Sour pressure swing adsorption process

Patent metadata

Field	Value
Publication number	US-9808755-B2
Application number	US-201514808069-A
Country	US
Kind code	B2
Filing date	Jul 24, 2015
Priority date	Jul 24, 2015
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

Methods and apparatuses for separating CO 2 and sulfur-containing compounds from a synthesis gas obtained from gasification of a carbonaceous feedstock. The primary separating steps are performed using a sour pressure swing adsorption (SPSA) system, followed by an acid gas enrichment system and a sulfur removal unit. The SPSA system includes multiple pressure equalization steps and a rinse step using a rinse gas that is supplied from a source other than directly from one of the adsorber beds of the SPSA system.

First claim

The invention claimed is:

1. A method comprising:
(a) gasifying a carbonaceous feedstock to form a gasified stream comprising H2S, CO2, CO and H2;
(b) converting at least a portion of the CO in the gasified stream to CO2 and H2 using a water-gas shift reaction, resulting in a sour syngas stream;
(c) introducing the sour syngas stream into a sour pressure swing adsorption (SPSA) system having a plurality of adsorber beds;
(d) performing a cyclic PSA process using the SPSA system comprising the following steps:
(i) pressurizing a first bed of the plurality of adsorber beds to a first pressure;
(ii) feeding the sour syngas stream into an inlet end of the pressurized first bed and discharging a first gas stream from an outlet end of the first bed;
(iii) after the feeding step, introducing a rinse gas comprising at least 99 mol % N2 into the first bed, the rinse gas being from a source other than directly from another of the plurality of adsorber beds;
(e) removing a product stream from the SPSA system, the product stream having a greater concentration of H2 than the sour syngas stream and comprising at least 80 mol % H2 and at least 10 mol % N2;
(f) removing a tail gas stream from the SPSA system, the tail gas stream having a greater concentration of CO2 and H2S than the sour syngas stream; and
(g) separating the tail gas stream into an H2S-enriched stream and a H2S-depleted stream using an acid gas enrichment (AGE) system.

2. The method of claim 1 , wherein step (a) comprises gasifying a carbonaceous feedstock to form a gasified stream comprising CO, H2, at least 1000 ppm H2S, and at least 20 mol % CO2.

3. The method of claim 1 , further comprising:
(h) synthesizing a reactor product stream comprising at least 10 mol % NH3 from the product stream.

4. The method of claim 1 , wherein step (d) further comprises:
(iv) reducing the pressure of the first bed to a second pressure by placing the outlet end of the first bed in flow communication with an outlet end of a second bed of the plurality of adsorber beds while performing step (d)(iii).

5. The method of claim 4 , wherein step (d) further comprises:
(v) further reducing the pressure of the first bed to a third pressure by placing the outlet end of the first bed in flow communication with an outlet end of a third bed of the plurality of adsorber beds while performing (d)(iii).

6. The method of claim 5 , wherein step (d) further comprises:
(vi) after performing step (d)(iii) in the first bed, further reducing the pressure of the first bed to a fourth pressure by placing the outlet end of the first bed in flow communication with an outlet end of a fourth bed of the plurality of adsorber beds.

7. The method of claim 1 , wherein step (d)(iii) comprises after the feeding step, introducing a rinse gas into the inlet end of the first bed, the rinse gas being from a source other than directly from another of the plurality of adsorber beds.

8. The method of claim 1 , wherein step (d) further comprises:
(iv) after performing step (d)(iii) in the first bed, reducing the pressure of the first bed to a second pressure by placing the outlet end of the first bed in flow communication with an outlet end of a second bed of the plurality of adsorber beds.

9. The method of claim 1 , wherein step (g) comprises separating the tail gas stream into an H2S-enriched stream and a H2S-depleted stream using an acid gas enrichment (AGE) system, the H2S-enriched stream comprising at least 5 mol % H2S and no more than 95 mol % CO2.

10. The method of claim 1 , further comprising:
(k) converting at least a portion of the H2S-enriched stream to one or more selected from the group of sulfuric acid, elemental sulfur, a product derived from sulfuric acid, and a product derived from elemental sulfur using a sulfur recovery unit.

11. The method of claim 1 , wherein step (b) comprises converting at least a portion of the CO in the gasified stream to CO2 and H2 using a water-gas shift reaction, resulting in a sour syngas stream comprising at least 0.02 mol % sulfur-containing species and 25 mol % CO2.

12. The method of claim 1 , wherein step (c) comprises introducing the sour syngas stream into a sour pressure swing adsorption (SPSA) system having at least ten adsorber beds.

13. The method of claim 1 , further comprising:
(I) cooling the sour syngas stream after step (b) and before step (c).

14. The method of claim 1 , further comprising:
(m) after performing step (b) and before performing step (c), passing the sour syngas stream through a guard bed containing an adsorber adapted to remove organic tar compounds.

15. A method comprising:
(a) gasifying a carbonaceous feedstock to form a gasified stream comprising H2S, CO2, CO and H2;
(b) converting at least a portion of the CO in the gasified stream to CO2 and H2 using a water-gas shift reaction, resulting in a sour syngas stream;
(c) introducing the sour syngas stream into a sour pressure swing adsorption (SPSA) system having a plurality of adsorber beds;
(d) performing a cyclic PSA process using the SPSA system comprising the following steps:
(i) pressurizing a first bed of the plurality of adsorber beds to a first pressure;
(ii) feeding the sour syngas stream into an inlet end of the pressurized first bed and discharging a first gas stream from an outlet end of the first bed;
(iii) after the feeding step, introducing a rinse gas comprising at least 85 mol % of one or more selected from the group of CO2 and H2S into the first bed, the rinse gas being from a source other than directly from another of the plurality of adsorber beds.
(e) removing a product stream from the SPSA system, the product stream having a greater concentration of H2 than the sour syngas stream;
(f) removing a tail gas stream from the SPSA system, the tail gas stream having a greater concentration of CO2 and H2S than the sour syngas stream; and
(g) separating the tail gas stream into an H2S-enriched stream and a H2S-depleted stream using an acid gas enrichment (AGE) system.

16. The method of claim 15 , wherein step (e) comprises removing a product stream from the PSA system, the product stream comprising at least 60 mol % H2 and at least 25 mol % CO.

17. The method of claim 15 , further comprising:
(i) synthesizing a reactor product stream comprising at least 10 mol % MeOH from the product stream.

18. A method comprising:
(a) gasifying a carbonaceous feedstock to form a gasified stream comprising H2S, CO2, CO and H2;
(b) converting at least a portion of the CO in the gasified stream to CO2 and H2 using a water-gas shift reaction, resulting in a sour syngas stream;
(c) introducing the sour syngas stream into a sour pressure swing adsorption (SPSA) system having a plurality of adsorber beds;
(d) performing a cyclic PSA process using the SPSA system comprising the following steps:
(i) pressurizing a first bed of the plurality of adsorber beds to a first pressure;
(ii) feeding the sour syngas stream into an inlet end of the pressurized first bed and discharging a first gas stream from an outlet end of the first bed;
(iii) after the feeding step, introducing a rinse gas into the first bed, the rinse gas being from a source other than directly from another of the plurality of adsorber beds;
(e) removing a product stream from the SPSA system, the product stream having a greater concentration of H2 than the sour syngas stream;
(f) removing a tail gas stream from the SPSA system, the tail gas stream having a greater concentration of CO2 and H2S than the sour syngas stream;
(g) separati

Assignees

• Air Prod & Chem

Inventors

• Bhadra Shubhra Jyoti
• Wright Andrew David
• Hufton Jeffrey Raymond
• Kloosterman Jeffrey William
• Amy Fabrice
• Weist Jr Edward Landis

Classifications

• C01B3/56

  by contacting with solids; Regeneration of used solids · CPC title

• B01D2259/40056

  Gases other than recycled product or process gas · CPC title

• B01D2259/4067

  using ten beds · CPC title

• C01B2203/048

  the impurity being an organic compound · CPC title

• B01D2259/41

  using plural beds of the same adsorbent in series · CPC title