Sour gas combustion using in-situ oxygen production and chemical looping combustion

Patent metadata

Field	Value
Publication number	US-9566546-B2
Application number	US-201414159599-A
Country	US
Kind code	B2
Filing date	Jan 21, 2014
Priority date	Jan 21, 2014
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

A chemical looping combustion (CLC) process for sour gas combustion includes a number of reaction zones and is configured to provide in-situ oxygen production and in-situ removal of SO 2 from a product gas stream by reacting the SO 2 with a calcium-based sorbent at a location within one reaction zone. The CLC process is also configured such that the in-situ oxygen production results from the use of a metal oxide oxygen carrier which is purposely located such that it does not directly contact the sour gas, thereby eliminating the generation of undesirable sulfur-based metal oxides.

First claim

What is claimed is:

1. A process for in-situ oxygen production and sour gas combustion using chemical looping combustion while producing a product stream comprising the steps of:
reducing a bed of metal oxide oxygen carriers that is disposed on a perforated substrate in a lower portion of a fuel reactor to provide gas-phase oxygen which flows to a riser that is in fluid communication with the fuel reactor;
delivering sour gas into the riser at a location that is downstream of the bed of metal oxide oxygen carriers such that the sour gas is free of direct contact with the metal oxide oxygen carriers;
combusting the sour gas under oxy-combustion conditions within the riser to produce the product stream which includes SO 2 ;
removing the SO 2 from the product stream;
oxidizing the reduced metal oxides with air in an air reactor to produce the metal oxide oxygen carriers; and
delivering the oxidized metal oxide oxygen carriers back to the fuel reactor.

2. The process of claim 1 , wherein the bed is fluidized by a stream of CO 2 , steam, or a combination thereof.

3. The process of claim 1 , wherein the metal oxide oxygen carriers are copper-based, cobalt-based, manganese-based, or a mixture thereof.

4. The process of claim 1 , wherein the metal oxide oxygen carriers are manganese-based oxygen carriers.

5. The process of claim 1 , wherein the sour gas is a liquid feed that flows into an inlet formed in the riser at a location downstream of the fuel reactor.

6. The process of claim 1 , wherein the product stream includes CO 2 and H 2 O.

7. The process of claim 6 , wherein the product stream further includes amounts of unburnt CO and H 2 .

8. The process of claim 1 , wherein heat and steam are generated as by-products.

9. A process for in-situ oxygen production and sour gas combustion using chemical looping combustion while producing a product stream comprising the steps of:
reducing a bed of metal oxide oxygen carriers that is disposed on a perforated substrate in a lower portion of a fuel reactor to provide gas-phase oxygen which flows to a riser that is in fluid communication with the fuel reactor;
delivering sour gas into the riser at a location that is downstream of the metal oxide oxygen carriers such that the sour gas is free of direct contact with the metal oxide oxygen carriers;
combusting the sour gas under oxy-combustion conditions within the riser to produce the product stream which includes SO 2 ;
removing the SO 2 from the product stream, wherein the SO 2 is removed from the product stream by reacting the SO 2 with a calcium-based sorbent that is introduced into the riser to form CaSO 4 ;
oxidizing the reduced metal oxide with air in an air reactor to produce the metal oxide oxygen carriers; and
delivering the oxidized metal oxide oxygen carriers back to the fuel reactor.

10. The process of claim 9 , further including the step of separating the CaSO 4 from the product stream using a gas-solid separation device.

11. The process of claim 10 , wherein the gas-solid separation device is a cyclone.

12. The process of claim 9 , wherein at least a portion of the CaSO 4 is delivered back to the riser to act as a nonmetal oxygen carrier which provides additional oxygen as a result of reacting with the sour gas and other gases within the riser.

13. The process of claim 12 , wherein the CaSO 4 reacts with CO and H 2 in the riser to produce CO 2 and steam.

14. The process of claim 12 , further including the steps of reducing the CaSO 4 nonmetal oxygen carrier to CaS and separating the CaS from the product stream.

15. The process of claim 14 , further including the step of oxidizing the separated CaS to form the CaSO 4 nonmetal oxygen carrier which is then delivered back to the riser.

16. The process of claim 15 , wherein the step of oxidizing the separated CaS comprises the step of delivering the separated CaS to a hopper and injecting air into the hopper to oxidize the CaS to form the CaSO 4 nonmetal oxygen carrier which is delivered to the riser.

17. The process of claim 9 , wherein the calcium-based sorbent is limestone.

18. The process of claim 9 , wherein a ratio of Ca/S is between about 2 and 2.5.

19. A process for in-situ oxygen production and in-situ reduction of the emission of sulfur compounds that are produced during sour gas combustion using chemical looping combustion while producing a product stream comprising the steps of:
reducing a metal oxide oxygen carrier that is disposed within a fuel reactor to provide gas-phase oxygen which flows to a riser that is in fluid communication with the fuel reactor;
delivering sour gas into the riser at a location that is downstream of the metal oxide oxygen carrier such that the sour gas is free of direct contact with the metal oxide oxygen carrier;
combusting the sour gas under oxy-combustion conditions within the riser to produce the product stream which includes SO 2 ;
removing the SO 2 from the product stream in-situ within the riser by reacting the SO 2 with a calcium-based sorbent that is introduced into the riser and reacts with the SO 2 to form CaSO 4 which is separated from the product stream;
oxidizing the reduced metal oxide with air in an air reactor to produce the metal oxide oxygen carrier; and
delivering the oxidized metal oxide oxygen carrier back to the fuel reactor.

20. The process of claim 19 , further including the step of using the CaSO 4 which is separated from the product stream as a nonmetal oxygen carrier in the riser to increase sour gas conversion as a result of the CaSO 4 reacting with CO and H 2 in the riser to produce CO 2 and steam.

Assignees

• Saudi Arabian Oil Co

Inventors

• Hoteit Ali

Classifications

• B01D53/1481 Primary

  Removing sulfur dioxide or sulfur trioxide · CPC title

• C01B17/508

  by oxidation of sulfur compounds · CPC title

• F23C10/10

  the separation apparatus being located outside the combustion chamber · CPC title

• F23C2900/99008

  Unmixed combustion, i.e. without direct mixing of oxygen gas and fuel, but using the oxygen from a metal oxide, e.g. FeO · CPC title

• C01F11/464

  Sulfates of Ca from gases containing sulfur oxides · CPC title