Generating elemental sulfur

Patent metadata

Field	Value
Publication number	US-9504984-B2
Application number	US-201514643726-A
Country	US
Kind code	B2
Filing date	Mar 10, 2015
Priority date	Apr 9, 2014
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

Techniques for generating elemental sulfur are provided herein. The disclosed methods may include a gas processing system including a processed feed gas. The methods may include a distillation column configured to receive the processed feed gas and to generate a high-pressure acid gas stream. The methods may include a reactor configured to partially combust the high-pressure acid gas stream to generate a limiting reactant. The methods may include a plurality of reactors configured with a shell side and a plurality of reaction tubes, where a reaction between the high-pressure acid gas stream and the limiting reactant produces a partially-reacted high-pressure acid gas containing elemental sulfur. The methods may include a plurality of condensers configured to condense the elemental sulfur. The methods may include a plurality of separators configured to separate out the partially-reacted high-pressure acid gas stream to recover elemental sulfur.

First claim

What is claimed is:

1. A system for generating elemental sulfur, comprising:
a gas treatment system to provide a processed feed gas comprising carbon dioxide, hydrogen sulfide, and hydrocarbons;
a distillation column comprising a rectifying section, a freeze zone section, and a stripping section, wherein the distillation column is configured to receive the processed feed gas, freeze carbon dioxide from the processed feed gas in the freeze zone section, and generate a natural gas stream and a liquid high-pressure acid gas stream, wherein the liquid high-pressure acid gas stream comprises hydrogen sulfide and carbon dioxide and is at a pressure of at least 500 psig;
a reactor configured to receive a portion of the liquid high-pressure acid gas stream and to partially combust the portion of the liquid high-pressure acid gas stream to generate a limiting reactant;
a plurality of reactors configured with a shell side and a tube side, wherein the tube side comprises a plurality of reaction tubes, and wherein a reaction in each of the reaction tubes between a portion of the liquid high-pressure acid gas stream from the distillation column and the limiting reactant produces a partially-reacted high-pressure acid gas containing elemental sulfur;
a plurality of condensers configured to condense the partially-reacted high-pressure acid gas and form an overhead acid gas stream and a liquid elemental sulfur stream; and
a plurality of separators configured to recover elemental sulfur.

2. The system of claim 1 , wherein the high-pressure acid gas stream is at a pressure of from at least 500 psig to 1000 psig.

3. The system of claim 1 , wherein the processed feed gas comprises substantially carbon dioxide (CO 2 ), hydrogen sulfide (H 2 S), and hydrocarbons.

4. The system of claim 1 , wherein the limiting reactant is injected into each of the plurality of reactors.

5. The system of claim 1 , wherein the limiting reactant is sulfur dioxide (SO 2 ).

6. The system of claim 1 , wherein the shell side of each of the plurality of reactors circulates a fluid medium to remove a substantial amount of heat due to an exothermic reaction.

7. The system of claim 1 , wherein the plurality of separators comprises a sulfur trap to collect and direct the elemental sulfur into a single liquid sulfur vessel.

8. The system of claim 1 , comprising a plurality of heaters to reheat the partially-reacted high-pressure gas stream to prevent elemental sulfur from condensing in the reactors.

9. The system of claim 1 , wherein the partially-reacted high-pressure acid gas stream circulates through the plurality of reactors, the plurality of condensers, and the plurality of separators.

10. The system of claim 1 , wherein the partially-reacted high-pressure acid gas stream from a final reactor is a vaporized high-pressure gas stream that is substantially comprised of high-pressure CO 2 and substantially free of H 2 S.

11. The system of claim 10 , wherein the vaporized high-pressure gas stream from the final reactor is recovered for enhanced oil recovery (EOR) using CO 2 .

12. The system of claim 1 , comprising a prilling tank configured to convert the elemental sulfur into solid sulfur prills.

13. A system for generating elemental sulfur from a high-pressure acid gas stream, comprising:
a distillation column comprising a rectifying section, a freeze zone section, and a stripping section, wherein the distillation column is configured to receive a feed gas stream comprising carbon dioxide, hydrogen sulphide, and hydrocarbons, freeze carbon dioxide from the feed gas stream, and provide a high-pressure liquid gas stream comprising hydrogen sulfide and carbon dioxide;
a plurality of shell and tube reactors, wherein the tubes of the shell and tube reactors are injected with the high-pressure liquid acid gas stream and a recirculating solvent and are configured to produce dissolved elemental sulfur in an exothermic reaction;
a plurality of coolers configured to crystallize the dissolved elemental sulfur and to separate crystallized elemental sulfur from gaseous products formed in each of the plurality of shell and tube reactors.

14. The system of claim 13 , comprising a gas processing system configured to feed a processed gas to the distillation column.

15. The system of claim 13 , wherein the each of the plurality of shell and tube reactors is an absorber reactor configured to react hydrogen sulfide (H 2 S) from the high-pressure liquid gas stream with a limiting reactant to produce elemental sulfur.

16. The system of claim 15 , wherein the shell and tube reactors releases carbon dioxide (CO 2 ) from the high-pressure liquid gas stream of the distillation column.

17. The system of claim 15 , wherein the limiting reactant furthers a reaction between the H 2 S in the high-pressure liquid gas stream from the distillation column and the limiting reactant to produce the dissolved elemental sulfur.

18. The system of claim 13 , wherein the plurality of coolers includes a hydro-cyclone to collect the crystallized elemental sulfur.

19. A method for generating elemental sulfur, comprising providing a processed feed gas stream;
feeding the processed feed gas stream to a distillation column comprising a rectifying section, a freeze zone section, and a stripping section;
generating a liquid high-pressure acid gas stream from the processed feed gas stream in the distillation column, wherein the liquid high-pressure acid gas stream is at a pressure of at least 500 psig and comprises H 2 S and CO 2 ;
partially reacting the liquid high-pressure acid gas stream with a limiting reactant in a shell and tube reactor to produce a gaseous high-pressure stream containing elemental sulfur;
removing excess heat of reaction using the shell and tube reactor generated during the production of the gaseous high-pressure stream;
cooling the gaseous high-pressure stream to provide a liquid high-pressure stream; and
separating the liquid high-pressure stream out of the gaseous high-pressure stream to recover elemental sulfur.

20. The method of claim 19 , wherein the processed feed gas stream comprises substantially carbon dioxide (CO 2 ), hydrogen sulfide (H 2 S), and hydrocarbons.

21. The method of claim 19 , comprising oxidizing a portion of the liquid high-pressure acid gas stream in a furnace to generate the limiting reactant.

22. The method of claim 19 , comprising injecting the limiting reactant into the shell and tube reactor.

23. The method of claim 19 , comprising:
forming droplets of elemental sulfur; and
cooling the droplets to form sulfur prills.

Assignees

• Northrop P Scott
• Exxonmobil Upstream Res Co

Inventors

• Northrop P Scott

Classifications

• B01J2219/00006

  Large-scale industrial plants · CPC title

• C01B17/0447

  Separation of the obtained sulfur · CPC title

• C01B17/0408

  Pretreatment of the hydrogen sulfide containing gases · CPC title

• B01J19/2425 Primary

  in parallel · CPC title

• B01J2219/00085

  Plates; Jackets; Cylinders · CPC title