	Jun 26, 2018
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

Hydrocarbon gas treatment systems and methods. The hydrocarbon gas treatment systems include a feed gas supply system configured to provide a feed gas stream and a hydrogen sulfide removal system configured to separate the feed gas stream into a product gas stream and an acid gas stream. The hydrocarbon gas treatment systems also include a heat exchanger configured to cool the acid gas stream to generate a cooled acid gas stream and an acid gas enrichment system configured to separate the cooled acid gas stream into a treated gas stream and an enriched acid gas stream. The methods include providing a feed gas stream, separating the feed gas stream into a product gas stream and an acid gas stream, cooling the acid gas stream to generate a cooled acid gas stream, and separating the cooled acid gas stream into a treated gas stream and an enriched acid gas stream.

First claim

What is claimed is:

1. A hydrocarbon gas treatment system, comprising:
a feed gas supply system configured to provide a feed gas stream, wherein the feed gas stream includes hydrocarbon gas, carbon dioxide, and hydrogen sulfide;
a hydrogen sulfide removal system configured to receive the feed gas stream and to separate the feed gas stream into a product gas stream, which includes a portion of the hydrocarbon gas from the feed gas stream, and an acid gas stream, which includes carbon dioxide and a portion of the hydrogen sulfide from the feed gas stream;
a sub-ambient heat exchanger downstream and not upstream of the hydrogen sulfide removal system and configured to receive the acid gas stream and to cool the acid gas stream to a sub-ambient temperature to thereby generate a cooled acid gas stream;
a water separation assembly downstream and not upstream of the sub-ambient heat exchanger and configured to remove liquid water from the cooled acid gas stream to thereby generate a dewatered cooled acid gas stream; and
an acid gas enrichment system downstream and not upstream of the water separation assembly and configured to receive at least a portion of the dewatered cooled acid gas stream from the water separation assembly and to separate the portion of the dewatered cooled acid gas stream into a treated gas stream, which includes at least 50 weight percent of the carbon dioxide from the portion of the cooled acid gas stream, and an enriched acid gas stream, which includes at least 50 weight percent of the hydrogen sulfide from the portion of the dewatered cooled acid gas stream.

2. The hydrocarbon gas treatment system of claim 1 , wherein the heat exchanger is configured to transfer thermal energy from the acid gas stream to a thermal management fluid stream to generate the cooled acid gas stream and to maintain fluid separation between the acid gas stream and the thermal management fluid stream.

3. The hydrocarbon gas treatment system of claim 1 , wherein a cooled acid gas stream temperature of the cooled acid gas stream is less than an acid gas stream temperature of the acid gas stream.

4. The hydrocarbon gas treatment system of claim 3 , wherein at least one of:
(i) the cooled acid gas stream temperature is at most 15 degrees Celsius;
(ii) the cooled acid gas stream temperature is at least 4 degrees Celsius; and
(iii) the cooled acid gas stream temperature is at least 25 degrees Celsius less than the acid gas stream temperature.

5. The hydrocarbon gas treatment system of claim 1 , wherein the acid gas enrichment system includes:
(i) a solvent contacting assembly configured to fluidly contact the portion of the dewatered cooled acid gas stream with a lean solvent stream, which includes a hydrogen sulfide-absorbing solvent, to partition at least a portion of the hydrogen sulfide from the portion of the dewatered cooled acid gas stream into the lean solvent stream, and to generate a rich solvent stream, which includes the portion of the hydrogen sulfide from the portion of the dewatered cooled acid gas stream, and the treated gas stream;
(ii) a solvent regeneration assembly configured to separate the hydrogen sulfide from the rich solvent stream to generate the enriched acid gas stream and a lean solvent recycle stream; and
(iii) a solvent recirculation assembly configured to provide the lean solvent recycle stream to the solvent contacting assembly as the lean solvent stream.

6. The hydrocarbon gas treatment system of claim 5 , wherein the solvent regeneration assembly includes a stripping vessel.

7. The hydrocarbon gas treatment system of claim 6 , wherein the solvent regeneration assembly further includes a reboiler assembly configured to receive the lean solvent recycle stream from the stripping vessel and to vaporize at least a portion of the lean solvent recycle stream to generate a vaporized solvent return stream, wherein the stripping vessel includes a vaporized solvent return stream inlet configured to receive a portion of the vaporized solvent return stream.

8. The hydrocarbon gas treatment system of claim 7 , wherein the solvent regeneration assembly further includes a reflux system configured to return at least a portion of the enriched acid gas stream to the stripping vessel as a reflux stream.

9. The hydrocarbon gas treatment system of claim 8 , wherein the reflux system includes:
(i) a condenser configured to condense moisture from the enriched acid gas stream to generate a condensed water stream;
(ii) a reflux accumulator configured to accumulate at least a portion of the condensed water stream; and
(iii) a reflux pump configured to return the portion of the condensed water stream to the stripping vessel as the reflux stream.

10. The hydrocarbon gas treatment system of claim 5 , wherein the solvent recirculation assembly includes a circulation pump configured to convey the lean solvent recycle stream from the solvent regeneration assembly to the solvent contacting assembly as the lean solvent stream.

11. The hydrocarbon gas treatment system of claim 5 , wherein the solvent recirculation assembly includes a filter configured to remove particulate material from at least a portion of the lean solvent recycle stream.

12. The hydrocarbon gas treatment system of claim 5 , wherein the solvent recirculation assembly includes a lean solvent cooling assembly configured to cool the lean solvent recycle stream to generate a cooled lean solvent recycle stream, which is provided to the solvent contacting assembly as the lean solvent stream.

13. The hydrocarbon gas treatment system of claim 12 , wherein a cooled lean solvent recycle stream temperature of the cooled lean solvent recycle stream is less than a lean solvent recycle stream temperature of the lean solvent recycle stream.

14. The hydrocarbon gas treatment system of claim 13 , wherein at least one of:
(i) the cooled lean solvent recycle stream temperature is at most 15 degrees Celsius;
(ii) the cooled lean solvent recycle stream temperature is at least 4 degrees Celsius; and
(iii) the cooled lean solvent recycle stream temperature is at least 25 degrees Celsius less than the lean solvent recycle stream temperature.

15. The hydrocarbon gas treatment system of claim 5 , wherein the acid gas enrichment system includes a flash vessel configured to vaporize a portion of the rich solvent stream to generate a vaporized rich solvent stream prior to supply of a remainder of the rich solvent stream to the solvent regeneration assembly.

16. The hydrocarbon gas treatment system of claim 5 , wherein the acid gas enrichment system includes a rich/lean heat exchanger configured to exchange thermal energy between the rich solvent stream and the lean solvent recycle stream.

17. The hydrocarbon gas treatment system of claim 5 , wherein the acid gas enrichment system includes the hydrogen sulfide-absorbing solvent.

18. The hydrocarbon gas treatment system of claim 5 , wherein the hydrogen sulfide-absorbing solvent includes at least one of an amine solution, a tertiary amine solution, and a sterically hindered amine solution.

19. The hydrocarbon gas treatment system of claim 5 , wherein the hydrocarbon gas treatment system further includes a sulfur recovery unit configured to receive the enriched acid gas stream and to generate an elemental sulfur stream and a tail gas stream from the enriched acid gas stream.

20. A method of treating a hydrocarbon gas using the hydrocarbon gas treatment system of claim 1 , the method comprising:
providing a feed gas stream to a hyd

Assignees

• Mondkar Suhas P
• Northrop P Scott
• Exxonmobil Upstream Res Co

Inventors

• Mondkar Suhas P
• Northrop P Scott

Classifications

• E21B43/34 Primary

  Arrangements for separating materials produced by the well · CPC title

• Y02C20/40

  of CO2 · CPC title

• C10L2290/543

  Distillation, fractionation or rectification for separating fractions, components or impurities during preparation or upgrading of a fuel · CPC title

• B01D53/1425

  Regeneration of liquid absorbents · CPC title

• C10L3/103 Primary

  Sulfur containing contaminants · CPC title