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

Description

BACKGROUND

Fluid catalytic cracking (FCC) is a hydrocarbon conversion process accomplished by contacting hydrocarbons in a fluidized reaction zone with a catalyst composed of finely divided particulate material. The reaction in catalytic cracking, as opposed to hydrocracking, is carried out in the absence of substantial added hydrogen or the consumption of hydrogen. As the cracking reaction proceeds substantial amounts of highly carbonaceous material referred to as coke is deposited on the catalyst. A high temperature regeneration operation within a regenerator zone combusts coke from the catalyst. Coke-containing catalyst, referred to herein as coked catalyst, is continually removed from the reaction zone and replaced by essentially coke-free catalyst from the regeneration zone. Fluidization of the catalyst particles by various gaseous streams allows the transport of catalyst between the reaction zone and regeneration zone. Spent catalyst from the reaction zone can be completely or partially regenerated in the regeneration zone.

The regenerator zone can be a complete burn unit or a partial burn unit. In a complete burn regenerator unit, the carbon in coke is combusted to CO2 releasing heat which is recovered. In a partial burn regenerator unit, the carbon in coke is partially combusted to CO2 and the rest to CO. The flue gas contains CO, typically up to about 10%, and more specifically between about 2% to about 5%, which is used as the primary fuel source in a downstream CO boiler or combustion chamber where the CO is combusted to CO2 releasing heat which is recovered. By running regenerator in a partial burn mode to maximize the CO yield, the unit will limit the amount of heat released in the regenerator relative to complete burn of the carbon to CO₂. This will lower the regenerator temperature and permit a higher catalyst to oil ratio in the FCC riser.

Conventional treatment of flue gas from FCC units and fluidized bed dehydrogenation units involves the use of wet gas scrubbing technology, such as a caustic scrubber, to remove sulfur compounds from the flue gas. In this process, the flue gas from the FCC regenerator is heat exchanged with boiler feed water to make steam and cool the flue gas. The flue gas is further cooled from a temperature of 205-315° C. to a temperature of 35-100° C. using a water quench. The cooled flue gas is contacted with NaOH which reacts with the sulfur compounds to form Na₂SO₃and/or Na₂SO₄and water, which are removed. The flue gas can optionally be heated and treated to remove nitrogen compounds. Alternately, other suitable reagents or sea water can be used for removing the sulfur compounds in the flue gas. The flue gas can also optionally be treated to remove catalyst fines and other particulate. The treated flue gas can then be discharged to the atmosphere.

The alternate process involves the use of a dry sorbent injection (DSI) unit or a slurry reagent injection (SRI) unit to remove sulfur compounds from flue gas. In this process, the flue gas from the FCC regenerator is heat exchanged with boiler feed water to make steam and cool the flue gas. The flue gas is then sent to a DSI unit to remove the sulfur compounds, and then to an economizer (or heat exchanger) to heat boiler feed water, thermal oil, or combustion air. Because the flue gas temperature does not reduce as much as with a wet scrubber process, additional thermal energy can be recovered from the flue gas in a DSI/SRI process.

The decontamination reactor of DSI unit may contain a reactant, such as one or more of NaHCO₃, Na₂CO₃, NaHCO₃·Na₂CO₃·2(H₂O), Na₂CO₃·2Na₂CO₃·3(H₂O), CaCO₃, Ca(HCO₃)₂, Ca(OH)₂, Mg(OH)₂, CaO, CaCO₃·MgCO₃, and (Ca(OH)₂·(Mg(OH)₂). The decontamination reactor converts one or more of the compounds in the flue gas stream.

The decontamination reactor effluent stream is filtered to remove one or more of NaHCO₃, Na₂CO₃, NaHCO₃·Na₂CO₃·2(H₂O), Na₂CO₃·2Na₂CO₃·3(H₂O), CaCO₃, Ca(HCO₃)₂, Ca(OH)₂, Mg(OH)₂, CaO, CaCO₃·MgCO₃, (Ca(OH)₂·(Mg(OH)₂), Na₂SO₄, NaNO₃, NaNO₂, Na₂CO₃, K₂SO₄, KNO₃, catalyst fines and fine particulate matter to form a filtered decontamination reactor effluent stream. The inlet temperature for the filtration section is typically in the range of 205-315° C. with a pressure of −5 kPa(g) to 50 kPa(g). The outlet temperature for the filtration section is typically in the range of 205-315° C. with a pressure of −7 kPa(g) to 50 kPa(g). After heat recovery from the filtered effluent, the treated flue gas can then be discharged to the atmosphere.

The decontamination reactor effluent stream may be filtered using any suitable filter unit. Suitable filter units include, but are not limited to, a bag filter or an electrostatic precipitator.

Environmental concerns over greenhouse gas emissions have led to an increasing emphasis on separating the greenhouse gases before releasing the flue gases into atmosphere. Carbon dioxide (CO₂) is the most significant long-lived greenhouse gas in earth's atmosphere. CO₂capture from FCC flue gases is expensive, both from a capital expenditures and operational utility costs (CAPEX and OPEX) standpoint. For fluidized catalytic processes, air is used for regenerating the spent catalyst. As a result of this operation, the amount of CO₂in the FCC flue gas is lower in contrast to the amount of undesired components from a CO₂capture perspective. This leads to high capital expenditures due to a large volume of the flue gas. In addition, in solvent-based CO₂capture processes, it also leads to large OPEX due to high solvent circulating rates and solvent regeneration duties.

The issue of flue gas treatment increases multifold in FCC units operating with partial burn regenerator due to the combustion of CO in a CO Boiler. The CO combustion in CO Boiler requires additional fuel firing (like fuel gas or fuel oil) to maintain a minimum temperature within combustion chamber to ensure complete combustion of CO to CO2. This results in an increase in quantity of CO2 generation by the FCC process and hence an increase in quantity of flue gas to be handled by the CO2 capture process. Also, high temperature operation of the CO Boiler combustion chamber results in additional NOx generation and leading to contamination of the flue gas.

Moreover, the flue gas requires extensive flue gas treatment prior to carbon capture in order to meet stringent specifications to avoid high solvent degradation rates, resulting in high capital expenditures and operational utility costs with required impurity removal operations.

Therefore, there is a need for improved processes for treating flue gas from FCC Unit in particular operating with partial burn regenerators containing CO₂, CO, and sulfur compounds. Also, there is a need for a process and an apparatus which reduces capital expenditures and operational utility costs of the CO2 capture section.

BRIEF DESCRIPTION OF THE DRAWING

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

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

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

FIG. 4 illustrates another embodiment of the process of FIG. 1.

FIG. 5 illustrates another embodiment of the process of FIG. 2.

FIG. 6 illustrates another embodiment of the process of FIG. 3.

DESCRIPTION OF THE INVENTION

The process involves processes for separating CO from CO₂in 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 CO₂product stream, a CO₂recycle 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 (VPSA), and temperature swing adsorption (TSA) processes. The flue gas can be used to preheat the CO₂recycle stream.

The outlet temperature from the FCC regenerator for a partial combustion FCC unit is about 650-815° C.

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 TiO₂, WO₃and V₂O₅, 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.

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.

One aspect of the invention comprises a process for separating CO from CO₂in 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 CO₂recycle stream and a concentrated oxygen stream to the partial oxidation regenerator to generate the flue gas stream comprising CO₂, CO, SOx, NOx, catalyst fines, O₂, and H₂O; 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 CO₂recycle stream with the reactor effluent gas stream to produce the preheated CO₂recycle stream and a cooled reactor effluent stream; and separating the cooled reactor effluent stream into a CO₂product stream, the CO₂recycle stream, and a CO product stream.

In some embodiments, the process further comprises: compressing or expanding the recycle CO₂stream before introducing the CO₂recycle stream into the regenerator.

In some embodiments, the process further comprises: recycling a portion of the CO₂recycle stream to the compressor.

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 CO₂recycle stream, or wherein the compressed portion of the cooled reactor effluent stream is the CO₂recycle stream.

In some embodiments, separating the reactor effluent stream into the CO₂product stream, the CO₂recycle 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 CO₂-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 CO₂-containing stream to form a high pressure CO₂-containing stream and an intermediate pressure CO₂-containing stream; co-feeding the intermediate pressure CO₂-containing stream to the PSA or VPSA unit; dehydrating the high pressure CO₂-containing stream to form the CO₂product 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 CO₂-containing stream comprises the CO₂recycle 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 CO₂recycle 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 CO₂recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream; and wherein a part of the intermediate pressure CO₂-containing stream comprises the CO₂recycle 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 CO₂recycle 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 CO₂recycle stream; or combinations thereof.

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 CO₂recycle stream, or wherein the compressed portion of the cooled reactor effluent stream comprises the CO₂recycle stream.

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.

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 CO₂recycle stream; or wherein the compressed portion of the cooled reactor effluent stream comprises the CO₂recycle stream.

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.

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

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.

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

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 H₂O, CO₂, CO, N₂, O₂, Na₂CO₃, Na₂SO₄, NaNO₃, CaSO₄, CaCO₃, Ca(NO₃)₂, MgCO₃, MgSO₄, Mg(NO₃)₂, and NOx, wherein the reactant comprises at least one of NaHCO₃, NaHCO₃·Na₂CO₃·2(H₂O), CaCO₃, Ca(OH)₂, and Mg(OH)₂; and filtering the dry SOx reaction section flue gas stream in a filtration section to remove Na₂CO₃, Na₂SO₄, NaNO₃, CaSO₄, CaCO₃, Ca(NO₃)₂, MgCO₃, MgSO₄, Mg(NO₃)₂and catalyst fines to form the reactor effluent stream and a filtered material stream.

Another aspect of the invention is a process for separating CO from CO₂in 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 CO₂recycle stream and a concentrated oxygen stream to the partial oxidation regenerator to generate the flue gas stream comprising CO₂, CO, SOx, NOx, catalyst fines, O₂and H₂O; 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 CO₂recycle stream with the partially cooled flue gas stream to produce the preheated CO₂recycle 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 CO₂product stream, the CO₂recycle 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 NH₃based 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 H₂O, CO₂, CO, N₂, O₂, Na₂SO₃, Na₂SO₄, NaHSO₃, Na₂CO₃, (NH₄)₂SO₄, NH₄Cl and catalyst fines.

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

In some embodiments, the process further comprises: compressing or expanding the recycle CO₂stream before introducing the CO₂recycle stream into the regenerator.

In some embodiments, the process further comprises: recycling a portion of the CO₂recycle stream to the compressor.

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 CO₂recycle stream; or wherein the compressed portion of the cooled reactor effluent stream comprises the CO₂recycle stream.

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

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

FIG. 1 illustrates one embodiment of the process 100 with a cryogenic CO₂separation 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.

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.

A stream 135 containing a mixture of a preheated CO₂recycle 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.

The partially combusted flue gas stream 150 comprises un-combusted CO, along with CO₂, SOx, NOx, catalyst fines, O₂and H₂O. The flue gas outlet temperature for the FCC regenerator for a partial combustion FCC is in the range of about 650-815° C.

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.

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.

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.

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 TiO₂, WO₃and V₂O₅, 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.

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 Na₂SO₄, NaNO₃, NaNO₂, Na₂CO₃, K₂SO₄, and KNO₃, 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 Na₂CO₃conversion yield (i.e., from 85 wt % to 98 wt %).

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.

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

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 CO₂recycle stream 240 to form the preheated CO₂recycle stream 140 and a cooled reactor effluent stream 250.

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.

The cooled reactor effluent stream 250 (or 253) is separated into a CO₂product stream, the CO₂recycle stream 140, and a CO product stream.

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 CO₂fractionation system 290 where it is separated into a CO₂product stream 295 and a CO-containing overhead stream 300.

The CO-containing overhead stream 300 may be sent to a separation section 305 where it is separated into CO product stream 310 and CO₂recycle stream 315.

The CO₂recycle stream 315 may be compressed or expanded in compressor or expander 320 forming the CO₂recycle stream 240 before being heat exchanged with the reactor effluent stream 220 (or 230) if needed. The CO₂recycle stream 240 may comprise all or a portion of the CO₂recycle stream 315.

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 CO₂recycle stream 240 may be a portion 325 of the CO₂product stream 295.

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 CO₂recycle stream 240 may be the compressed stream 340.

In another alternative, all or a portion of the CO₂recycle stream 240 may be a portion 345 of the compressed reactor effluent stream 275.

A portion 350 of the CO₂recycle stream 315 may be recycled to the compressor 270.

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.

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 Na₂SO₄, NaNO₃, NaNO₂, Na₂CO₃, K₂SO₄, and KNO₃, 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 Na₂CO₃conversion yield (i.e., from 85 wt % to 98 wt %).

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

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.

The cooled reactor effluent stream 250 (or 253) is separated into a CO₂product stream, the CO₂recycle stream 140, and a CO product stream.

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 CO₂-containing stream 410 and a high pressure CO-containing overhead stream 415.

The low-pressure CO₂-containing stream 410 is compressed in compressor 417 to form a high pressure CO₂-containing stream 420. The high pressure CO₂-containing stream 420 is sent to dehydrator 425 forming a dehydrated high pressure CO₂-containing stream 430 which is the CO₂product stream.

An intermediate pressure CO₂-containing stream 435 is also formed in the compressor 417 from the low-pressure CO₂-containing stream 410. The intermediate pressure CO₂-containing stream 435 is co-fed to the PSA unit 405.

A portion 440 of the intermediate pressure CO₂-containing stream 435 may comprise all or a portion of the CO₂recycle stream 240.

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.

The CO₂recycle stream 440 may be expanded in an expander or a pressure valve (not shown) to reduce the pressure in the CO₂recycle stream 440 before being heat exchanged with the reactor effluent stream 220 (or 230) if needed. The CO₂recycle stream 240 may comprise all or a portion of the CO₂recycle stream 440.

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

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 CO₂recycle stream 240 may be the compressed stream 340.

In another alternative, all or a portion of the CO₂recycle stream 240 may be a portion 345 of the compressed reactor effluent stream 275.

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.

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.

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 Na₂SO₄, NaNO₃, NaNO₂, Na₂CO₃, K₂SO₄, and KNO₃, 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 Na₂CO₃conversion yield (i.e., from 85 wt % to 98 wt %).

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

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.

The cooled reactor effluent stream 515 is sent to heat exchanger 520 where it is heat exchanged with CO₂recycle stream 240 to form the preheated CO₂recycle stream 140 and a second cooled reactor effluent stream 525.

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

The second cooled reactor effluent stream 525 (or stream 529) is separated into a CO₂product stream, the CO₂recycle stream 240, and a CO product stream.

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 CO₂-containing stream 560 and a CO-containing stream 565.

The CO₂-containing stream 560 is sent to a compressor 570 forming CO₂product stream 575.

A portion 580 of the CO₂-containing stream 560 forms the CO₂recycle 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 CO₂-containing stream 560 may comprise all or a portion of the CO₂recycle stream 240.

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 CO₂recycle stream 240 or it may be combined with the preheated CO₂recycle stream 140.

Alternatively, a portion 597 of the compressed stream 550 may comprise all or a portion of the CO₂recycle stream 240 or it may be combined with the preheated CO₂recycle stream 140.

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.

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.

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.

In another alternative, all or a portion of the CO₂recycle stream 240 may be a portion 597 of the compressed reactor effluent stream 550.

FIG. 4 illustrates an embodiment including the cryogenic CO₂separation 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 CO₂recycle stream 140 in heat exchanger 705, forming a second preheated CO₂recycle stream 710 which is combined with the concentrated oxygen stream 145 and sent to the partial combustion regenerator 125.

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

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 NH₃based 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 H₂O, Na₂SO₃, Na₂SO₄, NaHSO₃, Na₂CO₃, (NH₄)₂SO₄and catalyst fines.

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.

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.

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 CO₂recycle stream 240 in heat exchanger 805, forming a preheated CO₂recycle stream 140 which is combined with the concentrated oxygen stream 145 and sent to the partial combustion regenerator 125.

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

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 NH₃based 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 H₂O, Na₂SO₃, Na₂SO₄, NaHSO₃, Na₂CO₃, (NH₄)₂SO₄and catalyst fines.

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.

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.

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 CO₂recycle stream 240 in heat exchanger 920 forming the preheated CO₂recycle stream 140 which is combined with the concentrated oxygen stream 145 and sent to the partial combustion regenerator 125.

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

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 NH₃based 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 H₂O, Na₂SO₃, Na₂SO₄, NaHSO₃, Na₂CO₃, (NH₄)₂SO₄and catalyst fines.

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.

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

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.

Alternatively, the decontamination reactor (720) can contain a wet SO_xreaction section, which slightly changes the location of the heat exchanger noted below, but does not change the CO₂separation 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.

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 CO₂upstream of the CO₂separation system (305), PSA system (405), or TSA (555)—collectively referred to as the CO₂capture system in this example section. The key difference in each example is the CO₂capture system utilized. Each example follows similar process steps outlined above.

All examples utilize CO₂product recycle. Not shown in the examples is the ability to recycle from a stream other than the CO₂product 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.

This holds true for the similar streams in the PSA and TSA examples as well. The selected examples involve high purity CO₂recycle, but the same recycle concept can be applied to these alternate streams. The selection of which stream to recycle CO₂from is typically based on overall economics and operability of the combined system.

Example 1

An example case was developed for the cryogenic fractionation separation technology only separation case. Key material balances from streams up to the CO₂capture system can be found in Table 1. Temperatures, pressures, and overall mass flow rate for the section upstream of the CO₂capture system can vary depending on upstream FCC unit operation and the specific composition of the CO₂recycle stream from the downstream CO₂separation unit.

TABLE 1

Typical Example of Key Stream Information Upstream of

CO₂Capture System for Cryogenic Fractionation Only Separation

Stream #

Units
145
135
150
185
220
253

Stream

Concentrated
Mixture of
Partially
Cooled
Reactor
Cooled

Description

O₂
Preheated CO₂
Combusted
Flue Gas
Effluent
Reactor

Recycle and
Flue Gas
Stream

Effluent

Concentrated O₂

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 %

H₂O

0
0
8.3
8.3
8.3
8.3

O₂

99.5
18.9
0.2
0.2
0.2
0.2

N₂

0.5
0.1
0.1
0.1
0.1
0.1

CO

0
0
3.7
3.7
3.7
3.7

CO₂

0
81.0
87.6
87.6
87.7
87.7

SO₂

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

SO₃

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

NO

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

NO₂

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

The CO and CO₂product stream material balances can be seen in Table 2. The cryogenic only solution can allow for the highest CO₂purity, typically 99+ mol % CO₂, while generating a CO stream that is typically 65 mol % or greater CO. Temperatures and pressures of the CO₂fractionation system can be set to target the required CO₂purity, which result in a secondary stream concentrated in CO.

TABLE 2

Typical Example of Key Stream Information

for Cryogenic Fractionation Only Separation

Stream #

Difference of

Units
275
295 & 325
300
325

Stream

Compressed
CO₂Product
CO Containing
CO₂Product

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 %

H₂O

0.6
0
0
0

O₂

0.2
5
ppm
4.4
5
ppm

N₂

0.1
0
1.8
0

CO

4.0
10
ppm
72.7
10
ppm

CO₂

95.1
99.9+
21.1
99.9+

SO₂

<10 ppm
<10
ppm
0
<10
ppm

SO₃

<10 ppm
<10
ppm
0
<10
ppm

NO

<10 ppm
0
<50 ppm
0

NO₂

<10 ppm
<10
ppm
0
<10
ppm

Example 2

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 CO₂capture system can be found in Table 3. Temperatures, pressures, and overall mass flow rate for the section upstream of the CO₂capture system can vary depending on upstream FCC unit operation and the specific composition of the CO₂recycle stream from the downstream CO₂separation unit.

TABLE 3

Typical Example of Key Stream Information Upstream of CO₂Capture 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

O₂
Preheated CO₂
Combusted
Flue Gas
Effluent
Reactor

Recycle and
Flue Gas
Stream

Effluent

Concentrated O₂

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 %

H₂O

0
0
9.2
9.2
9.2
9.2

O₂

99.5
21.2
0.2
0.2
0.2
0.2

N₂

0.5
0.1
0.1
0.1
0.1
0.1

CO

0
0
4.1
4.1
4.1
4.1

CO₂

0
78.7
86.3
86.3
86.4
86.4

SO₂

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

SO₃

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

NO

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

NO₂

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

The CO and CO₂product stream material balances can be seen in Table 4. This example case maintains the high CO₂purity from the previous example with the same temperature and pressure requirements, while increasing CO product purity typically to higher than 80 mol %.

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
CO₂Product
CO
CO₂Product
CO₂Recycle

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 %

H₂O

0.6
0
0
0
0

O₂

0.3
5 ppm
5.5
5 ppm
3.0

N₂

0.1
0
2.2
0
0.5

CO

5.0
10 ppm
92.0
10 ppm
30.7

CO₂

93.9
99.9+
0.2
99.9+
66.8

SO₂

<10 ppm
<10 ppm
0
<10 ppm
<10 ppm

SO₃

<10 ppm
<10 ppm
0
<10 ppm
<10 ppm

NO

<10 ppm
0
<50 ppm
0
<10 ppm

NO₂

<10 ppm
<10 ppm
0
<10 ppm
<10 ppm

Example 3

An example case was developed for the pressure swing adsorption (PSA) only separation case. Key material balances from streams up to the CO₂capture system can be found in Table 5. Temperatures, pressures, and overall mass flow rate for the section upstream of the CO₂capture system can vary depending on upstream FCC unit operation and the specific composition of the CO₂recycle stream from the downstream CO₂separation unit.

TABLE 5

Typical Example of Key Stream Information Upstream of CO₂Capture

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

O₂
Preheated CO₂
Combusted
Flue Gas
Effluent
Reactor

Recycle and
Flue Gas
Stream

Effluent

Concentrated O₂

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 %

H₂O

0
0
9.0
9.0
9.0
9.0

O₂

99.5
20.5
0.2
0.2
0.2
0.2

N₂

0.5
0.1
0.1
0.1
0.1
0.1

CO

0
0.5
4.4
4.4
4.5
4.5

CO₂

0
78.8
86.2
86.2
86.2
86.2

SO₂

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

SO₃

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

NO

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

NO₂

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

The CO and CO₂product stream material balances can be seen in Table 6. The PSA only case can achieve CO₂concentration 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 CO₂purity for additional CO concentration in the overhead stream, allowing for flexibility of overall design and operation to meet a specific need.

TABLE 6

Typical Example of Key Stream Information for

Pressure Swing Adsorption (PSA) Only Separation

Stream #

Units
275
430
415
440

Stream

Compressed
CO₂Product
CO Containing
Portion of

Description

Reactor

Overhead
Intermediate

Effluent

Pressure CO₂

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 %

H₂O

0.6
0
0
0.6

O₂

0.3
<600
ppm
4.0
<600
ppm

N₂

0.1
<200
ppm
2.0
<200
ppm

CO

4.9
0.7
12.7
0.7

CO₂

94.1
99.2
81.3
98.6

SO₂

<10 ppm
<10
ppm
0
<10
ppm

SO₃

<10 ppm
<10
ppm
0
<10
ppm

NO

<10 ppm
<10
ppm
<50 ppm
<10
ppm

NO₂

<10 ppm
<10
ppm
0
<10
ppm

Example 4

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 CO₂capture system can be found in Table 7. Temperatures, pressures, and overall mass flow rate for the section upstream of the CO₂capture system can vary depending on upstream FCC unit operation and the specific composition of the CO₂recycle stream from the downstream CO₂separation unit.

TABLE 7

Typical Example of Key Stream Information Upstream of CO₂Capture 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

O₂
Preheated CO₂
Combusted
Flue Gas
Effluent
Reactor

Recycle and
Flue Gas
Stream

Effluent

Concentrated O₂

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 %

H₂O

0
0
9.0
9.0
9.0
9.0

O₂

99.5
20.5
0.2
0.2
0.2
0.2

N₂

0.5
0.1
0.1
0.1
0.1
0.1

CO

0
0.5
4.4
4.4
4.5
4.5

CO₂

0
78.8
86.2
86.2
86.2
86.2

SO₂

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

SO₃

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

NO

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

NO₂

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

The CO and CO₂product stream material balances can be seen in Table 8. The initial PSA step targets CO₂recovery, as described in the previous example and has the same flexibility regarding CO₂stream 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 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
CO₂
CO
Portion of
Inert

Description

Reactor
Product
Product
Intermediate
Purge

Effluent

Pressure CO₂

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 %

H₂O

0.6
0
0
0.6
0

O₂

0.3
<600 ppm
<200 ppm
<600 ppm
22.1

N₂

0.1
<200 ppm
<500 ppm
<200 ppm
77.8

CO

4.9
0.7
86.3
0.7
0

CO₂

94.1
99.2
13.5
98.6
0

SO₂

<10 ppm
<10 ppm
0
<10 ppm
0

SO₃

<10 ppm
<10 ppm
0
<10 ppm
0

NO

<10 ppm
<10 ppm
<10 ppm
<10 ppm
0.1

NO₂

<10 ppm
<10 ppm
0
<10 ppm
0

Example 5

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 CO₂separation 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 CO₂capture system can be found in Table 9. Temperatures, pressures, and overall mass flow rate for the section upstream of the CO₂capture system can vary depending on upstream FCC unit operation and the specific composition of the CO₂recycle stream from the downstream CO₂separation unit.

TABLE 9

Typical Example of Key Stream Information Upstream of CO₂Capture

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

O₂
Preheated CO₂
Combusted
Flue Gas
Effluent
Reactor

Recycle and
Flue Gas
Stream

Effluent

Concentrated O₂

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 %

H₂O

0
0
8.8
8.8
9.0
9.0

O₂

99.5
20.3
0.2
0.2
0.2
0.2

N₂

0.5
0.7
0.6
0.6
0.1
0.1

CO

0
0.0
3.9
3.9
4.5
4.5

CO₂

0
79.1
86.3
86.3
86.4
86.4

SO₂

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

SO₃

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

NO

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

NO₂

0
Trace
<1000 ppm
<1000 ppm
<10 ppm
<10 ppm

The CO and CO₂product stream material balances can be seen in Table 10. For this case, a relatively high purity for both CO₂stream (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 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
CO₂
CO Product
Portion of CO₂

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 %

H₂O

0.6
0
0
0

O₂

0.3
0.3
<300
ppm
0.3

N₂

0.6
0.7
<800
ppm
0.7

CO

4.3
0
90.0
0

CO₂

94.2
99.0
9.9
99.0

SO₂

<10 ppm
<10 ppm
<10
ppm
<10 ppm

SO₃

<10 ppm
<10 ppm
<10
ppm
<10 ppm

NO

<10 ppm
<10 ppm
<10
ppm
<10 ppm

NO₂

<10 ppm
<10 ppm
<10
ppm
<10 ppm

The 5 examples above illustrate that the purification of both CO and CO₂product 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 CO₂product 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 CO₂product 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

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.

A first embodiment of the invention is a process for separating CO from CO₂in a flue gas stream from a partial oxidation regenerator of a fluid catalytic cracking (FCC) process comprising passing a mixture of a preheated CO₂recycle stream and a concentrated oxygen stream to the partial oxidation regenerator to generate the flue gas stream comprising CO₂, CO, SOx, NOx, catalyst fines, O₂, and H₂O; 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 CO₂recycle stream with the reactor effluent gas stream to produce the preheated CO₂recycle stream and a cooled reactor effluent stream; and separating the cooled reactor effluent stream into a CO₂product stream, the CO₂recycle 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 CO₂product stream, the CO₂recycle 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 CO₂product stream and a CO-containing overhead stream in a cryogenic CO₂fractionation system; and separating the CO-containing overhead stream into the CO₂recycle stream and the CO product stream in a separation section; or recycling a portion of the CO₂product stream as the CO₂recycle 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 CO₂recycle 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 CO₂recycle 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 CO₂stream before introducing the CO₂recycle 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 CO₂recycle 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 CO₂recycle stream, or wherein the compressed portion of the cooled reactor effluent stream is the CO₂recycle 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 CO₂product stream, the CO₂recycle 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 CO₂-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 CO₂-containing stream to form a high pressure CO2-containing stream and an intermediate pressure CO₂-containing stream; co-feeding the intermediate pressure CO₂-containing stream to the PSA or VPSA unit; dehydrating the high pressure CO₂-containing stream to form the CO₂product 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 CO₂-containing stream comprises the CO₂recycle 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 CO₂recycle 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 CO₂recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream; and wherein a part of the intermediate pressure CO₂-containing stream comprises the CO₂recycle 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 CO₂recycle 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 CO₂recycle 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 CO₂recycle stream, or wherein the compressed portion of the cooled reactor effluent stream comprises the CO₂recycle 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 CO₂product stream, the CO₂recycle 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 CO₂-containing stream and a CO-containing stream in a temperature swing absorption (TSA) unit; compressing the CO₂-containing stream to form the CO₂product 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 CO₂-containing stream comprises the CO₂recycle stream; or compressing a portion of the cooled reactor effluent stream to form the CO₂recycle stream; or a portion of the compressed reactor effluent stream comprises the CO₂recycle 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 CO₂recycle stream; or wherein the compressed portion of the cooled reactor effluent stream comprises the CO₂recycle 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 H₂O, CO₂, CO, N₂, O₂, Na₂CO₃, Na₂SO₄, NaNO₃, CaSO₄, CaCO₃, Ca(NO₃)₂, MgCO₃, MgSO₄, Mg(NO₃)₂, and NOx, wherein the reactant comprises at least one of NaHCO₃, NaHCO₃·Na₂CO₃·2(H₂O), CaCO₃, Ca(OH)₂, and Mg(OH)₂; and filtering the dry SOx reaction section flue gas stream in a filtration section to remove Na₂CO₃, Na₂SO₄, NaNO₃, CaSO₄, CaCO₃, Ca(NO₃)₂, MgCO₃, MgSO₄, Mg(NO₃)₂and catalyst fines to form the reactor effluent stream and a filtered material stream.

A second embodiment of the invention is a process for separating CO from CO₂in 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 CO₂, CO, SOx, NOx, catalyst fines, O and H₂O; 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 CO₂recycle stream with the partially cooled flue gas stream to produce the preheated CO₂recycle 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 CO₂recycle 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 H₂O, CO, CO, N₂, O², Na₂SO₃, Na₂SO₄, NaHSO₃, Na₂CO₃, (NH₄)2SO₄, 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 CO₂product stream, the CO₂recycle 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 CO₂product stream and a CO-containing overhead stream in a cryogenic CO₂fractionation system; and separating the CO-containing overhead stream into the CO₂recycle stream and the CO product stream in a separation section; or recycling a portion of the CO₂product stream as the CO₂recycle 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 CO₂recycle 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 CO₂recycle 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 CO₂stream before introducing the CO₂recycle 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 CO₂recycle 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 CO₂recycle 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 CO₂product stream, the CO₂recycle 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 CO₂-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 CO₂-containing stream to form a high pressure CO₂-containing stream and an intermediate pressure CO₂-containing stream; co-feeding the intermediate pressure CO₂-containing stream to the PSA or VPSA unit; dehydrating the high pressure CO₂-containing stream to form the CO₂product 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 CO₂-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 CO₂recycle 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 CO₂recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream; and wherein a part of the intermediate pressure CO₂-containing stream comprises the CO₂recycle 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 CO₂recycle 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 CO₂recycle 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 CO₂recycle stream, or wherein the compressed portion of the cooled reactor effluent stream comprises the CO₂recycle 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 CO₂product 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 CO₂-containing stream and a CO-containing stream in a temperature swing absorption (TSA) unit; compressing the CO₂-containing stream to form the CO₂product 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 CO₂-containing stream comprises the CO₂recycle stream; or compressing a portion of the cooled reactor effluent stream to form the CO₂recycle stream; or a portion of the compressed reactor effluent stream comprises the CO₂recycle 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 CO₂recycle stream; or wherein the compressed portion of the cooled reactor effluent stream comprises the CO₂recycle 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.

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.

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

Claims

1. A process for separating CO from CO2 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 CO2, CO, SOx, NOx, catalyst fines, O2, and H2O;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 CO2 recycle stream with the reactor effluent gas stream to produce the preheated CO2 recycle stream and a cooled reactor effluent stream; andseparating the cooled reactor effluent stream into a CO2 product stream, the CO2 recycle stream, and a CO product stream.
2. The process of claim 1 wherein separating the reactor effluent stream into the CO2 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;dehydrating the compressed reactor effluent stream to form a dehydrated reactor effluent stream;separating the dehydrated reactor effluent stream into the CO2 product stream and a CO-containing overhead stream in a cryogenic CO2 fractionation system; andseparating the CO-containing overhead stream into the CO2 recycle stream and the CO product stream in a separation section; or recycling a portion of the CO2 product stream as the CO2 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 CO2 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 CO2 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 CO2 stream before introducing the CO2 recycle stream into the regenerator.
4. The process of claim 2 further comprising: recycling a portion of the CO2 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; andcombining the compressed portion of the cooled reactor effluent stream with the CO2 recycle stream, or wherein the compressed portion of the cooled reactor effluent stream is the CO2 recycle stream.
6. The process of claim 1 wherein separating the reactor effluent stream into the CO2 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 low pressure CO2-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 CO2-containing stream to form a high pressure CO2-containing stream and an intermediate pressure CO2-containing stream;co-feeding the intermediate pressure CO2-containing stream to the PSA or VPSA unit;dehydrating the high pressure CO2-containing stream to form the CO2 product stream; andpurifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a part of the intermediate pressure CO2-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 CO2 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 CO2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream; and wherein a part of the intermediate pressure CO2-containing stream comprises the CO2 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 CO2 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 CO2 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; andcombining the compressed portion of the cooled reactor effluent stream with the CO2 recycle stream, or wherein the compressed portion of the cooled reactor effluent stream comprises the CO2 recycle stream.
8. The process of claim 1 wherein separating the reactor effluent stream into the CO2 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 CO2-containing stream and a CO-containing stream in a temperature swing absorption (TSA) unit;compressing the CO2-containing stream to form the CO2 product stream;compressing the CO-containing stream to form a high pressure CO stream; anddehydrating the high pressure CO-containing stream to form the CO product stream;wherein a part of the CO2-containing stream comprises the CO2 recycle stream; or compressing a portion of the cooled reactor effluent stream to form the CO2 recycle stream; or a portion of the compressed reactor effluent stream comprises the CO2 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; andintroducing 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; andcombining the compressed portion of the cooled reactor effluent stream with the CO2 recycle stream; or wherein the compressed portion of the cooled reactor effluent stream comprises the CO2 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; andwherein 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 H2O, CO2, CO, N2, O2, Na2CO3, Na2SO4, NaNO3, CaSO4, CaCO3, Ca(NO3)2, MgCO3, MgSO4, Mg(NO3)2, and NOx, wherein the reactant comprises at least one of NaHCO3, NaHCO3·Na2CO3·2(H2O), CaCO3, Ca(OH)2, and Mg(OH)2; andfiltering the dry SOx reaction section flue gas stream in a filtration section to remove Na2CO3, Na2SO4, NaNO3, CaSO4, CaCO3, Ca(NO3)2, MgCO3, MgSO4, Mg(NO3)2 and catalyst fines to form the reactor effluent stream and a filtered material stream.
16. A process for separating CO from CO2 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 CO2, CO, SOx, NOx, catalyst fines, O2 and H2O;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 CO2 recycle stream with the partially cooled flue gas stream to produce the preheated CO2 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 CO2 product stream, the CO2 recycle stream, and a CO product stream; andwherein 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 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 H2O, CO2, CO, N2, O2, Na2SO3, Na2SO4, NaHSO3, Na2CO3, (NH4)2SO4, 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 CO2 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;dehydrating the compressed reactor effluent stream to form a dehydrated reactor effluent stream;separating the dehydrated reactor effluent stream into the CO2 product stream and a CO-containing overhead stream in a cryogenic CO2 fractionation system; andseparating the CO-containing overhead stream into the CO2 recycle stream and the CO product stream in a separation section; or recycling a portion of the CO2 product stream as the CO2 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 CO2 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 CO2 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 CO2 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 low pressure CO2-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 CO2-containing stream to form a high pressure CO2-containing stream and an intermediate pressure CO2-containing stream;co-feeding the intermediate pressure CO2-containing stream to the PSA or VPSA unit;dehydrating the high pressure CO2-containing stream to form the CO2 product stream; andpurifying the high pressure CO-containing stream in a polishing section to form the CO product stream and wherein a part of the intermediate pressure CO2-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 CO2 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 CO2 recycle stream; or wherein the high pressure CO-containing stream comprises the CO product stream; and wherein a part of the intermediate pressure CO2-containing stream comprises the CO2 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 CO2 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 CO2 recycle stream; or combinations thereof.
20. The process of claim 16 wherein separating the reactor effluent stream into the CO2 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 CO2-containing stream and a CO-containing stream in a temperature swing absorption (TSA) unit;compressing the CO2-containing stream to form the CO2 product stream;compressing the CO-containing stream to form a high pressure CO stream; anddehydrating the high pressure CO-containing stream to form the CO product stream;wherein a part of the CO2-containing stream comprises the CO2 recycle stream; or compressing a portion of the cooled reactor effluent stream to form the CO2 recycle stream; or a portion of the compressed reactor effluent stream comprises the CO2 recycle stream; or combinations thereof.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application Ser. No. 63/483,790, filed on Feb. 8, 2023, the entirety of which is incorporated herein by reference.

Provisional Applications (1)

	Number	Date	Country
	63483790	Feb 2023	US

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

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CPC

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RELATED APPLICATIONS

Provisional Applications (1)