System for tail gas treatment of sulfur recovery units

Patent metadata

Field	Value
Publication number	US-10239763-B1
Application number	US-201715832136-A
Country	US
Kind code	B1
Filing date	Dec 5, 2017
Priority date	Dec 5, 2017
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

A process for recovering sulfur from a tail gas stream comprising the steps of providing a tail gas stream to a chemical looping combustion (CLC) unit, the tail gas stream comprising a sulfide component, providing an oxygen carrier to the CLC unit, the oxygen carrier comprising a calcium carbonate, providing an air stream to the CLC unit, the air stream comprising oxygen, and reacting the sulfide component in the CLC unit with the calcium compound and the air to produce a product effluent, the product effluent comprising calcium sulfate.

First claim

That which is claimed is:

1. A process for recovering sulfur from a tail gas stream, the process comprising the steps of:
providing a tail gas stream to a chemical looping combustion (CLC) unit, where the tail gas stream comprises a sulfide component;
providing an oxygen carrier to the CLC unit, where the oxygen carrier comprises calcium carbonate;
providing an air stream to the CLC unit, where the air stream comprises oxygen; and
reacting the sulfide component in the CLC unit with the calcium carbonate and the oxygen to produce a product effluent, where the product effluent comprises calcium sulfate.

2. The process of claim 1 , further comprising the steps of:
introducing the oxygen carrier to an air reactor of the CLC unit;
introducing the air stream to the air reactor of the CLC unit;
allowing the calcium carbonate to decompose in the air reactor to produce an air reactor effluent, the air reactor effluent comprises calcium oxide;
introducing the air reactor effluent to an air reactor separator, where the air reactor separator comprises a solid-gas separation unit;
separating calcium oxide from the air reactor effluent in the air reactor separator to produce an air reactor exhaust and an air reactor discharge, where the air reactor discharge comprises the calcium oxide;
introducing the air reactor discharge to a fuel reactor of the CLC unit;
introducing the tail gas stream to the fuel reactor;
reacting the calcium oxide and the hydrogen sulfide to produce a fuel reactor effluent, where the fuel reactor effluent comprises calcium sulfide and calcium carbonate;
introducing the fuel reactor effluent to a fuel reactor separator, where the fuel reactor separator comprises a solid-gas separation unit;
separating the calcium sulfide and calcium carbonate from the fuel reactor effluent in the fuel reactor separator to produce a flue gas exhaust and a fuel reactor discharge, where the fuel reactor discharge comprises the calcium sulfide and calcium carbonate;
introducing the fuel reactor discharge to the air reactor;
reacting the calcium sulfide and the oxygen in the air reactor to produce calcium sulfate; and
withdrawing a product effluent from the air reactor discharge, where the product effluent comprises a fraction of the calcium sulfate.

3. The process of claim 2 , wherein the fuel reactor is operated at a fuel reaction pressure of atmospheric pressure, and further wherein the fuel reactor is operated at a fuel reaction temperature of 650 deg C.

4. The process of claim 2 , wherein the air reactor is operated at an air reaction pressure of atmospheric pressure, and further wherein the air reactor is operated at an air reaction temperature of 900 deg C.

5. The process of claim 2 , wherein the air reactor is a fluidized bed reactor packed with calcium carbonate, and further wherein the fuel reactor is a fluidized bed reactor packed with calcium carbonate.

6. The process of claim 1 , further comprising the steps of:
introducing the oxygen carrier to a calciner unit of the CLC unit;
calcining the calcium carbonate in the oxygen carrier to produce a calciner effluent, where the calciner effluent comprises calcium oxide;
introducing the calciner effluent to a calciner separator, where the calciner separator comprises a solid-gas separation unit;
separating the calcium oxide from the calciner effluent in the calciner separator to produce a calciner exhaust and a calciner discharge;
introducing the calciner discharge to a fuel reactor of the CLC unit;
introducing the tail gas stream to the fuel reactor;
reacting the calcium oxide and the hydrogen sulfide to produce a fuel reactor effluent, where the fuel reactor effluent comprises calcium sulfide and calcium carbonate;
introducing the fuel reactor effluent to a fuel reactor separator, where the fuel reactor separator comprises a solid-gas separation unit;
separating the calcium sulfide and calcium carbonate from the fuel reactor effluent in the fuel reactor separator to produce a flue gas exhaust and a fuel reactor discharge, where the fuel reactor discharge comprises the calcium sulfide and calcium carbonate;
introducing the fuel reactor discharge to an air reactor of the CLC unit;
reacting the calcium sulfide and the oxygen in the air reactor to produce an air reactor effluent, where the air reactor effluent comprises calcium sulfate;
introducing the air reactor effluent to an air reactor separator, where the air reactor separator comprises a solid-gas separation unit;
separating calcium oxide from the air reactor effluent in the air reactor separator to produce an air reactor exhaust and an air reactor outlet, where the air reactor outlet comprises the calcium sulfate;
withdrawing a product effluent from the air reactor outlet, where the product effluent comprises a fraction of the calcium sulfate.

7. The process of claim 6 , wherein the fuel reactor is operated at a fuel reaction pressure of atmospheric pressure, and further wherein the fuel reactor is operated at a fuel reaction temperature of 650 deg C.

8. The process of claim 6 , wherein the air reactor is operated at an air reaction pressure of atmospheric pressure, and further wherein the air reactor is operated at an air reaction temperature of 900 deg C.

9. The process of claim 6 , wherein the calciner unit is operated at a calciner reaction pressure of atmospheric pressure, and further wherein the calciner unit is operated at a calciner reaction temperature of 900 deg C.

10. The process of claim 6 , wherein the air reactor is a fluidized bed reactor packed with calcium carbonate, and further wherein the fuel reactor is a fluidized bed reactor packed with calcium carbonate.

11. The process of claim 1 , further comprising the steps of:
introducing the oxygen carrier to a calciner unit of the CLC unit;
calcining the calcium carbonate in the oxygen carrier to produce a calciner effluent, where the calciner effluent comprises calcium oxide;
introducing the calciner effluent to a calciner separator, where the calciner separator comprises a solid-gas separation unit;
separating the calcium oxide from the calciner effluent in the calciner separator to produce a calciner exhaust and a calciner discharge;
diverting a portion of the calciner discharge to produce a calciner slipstream;
introducing the calciner discharge to a fuel reactor of the CLC unit;
introducing the tail gas stream to the fuel reactor;
reacting the calcium oxide and the hydrogen sulfide to produce a fuel reactor effluent, where the fuel reactor effluent comprises calcium sulfide and calcium carbonate;
introducing the fuel reactor effluent to a fuel reactor separator, where the fuel reactor separator comprises a solid-gas separation unit;
separating the calcium sulfide and calcium carbonate from the fuel reactor effluent in the fuel reactor separator to produce a flue gas exhaust and a fuel reactor discharge, where the fuel reactor discharge comprises the calcium sulfide and calcium carbonate;
introducing the flue gas exhaust and the calciner slipstream to a reducing reactor of the CLC unit;
reacting the calcium oxide and hydrogen sulfide in the reducing reactor to produce a reducing reactor effluent;
separating the reducing reactor effluent in a reducing reactor separator to produce an exhaust gases stream and a reducing reactor discharge, where the reducing reactor separator comprises a solid-gas separation unit;
introducing the reducing reactor discharge to the calciner unit;
introducing the fuel reactor discharge to an air reactor of the CLC unit;
reacting the calcium sulfide and the oxygen in the air reactor to produce an air reactor effluent, where the air reactor effl

Assignees

• Saudi Arabian Oil Co

Inventors

• Harale Aadesh
• Younes Mourad
• Musawi Maytham

Classifications

• F23C10/10

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

• B01J8/26

  with two or more fluidised beds, e.g. reactor and regeneration installations · 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

• B01D2251/102

  Oxygen · CPC title

• B01D2251/404

  of calcium · CPC title