HIGH RECOVERY CO AND CO2 SEPARATION PROCESS FROM FLUE GAS FROM A PARTIAL BURN FLUID CATALYTIC CRACKING PROCESS

Abstract

Processes for separating CO from CO.sub.2 in flue gas streams from partial oxidation regenerator in FCC processes, as well as reducing the sulfur content of the flue gas stream are described. The processes involve separating the cooled reactor effluent stream into a CO.sub.2 product stream, the CO.sub.2 recycle stream, and a CO product stream. The processes may incorporate either dry sorbent injection (DSI) units or wet gas scrubbing units to remove sulfur compounds. The separation processes can utilize cryogenic fractionation, pressure swing adsorption (PSA) processes including vacuum PSA, and temperature swing adsorption (TSA) processes. The flue gas stream can be used to preheat the CO.sub.2 recycle stream.

Claims

1. A process for separating CO from CO.sub.2 in a flue gas stream from a partial oxidation regenerator of a fluid catalytic cracking (FCC) process comprising: passing a mixture of a preheated CO.sub.2 recycle stream and a concentrated oxygen stream to the partial oxidation regenerator to generate the flue gas stream comprising CO.sub.2, CO, SOx, NOx, catalyst fines, O.sub.2, and H.sub.2O; transferring heat from the flue gas stream to a boiler feed water stream in a heat recovery section to form a partially cooled flue gas stream and a steam stream; reacting one or more of a sulfur-containing compound in the flue gas stream with a reactant in a decontamination reactor to form a reactor effluent flue gas stream and a contaminant stream, the reactor effluent gas stream having a level of the sulfur-containing compound less than a level of the sulfur-containing compound in the flue gas stream; heating a CO.sub.2 recycle stream with the reactor effluent gas stream to produce the preheated CO.sub.2 recycle stream and a cooled reactor effluent stream; and separating the cooled reactor effluent stream into a CO.sub.2 product stream, the CO.sub.2 recycle stream, and a CO product stream.

2. The process of claim 1 wherein separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises: compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; dehydrating the compressed reactor effluent stream to form a dehydrated reactor effluent stream; separating the dehydrated reactor effluent stream into the CO.sub.2 product stream and a CO-containing overhead stream in a cryogenic CO.sub.2 fractionation system; and separating the CO-containing overhead stream into the CO.sub.2 recycle stream and the CO product stream in a separation section; or recycling a portion of the CO.sub.2 product stream as the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or combinations thereof.

3. The process of claim 2 further comprising: compressing or expanding the recycle CO.sub.2 stream before introducing the CO.sub.2 recycle stream into the regenerator.

4. The process of claim 2 further comprising: recycling a portion of the CO.sub.2 recycle stream to the compressor.

5. The process of claim 2 further comprising: separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream, or wherein the compressed portion of the cooled reactor effluent stream is the CO.sub.2 recycle stream.

6. The process of claim 1 wherein separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises: compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; separating the compressed reactor effluent stream into a low pressure CO.sub.2-containing stream and a high pressure CO-containing stream in a pressure swing absorption (PSA) unit or a vacuum swing adsorption (VPSA) unit; compressing the low pressure CO.sub.2-containing stream to form a high pressure CO.sub.2-containing stream and an intermediate pressure CO.sub.2-containing stream; co-feeding the intermediate pressure CO.sub.2-containing stream to the PSA or VPSA unit; dehydrating the high pressure CO.sub.2-containing stream to form the CO.sub.2 product stream; and purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a part of the intermediate pressure CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream; and wherein a part of the intermediate pressure CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream and compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream and wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or combinations thereof.

7. The process of claim 6 further comprising: separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream, or wherein the compressed portion of the cooled reactor effluent stream comprises the CO.sub.2 recycle stream.

8. The process of claim 1 wherein separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises: compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; separating the compressed reactor effluent stream into a CO.sub.2-containing stream and a CO-containing stream in a temperature swing absorption (TSA) unit; compressing the CO.sub.2-containing stream to form the CO.sub.2 product stream; compressing the CO-containing stream to form a high pressure CO stream; and dehydrating the high pressure CO-containing stream to form the CO product stream; wherein a part of the CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or combinations thereof.

9. The process of claim 8 further comprising: dividing the CO-containing stream from the TSA unit into a first part and a second part, wherein the first part is compressed to form the high pressure CO stream; compressing and cooling the second portion of the CO-containing stream and optionally removing water from the cooled, compressed second portion of the CO-containing stream water removal; heating the cooled, compressed second portion of the CO-containing stream to form a heated second portion of the CO-containing stream; and introducing the heated second portion of the CO-containing stream to the TSA unit.

10. The process of claim 8 further comprising: separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream; or wherein the compressed portion of the cooled reactor effluent stream comprises the CO.sub.2 recycle stream.

11. The process of claim 1 further comprising: further cooling the cooled reactor effluent stream and removing water from the cooled reactor effluent stream before separating the cooled reactor effluent stream.

12. The process of claim 1 further comprising: recovering heat from the reactor effluent stream before cooling the reactor effluent stream.

13. The process of claim 1 further comprising: introducing the flue gas stream into a superheated steam section of a heat recovery steam generator (HRSG) before the decontamination reactor to produce a superheated steam stream and a partially cooled flue gas stream, the HRSG comprising the superheated steam section and a saturated steam section; introducing a boiler feed water stream and the partially cooled flue gas stream into the saturated steam section to produce a saturated steam stream and a second partially cooled flue gas stream; introducing at least a portion of the saturated steam stream into the superheated steam section; superheating the saturated steam stream with the flue gas stream to produce the superheated steam stream; and wherein reacting one or more of the sulfur-containing compound, the nitrogen-containing compound, or both in the flue gas stream with the reactant in the decontamination reactor comprises reacting one or more of the sulfur-containing compound, the nitrogen-containing compound, or both in the partially cooled flue gas stream with the reactant.

14. The process of claim 1 wherein the concentrated oxygen stream is made in an air separation unit or an electrolyzer.

15. The process of claim 1 wherein reacting one or more of the sulfur-containing compound in the flue gas stream with the reactant in the decontamination reactor comprises: reacting the flue gas stream with a reactant in a dry SOx reaction section to form a dry SOx reaction section flue gas stream consisting essentially of at least one of H.sub.2O, CO.sub.2, CO, N.sub.2, O.sub.2, Na.sub.2CO.sub.3, Na.sub.2SO.sub.4, NaNO.sub.3, CaSO.sub.4, CaCO.sub.3, Ca(NO.sub.3).sub.2, MgCO.sub.3, MgSO.sub.4, Mg(NO.sub.3).sub.2, and NOx, wherein the reactant comprises at least one of NaHCO.sub.3, NaHCO.sub.3.Math.Na.sub.2CO.sub.3.Math.2(H.sub.2O), CaCO.sub.3, Ca(OH).sub.2, and Mg(OH).sub.2; and filtering the dry SOx reaction section flue gas stream in a filtration section to remove Na.sub.2CO.sub.3, Na.sub.2SO.sub.4, NaNO.sub.3, CaSO.sub.4, CaCO.sub.3, Ca(NO.sub.3).sub.2, MgCO.sub.3, MgSO.sub.4, Mg(NO.sub.3).sub.2 and catalyst fines to form the reactor effluent stream and a filtered material stream.

16. A process for separating CO from CO.sub.2 in a flue gas stream from a partial oxidation regenerator of a fluid catalytic cracking (FCC) process comprising: passing a mixture of a preheated CO.sub.2 recycle stream and a concentrated oxygen stream to the partial oxidation regenerator to generate the flue gas stream comprising CO.sub.2, CO, SOx, NOx, catalyst fines, O.sub.2 and H.sub.2O; transferring heat from the flue gas stream to a boiler feed water stream in a heat recovery section to form a partially cooled flue gas stream and a steam stream; heating a CO.sub.2 recycle stream with the partially cooled flue gas stream to produce the preheated CO.sub.2 recycle stream and a cooled flue gas stream; reacting one or more of a sulfur-containing compound, in the cooled flue gas stream with a reactant in a decontamination reactor to form a reactor effluent flue gas stream and a contaminant stream, the reactor effluent gas stream having a level of the sulfur-containing compound less than a level of the sulfur-containing compound in the flue gas stream; separating the reactor effluent stream into a CO.sub.2 product stream, the CO.sub.2 recycle stream, and a CO product stream; and wherein reacting one or more of the sulfur-containing compound, the nitrogen-containing compound, or both in the cooled flue gas stream with the reactant in the decontamination reactor comprises: reacting a caustic solution or an NH.sub.3 based solution with the cooled flue gas stream in a wet SOx reaction section to form the reactor effluent flue gas stream and a liquid stream comprising at least one of H.sub.2O, CO.sub.2, CO, N.sub.2, O.sub.2, Na.sub.2SO.sub.3, Na.sub.2SO.sub.4, NaHSO.sub.3, Na.sub.2CO.sub.3, (NH.sub.4).sub.2SO.sub.4, and catalyst fines.

17. The process of claim 16 further comprising: cooling the reactor effluent stream before separating the reactor effluent stream.

18. The process of claim 16 wherein separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises: compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; dehydrating the compressed reactor effluent stream to form a dehydrated reactor effluent stream; separating the dehydrated reactor effluent stream into the CO.sub.2 product stream and a CO-containing overhead stream in a cryogenic CO.sub.2 fractionation system; and separating the CO-containing overhead stream into the CO.sub.2 recycle stream and the CO product stream in a separation section; or recycling a portion of the CO.sub.2 product stream as the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or combinations thereof.

19. The process of claim 16 wherein separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises: compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; separating the compressed reactor effluent stream into a low pressure CO.sub.2-containing stream and a high pressure CO-containing stream in a pressure swing absorption (PSA) unit or a vacuum swing adsorption (VPSA) unit; compressing the low pressure CO.sub.2-containing stream to form a high pressure CO.sub.2-containing stream and an intermediate pressure CO.sub.2-containing stream; co-feeding the intermediate pressure CO.sub.2-containing stream to the PSA or VPSA unit; dehydrating the high pressure CO.sub.2-containing stream to form the CO.sub.2 product stream; and purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a part of the intermediate pressure CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream; and wherein a part of the intermediate pressure CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream and compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream and wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or combinations thereof.

20. The process of claim 16 wherein separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises: compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; separating the compressed reactor effluent stream into a CO.sub.2-containing stream and a CO-containing stream in a temperature swing absorption (TSA) unit; compressing the CO.sub.2-containing stream to form the CO.sub.2 product stream; compressing the CO-containing stream to form a high pressure CO stream; and dehydrating the high pressure CO-containing stream to form the CO product stream; wherein a part of the CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or combinations thereof.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0013] FIG. 1 illustrates one embodiment of a process according to the present invention.

[0014] FIG. 2 illustrates another embodiment of a process according to the present invention.

[0015] FIG. 3 illustrates another embodiment of a process according to the present invention.

[0016] FIG. 4 illustrates another embodiment of the process of FIG. 1.

[0017] FIG. 5 illustrates another embodiment of the process of FIG. 2.

[0018] FIG. 6 illustrates another embodiment of the process of FIG. 3.

DESCRIPTION OF THE INVENTION

[0019] The process involves processes for separating CO from CO.sub.2 in flue gas streams from partial oxidation regenerator in FCC processes, as well as reducing the sulfur content of the flue gas stream. The processes involve separating the cooled reactor effluent stream into a CO.sub.2 product stream, a CO.sub.2 recycle stream, and a CO product stream. The processes may incorporate either dry sorbent injection (DSI) units or wet gas scrubbing units to remove sulfur compounds.

[0020] The separation processes can utilize cryogenic fractionation, pressure swing adsorption (PSA) processes including vacuum PSA (VPSA), and temperature swing adsorption (TSA) processes. The flue gas can be used to preheat the CO.sub.2 recycle stream.

[0021] The outlet temperature from the FCC regenerator for a partial combustion FCC unit is about 650-815? C.

[0022] In some embodiments, there is a NOx reactor section where nitrogen-containing compounds are reacted. The NOx reactor section may comprise a selective catalytic reduction (SCR) reactor to form a NOx reactor effluent stream with a reduced level of nitrogen-containing compounds compared to the incoming stream. Any suitable SCR catalyst could be used, including but not limited to, ceramic carrier materials such as titanium oxide with active catalytic components such as oxides of base metals including TiO.sub.2, WO.sub.3 and V.sub.2O.sub.5, or an activated carbon-based catalyst. An ammonia and/or urea stream is introduced into the NOx reactor section where it reacts with the NOx present in the incoming stream.

[0023] In some embodiments, a HRSG is included before the SOx reaction section. The HRSG comprises a superheated steam section and a saturated steam section. In this case, the waste gas stream comprises a flue gas stream, which is introduced into the superheated steam section of the HRSG to produce a superheated steam stream and a partially cooled flue gas stream. A boiler feed water stream and the partially cooled flue gas stream are introduced into the saturated steam section to produce a saturated steam stream and a second partially cooled flue gas stream. All or a portion of the saturated steam stream is introduced into the superheated steam section, where it is superheated with the flue gas stream to produce the superheated steam stream. The second partially cooled flue gas stream is sent to the SOx reaction section.

[0024] One aspect of the invention comprises a process for separating CO from CO.sub.2 in a flue gas stream from a partial oxidation regenerator of a fluid catalytic cracking (FCC) process. In one embodiment, the process comprises: passing a mixture of a preheated CO.sub.2 recycle stream and a concentrated oxygen stream to the partial oxidation regenerator to generate the flue gas stream comprising CO.sub.2, CO, SOx, NOx, catalyst fines, O.sub.2, and H.sub.2O; transferring heat from the flue gas stream to a boiler feed water stream in a heat recovery section to form a partially cooled flue gas stream and a steam stream; reacting one or more of a sulfur-containing compound in the flue gas stream with a reactant in a decontamination reactor to form a reactor effluent flue gas stream and a contaminant stream, the reactor effluent gas stream having a level of the sulfur-containing compound less than a level of the sulfur-containing compound in the flue gas stream; heating a CO.sub.2 recycle stream with the reactor effluent gas stream to produce the preheated CO.sub.2 recycle stream and a cooled reactor effluent stream; and separating the cooled reactor effluent stream into a CO.sub.2 product stream, the CO.sub.2 recycle stream, and a CO product stream.

[0025] In some embodiments, separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises: compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; dehydrating the compressed reactor effluent stream to form a dehydrated reactor effluent stream; separating the dehydrated reactor effluent stream into the CO.sub.2 product stream and a CO-containing overhead stream in a cryogenic CO.sub.2 fractionation system; and separating the CO-containing overhead stream into the CO.sub.2 recycle stream and the CO product stream in a separation section; or recycling a portion of the CO.sub.2 product stream as the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or combinations thereof.

[0026] In some embodiments, the process further comprises: compressing or expanding the recycle CO.sub.2 stream before introducing the CO.sub.2 recycle stream into the regenerator.

[0027] In some embodiments, the process further comprises: recycling a portion of the CO.sub.2 recycle stream to the compressor.

[0028] In some embodiments, the process further comprises: separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream, or wherein the compressed portion of the cooled reactor effluent stream is the CO.sub.2 recycle stream.

[0029] In some embodiments, separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises: compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; separating the compressed reactor effluent stream into a low pressure CO.sub.2-containing stream and a high pressure CO-containing stream in a pressure swing absorption (PSA) unit or a vacuum swing adsorption (VPSA) unit; compressing the low pressure CO.sub.2-containing stream to form a high pressure CO.sub.2-containing stream and an intermediate pressure CO.sub.2-containing stream; co-feeding the intermediate pressure CO.sub.2-containing stream to the PSA or VPSA unit; dehydrating the high pressure CO.sub.2-containing stream to form the CO.sub.2 product stream; purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a part of the intermediate pressure CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream; and wherein a part of the intermediate pressure CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream and compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream and wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or combinations thereof.

[0030] In some embodiments, the process of further comprises: separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream, or wherein the compressed portion of the cooled reactor effluent stream comprises the CO.sub.2 recycle stream.

[0031] In some embodiments, separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises: compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; separating the compressed reactor effluent stream into a CO.sub.2-containing stream and a CO-containing stream in a temperature swing absorption (TSA) unit; compressing the CO.sub.2-containing stream to form the CO.sub.2 product stream; compressing the CO-containing stream to form a high pressure CO stream; dehydrating the high pressure CO-containing stream to form the CO product stream; wherein a part of the CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or combinations thereof.

[0032] In some embodiments, the process further comprises: dividing the CO-containing stream from the TSA unit into a first part and a second part, wherein the first part is compressed to form the high pressure CO stream; compressing and cooling the second portion of the CO-containing stream and optionally removing water from the cooled, compressed second portion of the CO-containing stream water removal; heating the cooled, compressed second portion of the CO-containing stream to form a heated second portion of the CO-containing stream; introducing the heated second portion of the CO-containing stream to the TSA unit.

[0033] In some embodiments, the process further comprises: separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream; or wherein the compressed portion of the cooled reactor effluent stream comprises the CO.sub.2 recycle stream.

[0034] In some embodiments, the process further comprises: further cooling the cooled reactor effluent stream and removing water from the cooled reactor effluent stream before separating the cooled reactor effluent stream.

[0035] In some embodiments, the process further comprises: recovering heat from the reactor effluent stream before cooling the reactor effluent stream.

[0036] In some embodiments, the process further comprises: introducing the flue gas stream into a superheated steam section of a heat recovery steam generator (HRSG) before the decontamination reactor to produce a superheated steam stream and a partially cooled flue gas stream, the HRSG comprising the superheated steam section and a saturated steam section; introducing a boiler feed water stream and the partially cooled flue gas stream into the saturated steam section to produce a saturated steam stream and a second partially cooled flue gas stream; introducing at least a portion of the saturated steam stream into the superheated steam section; superheating the saturated steam stream with the flue gas stream to produce the superheated steam stream; and wherein reacting one or more of the sulfur-containing compound, the nitrogen-containing compound, or both in the flue gas stream with the reactant in the decontamination reactor comprises reacting one or more of the sulfur-containing compound, the nitrogen-containing compound, or both in the partially cooled flue gas stream with the reactant.

[0037] In some embodiments, the concentrated oxygen stream is made in an air separation unit or an electrolyzer.

[0038] In some embodiments, reacting one or more of the sulfur-containing compound, in the flue gas stream with the reactant in the decontamination reactor comprises: reacting the flue gas stream with a reactant in a dry SOx reaction section to form a dry SOx reaction section flue gas stream consisting essentially of at least one of H.sub.2O, CO.sub.2, CO, N.sub.2, O.sub.2, Na.sub.2CO.sub.3, Na.sub.2SO.sub.4, NaNO.sub.3, CaSO.sub.4, CaCO.sub.3, Ca(NO.sub.3).sub.2, MgCO.sub.3, MgSO.sub.4, Mg(NO.sub.3).sub.2, and NOx, wherein the reactant comprises at least one of NaHCO.sub.3, NaHCO.sub.3.Math.Na.sub.2CO.sub.3.Math.2(H.sub.2O), CaCO.sub.3, Ca(OH).sub.2, and Mg(OH).sub.2; and filtering the dry SOx reaction section flue gas stream in a filtration section to remove Na.sub.2CO.sub.3, Na.sub.2SO.sub.4, NaNO.sub.3, CaSO.sub.4, CaCO.sub.3, Ca(NO.sub.3).sub.2, MgCO.sub.3, MgSO.sub.4, Mg(NO.sub.3).sub.2 and catalyst fines to form the reactor effluent stream and a filtered material stream.

[0039] Another aspect of the invention is a process for separating CO from CO.sub.2 in a flue gas stream from a partial oxidation regenerator of a fluid catalytic cracking (FCC) process. In one embodiment, the process comprises: passing a mixture of a preheated CO.sub.2 recycle stream and a concentrated oxygen stream to the partial oxidation regenerator to generate the flue gas stream comprising CO.sub.2, CO, SOx, NOx, catalyst fines, O.sub.2 and H.sub.2O; transferring heat from the flue gas stream to a boiler feed water stream in a heat recovery section to form a partially cooled flue gas stream and a steam stream; heating a CO.sub.2 recycle stream with the partially cooled flue gas stream to produce the preheated CO.sub.2 recycle stream and a cooled flue gas stream; reacting one or more of a sulfur-containing compound, a nitrogen-containing compound, or both in the cooled flue gas stream with a reactant in a decontamination reactor to form a reactor effluent flue gas stream and a contaminant stream, the reactor effluent gas stream having a level of the sulfur-containing compound less than a level of the sulfur-containing compound in the flue gas stream; and separating the reactor effluent stream into a CO.sub.2 product stream, the CO.sub.2 recycle stream, and a CO product stream; and wherein reacting one or more of the sulfur-containing compound, the nitrogen-containing compound, or both in the cooled flue gas stream with the reactant in the decontamination reactor comprises: reacting a caustic solution or an NH.sub.3 based solution with the cooled flue gas stream in a wet SOx reaction section to form the reactor effluent flue gas stream and a liquid stream comprising at least one of H.sub.2O, CO.sub.2, CO, N.sub.2, O.sub.2, Na.sub.2SO.sub.3, Na.sub.2SO.sub.4, NaHSO.sub.3, Na.sub.2CO.sub.3, (NH.sub.4).sub.2SO.sub.4, NH.sub.4Cl and catalyst fines.

[0040] In some embodiments, the process further comprises cooling the reactor effluent stream before separating the reactor effluent stream.

[0041] In some embodiments, separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises: compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; dehydrating the compressed reactor effluent stream to form a dehydrated reactor effluent stream; separating the dehydrated reactor effluent stream into the CO.sub.2 product stream and a CO-containing overhead stream in a cryogenic CO.sub.2 fractionation system; and separating the CO-containing overhead stream into the CO.sub.2 recycle stream and the CO product stream in a separation section; or recycling a portion of the CO.sub.2 product stream as the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or combinations thereof.

[0042] In some embodiments, the process further comprises: compressing or expanding the recycle CO.sub.2 stream before introducing the CO.sub.2 recycle stream into the regenerator.

[0043] In some embodiments, the process further comprises: recycling a portion of the CO.sub.2 recycle stream to the compressor.

[0044] In some embodiments, the process further comprises: separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream, or wherein the compressed portion of the cooled reactor effluent stream is the CO.sub.2 recycle stream.

[0045] In some embodiments, separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises: compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; separating the compressed reactor effluent stream into a low pressure CO.sub.2-containing stream and a high pressure CO-containing stream in a pressure swing absorption (PSA) unit or a vacuum swing adsorption (VPSA) unit; compressing the low pressure CO.sub.2-containing stream to form a high pressure CO.sub.2-containing stream and an intermediate pressure CO.sub.2-containing stream; co-feeding the intermediate pressure CO.sub.2-containing stream to the PSA or VPSA unit; dehydrating the high pressure CO.sub.2-containing stream to form the CO.sub.2 product stream; purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a part of the intermediate pressure CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream; and wherein a part of the intermediate pressure CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream and compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream and wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or combinations thereof.

[0046] In some embodiments, the process further comprises: separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream, or wherein the compressed portion of the cooled reactor effluent stream comprises the CO.sub.2 recycle stream.

[0047] In some embodiments, separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises: compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; separating the compressed reactor effluent stream into a CO.sub.2-containing stream and a CO-containing stream in a temperature swing absorption (TSA) unit; compressing the CO.sub.2-containing stream to form the CO.sub.2 product stream; compressing the CO-containing stream to form a high pressure CO stream; dehydrating the high pressure CO-containing stream to form the CO product stream; wherein a part of the CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or combinations thereof.

[0048] In some embodiments, the process further comprises: dividing the CO-containing stream from the TSA unit into a first part and a second part, wherein the first part is compressed to form the high pressure CO stream; compressing and cooling the second portion of the CO-containing stream and optionally removing water from the cooled, compressed second portion of the CO-containing stream water removal; heating the cooled, compressed second portion of the CO-containing stream to form a heated second portion of the CO-containing stream; introducing the heated second portion of the CO-containing stream to the TSA unit.

[0049] In some embodiments, the process further comprises: separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream; or wherein the compressed portion of the cooled reactor effluent stream comprises the CO.sub.2 recycle stream.

[0050] In some embodiments, the process further comprises: further cooling the cooled reactor effluent stream and removing water from the cooled reactor effluent stream before separating the cooled reactor effluent stream.

[0051] In some embodiments, the process further comprises: recovering heat from the reactor effluent stream before cooling the reactor effluent stream.

[0052] In some embodiments, the process further comprises: introducing the flue gas stream into a superheated steam section of a heat recovery steam generator (HRSG) before the decontamination reactor to produce a superheated steam stream and a partially cooled flue gas stream, the HRSG comprising the superheated steam section and a saturated steam section; introducing a boiler feed water stream and the partially cooled flue gas stream into the saturated steam section to produce a saturated steam stream and a second partially cooled flue gas stream; introducing at least a portion of the saturated steam stream into the superheated steam section; superheating the saturated steam stream with the flue gas stream to produce the superheated steam stream; and wherein reacting one or more of the sulfur-containing compound, the nitrogen-containing compound, or both in the flue gas stream with the reactant in the decontamination reactor comprises reacting one or more of the sulfur-containing compound, the nitrogen-containing compound, or both in the partially cooled flue gas stream with the reactant.

[0053] In some embodiments, the concentrated oxygen stream is made in an air separation unit or an electrolyzer.

[0054] FIG. 1 illustrates one embodiment of the process 100 with a cryogenic CO.sub.2 separation process. The feed stream 105 is sent to the FCC reactor 110 containing catalyst. The product is separated from the catalyst and the product containing stream 115 is sent for further processing.

[0055] The spent catalyst stream 120 is sent to the partial combustion regenerator 125 where coke on the catalyst is burned to regenerate the catalyst. The regenerated catalyst 130 is returned to the FCC reactor 110.

[0056] A stream 135 containing a mixture of a preheated CO.sub.2 recycle stream 140 and a concentrated oxygen stream 145 is introduced into the partial combustion regenerator 125. The concentrated oxygen stream 145 may be formed in an air separation unit (ASU) or an electrolyser unit 147. The concentrated oxygen stream 145 may have a concentration of 50 mol % oxygen or more, or 60 mol % or more, or 70 mol % or more, or 80 mol % or more, or 90 mol % or more, or 95 mol % or more, or 99 mol % or more, or 99.5 mol % or more, or 99.9 mol % or more.

[0057] The partially combusted flue gas stream 150 comprises un-combusted CO, along with CO.sub.2, SOx, NOx, catalyst fines, O.sub.2 and H.sub.2O. The flue gas outlet temperature for the FCC regenerator for a partial combustion FCC is in the range of about 650-815? C.

[0058] The partially combusted flue gas stream 150 is sent to the HRSG superheated steam unit 155 where it superheats a portion 160A of the saturated steam stream 160 from the HRSG saturated steam unit 165 forming superheated steam stream 172.

[0059] The partially cooled flue gas stream 170 is sent to the HRSG saturated steam unit 165. Boiler feed water stream 175 is heated by the partially cooled flue gas stream 170 forming saturated steam stream 160, condensate stream 180, and a second partially cooled flue gas stream 185. A portion 160A of the saturated steam stream 160 is sent to the HRSG superheated steam unit 155. The remainder 160B of the saturated steam stream 160 can be sent to other parts of the plant for use as needed.

[0060] The second partially cooled flue gas stream 185 from the HRSG saturated steam unit 165 is sent to the decontamination reactor 190 which comprises a dry SOx reaction section 195, a filtration section 200. The second partially cooled flue gas stream 185 and the reactant 210 (dry or slurry) are sent to the SOx reaction section where the reactant reacts with the sulfur-containing compounds.

[0061] In some embodiments, the NOx compounds are reacted in a NOx reaction section (not shown) before the decontamination reactor 190. The NOx reaction section may comprise a selective catalytic reduction (SCR) reactor to form a NOx reactor effluent stream with a reduced level of nitrogen-containing compounds compared to the incoming stream. Any suitable SCR catalyst could be used, including but not limited to, ceramic carrier materials such as titanium oxide with active catalytic components such as oxides of base metals including TiO.sub.2, WO.sub.3 and V.sub.2O.sub.5, or an activated carbon-based catalyst. An ammonia and/or urea stream is introduced into the NOx reactor section where it reacts with the NOx present in the incoming stream. If a NOx reaction section is included, the effluent stream from the NOx reaction section contains a lower level of NOx compounds than the level of NOx compounds in the incoming stream.

[0062] The SOx reaction products are filtered out of the dry SOx reaction section flue gas stream in the filtration section 200 forming the filtered material stream 215. The filtration section 200 removes particulate and fines. Electricity is supplied to the filtration section 200 when the filtration section 200 comprises an electrostatic precipitator, and/or instrument air (IA) is supplied to the filtration section 200 comprises a bag filter. The filtered material stream 215 including one or more of Na.sub.2SO.sub.4, NaNO.sub.3, NaNO.sub.2, Na.sub.2CO.sub.3, K.sub.2SO.sub.4, and KNO.sub.3, and catalyst fines is removed from the filtration section 200. The filtered material stream 215 can be removed from process. Alternatively, or additionally, the filtered material stream 215 can be recycled to the decontamination reactor 190 to increase the Na.sub.2CO.sub.3 conversion yield (i.e., from 85 wt % to 98 wt %).

[0063] The reactor effluent stream 220 from the decontamination reactor 190 contains a lower level of SOx compounds than the level of SOx compounds in the incoming second partially cooled flue gas stream 185 from the HRSG saturated steam unit 165.

[0064] The reactor effluent stream 220 may optionally be sent to a heat exchanger 225 to recover heat.

[0065] The reactor effluent stream 220 (or reactor effluent stream 230 if the optional heat exchanger 225 is present) is sent to heat exchanger 235 where it is heat exchanged with CO.sub.2 recycle stream 240 to form the preheated CO.sub.2 recycle stream 140 and a cooled reactor effluent stream 250.

[0066] The cooled reactor effluent stream 250 may be sent to an optional heat exchanger 251 to further cool and condense it forming cooled reactor effluent stream 253.

[0067] The cooled reactor effluent stream 250 (or 253) is separated into a CO.sub.2 product stream, the CO.sub.2 recycle stream 140, and a CO product stream.

[0068] In FIG. 1, the cooled reactor effluent stream 253 (or 250) is sent to a knock-out drum 255 to remove a water stream 260. The overhead cooled reactor effluent stream 265 is compressed in compressor 270 forming a compressed reactor effluent stream 275 which is sent to dehydrator 280. The dehydrated reactor effluent stream 285 is sent to a cryogenic CO.sub.2 fractionation system 290 where it is separated into a CO.sub.2 product stream 295 and a CO-containing overhead stream 300.

[0069] The CO-containing overhead stream 300 may be sent to a separation section 305 where it is separated into CO product stream 310 and CO.sub.2 recycle stream 315.

[0070] The CO.sub.2 recycle stream 315 may be compressed or expanded in compressor or expander 320 forming the CO.sub.2 recycle stream 240 before being heat exchanged with the reactor effluent stream 220 (or 230) if needed. The CO.sub.2 recycle stream 240 may comprise all or a portion of the CO.sub.2 recycle stream 315.

[0071] Alternatively, the separation section 305 may be omitted. In this case, the CO-containing overhead stream 300 is the CO product stream. All or a portion of the CO.sub.2 recycle stream 240 may be a portion 325 of the CO.sub.2 product stream 295.

[0072] In another alternative, a portion 330 of the overhead cooled reactor effluent stream 265 may be compressed in a compressor 335 to form a compressed stream 340. All or a portion of the CO.sub.2 recycle stream 240 may be the compressed stream 340.

[0073] In another alternative, all or a portion of the CO.sub.2 recycle stream 240 may be a portion 345 of the compressed reactor effluent stream 275.

[0074] A portion 350 of the CO.sub.2 recycle stream 315 may be recycled to the compressor 270.

[0075] FIG. 2 illustrates one embodiment of the process 400 including a PSA separation process. The feed stream 105 is sent to the FCC reactor 110 containing catalyst. The product is separated from the catalyst and the product containing stream 115 is sent for further processing.

[0076] The spent catalyst stream 120 is sent to the partial combustion regenerator 125 where coke on the catalyst is burned to regenerate the catalyst. The regenerated catalyst 130 is returned to the FCC reactor 110.

[0077] A stream 135 containing a mixture of a preheated CO.sub.2 recycle stream 140 and a concentrated oxygen stream 145 is introduced into the partial combustion regenerator 125. The concentrated oxygen stream 145 may be formed in an Air Separation Unit (ASU) unit or an electrolyser unit 147.

[0078] The partially combusted flue gas stream 150 comprises un-combusted CO, along with CO.sub.2, SOx, NOx, catalyst fines, O.sub.2 and H.sub.2O. The flue gas outlet temperature for the FCC regenerator for a partial combustion FCC is in the range of about 650-815? C.

[0079] The partially combusted flue gas stream 150 is sent to the HRSG superheated steam unit 155 where it superheats a portion 160A of the saturated steam stream 160 from the HRSG saturated steam unit 165 forming superheated steam stream 172.

[0080] The partially cooled flue gas stream 170 is sent to the HRSG saturated steam unit 165. Boiler feed water stream 175 is heated by the partially cooled flue gas stream 170 forming saturated steam stream 160, condensate stream 180, and a second partially cooled flue gas stream 185. A portion 160A of the saturated steam stream 160 is sent to the HRSG superheated steam unit 155. The remainder 160B of the saturated steam stream 160 can be sent to other parts of the plant for use as needed.

[0081] The second partially cooled flue gas stream 185 from the HRSG saturated steam unit 165 is sent to the decontamination reactor 190 which comprises a dry SOx reaction section 195, a filtration section 200. The second partially cooled flue gas stream 185 and the reactant 210 (dry or slurry) are sent to the SOx reaction section where the reactant reacts with the sulfur-containing compounds.

[0082] In some embodiments, the NOx compounds are reacted in a NOx reaction section (not shown) before the decontamination reactor 190. The NOx reaction section may comprise a selective catalytic reduction (SCR) reactor to form a NOx reactor effluent stream with a reduced level of nitrogen-containing compounds compared to the incoming stream. Any suitable SCR catalyst could be used, including but not limited to, ceramic carrier materials such as titanium oxide with active catalytic components such as oxides of base metals including TiO.sub.2, WO.sub.3 and V.sub.2O.sub.5, or an activated carbon-based catalyst. An ammonia and/or urea stream is introduced into the NOx reactor section where it reacts with the NOx present in the incoming stream. If a NOx reaction section is included, the effluent stream from the NOx reaction section contains a lower level of NOx compounds than the level of NOx compounds in the incoming stream.

[0083] The SOx reaction products are filtered out of the dry SOx reaction section flue gas stream in the filtration section 200 forming the filtered material stream 215. The filtration section 200 removes particulate and fines. Electricity is supplied to the filtration section 200 when the filtration section 200 comprises an electrostatic precipitator, and/or IA is supplied to the filtration section 200 comprises a bag filter. The filtered material stream 215 including one or more of Na.sub.2SO.sub.4, NaNO.sub.3, NaNO.sub.2, Na.sub.2CO.sub.3, K.sub.2SO.sub.4, and KNO.sub.3, and catalyst fines is removed from the filtration section 200. The filtered material stream 215 can be removed from process. Alternatively, or additionally, the filtered material stream 215 can be recycled to the decontamination reactor 190 to increase the Na.sub.2CO.sub.3 conversion yield (i.e., from 85 wt % to 98 wt %).

[0084] The reactor effluent stream 220 from the decontamination reactor 190 contains a lower level of SOx compounds than the level of SOx compounds in the incoming second partially cooled flue gas stream 185 from the HRSG saturated steam unit 165.

[0085] The reactor effluent stream 220 may optionally be sent to a heat exchanger 225 to recover heat.

[0086] The reactor effluent stream 220 (or reactor effluent stream 230 if the optional heat exchanger 225 is present) is sent to heat exchanger 235 where it is heat exchanged with CO.sub.2 recycle stream 240 to form the preheated CO.sub.2 recycle stream 140 and a cooled reactor effluent stream 250.

[0087] The cooled reactor effluent stream 250 may be sent to an optional heat exchanger 251 to further cool and condense it forming cooled reactor effluent stream 253.

[0088] The cooled reactor effluent stream 250 (or 253) is separated into a CO.sub.2 product stream, the CO.sub.2 recycle stream 140, and a CO product stream.

[0089] In FIG. 2, the cooled reactor effluent stream 250 is sent to a knock-out drum 255 to remove a water stream 260. The overhead cooled reactor effluent stream 265 is compressed in compressor 270 forming a compressed reactor effluent stream 275 which is sent to PSA unit 405 where it is separated into a low-pressure CO.sub.2-containing stream 410 and a high pressure CO-containing overhead stream 415.

[0090] The low-pressure CO.sub.2-containing stream 410 is compressed in compressor 417 to form a high pressure CO.sub.2-containing stream 420. The high pressure CO.sub.2-containing stream 420 is sent to dehydrator 425 forming a dehydrated high pressure CO.sub.2-containing stream 430 which is the CO.sub.2 product stream.

[0091] An intermediate pressure CO.sub.2-containing stream 435 is also formed in the compressor 417 from the low-pressure CO.sub.2-containing stream 410. The intermediate pressure CO.sub.2-containing stream 435 is co-fed to the PSA unit 405.

[0092] A portion 440 of the intermediate pressure CO.sub.2-containing stream 435 may comprise all or a portion of the CO.sub.2 recycle stream 240.

[0093] The high pressure CO-containing overhead stream 415 may be sent to a polishing section 445 to purify the high pressure CO-containing overhead stream 415 to form CO product stream 450.

[0094] The CO.sub.2 recycle stream 440 may be expanded in an expander or a pressure valve (not shown) to reduce the pressure in the CO.sub.2 recycle stream 440 before being heat exchanged with the reactor effluent stream 220 (or 230) if needed. The CO.sub.2 recycle stream 240 may comprise all or a portion of the CO.sub.2 recycle stream 440.

[0095] Alternatively, the polishing section 445 may be omitted. In this case, the high pressure CO-containing overhead stream 415 is the CO product stream.

[0096] In another alternative, a portion 330 of the overhead cooled reactor effluent stream 265 may be compressed to form a compressed stream 340. All or a portion of the CO.sub.2 recycle stream 240 may be the compressed stream 340.

[0097] In another alternative, all or a portion of the CO.sub.2 recycle stream 240 may be a portion 345 of the compressed reactor effluent stream 275.

[0098] FIG. 3 illustrates one embodiment of the process 500 with a TSA separation process. The feed stream 105 is sent to the FCC reactor 110 containing catalyst. The product is separated from the catalyst and the product containing stream 115 is sent for further processing.

[0099] The spent catalyst stream 120 is sent to the partial combustion regenerator 125 where coke on the catalyst is burned to regenerate the catalyst. The regenerated catalyst 130 is returned to the FCC reactor 110.

[0100] A stream 135 containing a mixture of a preheated CO.sub.2 recycle stream 140 and a concentrated oxygen stream 145 is introduced into the partial combustion regenerator 125. The concentrated oxygen stream 145 may be formed in an Air Separation Unit (ASU) unit or an electrolyser unit 147.

[0101] The partially combusted flue gas stream 150 comprises un-combusted CO, along with CO.sub.2, SOx, NOx, catalyst fines, O.sub.2 and H.sub.2O. The flue gas outlet temperature for the FCC regenerator for a partial combustion FCC is in the range of about 650-815? C.

[0102] The partially combusted flue gas stream 150 is sent to the HRSG superheated steam unit 155 where it superheats a portion 160A of the saturated steam stream 160 from the HRSG saturated steam unit 165 forming superheated steam stream 172.

[0103] The partially cooled flue gas stream 170 is sent to the HRSG saturated steam unit 165. Boiler feed water stream 175 is heated by the partially cooled flue gas stream 172 forming saturated steam stream 160, condensate stream 180, and a second partially cooled flue gas stream 185. A portion 160A of the saturated steam stream 160 is sent to the HRSG superheated steam unit 155. The remainder 160B of the saturated steam stream 160 can be sent to other parts of the plant for use as needed.

[0104] The second partially cooled flue gas stream 185 from the HRSG saturated steam unit 165 is sent to the decontamination reactor 190 which comprises a dry SOx reaction section 195, a filtration section 200. The second partially cooled flue gas stream 185 and the reactant 210 (dry or slurry) are sent to the SOx reaction section where the reactant reacts with the sulfur-containing compounds.

[0105] In some embodiments, the NOx compounds are reacted in a NOx reaction section (not shown) before the decontamination reactor 190. The NOx reaction section may comprise a selective catalytic reduction (SCR) reactor to form a NOx reactor effluent stream with a reduced level of nitrogen-containing compounds compared to the incoming stream. Any suitable SCR catalyst could be used, including but not limited to, ceramic carrier materials such as titanium oxide with active catalytic components such as oxides of base metals including TiO.sub.2, WO.sub.3 and V.sub.2O.sub.5, or an activated carbon-based catalyst. An ammonia and/or urea stream is introduced into the NOx reactor section where it reacts with the NOx present in the incoming stream. If a NOx reaction section is included, the effluent stream from the NOx reaction section contains a lower level of NOx compounds than the level of NOx compounds in the incoming stream.

[0106] The SOx reaction products are filtered out of the dry SOx reaction section flue gas stream in the filtration section 200 forming the filtered material stream 215. The filtration section 200 removes particulate and fines. Electricity is supplied to the filtration section 200 when the filtration section 200 comprises an electrostatic precipitator, and/or IA is supplied to the filtration section 200 comprises a bag filter. The filtered material stream 215 including one or more of Na.sub.2SO.sub.4, NaNO.sub.3, NaNO.sub.2, Na.sub.2CO.sub.3, K.sub.2SO.sub.4, and KNO.sub.3, and catalyst fines is removed from the filtration section 200. The filtered material stream 215 can be removed from process. Alternatively, or additionally, the filtered material stream 215 can be recycled to the decontamination reactor 190 to increase the Na.sub.2CO.sub.3 conversion yield (i.e., from 85 wt % to 98 wt %).

[0107] The reactor effluent stream 220 from the decontamination reactor 190 contains a lower level of SOx compounds than the level of SOx compounds in the incoming second partially cooled flue gas stream 185 from the HRSG saturated steam unit 165.

[0108] The reactor effluent stream 220 may optionally be sent to a heat exchanger 225 to recover heat.

[0109] The reactor effluent stream 220 (or reactor effluent stream 230 if the optional heat exchanger 225 is present) is sent to heat exchanger 505 where it is heat exchanged with stream 510.

[0110] The cooled reactor effluent stream 515 is sent to heat exchanger 520 where it is heat exchanged with CO.sub.2 recycle stream 240 to form the preheated CO.sub.2 recycle stream 140 and a second cooled reactor effluent stream 525.

[0111] The second cooled reactor effluent stream 525 may be sent to optional heat exchanger 527 where it is cooled and condensed forming stream 529.

[0112] The second cooled reactor effluent stream 525 (or stream 529) is separated into a CO.sub.2 product stream, the CO.sub.2 recycle stream 240, and a CO product stream.

[0113] In FIG. 3, the second cooled reactor effluent stream 525 is sent to a knock-out drum 530 to remove a water stream 535. The overhead cooled reactor effluent stream 540 is compressed in compressor 545 forming a compressed reactor effluent stream 550 which is sent to TSA unit 555 where it is separated into a CO.sub.2-containing stream 560 and a CO-containing stream 565.

[0114] The CO.sub.2-containing stream 560 is sent to a compressor 570 forming CO.sub.2 product stream 575.

[0115] A portion 580 of the CO.sub.2-containing stream 560 forms the CO.sub.2 recycle stream 240 which heat exchanged with the cooled reactor effluent stream 515. The portion 580 can optionally be expanded and heat exchanged before being heat exchanged with the cooled reactor effluent stream 515 (not shown). The portion 580 of the CO.sub.2-containing stream 560 may comprise all or a portion of the CO.sub.2 recycle stream 240.

[0116] Alternatively, a portion 585 of the overhead cooled reactor effluent stream 540 may be compressed in a compressor 590 to form a compressed stream 595. The compressed stream 595 may comprise all or a portion of the CO.sub.2 recycle stream 240 or it may be combined with the preheated CO.sub.2 recycle stream 140.

[0117] Alternatively, a portion 597 of the compressed stream 550 may comprise all or a portion of the CO.sub.2 recycle stream 240 or it may be combined with the preheated CO.sub.2 recycle stream 140.

[0118] The CO-containing stream 565 is sent to compressor 600 forming high pressure CO stream 610. The high-pressure CO stream 610 is sent to dehydrator 615 forming the CO product stream 620.

[0119] A portion 625 of the CO-containing stream 565 is compressed in compressor 630 forming compressed CO-containing stream 635. The compressed CO-containing stream 635 is sent to heat exchanger 640 forming cooled CO-containing stream 645. The cooled CO-containing stream 645 is sent to knockout drum 650 to form water stream 660 and stream 510.

[0120] Stream 510 is heat exchanged with the reactor effluent stream 220 (or 230) in heat exchanger 505 to form heated CO-containing stream 647. The heated CO-containing stream 647 is recycled to the TSA unit 555 for regeneration.

[0121] In another alternative, all or a portion of the CO.sub.2 recycle stream 240 may be a portion 597 of the compressed reactor effluent stream 550.

[0122] FIG. 4 illustrates an embodiment including the cryogenic CO.sub.2 separation process 400 and incorporating a wet scrubbing process. In this case, the second partially cooled flue gas stream 185 from the HRSG saturated steam unit 165 is used to further pre-heat preheated CO.sub.2 recycle stream 140 in heat exchanger 705, forming a second preheated CO.sub.2 recycle stream 710 which is combined with the concentrated oxygen stream 145 and sent to the partial combustion regenerator 125.

[0123] In some embodiments, the NOx compounds are reacted in a NOx reaction section as described above.

[0124] The third partially cooled flue gas stream 715 is sent to the decontamination reactor 720 which comprises a wet SOx reaction section. A stream 735 comprising a caustic solution or an NH.sub.3 based solution reacts with the SOx compounds in the third partially cooled flue gas stream 715 in the wet SOx reaction section to form a SOx reactor effluent stream and a liquid stream 740 comprising at least one of H.sub.2O, Na.sub.2SO.sub.3, Na.sub.2SO.sub.4, NaHSO.sub.3, Na.sub.2CO.sub.3, (NH.sub.4).sub.2SO.sub.4 and catalyst fines.

[0125] The reactor effluent stream 745 from the decontamination reactor 720 contains a lower level of SOx compounds than the level of SOx compounds in the incoming third partially cooled flue gas stream 715.

[0126] The reactor effluent stream 745 from the decontamination reactor 720 is sent to heat exchanger 235 and the process continues as described above in FIG. 1.

[0127] FIG. 5 illustrates an embodiment of the PSA separation process 800 incorporating a wet scrubbing process. In this case, the second partially cooled flue gas stream 185 from the HRSG saturated steam unit 165 is used to pre-heat CO.sub.2 recycle stream 240 in heat exchanger 805, forming a preheated CO.sub.2 recycle stream 140 which is combined with the concentrated oxygen stream 145 and sent to the partial combustion regenerator 125.

[0128] In some embodiments, the NOx compounds are reacted in a NOx reaction section as described above.

[0129] The fourth partially cooled flue gas stream 810 is sent to the decontamination reactor 815 which comprises a wet SOx reaction section. A stream 820 comprising a caustic solution or an NH.sub.3 based solution reacts with the SOx compounds in the fourth partially cooled flue gas stream 810 in the wet SOx reaction section to form a liquid stream 825 comprising at least one of H.sub.2O, Na.sub.2SO.sub.3, Na.sub.2SO.sub.4, NaHSO.sub.3, Na.sub.2CO.sub.3, (NH.sub.4).sub.2SO.sub.4 and catalyst fines.

[0130] The reactor effluent stream 830 from the decontamination reactor 815 contains a lower level of SOx compounds than the level of SOx compounds in the incoming fourth partially cooled flue gas stream 810.

[0131] The reactor effluent stream 830 is passed through optional heat exchanger 835 forming the cooled reactor effluent stream 840 which is sent to knock-out drum 255. The rest of the process is as described with respect to FIG. 2.

[0132] FIG. 6 illustrates an embodiment including the TSA separation process 900 and incorporating a wet scrubbing process. In this case, the second partially cooled flue gas stream 185 from the HRSG saturated steam unit 165 heats stream 910 in heat exchanger 905. The third partially cooled stream 915 is used to pre-heat CO.sub.2 recycle stream 240 in heat exchanger 920 forming the preheated CO.sub.2 recycle stream 140 which is combined with the concentrated oxygen stream 145 and sent to the partial combustion regenerator 125.

[0133] In some embodiments, the NOx compounds are reacted in a NOx reaction section as described above.

[0134] The fourth partially cooled flue gas stream 925 is sent to the decontamination reactor 930 which comprises a wet SOx reaction section. A stream 935 comprising a caustic solution or an NH.sub.3 based solution reacts with the SOx compounds in the fourth partially cooled flue gas stream 925 in the wet SOx reaction section to form a liquid stream 940 comprising at least one of H.sub.2O, Na.sub.2SO.sub.3, Na.sub.2SO.sub.4, NaHSO.sub.3, Na.sub.2CO.sub.3, (NH.sub.4).sub.2SO.sub.4 and catalyst fines.

[0135] The reactor effluent stream 945 from the decontamination reactor 930 contains a lower level of SOx compounds than the level of SOx compounds in the incoming fourth partially cooled flue gas stream 925.

[0136] The reactor effluent stream 945 from the decontamination reactor 930 is sent to heat exchanger 950, and the fifth cooled reactor effluent stream 955 is sent to the knock-out drum 530. The process then continues as described above with respect to FIG. 3.

EXAMPLES

FCC Oxyfuel Combustion CO Valorization Example

[0137] Several examples for FCC oxyfuel combustion have been evaluated for this case, each with the same combustion and NOx/SOx removal technology and heat integration. The partial combustion regenerator (125) is operated in partial combustion mode and is followed by a HRSG superheated steam unit (155) and HRSG saturated steam unit (165). The stream then goes to a decontamination reactor (190) to remove contaminants such as SOx and NOx. SOx removal in this example is achieved via dry-sorbent injection. This is true in all the examples below.

[0138] Alternatively, the decontamination reactor (720) can contain a wet SO.sub.x reaction section, which slightly changes the location of the heat exchanger noted below, but does not change the CO.sub.2 separation system (305), PSA system (405), or TSA (555). An example is not shown for this scheme, as it only slightly alters the heat recovery network.

[0139] The decontamination reactor (190) is followed by heat recovery in a process-process heat exchanger (235) and a KO drum (255). All examples below involve recycling CO.sub.2 upstream of the CO.sub.2 separation system (305), PSA system (405), or TSA (555)collectively referred to as the CO.sub.2 capture system in this example section. The key difference in each example is the CO.sub.2 capture system utilized. Each example follows similar process steps outlined above.

[0140] All examples utilize CO.sub.2 product recycle. Not shown in the examples is the ability to recycle from a stream other than the CO.sub.2 product stream to the regenerator. For the cryogenic solutions (Examples 1 and 2, as shown in FIGS. 1 and 2), this would involve recycle from streams such as Streams 330/340, Stream 345, and the difference of streams 350 and 315.

[0141] This holds true for the similar streams in the PSA and TSA examples as well. The selected examples involve high purity CO.sub.2 recycle, but the same recycle concept can be applied to these alternate streams. The selection of which stream to recycle CO.sub.2 from is typically based on overall economics and operability of the combined system.

Example 1

[0142] An example case was developed for the cryogenic fractionation separation technology only separation case. Key material balances from streams up to the CO.sub.2 capture system can be found in Table 1. Temperatures, pressures, and overall mass flow rate for the section upstream of the CO.sub.2 capture system can vary depending on upstream FCC unit operation and the specific composition of the CO.sub.2 recycle stream from the downstream CO.sub.2 separation unit.

TABLE-US-00001 TABLE 1 Typical Example of Key Stream Information Upstream of CO.sub.2 Capture System for Cryogenic Fractionation Only Separation Stream # Units 145 135 150 185 220 253 Stream Concentrated Mixture of Partially Cooled Reactor Cooled Description O.sub.2 Preheated CO.sub.2 Combusted Flue Gas Effluent Reactor Recycle and Flue Gas Stream Effluent Concentrated O.sub.2 Temperature ? F. 90 291 1317 450 450 120 Pressure psig 50 32 19 3 2 0.25 Molar Flow lbmol/ 3827 20100 21418 21418 21404 21404 hr Mass Flow lb/hr 122380 838559 883157 883157 882233 882233 Composition mol % H.sub.2O 0 0 8.3 8.3 8.3 8.3 O.sub.2 99.5 18.9 0.2 0.2 0.2 0.2 N.sub.2 0.5 0.1 0.1 0.1 0.1 0.1 CO 0 0 3.7 3.7 3.7 3.7 CO.sub.2 0 81.0 87.6 87.6 87.7 87.7 SO.sub.2 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm SO.sub.3 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm NO 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm NO.sub.2 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm

[0143] The CO and CO.sub.2 product stream material balances can be seen in Table 2. The cryogenic only solution can allow for the highest CO.sub.2 purity, typically 99+ mol % CO.sub.2, while generating a CO stream that is typically 65 mol % or greater CO. Temperatures and pressures of the CO.sub.2 fractionation system can be set to target the required CO.sub.2 purity, which result in a secondary stream concentrated in CO.

TABLE-US-00002 TABLE 2 Typical Example of Key Stream Information for Cryogenic Fractionation Only Separation Stream # Difference of Units 275 295 & 325 300 325 Stream Compressed CO.sub.2 Product CO Containing CO.sub.2 Product Description Reactor Effluent Stream Overhead Recycle Temperature ? F. 158 82 77 120 Pressure psig 603 980 5 50 Molar Flow lbmol/hr 19735 2503 1081 16273 Mass Flow lb/hr 852080 110136 34131 716178 Composition mol % H.sub.2O 0.6 0 0 0 O.sub.2 0.2 5 ppm 4.4 5 ppm N.sub.2 0.1 0 1.8 0 CO 4.0 10 ppm 72.7 10 ppm CO.sub.2 95.1 99.9+ 21.1 99.9+ SO.sub.2 <10 ppm <10 ppm 0 <10 ppm SO.sub.3 <10 ppm <10 ppm 0 <10 ppm NO <10 ppm 0 <50 ppm 0 NO.sub.2 <10 ppm <10 ppm 0 <10 ppm

Example 2

[0144] An example case was developed for the cryogenic separation case followed by an additional CO purification step. The required CO purity dictates the technology type/s that is/are selected for this additional purification step. In this example, the additional CO purification step is a pressure swing adsorption (PSA) unit. Key material balances from streams up to the CO.sub.2 capture system can be found in Table 3. Temperatures, pressures, and overall mass flow rate for the section upstream of the CO.sub.2 capture system can vary depending on upstream FCC unit operation and the specific composition of the CO.sub.2 recycle stream from the downstream CO.sub.2 separation unit.

TABLE-US-00003 TABLE 3 Typical Example of Key Stream Information Upstream of CO.sub.2 Capture System for Cryogenic Fractionation with Additional Pressure Swing Adsorption (PSA) Separation Stream # Units 145 135 150 185 220 253 Stream Concentrated Mixture of Partially Cooled Reactor Cooled Description O.sub.2 Preheated CO.sub.2 Combusted Flue Gas Effluent Reactor Recycle and Flue Gas Stream Effluent Concentrated O.sub.2 Temperature ? F. 90 291 1317 450 450 120 Pressure psig 50 32 19 3 2 0.25 Molar Flow lbmol/ 3827 17979 19296 19296 19281 19281 hr Mass Flow lb/hr 122380 745189 789802 789802 788846 788846 Composition mol % H.sub.2O 0 0 9.2 9.2 9.2 9.2 O.sub.2 99.5 21.2 0.2 0.2 0.2 0.2 N.sub.2 0.5 0.1 0.1 0.1 0.1 0.1 CO 0 0 4.1 4.1 4.1 4.1 CO.sub.2 0 78.7 86.3 86.3 86.4 86.4 SO.sub.2 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm SO.sub.3 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm NO 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm NO.sub.2 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm

[0145] The CO and CO.sub.2 product stream material balances can be seen in Table 4. This example case maintains the high CO.sub.2 purity from the previous example with the same temperature and pressure requirements, while increasing CO product purity typically to higher than 80 mol %.

TABLE-US-00004 TABLE 4 Typical Example of Key Stream Information for Cryogenic Fractionation with Additional Pressure Swing Adsorption (PSA) Separation Stream # Difference of Units 275 295 & 325 310 325 315 Stream Compressed CO.sub.2 Product CO CO.sub.2 Product CO.sub.2 Recycle Description Reactor Effluent Product Recycle Temperature ? F. 158 82 85 120 65 Pressure psig 603 980 185 50 5 Molar Flow lbmol/hr 18003 2497 785 14147 399 Mass Flow lb/hr 773971 109870 22052 622594 15417 Composition mol % H.sub.2O 0.6 0 0 0 0 O.sub.2 0.3 5 ppm 5.5 5 ppm 3.0 N.sub.2 0.1 0 2.2 0 0.5 CO 5.0 10 ppm 92.0 10 ppm 30.7 CO.sub.2 93.9 99.9+ 0.2 99.9+ 66.8 SO.sub.2 <10 ppm <10 ppm 0 <10 ppm <10 ppm SO.sub.3 <10 ppm <10 ppm 0 <10 ppm <10 ppm NO <10 ppm 0 <50 ppm 0 <10 ppm NO.sub.2 <10 ppm <10 ppm 0 <10 ppm <10 ppm

Example 3

[0146] An example case was developed for the pressure swing adsorption (PSA) only separation case. Key material balances from streams up to the CO.sub.2 capture system can be found in Table 5. Temperatures, pressures, and overall mass flow rate for the section upstream of the CO.sub.2 capture system can vary depending on upstream FCC unit operation and the specific composition of the CO.sub.2 recycle stream from the downstream CO.sub.2 separation unit.

TABLE-US-00005 TABLE 5 Typical Example of Key Stream Information Upstream of CO.sub.2 Capture System for Pressure Swing Adsorption (PSA) Only Separation Stream # Units 145 135 150 185 220 253 Stream Concentrated Mixture of Partially Cooled Reactor Cooled Description O.sub.2 Preheated CO.sub.2 Combusted Flue Gas Effluent Reactor Recycle and Flue Gas Stream Effluent Concentrated O.sub.2 Temperature ? F. 90 291 1317 450 450 120 Pressure psig 50 32 19 3 2 0.25 Molar Flow lbmol/ 3819 18537 19854 19854 19840 19840 hr Mass Flow lb/hr 122124 768194 812807 812807 811866 811866 Composition mol % H.sub.2O 0 0 9.0 9.0 9.0 9.0 O.sub.2 99.5 20.5 0.2 0.2 0.2 0.2 N.sub.2 0.5 0.1 0.1 0.1 0.1 0.1 CO 0 0.5 4.4 4.4 4.5 4.5 CO.sub.2 0 78.8 86.2 86.2 86.2 86.2 SO.sub.2 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm SO.sub.3 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm NO 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm NO.sub.2 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm

[0147] The CO and CO.sub.2 product stream material balances can be seen in Table 6. The PSA only case can achieve CO.sub.2 concentration typically between 97-99.5% with a slight increase in CO concentration, as shown in the example below. Alternatively, the PSA only case can sacrifice CO.sub.2 purity for additional CO concentration in the overhead stream, allowing for flexibility of overall design and operation to meet a specific need.

TABLE-US-00006 TABLE 6 Typical Example of Key Stream Information for Pressure Swing Adsorption (PSA) Only Separation Stream # Units 275 430 415 440 Stream Compressed CO.sub.2 Product CO Containing Portion of Description Reactor Overhead Intermediate Effluent Pressure CO.sub.2 Containing Stream Temperature ? F. 122 120 85 120 Pressure psig 200 1030 190 50 Molar Flow lbmol/hr 18164 2396 940 14721 Mass Flow lb/hr 781588 105178 28390 646093 Composition mol % H.sub.2O 0.6 0 0 0.6 O.sub.2 0.3 <600 ppm 4.0 <600 ppm N.sub.2 0.1 <200 ppm 2.0 <200 ppm CO 4.9 0.7 12.7 0.7 CO.sub.2 94.1 99.2 81.3 98.6 SO.sub.2 <10 ppm <10 ppm 0 <10 ppm SO.sub.3 <10 ppm <10 ppm 0 <10 ppm NO <10 ppm <10 ppm <50 ppm <10 ppm NO.sub.2 <10 ppm <10 ppm 0 <10 ppm

Example 4

[0148] An example case was developed for the pressure swing adsorption (PSA) separation case followed by an additional CO purification step. The required CO purity dictates the technology type/s that is/are selected for this additional purification step. In this example, the additional CO purification step is a pressure swing adsorption (PSA) unit. Key material balances from streams up to the CO.sub.2 capture system can be found in Table 7. Temperatures, pressures, and overall mass flow rate for the section upstream of the CO.sub.2 capture system can vary depending on upstream FCC unit operation and the specific composition of the CO.sub.2 recycle stream from the downstream CO.sub.2 separation unit.

TABLE-US-00007 TABLE 7 Typical Example of Key Stream Information Upstream of CO.sub.2 Capture System for Pressure Swing Adsorption (PSA) with Additional Pressure Swing Adsorption (PSA) Separation Stream # Units 145 135 150 185 220 253 Stream Concentrated Mixture of Partially Cooled Reactor Cooled Description O.sub.2 Preheated CO.sub.2 Combusted Flue Gas Effluent Reactor Recycle and Flue Gas Stream Effluent Concentrated O.sub.2 Temperature ? F. 90 291 1317 450 450 120 Pressure psig 50 32 19 3 2 0.25 Molar Flow lbmol/ 3819 18540 19857 19857 19843 19843 hr Mass Flow lb/hr 122124 768311 812924 812924 812001 812001 Composition mol % H.sub.2O 0 0 9.0 9.0 9.0 9.0 O.sub.2 99.5 20.5 0.2 0.2 0.2 0.2 N.sub.2 0.5 0.1 0.1 0.1 0.1 0.1 CO 0 0.5 4.4 4.4 4.5 4.5 CO.sub.2 0 78.8 86.2 86.2 86.2 86.2 SO.sub.2 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm SO.sub.3 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm NO 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm NO.sub.2 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm

[0149] The CO and CO.sub.2 product stream material balances can be seen in Table 8. The initial PSA step targets CO.sub.2 recovery, as described in the previous example and has the same flexibility regarding CO.sub.2 stream purity and CO stream purity. An additional separation step (in this example, another PSA unit) it used to increase the CO stream purity. The additional separation step can increase CO stream purity to more than 75 mol %, but its design can be tailored to target a specific CO purity. An inert purge stream may be needed to remove any inert gas build up in the system to achieve the higher CO product purity.

TABLE-US-00008 TABLE 8 Typical Example of Key Stream Information for Pressure Swing Adsorption (PSA) with Additional Pressure Swing Adsorption (PSA) Separation Stream # Units 275 430 450 440 N/A Stream Compressed CO.sub.2 CO Portion of Inert Description Reactor Product Product Intermediate Purge Effluent Pressure CO.sub.2 Containing Stream Temperature ? F. 122 120 85 120 85 Pressure psig 200 1030 5 50 180 Molar Flow lbmol/hr 18164 2396 885 14721 21 Mass Flow lb/hr 781588 105178 26695 646093 604 Composition mol % H.sub.2O 0.6 0 0 0.6 0 O.sub.2 0.3 <600 ppm <200 ppm <600 ppm 22.1 N.sub.2 0.1 <200 ppm <500 ppm <200 ppm 77.8 CO 4.9 0.7 86.3 0.7 0 CO.sub.2 94.1 99.2 13.5 98.6 0 SO.sub.2 <10 ppm <10 ppm 0 <10 ppm 0 SO.sub.3 <10 ppm <10 ppm 0 <10 ppm 0 NO <10 ppm <10 ppm <10 ppm <10 ppm 0.1 NO.sub.2 <10 ppm <10 ppm 0 <10 ppm 0

Example 5

[0150] An example case was developed for the temperature swing adsorption (TSA) only separation case. For this example, the heat exchanger network is slightly modified from the description of the process upstream of the CO.sub.2 separation unit, which allows for the option of heat integration with the temperature swing adsorption regeneration loop. Additionally, equipment numbers are slightly different from the generic description above. Key material balances from streams up to the CO.sub.2 capture system can be found in Table 9. Temperatures, pressures, and overall mass flow rate for the section upstream of the CO.sub.2 capture system can vary depending on upstream FCC unit operation and the specific composition of the CO.sub.2 recycle stream from the downstream CO.sub.2 separation unit.

TABLE-US-00009 TABLE 9 Typical Example of Key Stream Information Upstream of CO.sub.2 Capture System for Temperature Swing Adsorption (TSA) Only Separation Stream # Units 145 135 150 185 220 529 Stream Concentrated Mixture of Partially Cooled Reactor Cooled Description O.sub.2 Preheated CO.sub.2 Combusted Flue Gas Effluent Reactor Recycle and Flue Gas Stream Effluent Concentrated O.sub.2 Temperature ? F. 90 291 1317 450 450 120 Pressure psig 50 32 19 3 2 0.25 Molar Flow lbmol/ 3788 18782 20100 20100 20086 20086 hr Mass Flow lb/hr 121063 778853 823469 823469 822546 822546 Composition mol % H.sub.2O 0 0 8.8 8.8 9.0 9.0 O.sub.2 99.5 20.3 0.2 0.2 0.2 0.2 N.sub.2 0.5 0.7 0.6 0.6 0.1 0.1 CO 0 0.0 3.9 3.9 4.5 4.5 CO.sub.2 0 79.1 86.3 86.3 86.4 86.4 SO.sub.2 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm SO.sub.3 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm NO 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm NO.sub.2 0 Trace <1000 ppm <1000 ppm <10 ppm <10 ppm

[0151] The CO and CO.sub.2 product stream material balances can be seen in Table 10. For this case, a relatively high purity for both CO.sub.2 stream (97%+) and CO stream (80%+) typically possible, although the system can be designed to target the specific purity needed. The CO in this case can be delivered at a high pressure (as shown in the example below), but lower pressure delivery is possible.

TABLE-US-00010 TABLE 10 Typical Example of Key Stream Information for Temperature Swing Adsorption (TSA) Only Separation Stream # Difference of Units 550 560 & 580 620 580 Stream Compressed CO.sub.2 CO Product Portion of CO.sub.2 Description Reactor Containing Stream Containing Effluent Stream Stream Temperature ? F. 122 85 120 85 Pressure psig 150 140 1030 140 Molar Flow lbmol/hr 18410 2541 772 14989 Mass Flow lb/hr 792284 111488 21835 657450 Composition mol % H.sub.2O 0.6 0 0 0 O.sub.2 0.3 0.3 <300 ppm 0.3 N.sub.2 0.6 0.7 <800 ppm 0.7 CO 4.3 0 90.0 0 CO.sub.2 94.2 99.0 9.9 99.0 SO.sub.2 <10 ppm <10 ppm <10 ppm <10 ppm SO.sub.3 <10 ppm <10 ppm <10 ppm <10 ppm NO <10 ppm <10 ppm <10 ppm <10 ppm NO.sub.2 <10 ppm <10 ppm <10 ppm <10 ppm

[0152] The 5 examples above illustrate that the purification of both CO and CO.sub.2 product streams can be achieved by different technologies to different purity levels. The selection of which technology approach to use for a specific purification step will depend on the combination of the required CO and CO.sub.2 product requirements, including purity, temperature, and pressure. The above examples merely represent specific case studies, and modifications to the designs can lead to different product specifications achieved in each example. The two cryogenic fractionation routes provide the most overall flexibility to both CO and CO.sub.2 product streams, with the TSA only solution having the next most flexibility. The two PSA solutions are envisioned to be more case specific, especially the PSA only solution due to the lower product purity of CO stream. Adding a CO separation unit to the PSA only case yields CO stream purities similar to the other examples provided.

Specific Embodiments

[0153] While the following is described in conjunction with specific embodiments, it will be understood that this description is intended to illustrate and not limit the scope of the preceding description and the appended claims.

[0154] A first embodiment of the invention is a process for separating CO from CO.sub.2 in a flue gas stream from a partial oxidation regenerator of a fluid catalytic cracking (FCC) process comprising passing a mixture of a preheated CO.sub.2 recycle stream and a concentrated oxygen stream to the partial oxidation regenerator to generate the flue gas stream comprising CO.sub.2, CO, SOx, NOx, catalyst fines, O.sub.2, and H.sub.2O; transferring heat from the flue gas stream to a boiler feed water stream in a heat recovery section to form a partially cooled flue gas stream and a steam stream; reacting one or more of a sulfur-containing compound, a nitrogen-containing compound, or both in the flue gas stream with a reactant in a decontamination reactor to form a reactor effluent flue gas stream and a contaminant stream, the reactor effluent gas stream having a level of the sulfur-containing compound less than a level of the sulfur-containing compound in the flue gas stream; heating a CO.sub.2 recycle stream with the reactor effluent gas stream to produce the preheated CO.sub.2 recycle stream and a cooled reactor effluent stream; and separating the cooled reactor effluent stream into a CO.sub.2 product stream, the CO.sub.2 recycle stream, and a CO product stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; dehydrating the compressed reactor effluent stream to form a dehydrated reactor effluent stream; separating the dehydrated reactor effluent stream into the CO.sub.2 product stream and a CO-containing overhead stream in a cryogenic CO.sub.2 fractionation system; and separating the CO-containing overhead stream into the CO.sub.2 recycle stream and the CO product stream in a separation section; or recycling a portion of the CO.sub.2 product stream as the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or combinations thereof. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising compressing or expanding the recycle CO.sub.2 stream before introducing the CO.sub.2 recycle stream into the regenerator. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising recycling a portion of the CO.sub.2 recycle stream to the compressor. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream, or wherein the compressed portion of the cooled reactor effluent stream is the CO.sub.2 recycle stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; separating the compressed reactor effluent stream into a low pressure CO.sub.2-containing stream and a high pressure CO-containing stream in a pressure swing absorption (PSA) unit or a vacuum swing adsorption (VPSA) unit; compressing the low pressure CO.sub.2-containing stream to form a high pressure CO2-containing stream and an intermediate pressure CO.sub.2-containing stream; co-feeding the intermediate pressure CO.sub.2-containing stream to the PSA or VPSA unit; dehydrating the high pressure CO.sub.2-containing stream to form the CO.sub.2 product stream; purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a part of the intermediate pressure CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream; and wherein a part of the intermediate pressure CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream and compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream and wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or combinations thereof. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream, or wherein the compressed portion of the cooled reactor effluent stream comprises the CO.sub.2 recycle stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; separating the compressed reactor effluent stream into a CO.sub.2-containing stream and a CO-containing stream in a temperature swing absorption (TSA) unit; compressing the CO.sub.2-containing stream to form the CO.sub.2 product stream; compressing the CO-containing stream to form a high pressure CO stream; dehydrating the high pressure CO-containing stream to form the CO product stream; wherein a part of the CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or combinations thereof. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising dividing the CO-containing stream from the TSA unit into a first part and a second part, wherein the first part is compressed to form the high pressure CO stream; compressing and cooling the second portion of the CO-containing stream and optionally removing water from the cooled, compressed second portion of the CO-containing stream water removal; heating the cooled, compressed second portion of the CO-containing stream to form a heated second portion of the CO-containing stream; introducing the heated second portion of the CO-containing stream to the TSA unit. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream; or wherein the compressed portion of the cooled reactor effluent stream comprises the CO.sub.2 recycle stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising further cooling the cooled reactor effluent stream and removing water from the cooled reactor effluent stream before separating the cooled reactor effluent stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising recovering heat from the reactor effluent stream before cooling the reactor effluent stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising introducing the flue gas stream into a superheated steam section of a heat recovery steam generator (HRSG) before the decontamination reactor to produce a superheated steam stream and a partially cooled flue gas stream, the HRSG comprising the superheated steam section and a saturated steam section; introducing a boiler feed water stream and the partially cooled flue gas stream into the saturated steam section to produce a saturated steam stream and a second partially cooled flue gas stream; introducing at least a portion of the saturated steam stream into the superheated steam section; superheating the saturated steam stream with the flue gas stream to produce the superheated steam stream; and wherein reacting one or more of the sulfur-containing compound in the flue gas stream with the reactant in the decontamination reactor comprises reacting one or more of the sulfur-containing compound in the partially cooled flue gas stream with the reactant. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the concentrated oxygen stream is made in an air separation unit or an electrolyzer. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein reacting one or more of the sulfur-containing compound, the nitrogen-containing compound, or both in the flue gas stream with the reactant in the decontamination reactor comprises reacting the flue gas stream with a reactant in a dry SOx reaction section to form a dry SOx reaction section flue gas stream consisting essentially of at least one of H.sub.2O, CO.sub.2, CO, N.sub.2, O.sub.2, Na.sub.2CO.sub.3, Na.sub.2SO.sub.4, NaNO.sub.3, CaSO.sub.4, CaCO.sub.3, Ca(NO.sub.3).sub.2, MgCO.sub.3, MgSO.sub.4, Mg(NO.sub.3).sub.2, and NOx, wherein the reactant comprises at least one of NaHCO.sub.3, NaHCO.sub.3.Math.Na.sub.2CO.sub.3.Math.2(H.sub.2O), CaCO.sub.3, Ca(OH).sub.2, and Mg(OH).sub.2; and filtering the dry SOx reaction section flue gas stream in a filtration section to remove Na.sub.2CO.sub.3, Na.sub.2SO.sub.4, NaNO.sub.3, CaSO.sub.4, CaCO.sub.3, Ca(NO.sub.3).sub.2, MgCO.sub.3, MgSO.sub.4, Mg(NO.sub.3).sub.2 and catalyst fines to form the reactor effluent stream and a filtered material stream.

[0155] A second embodiment of the invention is a process for separating CO from CO.sub.2 in a flue gas stream from a partial oxidation regenerator of a fluid catalytic cracking (FCC) process comprising passing a mixture of a preheated CO2 recycle stream and a concentrated oxygen stream to the partial oxidation regenerator to generate the flue gas stream comprising CO.sub.2, CO, SOx, NOx, catalyst fines, O and H.sub.2O; transferring heat from the flue gas stream to a boiler feed water stream in a heat recovery section to form a partially cooled flue gas stream and a steam stream; heating a CO.sub.2 recycle stream with the partially cooled flue gas stream to produce the preheated CO.sub.2 recycle stream and a cooled flue gas stream; reacting one or more of a sulfur-containing compound in the cooled flue gas stream with a reactant in a decontamination reactor to form a reactor effluent flue gas stream and a contaminant stream, the reactor effluent gas stream having a level of the sulfur-containing compound less than a level of the sulfur-containing compound in the flue gas stream; and separating the reactor effluent stream into a CO2 product stream, the CO.sub.2 recycle stream, and a CO product stream; and wherein reacting one or more of the sulfur-containing compound in the cooled flue gas stream with the reactant in the decontamination reactor comprises reacting a caustic solution or an NH3 based solution with the cooled flue gas stream in a wet SOx reaction section to form the reactor effluent flue gas stream and a liquid stream comprising at least one of H.sub.2O, CO, CO, N.sub.2, O.sup.2, Na.sub.2SO.sub.3, Na.sub.2SO.sub.4, NaHSO.sub.3, Na.sub.2CO.sub.3, (NH.sub.4)2SO.sub.4, and catalyst fines. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising cooling the reactor effluent stream before separating the reactor effluent stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; dehydrating the compressed reactor effluent stream to form a dehydrated reactor effluent stream; separating the dehydrated reactor effluent stream into the CO.sub.2 product stream and a CO-containing overhead stream in a cryogenic CO.sub.2 fractionation system; and separating the CO-containing overhead stream into the CO.sub.2 recycle stream and the CO product stream in a separation section; or recycling a portion of the CO.sub.2 product stream as the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream and wherein the CO-containing overhead stream comprises the CO product stream; or combinations thereof. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising compressing or expanding the recycle CO.sub.2 stream before introducing the CO.sub.2 recycle stream into the regenerator. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising recycling a portion of the CO.sub.2 recycle stream to the compressor. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream, or wherein the compressed portion of the cooled reactor effluent stream is the CO2 recycle stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein separating the reactor effluent stream into the CO.sub.2 product stream, the CO.sub.2 recycle stream, and the CO product stream comprises compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; separating the compressed reactor effluent stream into a low pressure CO.sub.2-containing stream and a high pressure CO-containing stream in a pressure swing absorption (PSA) unit or a vacuum swing adsorption (VPSA) unit; compressing the low pressure CO.sub.2-containing stream to form a high pressure CO.sub.2-containing stream and an intermediate pressure CO.sub.2-containing stream; co-feeding the intermediate pressure CO.sub.2-containing stream to the PSA or VPSA unit; dehydrating the high pressure CO.sub.2-containing stream to form the CO.sub.2 product stream; purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a part of the intermediate pressure CO.sub.2-containing stream comprises the CO2 recycle stream; or purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or purifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream; and wherein a part of the intermediate pressure CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream and compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream and wherein a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or combinations thereof. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream, or wherein the compressed portion of the cooled reactor effluent stream comprises the CO.sub.2 recycle stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein separating the reactor effluent stream into the CO.sub.2 product stream, the CO2 recycle stream, and the CO product stream comprises compressing the cooled reactor effluent stream in a compressor to form a compressed reactor effluent stream; separating the compressed reactor effluent stream into a CO.sub.2-containing stream and a CO-containing stream in a temperature swing absorption (TSA) unit; compressing the CO.sub.2-containing stream to form the CO.sub.2 product stream; compressing the CO-containing stream to form a high pressure CO stream; dehydrating the high pressure CO-containing stream to form the CO product stream; wherein a part of the CO.sub.2-containing stream comprises the CO.sub.2 recycle stream; or compressing a portion of the cooled reactor effluent stream to form the CO.sub.2 recycle stream; or a portion of the compressed reactor effluent stream comprises the CO.sub.2 recycle stream; or combinations thereof. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising dividing the CO-containing stream from the TSA unit into a first part and a second part, wherein the first part is compressed to form the high pressure CO stream; compressing and cooling the second portion of the CO-containing stream and optionally removing water from the cooled, compressed second portion of the CO-containing stream water removal; heating the cooled, compressed second portion of the CO-containing stream to form a heated second portion of the CO-containing stream; introducing the heated second portion of the CO-containing stream to the TSA unit. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising separating water from the cooled reactor effluent stream in a knockout drum before compressing the cooled reactor effluent stream; compressing a portion of the cooled reactor effluent stream from the knockout drum; and combining the compressed portion of the cooled reactor effluent stream with the CO.sub.2 recycle stream; or wherein the compressed portion of the cooled reactor effluent stream comprises the CO.sub.2 recycle stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising further cooling the cooled reactor effluent stream and removing water from the cooled reactor effluent stream before separating the cooled reactor effluent stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising recovering heat from the reactor effluent stream before cooling the reactor effluent stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising introducing the flue gas stream into a superheated steam section of a heat recovery steam generator (HRSG) before the decontamination reactor to produce a superheated steam stream and a partially cooled flue gas stream, the HRSG comprising the superheated steam section and a saturated steam section; introducing a boiler feed water stream and the partially cooled flue gas stream into the saturated steam section to produce a saturated steam stream and a second partially cooled flue gas stream; introducing at least a portion of the saturated steam stream into the superheated steam section; superheating the saturated steam stream with the flue gas stream to produce the superheated steam stream; and wherein reacting one or more of the sulfur-containing compound, the nitrogen-containing compound, or both in the flue gas stream with the reactant in the decontamination reactor comprises reacting one or more of the sulfur-containing compound, the nitrogen-containing compound, or both in the partially cooled flue gas stream with the reactant. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein the concentrated oxygen stream is made in an air separation unit or an electrolyzer.

[0156] Without further elaboration, it is believed that using the preceding description that one skilled in the art can utilize the present invention to its fullest extent and easily ascertain the essential characteristics of this invention, without departing from the spirit and scope thereof, to make various changes and modifications of the invention and to adapt it to various usages and conditions. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limiting the remainder of the disclosure in any way whatsoever, and that it is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0157] In the foregoing, all temperatures are set forth in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.