Integrated system and method for removing acid gas from a gas stream

Abstract

Acid gas compounds are removed from a process gas such as, for example, syngas or natural gas, by flowing a feed gas into a desulfurization unit to remove a substantial fraction of sulfur compounds from the feed gas and flowing the resulting desulfurized gas into a CO 2 removal unit to remove a substantial fraction of CO 2 from the desulfurized gas.

What is claimed is: 
     
         1 . A gas processing system, comprising:
 a desulfurization unit comprising an adsorber unit in fluid communication with a regenerator unit, wherein:
 the adsorber unit is configured to flow a feed gas into contact with a flowing sorbent stream comprising a solid particulate sorbent to remove one or more sulfur compounds from the feed gas, and output a desulfurized gas and a sulfided sorbent; and 
 the regenerator unit is configured to produce a regenerated sorbent from the sulfided sorbent, and flow the regenerated sorbent into the adsorber unit; and 
   a CO 2  removal unit positioned downstream from the desulfurization unit, and configured to remove CO 2  from the desulfurized gas and output a treated gas comprising reduced fractions of sulfur and CO 2 .   
     
     
         2 . The gas processing system of  claim 1 , wherein the desulfurization unit is configured to separate the desulfurized gas from the sulfided sorbent. 
     
     
         3 . The gas processing system of  claim 2 , wherein the adsorber unit comprises a solids separation zone configured to separate the desulfurized gas from the sulfided sorbent, and the adsorber unit is configured to output the desulfurized gas separately from the sulfide sorbent. 
     
     
         4 . The gas processing system of  claim 2 , comprising a solids separator selected from the group consisting of:
 a solids separator configured to separate the desulfurized gas from the sulfided sorbent;   a solids separator configured to separate the desulfurized gas from the sulfided sorbent, wherein the solids separator is a cyclone separator;   a solids separator configured to separate the desulfurized gas from the sulfided sorbent, wherein the solids separator is an electrostatic precipitator;   a solids separator configured to separate the desulfurized gas from the sulfided sorbent, wherein the solids separator is a filter; and   a solids separator configured to separate the desulfurized gas from the sulfided sorbent, wherein the solids separator is a gravity settling chamber.   
     
     
         5 . The gas processing system of  claim 1 , wherein the adsorber unit comprises:
 a vessel comprising a mixing zone configured to flow the feed gas into contact with the sorbent stream;   a feed gas inlet configured to receive the feed gas into the vessel;   a regenerated sorbent inlet configured to receive the regenerated sorbent from the regenerator unit; and   an outlet configured to output the desulfurized gas and the sulfided sorbent.   
     
     
         6 . The gas processing system of  claim 5 , wherein the outlet configured to output the desulfurized gas and the sulfided sorbent is a first outlet, and the regenerator unit comprises:
 a sulfided sorbent inlet communicating with the adsorber unit and configured to receive the sulfided sorbent outputted from the adsorber unit; and   a second outlet communicating with the adsorber unit and configured to output the regenerated sorbent.   
     
     
         7 . The gas processing system of  claim 6 , wherein the regenerator unit comprises:
 a regenerating agent inlet configured to receive a regenerating agent; and   a vessel communicating with the sulfided sorbent inlet, the regenerating agent inlet, and the second outlet, the vessel comprising a mixing zone configured to flow the sulfided sorbent into contact with the regenerating agent.   
     
     
         8 . The gas processing system of  claim 5 , wherein the CO 2  removal unit comprises:
 a desulfurized gas inlet configured to receive the desulfurized gas outputted from the adsorber unit; and   a treated gas outlet configured to output the treated gas.   
     
     
         9 . The gas processing system of  claim 8 , wherein the CO 2  removal unit comprises a CO 2  absorber or adsorber vessel communicating with the desulfurized gas inlet and the treated gas outlet, the CO 2  absorber or adsorber vessel configured to flow the desulfurized gas into contact with a CO 2  removing agent. 
     
     
         10 . The gas processing system of  claim 8 , wherein the CO 2  removal unit comprises:
 a CO 2 -lean fluid inlet configured to receive a CO 2 -lean fluid comprising a regenerated CO 2  removing agent;   a CO 2  absorber or adsorber vessel communicating with the desulfurized gas inlet, the CO 2 -lean fluid inlet, and the treated gas outlet, the CO 2  absorber or adsorber vessel configured to flow the desulfurized gas into contact with the CO 2 -lean fluid and produce a CO 2 -rich fluid;   a CO 2 -rich fluid outlet communicating with the CO 2  absorber or adsorber vessel and configured to output the CO 2 -rich fluid;   a CO 2  removing agent regenerator vessel configured to receive the CO 2 -rich fluid and remove CO 2  from the CO 2 -rich fluid to produce the CO 2 -lean fluid; and   a CO 2 -lean fluid outlet configured to flow the CO 2 -lean fluid from the CO 2  removing agent regenerator vessel into the CO 2  absorber or adsorber vessel.   
     
     
         11 . The gas processing system of  claim 1 , wherein the regenerator unit is configured to produce a sulfur compound from the sulfided sorbent. 
     
     
         12 . The gas processing system of  claim 1 , wherein the desulfurization unit is configured to separate the regenerated sorbent from a sulfur compound produced from the sulfided sorbent in the regenerator unit. 
     
     
         13 . The gas processing system of  claim 12 , wherein the regenerator unit comprises a solids separation zone configured to separate the regenerated sorbent from the sulfur compound, and the regenerator unit is configured to output the sulfur compound separately from the regenerated sorbent. 
     
     
         14 . The gas processing system of  claim 12 , comprising a solids separator selected from the group consisting of:
 a solids separator configured to separate the regenerated sorbent from the sulfur compound;   a solids separator configured to separate the regenerated sorbent from the sulfur compound, wherein the solids separator is a cyclone separator;   a solids separator configured to separate the regenerated sorbent from the sulfur compound, wherein the solids separator is an electrostatic precipitator;   a solids separator configured to separate the regenerated sorbent from the sulfur compound, wherein the solids separator is a filter; and   a solids separator configured to separate the regenerated sorbent from the sulfur compound, wherein the solids separator is a gravity settling chamber.   
     
     
         15 . The gas processing system of  claim 12 , comprising a sulfur recovery unit configured to receive the sulfur compound produced from the sulfided sorbent in the regenerator unit. 
     
     
         16 . The gas processing system of  claim 1 , wherein the CO 2  removal unit is configured to flow the desulfurized gas into contact with a CO 2  removing agent. 
     
     
         17 . The gas processing system of  claim 1 , wherein the CO 2  removal unit comprises a CO 2  absorber or adsorber unit, and the CO 2  absorber or adsorber unit is configured to flow the desulfurized gas into contact with a CO 2  removing agent and outputting the treated gas. 
     
     
         18 . The gas processing system of  claim 17 , wherein:
 the CO 2  absorber or adsorber unit is configured to produce a CO 2 -rich stream comprising the CO 2  removing agent and CO 2 ; and   the CO 2  removal unit comprises a CO 2  removing agent regenerator unit configured to remove CO 2  from the CO 2 -rich stream to produce a CO 2 -lean stream comprising regenerated CO 2  removing agent, and flowing the regenerated CO 2  removing agent into the CO 2  absorber or adsorber unit.   
     
     
         19 . The gas processing system of  claim 1 , comprising a CO 2  recovery unit, wherein the CO 2  removal unit is configured to produce a CO 2  output stream, and the CO 2  recovery unit is configured to recover CO 2  from the CO 2  output stream. 
     
     
         20 . The gas processing system of  claim 1 , wherein the CO 2  removal unit has a configuration selected from the group consisting of:
 the CO 2  removal unit is configured to remove the CO 2  from the desulfurized gas without removing sulfur from the desulfurized gas;   the CO 2  removal unit is configured to remove the CO 2  from the desulfurized gas without actively removing sulfur from the desulfurized gas; and   the CO 2  removal unit is configured to receive the desulfurized gas without cryogenically cooling the desulfurized gas via external refrigeration.   
     
     
         21 . The gas processing system of  claim 1 , comprising a water-gas-shift unit selected from the group consisting of:
 the water-gas-shift unit is positioned upstream of the desulfurization unit, and configured to shift the feed gas to produce carbon dioxide (CO 2 ) and hydrogen gas (H 2 );   the water-gas-shift unit is positioned downstream from the desulfurization unit, and configured to shift the desulfurized gas to produce carbon dioxide (CO 2 ) and hydrogen gas (H 2 ); and   the water-gas-shift unit is positioned downstream from the desulfurization unit and upstream of the CO 2  removal unit, wherein the water-gas-shift unit is configured to shift the desulfurized gas to produce carbon dioxide (CO 2 ) and hydrogen gas (H 2 ), and the CO 2  removal unit is configured to receive shifted desulfurized gas from the water-gas-shift unit.