Carbon dioxide recovery method and carbon dioxide recovery system using a carbon dioxide cycle power generation facility

Abstract

The present invention uses: a CO2 cycle power generation facility comprising a power generation turbine that uses a CO2 fluid as a driving fluid, a first CO2 compression device that boosts the CO2 fluid after said fluid has been used to drive the power generation turbine, and a combustor that combusts, as a fuel, a light hydrocarbon gas comprising methane as a main ingredient using oxygen supplied from an air separation device in a state in which the boosted and heated CO2 fluid is mixed, a combustion gas obtained by the combustor being supplied to the power generation turbine as the driving fluid; and a CO2 recovery facility that recovers CO2 from an exhaust gas discharged by combustion of a fuel in an external combustion facility. Some of the CO2 fluid discharged from the CO2 cycle power generation facility and the CO2 recovered by the CO2 recovery facility are supplied to a CO2 receiving facility, and energy obtained by the CO2 cycle power generation facility is supplied to the CO2 recovery facility.

Description

[Technical Field]

[0001] The present invention relates to a carbon dioxide capture method and a carbon dioxide capture system. [Background technology]

[0002] Patent Document 1 describes that carbon dioxide recovered in a carbon dioxide absorption tower is made into a supercritical state, sent to a coal-fired power plant, and used as a working fluid for power generation. Patent Document 2 describes capturing carbon dioxide in the exhaust gas of a ship engine and converting it into a supercritical fluid, and using the electricity generated by the supercritical fluid to power the ship. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Chinese Patent Application Publication No. 107626185 [Patent Document 2] Korean Patent Publication No. 10-2017-0041531 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, exhaust gas from boilers, heating furnaces, gas turbines, etc. installed in oil plants, gas plants, chemical plants, power plants, steel mills, etc. (hereinafter referred to as "plants, etc.") has been released into the atmosphere after undergoing exhaust heat recovery and desulfurization or denitrification processes to meet environmental standards. At this time, the carbon dioxide (CO2) in the exhaust gas is released directly into the atmosphere.

[0005] When recovering CO2 in exhaust gas, for example, an acid gas removal facility (AGRU: Acid gas removal unit) using an amine absorption process or the like is used. It has been proposed that the recovered CO2 be stored in an underground aquifer or the like in a carbon dioxide capture and storage facility (CCS: Carbon dioxide Capture and Storage).

[0006] Conventionally, about 90% of the CO2 in exhaust gas can be recovered, and apparently, the CO2 emissions are suppressed. On the other hand, in order to recover CO2 by CCS, it is necessary to boost the pressure of CO2 to a predetermined pressure (200 - 300 bar). The compressor used for boosting the pressure of CO2 is driven by electricity. When the compressor is driven using electricity derived from a carbon-containing fuel, CO2 is emitted during power generation.

[0007] When recovering CO2 by AGRU, for example, a CO2 absorbent such as an amine is used to absorb CO2, and the CO2 absorbent is heated to release CO2, thereby regenerating the CO2 absorbent. A heat source such as steam is used for heating the CO2 absorbent, but if a fuel containing hydrocarbons is used for generating the heat source, CO2 is emitted.

[0008] It is also conceivable to supply the power for driving the compressor from renewable energy power generation such as solar power generation, wind power generation, solar thermal power generation, and geothermal power generation, or to use the above-mentioned renewable energy sources as the heat source for regenerating the CO2 absorbent. However, the utilization of renewable energy is greatly restricted by site conditions and the like, and it is difficult to stably supply power.

[0009] As described above, when recovering CO2 in the exhaust gas of a plant or the like and storing it in CCS, although the amount of CO2 released into the atmosphere can be significantly reduced apparently, in the entire equipment required for CO2 recovery, a certain amount of CO2 emissions are currently involved in order to recover CO2. However, if an AGRU is individually installed in these equipment with CO2 emissions in order to suppress the release of CO2 into the atmosphere, the cost of the entire equipment will increase.

[0010] The present invention has been made in view of the above circumstances, and an object thereof is to provide a carbon dioxide recovery method and a carbon dioxide recovery system using a carbon dioxide cycle power generation facility capable of suppressing the atmospheric emission of carbon dioxide when recovering carbon dioxide.

Means for Solving the Problems

[0011] A first aspect of the present invention is a power generation turbine using a carbon dioxide fluid as a driving fluid, a CO2 first compressor for boosting the carbon dioxide fluid after driving the power generation turbine, a CO2 heat exchanger for heating the carbon dioxide fluid boosted by the CO2 first compressor, a carbon dioxide fluid heated by the CO2 heat exchanger, oxygen supplied from an air separation device, and a light hydrocarbon gas mainly composed of methane are mixed and burned and heated, and a combustor for heating, and a carbon dioxide cycle power generation facility in which the combustion gas heated by the combustor is supplied to the power generation turbine as the driving fluid, and a carbon dioxide recovery facility for recovering carbon dioxide from exhaust gas containing carbon dioxide discharged by combustion of fuel in an external combustion facility. A carbon dioxide recovery method using a carbon dioxide recovery system, characterized in that a part of the carbon dioxide fluid discharged from the carbon dioxide cycle power generation facility and the carbon dioxide recovered by the carbon dioxide recovery facility are supplied to a carbon dioxide receiving facility capable of receiving carbon dioxide, and the energy obtained by the carbon dioxide cycle power generation facility is supplied to the carbon dioxide recovery facility.

[0012] A second aspect of the present invention is the carbon dioxide recovery method according to the first aspect, characterized in that the energy supplied from the carbon dioxide cycle power generation facility to the carbon dioxide recovery facility includes electric power obtained by the power generation turbine.

[0013] A third aspect of the present invention is the carbon dioxide recovery method according to the first or second aspect, characterized in that the energy supplied from the carbon dioxide cycle power generation facility to the carbon dioxide recovery facility includes the heat possessed by the carbon dioxide fluid.

[0014] The fourth aspect of the present invention is a carbon dioxide recovery method according to any one of the first to third aspects, characterized in that the energy supplied from the carbon dioxide cycle power generation facility to the carbon dioxide recovery facility includes mechanical power obtained from the combustion gas obtained in the combustor.

[0015] The fifth aspect of the present invention is a carbon dioxide recovery method according to the second aspect, characterized in that the carbon dioxide recovery facility includes a first acid gas removal facility for recovering carbon dioxide contained in the exhaust gas from the external combustion facility, and a first acid gas pressurization facility for pressurizing the carbon dioxide recovered by the first acid gas removal facility, and the electric power obtained by the power generation turbine is supplied to the first acid gas pressurization facility.

[0016] The sixth aspect of the present invention is a carbon dioxide recovery method according to the third aspect, characterized in that the carbon dioxide recovery facility includes a first acid gas removal facility for recovering carbon dioxide contained in the exhaust gas from the external combustion facility, and a first acid gas pressurization facility for pressurizing the carbon dioxide recovered by the first acid gas removal facility, and the heat possessed by the carbon dioxide fluid is supplied to the first acid gas removal facility by heat exchange.

[0017] The seventh aspect of the present invention is a carbon dioxide recovery method according to the sixth aspect, characterized in that the energy supplied from the carbon dioxide cycle power generation facility to the carbon dioxide recovery facility includes the electric power obtained by the power generation turbine and the heat possessed by the carbon dioxide fluid, and the electric power obtained by the power generation turbine is supplied to the first acid gas pressurization facility.

[0018] The eighth aspect of the present invention is a carbon dioxide recovery method according to the sixth or seventh aspect, characterized in that the first acid gas removal facility performs a recovery step of absorbing carbon dioxide contained in the exhaust gas from the external combustion facility into a carbon dioxide absorbent to recover carbon dioxide, and a regeneration step of heating the carbon dioxide absorbent to release carbon dioxide, and the heat possessed by the carbon dioxide fluid is supplied to the regeneration step by heat exchange.

[0019] The ninth aspect of the present invention is a carbon dioxide recovery method according to any one of the fifth to eighth aspects, characterized in that carbon dioxide pressurized by the first acidic gas pressurizing facility is supplied between the turbine for power generation and the first CO2 compression device and mixed with the carbon dioxide fluid.

[0020] The tenth aspect of the present invention is a carbon dioxide recovery method according to any one of the first to ninth aspects, characterized in that the carbon dioxide recovery facility includes a first acidic gas removal facility for recovering carbon dioxide contained in the exhaust gas from the external combustion facility, and a first acidic gas pressurizing facility for pressurizing the carbon dioxide recovered by the first acidic gas removal facility, and the first acidic gas pressurizing facility pressurizes a carbon dioxide-containing gas recovered by a second acidic gas removal facility, which is an acidic gas removal facility other than the first acidic gas removal facility, together with the carbon dioxide-containing gas recovered from the exhaust gas from the external combustion facility by the first acidic gas removal facility.

[0021] The eleventh aspect of the present invention is a carbon dioxide recovery method according to any one of the first to tenth aspects, characterized in that the heat of the exhaust gas from the external combustion facility is supplied to the carbon dioxide fluid circulating in the carbon dioxide cycle power generation facility by heat exchange, and the temperature of the carbon dioxide fluid is lower than that of the exhaust gas.

[0022] The twelfth aspect of the present invention is a carbon dioxide recovery method according to any one of the first to eleventh aspects, characterized in that the external combustion facility includes a combustion furnace, the carbon dioxide recovery system includes an air separation device for separating oxygen supplied to the carbon dioxide cycle power generation facility from air, and a part of the oxygen obtained by the air separation device is supplied to the combustion furnace.

[0023] The thirteenth aspect of the present invention is a carbon dioxide recovery method according to any one of the first to twelfth aspects, characterized in that the heat of the carbon dioxide fluid from the carbon dioxide cycle power generation facility is supplied outside the carbon dioxide cycle power generation facility.

[0024] The 14th aspect of the present invention is a power generation turbine using a carbon dioxide fluid as a driving fluid, a CO2 first compressor for boosting the carbon dioxide fluid after driving the power generation turbine, a CO2 heat exchanger for heating the carbon dioxide fluid boosted by the CO2 first compressor, a combustor that mixes and burns the carbon dioxide fluid heated by the CO2 heat exchanger, oxygen supplied from an air separation device, and a light hydrocarbon gas mainly composed of methane, and heats them, and a carbon dioxide cycle power generation facility in which the combustion gas heated by the combustor is supplied to the power generation turbine as the driving fluid, and a carbon dioxide recovery facility for recovering carbon dioxide from exhaust gas containing carbon dioxide discharged by combustion of fuel in an external combustion facility. A carbon dioxide recovery system comprising: a part of the carbon dioxide fluid discharged from the carbon dioxide cycle power generation facility and the carbon dioxide recovered by the carbon dioxide recovery facility are supplied to a carbon dioxide receiving facility capable of receiving carbon dioxide, and the energy obtained in the carbon dioxide cycle power generation facility is supplied to the carbon dioxide recovery facility. A carbon dioxide recovery system characterized by the above.

[0025] The 15th aspect of the present invention is that the energy supplied from the carbon dioxide cycle power generation facility to the carbon dioxide recovery facility includes at least one energy form selected from the electric power obtained by the power generation turbine, the heat possessed by the carbon dioxide fluid, and the mechanical power obtained from the combustion gas obtained by the combustor. The carbon dioxide recovery system according to the 14th aspect, characterized by the above.

Advantages of the Invention

[0026] According to the first aspect, by using a carbon dioxide cycle power generation facility as an energy source for the carbon dioxide recovery facility, it is possible to suppress the atmospheric emission of CO2 and reduce costs.

[0027] According to the second aspect, by supplying electric power from a carbon dioxide cycle power generation facility as a power source for the carbon dioxide recovery facility, it is possible to suppress the atmospheric emission of CO2 and reduce costs.

[0028] According to the third aspect, by using the heat from the carbon dioxide cycle power generation facility as the heat source required for the carbon dioxide recovery facility, it is possible to suppress the atmospheric emission of CO2 and reduce costs.

[0029] According to the fourth aspect, by using the energy generated in the carbon dioxide cycle power generation facility as the mechanical power source of the carbon dioxide recovery facility, it is possible to suppress the atmospheric emission of CO2 and reduce costs.

[0030] According to the fifth aspect, when recovering carbon dioxide contained in the exhaust gas from the external combustion facility with the first acid gas removal facility and boosting the carbon dioxide recovered by the first acid gas removal facility with the first acid gas boosting facility, by supplying power from the carbon dioxide cycle power generation facility as the power source of the first acid gas boosting facility, it is possible to suppress the atmospheric emission of CO2 and reduce costs.

[0031] According to the sixth aspect, when recovering carbon dioxide contained in the exhaust gas from the external combustion facility with the first acid gas removal facility and boosting or dehydrating the carbon dioxide recovered by the first acid gas removal facility with the first acid gas boosting facility, by using the heat from the carbon dioxide cycle power generation facility as the heat source required for the first acid gas removal facility, it is possible to suppress the atmospheric emission of CO2 and reduce costs.

[0032] According to the seventh aspect, by using the heat from the carbon dioxide cycle power generation facility as the heat source required for the first acid gas removal facility and supplying power from the carbon dioxide cycle power generation facility as the power source of the first acid gas boosting facility, it is possible to suppress the atmospheric emission of CO2 and reduce costs.

[0033] According to the eighth aspect, by using the heat from the carbon dioxide cycle power generation facility as the heat source required for the regeneration process in which the first acid gas removal facility heats the carbon dioxide absorbent to release carbon dioxide, it is possible to suppress the atmospheric emission of CO2 and reduce costs.

[0034] According to the ninth aspect, since it is only necessary that the performance of the first acid gas boosting facility used in the carbon dioxide recovery facility can boost the pressure to the same level as the carbon dioxide fluid before being boosted by the CO2 first compressor of the carbon dioxide cycle power generation facility, the cost required for boosting the pressure of carbon dioxide can be reduced.

[0035] According to the tenth aspect, in the first acid gas removal facility, regeneration of the CO2 absorbent and the like can be performed using the heat supplied from the carbon dioxide cycle power generation facility. Further, not only the carbon dioxide recovered from the first acid gas removal facility but also the carbon dioxide recovered from the second acid gas removal facility are combined and processed by the first acid gas boosting facility, so that the cost required for boosting the pressure of carbon dioxide can be further reduced.

[0036] According to the eleventh aspect, by using the heat of the exhaust gas from the external combustion facility to heat the carbon dioxide fluid in the carbon dioxide cycle power generation facility that is at a lower temperature than the exhaust gas, the power generation efficiency of the carbon dioxide cycle power generation facility can be improved.

[0037] According to the twelfth aspect, by using the air separation device attached to the carbon dioxide cycle power generation facility, the combustion efficiency in the combustion furnace of the external combustion facility can be improved, and since the exhaust gas of the combustion furnace is composed of high-concentration carbon dioxide, carbon dioxide can be easily recovered.

[0038] According to the thirteenth aspect, by using the heat of the carbon dioxide cycle power generation facility as a heat source for the carbon dioxide recovery facility or an external facility, the atmospheric emission of CO2 generated when obtaining the heat required in the external facility can be suppressed, and the cost can be reduced.

[0039] According to the fourteenth aspect, by using the carbon dioxide cycle power generation facility as an energy source for the carbon dioxide recovery facility, the atmospheric emission of CO2 can be suppressed, and the cost can be reduced.

[0040] According to the 15th aspect, as a power source for the carbon dioxide recovery facility, power is supplied from the carbon dioxide cycle power generation facility, as a heat source required for the carbon dioxide recovery facility, heat from the carbon dioxide cycle power generation facility is used, or as a mechanical power source for the carbon dioxide recovery facility, by using the energy generated in the carbon dioxide cycle power generation facility, it is possible to suppress the atmospheric emission of CO2 and reduce costs.

Brief Description of the Drawings

[0041]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0042] Hereinafter, the present invention will be described with reference to preferred embodiments.

[0043] In the description of the embodiments, "carbon dioxide", "carbon dioxide fluid", "carbon dioxide cycle power generation facility", "carbon dioxide recovery facility", "carbon dioxide receiving facility", "carbon dioxide recovery method", and "carbon dioxide recovery system" are respectively referred to as "CO2", "CO2 fluid", "CO2 cycle power generation facility", "CO2 recovery facility", "CO2 receiving facility", "CO2 recovery method", and "CO2 recovery system".

[0044] In the description of the embodiments, the "CO2 fluid" means CO2 circulating in the CO2 cycle power generation facility without distinguishing between states such as supercritical CO2, liquefied CO2, and CO2 gas. CO2 recovered from the exhaust gas of the external combustion facility is referred to as "exhaust gas-derived CO2" without distinguishing the state of CO2. CO2 recovered from the existing acid gas removal facility is referred to as "existing AGRU-derived CO2" without distinguishing the state of CO2.

[0045] Fig. 1 shows an overview of the CO2 recovery system 100. The CO2 recovery system 100 mainly includes a supercritical CO2 cycle power generation facility 10 and a CO2 recovery facility 90 for recovering CO2 contained in the exhaust gas of the external combustion facility 50. The supercritical CO2 cycle power generation facility 10 is an example of a CO2 cycle power generation facility and is a facility that generates electricity using supercritical CO2 as a driving fluid. When the external facility 200 described later is already installed, the supercritical CO2 cycle power generation facility 10 and the CO2 recovery facility 90 are newly installed facilities for recovering the exhaust gas from the external facility 200.

[0046] The CO2 recovery facility 90 includes an air separation device 20, a CO2 recovery device 30 with a newly installed first acid gas removal facility 31, and a fuel gas supply facility 60. The air separation device 20 preferably incorporates an oxygen booster (not shown) for boosting the oxygen separated from the air. The fuel gas supply facility 60 is a supply facility for light hydrocarbon gas mainly composed of methane. The CO2 recovery device 30 may include a first acid gas booster 32. Further, the CO2 recovery facility 90 may be provided with a second acid gas booster facility 72 added to the existing second acid gas removal facility 71, which is an existing acid gas removal facility.

[0047] The CO2 recovery facility 90 may be all facilities and devices other than the supercritical CO2 cycle power generation facility 10 among all the facilities and devices included in the CO2 recovery system 100. The CO2 recovery facility 90 may include an air separation device 20, a CO2 recovery device 30, a first acid gas removal facility 31, a first acid gas booster 32, a fuel gas supply facility 60, a second acid gas booster facility 72, etc. The second acid gas removal facility 71 and the external combustion facility 50 may be external facilities 200.

[0048] The CO2 recovery system 100 can supply the energy obtained from the supercritical CO2 cycle power generation facility 10 to at least any one selected from the air separation device 20, the CO2 recovery device 30, the fuel gas supply facility 60, and the second acid gas booster facility 72. The CO2 recovery system 100 may supply the energy obtained from the supercritical CO2 cycle power generation facility 10 to the entire CO2 recovery facility 90. In particular, at least one form of energy selected from electric power, heat, and mechanical power required in the air separation device 20, the CO2 recovery device 30, the fuel gas supply facility 60, the second acid gas booster facility 72, etc. may be supplied from the supercritical CO2 cycle power generation facility 10.

[0049] Oxygen and fuel gas are supplied as the fluid F from the air separation device 20 and the fuel gas supply facility 60 to the supercritical CO2 cycle power generation facility 10. At the same time, energy E is supplied from the supercritical CO2 cycle power generation facility 10 to the air separation device 20 and the fuel gas supply facility 60. Energy E is supplied bidirectionally between the external combustion facility 50 and the supercritical CO2 cycle power generation facility 10.

[0050] Exhaust gas is supplied as energy E and fluid F from the external combustion equipment 50 to the first acid gas removal equipment 31. From the first acid gas removal equipment 31 through the first acid gas booster 32, exhaust gas-derived CO2 is supplied as fluid F to the supercritical CO2 cycle power generation equipment 10. Energy E is supplied from the supercritical CO2 cycle power generation equipment 10 to at least one of the first acid gas removal equipment 31 and the first acid gas booster 32. A part of the CO2 fluid is discharged as fluid F from the supercritical CO2 cycle power generation equipment 10 to the CO2 receiving equipment 40.

[0051] From the second acid gas removal equipment 71 through the second acid gas booster 72, existing AGRU-derived CO2 is discharged as fluid F to the CO2 receiving equipment 40. Energy E is supplied from the supercritical CO2 cycle power generation equipment 10 to the second acid gas booster 72. Also, existing AGRU-derived CO2 may be supplied as fluid F from the second acid gas removal equipment 71 through the first acid gas booster 32 to the supercritical CO2 cycle power generation equipment 10.

[0052] The CO2 recovery method using the CO2 recovery system 100 includes a step of supplying a part of the CO2 fluid discharged from the supercritical CO2 cycle power generation equipment 10 and the CO2 recovered by the CO2 recovery equipment 90 to the CO2 receiving equipment 40, and a step of supplying the energy obtained in the supercritical CO2 cycle power generation equipment 10 to the CO2 recovery equipment 90. Specifically, the CO2 recovery systems 101, 102, 103, 104 of the first to fourth embodiments will be shown and described in more detail.

[0053] FIG. 2 shows the CO2 recovery system 101 of the first embodiment. The CO2 recovery system 101 mainly includes a supercritical CO2 cycle power generation equipment 10 and a CO2 recovery equipment 90 for recovering CO2 contained in the exhaust gas of the external combustion equipment 50.

[0054] The external combustion equipment 50 is not particularly limited as long as it is combustion equipment other than the combustion equipment included in the supercritical CO2 cycle power generation equipment 10 (that is, the combustor 11 for generating supercritical CO2 described later), and examples include a combustion furnace 51, a gas turbine device 52, and the like. The external combustion equipment 50 may be a part of the external equipment 200 not included in the CO2 recovery system 101. The external equipment 200 may be existing equipment that has existed since before the construction of the CO2 recovery system 101. At least a part of the equipment in the external equipment 200 may be newly installed or added after the construction of the CO2 recovery system 101. The external combustion equipment 50 discharges exhaust gas containing CO2 by burning a carbon-containing fuel.

[0055] The fuel used in the external combustion equipment 50 is not particularly limited, and examples include carbonaceous fuels such as coal and charcoal, hydrocarbon-containing fuels such as petroleum and natural gas, carbon compounds such as carbon monoxide, biomass, and combustible waste. The external combustion equipment 50 may burn two or more of the above-mentioned fuels mixed at the same time, or may select and burn different fuels at different times.

[0056] The external combustion equipment 50 may be equipment operated by the same operator as the supercritical CO2 cycle power generation equipment 10 and the CO2 recovery equipment 90, or may be equipment operated by another operator. The installation location of the external combustion equipment 50 is not particularly limited, and it may be within the same site as the supercritical CO2 cycle power generation equipment 10 or the CO2 recovery equipment 90, adjacent to these, or away from these.

[0057] The combustion furnace 51 mixes and burns the air supplied from the air path 51a and the fuel supplied from the fuel path 51b. The exhaust gas of the combustion furnace 51 is discharged from the exhaust gas path 51c.

[0058] The gas turbine device 52 includes a compressor 52b that compresses air supplied from an air passage 52a, a combustor 52d that mixes and burns the compressed air obtained by the compressor 52b and fuel supplied from a fuel passage 52c, and a turbine 52e that converts the high-temperature combustion gas generated by the combustor 52d into power. The use of the power of the turbine 52e is not particularly limited, and it may be used for power generation, driving machinery, etc. The exhaust gas of the combustor 52d is discharged from an exhaust gas passage 52g through an exhaust stack 52f.

[0059] The CO2 recovery facility 90 recovers the exhaust gas of the external combustion facility 50 from the exhaust gas passages 51c, 52g of the external combustion facility 50 through an exhaust gas recovery passage 30a. Transfer devices such as exhaust gas blowers 30b, 30c may be arranged in the exhaust gas recovery passage �0a to facilitate the transfer of the exhaust gas.

[0060] The CO2 recovery facility <90> includes a first acid gas removal facility <31> and a first acid gas booster <32>. The first acid gas removal facility <31>, the first acid gas booster <32>, devices similar thereto, or devices attached thereto, etc. may be collectively referred to as the CO2 recovery device <30>. The first acid gas removal facility <31> is an acid gas removal facility (AGRU) that recovers CO2 contained in the exhaust gas from the external combustion facility <50>. The first acid gas booster <32> boosts the pressure of the CO2 recovered by the first acid gas removal facility <31>. Although not particularly shown, electric power <120> or mechanical power (not shown) from the supercritical CO2 cycle power generation facility <10> may be supplied to at least one of the first acid gas removal facility <31> or the first acid gas booster <32>. The acid gas removal facility (AGRU) is a CO2 removal facility that removes CO2 in the exhaust gas.

[0061] In the first acid gas removal facility 31, CO2 in the exhaust gas is absorbed using a CO2 absorbent such as amine. Further, by heating the CO2 absorbent, CO2 is released from the CO2 absorbent, and at this time, the CO2 absorbent is regenerated. The CO2-containing gas separated from the CO2 absorbent is transferred from the CO2-containing gas transfer path 31a to the first acid gas booster 32. The CO2-containing gas transferred in the CO2-containing gas transfer path 31a may contain moisture or the like.

[0062] The CO2 absorbent may be a chemical absorbent that absorbs CO2 by an acid-base reaction such as amine, or an adsorbent that adsorbs CO2 by physical adsorption, chemical adsorption, or the like. Although not particularly shown, the CO2 recovery device 30 may separate and recover CO2 from the exhaust gas by membrane separation, cryogenic separation, or the like.

[0063] The treated gas after CO2 is absorbed from the exhaust gas using the first acid gas removal facility 31 is discharged from the treated gas discharge path 31b. When the treated gas contains nitrogen oxides (NOx), it can be discharged into the atmosphere as a gas with a sufficiently reduced nitrogen oxide concentration after appropriate treatment.

[0064] In the CO2 recovery facility 90 of the illustrated example, heat possessed by the CO2 fluid of the supercritical CO2 cycle power generation facility 10 is supplied to the first acid gas removal facility 31 via the CO2 heat exchanger 19. The heat transfer facility 33 of the illustrated example has a heat medium path 33a that circulates an independent heat medium, and a heat medium pump 33b that transfers the heat medium to the heat medium path 33a.

[0065] The heat medium circulating through the heat medium path 33a can receive heat supply from the CO2 fluid of the supercritical CO2 cycle power generation facility 10 via the CO2 heat exchanger 19. In the CO2 heat exchanger 19, heat possessed by the high-temperature CO2 fluid (600°C to 900°C) discharged from the turbine 12 for supercritical CO2 power generation, which will be described later, is exchanged. Also, in the first acid gas removal facility 31, the heat medium circulating through the heat medium path 33a supplies heat to the CO2 absorbent. Thereby, since the heat required for the regeneration of the CO2 absorbent is supplied from the supercritical CO2 cycle power generation facility 10, the use of a heat source accompanied by the atmospheric emission of CO2 can be suppressed.

[0066] The heat level required for the regeneration of the CO2 absorbent is heat in the low temperature range of 150°C to 200°C. In the illustrated example, heat is utilized via a heat medium for the relatively high-temperature CO2 fluid after it exits the turbine 12 for supercritical CO2 power generation. However, for example, the low-temperature CO2 fluid upstream of the CO2 second cooler 16, which will be described later, may be extracted and supplied to the first acid gas removal facility 31. In this case, heat in the low temperature range with low utilization value can be effectively utilized.

[0067] The heat medium is not particularly limited, and examples include metal compounds such as molten salts and organic compounds such as synthetic oils. Although not particularly illustrated, when the heat medium is water vapor, chlorofluorocarbons, etc., the heat possessed by the CO2 fluid of the supercritical CO2 cycle power generation facility 10 may be utilized for driving a heat engine (not shown), etc.

[0068] The CO2-containing gas transferred from the CO2-containing gas transfer path 31a to the first acid gas booster 32 is boosted by the first acid gas booster 32. The CO2 after boosting may be high-pressure gas or liquid CO2. When the CO2-containing gas contains moisture, it may be dehydrated using a dehydrating agent such as molecular sieve, silica gel, zeolite, etc. The moisture removed from the CO2-containing gas is discharged from the drainage path 32b.

[0069] When the first acid gas booster 32 has a dehydration facility (not shown) equipped with a dehydrating agent, in order to heat and regenerate the water-absorbed dehydrating agent, the high-temperature heat of the CO2 fluid of the supercritical CO2 cycle power generation facility 10 may be supplied to a heat exchanger provided in the first acid gas booster 32. Examples of the facility for supplying heat to the dehydration facility include facilities similar to the heat transport facility 33 that supplies the heat of the CO2 fluid of the supercritical CO2 cycle power generation facility 10 to the first acid gas removal facility 31.

[0070] Although not particularly shown, the facilities receiving heat supply from the CO2 fluid of the supercritical CO2 cycle power generation facility 10 via the heat transport facility 33 are not limited to the first acid gas removal facility 31 and the first acid gas booster 32, and may be other facilities. The facilities receiving heat supply may be facilities included in the CO2 recovery facility 90 or facilities included in the external facility 200, as long as they are facilities that require a heat source. In this case, the temperature level of the heat may be higher or lower than the heat level required by the first acid gas removal facility 31 and the first acid gas booster 32. That is, as long as it is a heat level that can be exchanged by the CO2 heat exchanger 19, heat can be supplied to various devices. Specific examples include the reboiler of the amine regeneration tower, and when used in the external facility 200, the reboiler of the distillation tower, the heater of the existing FEED gas or Fuel gas, etc.

[0071] The exhaust gas-derived CO2 pressurized by the first acid gas booster 32 is supplied to the supercritical CO2 cycle power generation facility 10 via the exhaust gas-derived CO2 transfer path 32a. Thereby, by adding the exhaust gas-derived CO2 recovered from the exhaust gas discharged from the external combustion facility 50 to the entire circulating fluid of the supercritical CO2 cycle power generation facility 10, integration of the pressurizing equipment can be achieved and the cost can be reduced.

[0072] The supercritical CO2 cycle power generation facility 10 includes a supercritical CO2 power generation turbine 12 that uses supercritical CO2 fluid as the driving fluid. Note that the power generation turbine of the CO2 cycle power generation facility may use non-supercritical CO2 fluid as the driving fluid. Further, the supercritical CO2 cycle power generation facility 10 may include a first CO2 compressor 18 that boosts the pressure of the CO2 fluid after driving the supercritical CO2 power generation turbine 12, and a supercritical CO2 generator combustor 11 that burns fuel using the boosted oxygen (O2) and light hydrocarbons mainly composed of methane.

[0073] In the supercritical CO2 generator combustor 11, with the CO2 fluid boosted by the first CO2 compressor 18 in a mixed state, a fuel of light hydrocarbons mainly composed of methane is burned using high-pressure oxygen of 200 to 400 bar. By using the supercritical CO2 cycle power generation facility 10, energy such as electric power, heat, and mechanical power required for the CO2 recovery facility 90 such as the air separation device 20, the first acid gas removal facility 31, the first acid gas booster 32, and the fuel gas supply facility 60 can be supplied.

[0074] When the temperature of the CO2 heated by the CO2 heat exchanger 19 after exiting the first CO2 compressor 18 is insufficient, it is necessary to further increase the temperature of the CO2. Therefore, oxygen is supplied from the air separation device 20 to the supercritical CO2 generator combustor 11 through the oxygen path 22, and the temperature of the CO2 is increased as the fuel burns. At this time, the temperature of the combustion gas discharged from the supercritical CO2 generator combustor 11 becomes a high-temperature combustion gas of 900°C to 1300°C. The air separation device 20 incorporates an oxygen booster (not shown) that boosts the pressure of the oxygen separated from the air. Further, as in the fourth embodiment described later, a part of the boosted oxygen may be supplied to the combustion furnace 51. The oxygen supplied through the oxygen path 22 may be, for example, at a high concentration of about 99% or more. By supplying high-concentration oxygen, it is possible to prevent a decrease in the performance of the burner due to nitrogen oxides (NOx) caused by nitrogen, which is an impurity.

[0075] The air separation device 20 separates oxygen (O2) and nitrogen (N2) from the air obtained through the air path 21. The oxygen separated from the air is compressed to a high pressure and supplied to the combustor 11 for supercritical CO2 generation through the oxygen path 22. The nitrogen separated from the air is recovered through the nitrogen path 23. The recovered nitrogen can also be used as nitrogen gas, liquefied nitrogen, etc. The air separation device 20 may be included in the CO2 recovery system 101 or may be included in the external equipment 200.

[0076] The method of the air separation device 20 is not particularly limited, and examples include temperature swing adsorption (TSA), pressure swing adsorption (PSA), pressure temperature swing adsorption (PTSA), cryogenic separation method, etc. In the air separation device 20, an adsorbent may be used to selectively separate gas components. The adsorbent is not particularly limited, and examples include activated carbon, molecular sieve, zeolite, etc.

[0077] In the combustor 11 for supercritical CO2 generation, a fuel gas composed of light hydrocarbons is used as the fuel. The fuel gas is not particularly limited, but preferably mainly composed of methane (C1) and including light hydrocarbon gases such as ethane (C2), propane (C3), butane (C4), etc. The light hydrocarbon gas can be obtained from natural gas such as liquefied natural gas (LNG), methanation, methane fermentation, etc. The fuel gas is supplied to the combustor 11 for supercritical CO2 generation from the fuel gas supply facility 60 through the fuel gas supply path 61. Although not particularly shown, a fuel gas booster may be used to boost the fuel gas before it is supplied to the combustor 11 for supercritical CO2 generation. The electric power or mechanical power for driving the fuel gas booster may be supplied from the supercritical CO2 cycle power generation facility 10.

[0078] The combustion gas generated in the combustor 11 for supercritical CO2 generation becomes high temperature and high pressure due to the combustion heat. The combustion gas is supplied as a supercritical CO2 fluid to the turbine 12 for supercritical CO2 power generation through the combustion gas path 11a. The supercritical CO2 fluid becomes the driving fluid of the turbine 12 for supercritical CO2 power generation, driving the generator 12a to generate electricity.

[0079] The electric power 120 obtained by the generator 12a can be supplied to and used by the CO₂ recovery facility 90, the external facility 200, etc. The use of the electric power 120 is not particularly limited, but as an example, it includes power sources such as electric motors, heat sources such as heaters, light sources such as lighting devices, and power supply to control devices, communication devices, cooling devices, air conditioning devices, etc. For example, as shown in FIG. 3, the electric power 120 may be transmitted from the electrical chamber 121 via the transmission line 122 and used to drive motors such as the turning device 123 and the blower 124. The electric power required for the CO₂ recovery facility 90 may be supplied only from the supercritical CO₂ cycle power generation facility 10. Optionally, the CO₂ recovery facility 90 may utilize external grid power derived from renewable energy or fossil fuels.

[0080] After driving the turbine 12 for supercritical CO₂ power generation, the CO₂ fluid passes through the first circulation path 12b and exchanges heat with the heat medium of the heat transport facility 33 or the normal-temperature CO₂ fluid before being supplied to the combustor 11 for supercritical CO₂ generation in the CO₂ heat exchanger 19. After the temperature is lowered, it may be further cooled by the CO₂ first cooler 13. Moisture in the CO₂ fluid condenses due to cooling, resulting in a gas-liquid mixed fluid. This gas-liquid mixed fluid is transferred to the CO₂ gas-liquid separator 14 via the second circulation path 13a, and the moisture is separated from the CO₂ gas fluid. The moisture separated from the CO₂ fluid in the CO₂ gas-liquid separator 14 is discharged from the drainage path 14b.

[0081] The CO₂ fluid from which moisture has been separated in the CO₂ gas-liquid separator 14 is transferred from the CO₂ gas-liquid separator 14 to the CO₂ second compressor 15 via the third circulation path 14a and recompressed. In the CO₂ second compressor 15, the CO₂ fluid may be pressurized from a low-pressure gas to a medium-pressure gas of about 20 bar to 80 bar. The CO₂ fluid compressed to the medium-pressure level is transferred to the CO₂ second cooler 16 via the fourth circulation path 15a and completely liquefied. The liquid CO₂ is stored in a liquefied CO₂ storage container 17 such as a drum via the fifth circulation path 16a.

[0082] The liquid CO2 in the liquefied CO2 storage container 17 is transferred to the CO2 first compression device 18 via the sixth circulation path 17a for circulation. The CO2 first compression device 18 is, for example, a pressure boosting pump. The liquid CO2 is pressurized and heated via the CO2 heat exchanger 19 to become supercritical CO2. The supercritical CO2 is supplied to the combustor 11 for generating supercritical CO2 and is directly heated by the supercritical high-temperature CO2 generated by combustion, becoming the driving fluid of the turbine 12 for supercritical CO2 power generation. In the case of the illustrated example, the CO2 fluid supplied from the combustor 11 for generating supercritical CO2 to the turbine 12 for supercritical CO2 power generation through the combustion gas path 11a circulates like the first circulation path 12b for circulation, the second circulation path 13a for circulation, the third circulation path 14a for circulation, the fourth circulation path 15a for circulation, the fifth circulation path 16a for circulation, the sixth circulation path 17a for circulation, and the seventh circulation path 18a for circulation. In the following description, the high-temperature CO2 fluid flowing through the first circulation path 12b for circulation is referred to as "high-temperature CO2 fluid 12b", and the normal-temperature CO2 fluid flowing through the seventh circulation path 18a for circulation is referred to as "normal-temperature CO2 fluid 18a". Also, the heat medium flowing through the heat medium path 33a may be referred to as "heat medium 33a".

[0083] The normal-temperature CO2 fluid 18a supplied to the combustor 11 for generating supercritical CO2 exchanges heat with the high-temperature CO2 fluid 12b discharged from the turbine 12 for supercritical CO2 power generation via the CO2 heat exchanger 19. Thereby, it can be supplied to the combustor 11 for generating supercritical CO2 in a state where the temperature of the normal-temperature CO2 fluid 18a is increased. The CO2 heat exchanger 19 has a first heat exchange function for supplying heat from the high-temperature CO2 fluid 12b to the normal-temperature CO2 fluid 18a and a second heat exchange function for supplying heat from the high-temperature CO2 fluid 12b to the heat medium 33a of the heat transport facility 33. The first heat exchange function and the second heat exchange function may be realized by one integrated CO2 heat exchanger 19 as shown in FIG. 2. The high-temperature CO2 fluid 12b may be branched on the first circulation path 12b for circulation, and the first heat exchange function and the second heat exchange function may be realized by different heat exchangers. Specifically, the heat exchanger where the high-temperature CO2 fluid 12b and the normal-temperature CO2 fluid 18a exchange heat and the heat exchanger where the branched high-temperature CO2 fluid 12b and the heat medium 33a exchange heat may be different heat exchangers.

[0084] In the supercritical CO2 cycle power generation facility 10, the kinetic energy of the supercritical circulating CO2 fluid circulating therein may be utilized as mechanical power. As shown in FIG. 3, for example, a part of the supercritical circulating CO2 fluid is extracted from downstream of the combustor 11 for generating supercritical CO2 and upstream of the turbine 12 for supercritical CO2 power generation, and is supplied via the CO2 fluid supply path 111 to a power turbine 112 provided separately from the turbine 12 for supercritical CO2 power generation. Then, the power obtained by driving the power turbine 112 with the supercritical circulating CO2 fluid may be supplied to mechanical devices such as a compression device 113 outside the supercritical CO2 cycle power generation facility 10. In this case, the CO2 fluid discharged from the power turbine 112 may be returned to the downstream side of the turbine 12 for supercritical CO2 power generation via the CO2 fluid return path 114 and circulated through the supercritical CO2 cycle power generation facility 10.

[0085] The power turbine 112 and the compression device 113 can be installed, for example, in an air separation device 20, a first acid gas booster 32, a fuel gas supply facility 60, a second acid gas booster 72, etc. Although not particularly shown, for example, the output shaft of the above-described power turbine 112 may be coupled to the drive shaft used when compressing exhaust gas-derived CO2 in the first acid gas booster 32 to supply mechanical power to the first acid gas booster 32. Further, the output shaft of the power turbine 112 may be coupled to the drive shaft of a booster other than the first acid gas booster 32. Thereby, the kinetic energy possessed by the supercritical circulating CO2 fluid can be directly supplied to exhaust gas-derived CO2 and a booster outside the supercritical CO2 cycle power generation facility 10.

[0086] As described above, when supplying the exhaust gas-derived CO2 pressurized by the first acid gas booster 32 to the supercritical CO2 cycle power generation facility 10, it is preferable to send it out in a state suitable for the mixed operation conditions with the supercritical circulating CO2 fluid circulating through the supercritical CO2 cycle power generation facility 10.

[0087] The position where the exhaust gas-derived CO2 is supplied to the supercritical CO2 cycle power generation facility 10 is not particularly limited. However, when it is supplied between the turbine 12 for supercritical CO2 power generation and the first CO2 compressor 18, since the pressure of the circulating CO2 fluid is relatively low, the load related to the pressure increase of the exhaust gas-derived CO2 can be reduced, and the equipment cost can be reduced. Specifically, the exhaust gas-derived CO2 may be supplied between the turbine 12 for supercritical CO2 power generation and the second CO2 compressor 15. In this case, the pressure after the exhaust gas-derived CO2 is pressurized by the first acid gas booster 32 may be approximately the same as the pressure before the CO2 fluid on the supercritical CO2 cycle power generation facility 10 side is pressurized by the first CO2 compressor 18. Therefore, when the exhaust gas-derived CO2 is supplied to the supercritical CO2 cycle power generation facility 10, the pressure may be lower than the critical pressure of CO2 (73.8 barA).

[0088] As described above, the CO2 fluid used in the supercritical CO2 cycle power generation facility 10 circulates in the supercritical CO2 cycle power generation facility 10 in a supercritical state, a liquid state, or a gaseous state. During that time, in order to supplement the energy taken away in the supercritical CO2 cycle power generation facility 10, in the supercritical CO2 generator combustor 11, a fuel of light hydrocarbon mainly composed of methane is burned by high-purity oxygen, and the energy is supplemented. Therefore, excessive CO2 is generated and needs to be discharged from the supercritical CO2 cycle power generation facility 10.

[0089] In the illustrated example, the CO2 discharge path 18b branches from between the first CO2 compressor 18 and the CO2 heat exchanger 19. In this case, since a part of the CO2 fluid with a relatively low temperature and low utilization value as temperature is discharged to the outside, the loss of thermal energy can be suppressed. Also, even when the CO2 receiving facility 40 requires high-pressure CO2 such as a CO2 storage facility (CCS), the necessary pressure can be applied to the discharged CO2 fluid. Further, since the CO2 fluid before being mixed with oxygen and fuel in the supercritical CO2 generator combustor 11 contains high-purity CO2, it is suitable as the acceptance condition for the CO2 receiving facility 40.

[0090] The CO2 receiving facility 40 may be any facility that can utilize surplus CO2 without releasing it into the atmosphere, and is not limited to CCS. Examples of the CO2 receiving facility 40 include an enhanced oil recovery (EOR) facility that injects CO2 into an oil field to increase oil production, a urea synthesis facility that reacts CO2 with ammonia (NH3) to synthesize urea, a carbonate synthesis facility that reacts CO2 with a metal compound such as calcium hydroxide or magnesium hydroxide to synthesize a carbonate, a methane synthesis (methanation) facility that reacts CO2 with hydrogen to synthesize methane, a photosynthesis promotion facility that utilizes CO2 for plant photosynthesis, etc. Further, the CO2 receiving facility 40 may be a transport ship or a lorry that transports liquefied CO2. The CO2 receiving facility 40 may be included in the CO2 recovery system 101 or may be included in the external facility 200. The CO2 recovery system 101 may utilize two or more types or two or more of the above-described CO2 receiving facilities 40.

[0091] The CO2 discharge path 18b does not have to be a facility dedicated to discharging surplus CO2 fluid in the supercritical CO2 cycle power generation facility 10, and may be shared with other CO2 discharge facilities. For example, when the external facility 200 has the second acid gas removal facility 71, the CO2 discharge path 72a for discharging the existing AGRU-derived CO2 recovered by the second acid gas removal facility 71 to the CO2 receiving facility 40 may be merged with the CO2 discharge path 18b.

[0092] Unlike the first acid gas removal facility 31, the second acid gas removal facility 71 does not have a heat transport facility 33 that supplies the heat possessed by the CO2 fluid of the supercritical CO2 cycle power generation facility 10. The existing AGRU-derived CO2 recovered by the second acid gas removal facility 71 is transferred to a newly installed second acid gas booster facility 72 via a CO2 transfer path 71a, and is discharged to a CO2 discharge path 72a after undergoing compression, dehydration, liquefaction, etc. The second acid gas booster facility 72 discharges impurities such as moisture separated from the existing AGRU-derived CO2 from an impurity discharge path 72b. The second acid gas booster facility 72 may remove components that are not preferable for the downstream CO2 receiving facility 40, such as hydrogen sulfide (H2S), etc. from the existing AGRU-derived CO2-containing gas, if necessary. Specifically, the second acid gas booster facility 72 may include at least one of a dehydration device and a liquefaction device. The second acid gas booster facility 72 may be included in the CO2 recovery system 101 or may be included in the external facility 200.

[0093] The exhaust gas-derived CO2 boosted by the first acid gas booster device 32 may be discharged to the CO2 receiving facility 40 via an exhaust gas-derived CO2 transfer path 32a and a CO2 discharge path 41. In this case, the first acid gas booster device 32 may boost the exhaust gas-derived CO2 to a pressure suitable for reception in the CO2 receiving facility 40. Instead of directly discharging CO2 to the CO2 receiving facility 40, the CO2 discharge path 41 may merge with the CO2 discharge path 18b of the supercritical CO2 cycle power generation facility 10. In short, the surplus CO2 fluid in the supercritical CO2 cycle power generation facility 10 and the CO2 recovered by the first and second acid gas removal facilities may be discharged toward the CO2 receiving facility 40 and recovered without being released into the atmosphere.

[0094] Next, with reference to FIG. 4, the CO2 recovery system 102 of the second embodiment will be described. Similar to the CO2 recovery system 101 of the first embodiment, the CO2 recovery system 102 of the second embodiment includes a supercritical CO2 cycle power generation facility 10 and a CO2 recovery facility 90 that recovers the exhaust gas of the external combustion facility 50. For elements common to the second embodiment and the first embodiment, the same reference numerals may be used, and duplicate explanations may be omitted.

[0095] In the case of the second embodiment, the existing AGRU-derived CO2 recovered by the second acid gas removal facility 71 is supplied to the supercritical CO2 cycle power generation facility 10. In order to transfer the existing AGRU-derived CO2 recovered by the second acid gas removal facility 71, a CO2 transfer path 71a is connected to the inlet side of the first acid gas booster 32. The first acid gas booster 32 boosts the pressure of the exhaust gas-derived CO2 recovered from the exhaust gas by the first acid gas removal facility 31 together with the existing AGRU-derived CO2 recovered from the second acid gas removal facility 71 of the external facility 200.

[0096] The existing AGRU-derived CO2 and exhaust gas-derived CO2 boosted by the first acid gas booster 32 are supplied to the supercritical CO2 cycle power generation facility 10 via the exhaust gas-derived CO2 transfer path 32a. The position where the exhaust gas-derived CO2 containing the existing AGRU-derived CO2 is supplied to the supercritical CO2 cycle power generation facility 10 is not particularly limited, similar to the first embodiment, but it may be supplied between the supercritical CO2 power generation turbine 12 and the CO2 first compressor 18.

[0097] In the case of the second embodiment, when the external facility 200 has the second acid gas removal facility 71 as an external acid gas removal facility together with the external combustion facility 50, the first acid gas booster 32 can be shared by the first acid gas removal facility 31 and the second acid gas removal facility 71, so that the cost of the equipment required for CO2 boosting can be reduced.

[0098] Although not particularly shown, also in the CO2 recovery systems 103 and 104 of the third or fourth embodiment described later, similar to the second embodiment, it is also possible to boost the pressure of the exhaust gas-derived CO2 recovered by the first acid gas removal facility 31 and the existing AGRU-derived CO2 recovered from the second acid gas removal facility 71 together with the first acid gas booster 32. In this case, the second acid gas boosting facility 72 can be omitted.

[0099] Next, with reference to FIG. 5, the CO2 recovery system 103 of the third embodiment will be described. The CO2 recovery system 103 of the third embodiment includes a supercritical CO2 cycle power generation facility 10 and a CO2 recovery facility 90 that recovers the exhaust gas of the external combustion facility 50, similar to the CO2 recovery system 101 of the first embodiment. For elements common to the third embodiment and the first embodiment, the same reference numerals may be used, and duplicate descriptions may be omitted. Also, the exhaust gas flowing through the exhaust gas recovery path 30a may be referred to as "exhaust gas fluid 30a".

[0100] In the third embodiment, when the exhaust gas of the external combustion facility 50 (specifically, the combustor 52d of the combustion furnace 51 and the gas turbine device 52) recovered through the exhaust gas recovery path 30a using the exhaust gas blowers 30b and 30c is at a high temperature of 150°C or higher, the heat of the exhaust gas is supplied to the normal-temperature CO2 fluid 18a of the supercritical CO2 cycle power generation facility 10 via the heat transport facility 34 by the exhaust gas heat exchanger 35. When the temperature of the normal-temperature CO2 fluid 18a of the supercritical CO2 cycle power generation facility 10 is lower than the temperature of the exhaust gas fluid 30a of the external combustion facility 50, heat can be supplied from the exhaust gas side to the CO2 fluid side. Thereby, a part of the energy required to heat the driving fluid of the supercritical CO2 cycle power generation facility 10 can be supplemented with the heat of the exhaust gas from the external combustion facility 50, and the fuel of the supercritical CO2 generation combustor 11 can be saved.

[0101] The heat transport facility 34 used in the CO2 recovery system 103 of the third embodiment includes a heat medium path 34a through which an independent heat medium is transferred, a heat medium pump 34b that transfers the heat medium in the heat medium path 34a, a heat medium path 34c that branches from the heat medium path 34a downstream of the heat medium pump 34b and passes through the CO2 heat exchanger 19 of the supercritical CO2 cycle power generation facility 10, a heat medium path 34d that branches from the heat medium path 34a and passes through the first acid gas removal facility 31 of the CO2 recovery facility 90, and an exhaust gas heat exchanger 35 that performs heat exchange between the high-temperature exhaust gas from the external combustion facility 50 and the heat medium.

[0102] According to the heat transport facility 34 shown in the figure example, the heat medium circulating through the heat medium path 34a and the heat medium path 34c can receive heat supply from the high-temperature exhaust gas from the external combustion facility 50 in the exhaust gas heat exchanger 35. Further, the heat medium of the heat transport facility 34 can exchange heat with the normal-temperature CO2 fluid of the supercritical CO2 cycle power generation facility 10 in the CO2 heat exchanger 19. Thereby, heat can be supplied from the high-temperature exhaust gas from the external combustion facility 50 to the normal-temperature CO2 fluid. Also, the heat medium of the heat transport facility 34 can supply heat for regenerating the CO2 absorbent in the first acid gas removal facility 31. Thereby, since the heat required for regenerating the CO2 absorbent is supplied from the high-temperature exhaust gas from the external combustion facility 50, the use of a heat source accompanied by the atmospheric emission of CO2 can be suppressed.

[0103] Although not particularly shown, the facilities receiving heat supply by the heat medium in the heat medium path 34d are not limited to the first acid gas removal facility 31, and may be targeted at various facilities of the CO2 recovery facility 90. Thereby, from the high-temperature exhaust gas from the external combustion facility 50, the necessary level of heat can be supplied to the apparatuses and facilities that require heat in the CO2 recovery facility 90.

[0104] As shown in FIG. 6, the heat supply from the high-temperature exhaust gas from the external combustion facility 50 to the CO2 fluid and the heat supply from the high-temperature exhaust gas to the first acid gas removal facility 31 may be performed by separate heat transport facilities 34. Specifically, the circulation path 340 for supplying heat to the CO2 fluid and the circulation path 341 for supplying heat to the first acid gas removal facility 31 may be independent. Heat medium pumps 34b and 34e are respectively provided in these circulation paths 340 and 341.

[0105] As shown in FIG. 7, the heat transport facility 33 of the first embodiment may be used in combination with the heat transport facility 34 of the third embodiment. In this case, the heat supply to the first acid gas removal facility 31 may be performed by the heat transport facility 33, and the heat supply to the CO2 fluid may be performed by the heat transport facility 34.

[0106] Next, with reference to FIG. 8, the CO2 recovery system 104 of the fourth embodiment will be described. The CO2 recovery system 104 of the fourth embodiment includes, similarly to the CO2 recovery system 101 of the first embodiment, a supercritical CO2 cycle power generation facility 10 and a CO2 recovery facility 90 that recovers the exhaust gas of the external combustion facility 50. For elements common to the fourth embodiment and the first embodiment, the same reference numerals may be used, and redundant descriptions may be omitted.

[0107] In the CO2 recovery system 104 of the fourth embodiment, a part of the oxygen separated by the air separation device 20 branches from the oxygen path 22 leading to the supercritical CO2 generator combustor 11 of the supercritical CO2 cycle power generation facility 10 and is supplied to the combustion furnace 51 to burn the fuel supplied from the fuel path 51b.

[0108] The exhaust gas of the combustion furnace 51 is discharged from the exhaust gas path 51c in a high-temperature state because the concentration of CO2 is high and the amount of nitrogen oxides (NOx) is extremely small due to oxy-fuel combustion. A circulation path 53b may be formed to return a part of the combustion gas from the exhaust gas path 51c to the combustion furnace 51 via the circulation blower 53a. By returning the exhaust gas to the combustion furnace 51, the inside of the combustion furnace 51 heated to a high temperature by oxy-fuel combustion can be cooled.

[0109] Although not particularly shown, an exhaust gas heat exchanger 35 of the heat transport facility 34 of the third embodiment may be provided in the exhaust gas circulation cycle 53 of the fourth embodiment. Thereby, a part of the heat of the high-temperature exhaust gas can be supplied to the supercritical CO2 cycle power generation facility 10 or the CO2 recovery facility 90.

[0110] When oxygen and fuel are burned while circulating the exhaust gas in the circulation path 53b including the combustion furnace 51, the amount of CO2 in the exhaust gas increases. Excess CO2 may be transferred to the second acid gas booster facility 72 through the CO2 recovery path 54 branching from the exhaust gas circulation cycle 53 and discharged to the CO2 receiving facility 40 through the CO2 discharge path 72a.

[0111] Although not particularly shown, the high-concentration CO2 recovered from the CO2 recovery path 54 may be transferred to the first acid gas booster 32 and supplied to the supercritical CO2 cycle power generation facility 10. When the CO2 recovered from the CO2 recovery path 54 contains nitrogen oxides (NOx) or the like, it may be transferred to the first acid gas removal facility 31. When the CO2 recovered from the CO2 recovery path 54 does not contain impurities other than oxygen or moisture, it may be transferred to the first acid gas booster 32 without passing through the first acid gas removal facility 31.

[0112] As described above, the present invention has been described based on preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present invention. Examples of modifications include addition, substitution, omission, and other changes of elements in each embodiment. It is also possible to appropriately combine elements used in two or more embodiments.

[0113] While there is a tendency to rely on power supply from unstable renewable energy for CO2 emission reduction, the present invention can constantly supply the necessary power to the self-power generation device and related external facilities by providing a CO2 cycle power generation facility using a CO2 fluid having supercritical high-level energy as a driving fluid.

[0114] Furthermore, after recovering the CO2 that has been discharged from the external combustion facility to the atmosphere using a newly installed acid gas removal facility, it can be temporarily fed into the CO2 cycle power generation facility, and the excess CO2 can be taken out as a high-concentration CO2 fluid. By preparing a geological isolation or reuse facility (CO2 receiving facility) as the recipient of the discharged high-concentration CO2 fluid, it is possible to significantly suppress the atmospheric emission of CO2.

[0115] When the exhaust gas of the external combustion device is at a high temperature, it is also possible to supply heat to the CO2 cycle power generation facility via a heat medium. In this way, a CO2 recovery system that can exchange electricity and heat as energy forms can be constructed, and an epoch-making environmental protection system aiming for zero emissions of GHG (greenhouse gas) that does not depend on renewable energy can be provided.

[0116] Specifically, CO2 discharged from an external combustion facility is directly recovered from a new acid gas removal facility, and the required power and heat are supplied from a CO2 cycle power generation facility. The CO2 taken out from the external combustion facility is once sent to the CO2 cycle power generation facility in a medium-pressure state, mixed with the large-circulation CO2 fluid, and then taken out as a high-purity high-pressure CO2 liquid in a form that is easy to extract. Only the excess is discharged from the CO2 cycle power generation facility.

[0117] Since the discharged CO2 is isolated underground or reused, the atmospheric emission of CO2 can be significantly suppressed. As for CO2 recovery other than external combustion facilities, it can also be applied to the recovery of CO2 discharged, for example, from the thermal decomposition of limestone. By mixing and treating the CO2 discharged from various plants including external CO2 emission facilities with the large-circulation CO2 fluid of the CO2 cycle power generation facility, scattered related equipment can be integrated. Furthermore, the excess of the CO2 fluid after mixing treatment can also be sent to the CO2 receiving facility in a lump.

Industrial Applicability

[0118] The present invention can be used in various industries that require CO2 recovery.

Explanation of Signs

[0119] E... Energy, F... Fluid, 10... Supercritical CO2 cycle power generation facility, 11... Combustor for generating supercritical CO2, 11a... Combustion gas path, 12... Turbine for supercritical CO2 power generation, 12a... Generator, 12b... First circulation path or high-temperature CO2 fluid, 13... CO2 first cooler, 13a... Second circulation path, 14... CO2 gas-liquid separator, 14a... Third circulation path, 14b... Drainage path of the CO2 gas-liquid separator, 15... Second CO2 compression device, 15a... Fourth circulation path, 16... CO2 second cooler, 16a... Fifth circulation path, 17... Liquefied CO2 storage container, 17a... Sixth circulation path, 18... First CO2 compression device, 18a... Seventh circulation path or normal-temperature CO2 fluid, 18b... CO2 discharge path, 19... CO2 heat exchanger, 20... Air separation device, 21... Air path, 22... Oxygen path, 23... Nitrogen path, 30... CO2 recovery device, 30a... Exhaust gas recovery path or exhaust gas fluid, 30b, 30c... Exhaust gas blowers, 31... First acid gas removal facility, 31a... CO2-containing gas transfer path, 31b... Treated gas discharge path, 32... First acid gas boosting device, 32a... CO2 transfer path derived from exhaust gas, 32b... Drainage path of the acid gas boosting device, 33, 34... Heat transfer facilities, 33a... Heat medium path or heat medium, 33b, 34b, 34e... Heat medium pumps, 34a, 34c, 34d... Heat medium paths, 35... Exhaust gas heat exchanger, 40... CO2 receiving facility, 41... CO2 discharge path, 50... External combustion facility, 51... Combustion furnace, 51a... Air path of the combustion furnace, 51b... Fuel path of the combustion furnace, 51c... Exhaust gas path of the combustion furnace, 52... Gas turbine device, 52a... Air path of the gas turbine device, 52b... Compressor of the gas turbine device, 52c... Fuel path of the gas turbine device, 52d... Combustor of the gas turbine device, 52e... Turbine, 52f... Exhaust stack, 52g... Exhaust gas path of the gas turbine device, 53... Exhaust gas circulation cycle, 53a... Circulation blower, 53b... Circulation path of the combustion furnace, 54... CO2 recovery path, 60... Fuel gas supply facility, 61... Fuel gas supply path, 71... Second acid gas removal facility, 71a... CO2 transfer path, 72... Second acid gas boosting facility, 72a... CO2 discharge path, 72b... Impurity discharge path, 90... CO2 recovery facility, 100, 101, 102, 103,104…CO2 recovery system, 111…CO2 fluid supply path, 112…turbine for power, 113…compression device, 114…CO2 fluid return path, 120…electric power, 121…electricity room, 122…transmission line, 123…swivel device, 124…blower, 200…external equipment, 340, 341…circulation paths of heat transport equipment.,

Claims

1. A turbine for power generation using carbon dioxide fluid as a driving fluid, and a CO that boosts the carbon dioxide fluid after driving the power generation turbine ２ first compressor, and the CO ２ CO that heats the carbon dioxide fluid boosted by the first compressor ２ heat exchanger, and the CO ２ A carbon dioxide cycle power generation facility comprising a combustor that mixes and burns, and heats the carbon dioxide fluid heated by the heat exchanger, oxygen supplied from an air separation device, and a light hydrocarbon gas mainly composed of methane, and the combustion gas heated by the combustor is supplied to the power generation turbine as the driving fluid A carbon dioxide recovery method using a carbon dioxide recovery system including a carbon dioxide recovery facility that recovers carbon dioxide from exhaust gas containing carbon dioxide discharged by combustion of fuel in an external combustion facility, comprising: supplying a part of the carbon dioxide fluid discharged from the carbon dioxide cycle power generation facility and the carbon dioxide recovered by the carbon dioxide recovery facility to a carbon dioxide receiving facility capable of receiving carbon dioxide, and supplying the energy obtained by the carbon dioxide cycle power generation facility to the carbon dioxide recovery facility; the energy supplied from the carbon dioxide cycle power generation facility to the carbon dioxide recovery facility includes the electric power obtained by the power generation turbine; the carbon dioxide recovery facility includes a first acid gas removal facility that recovers carbon dioxide contained in the exhaust gas from the external combustion facility, and a first acid gas pressure increasing facility that increases the pressure of the carbon dioxide recovered by the first acid gas removal facility, and the electric power obtained by the power generation turbine is supplied to the first acid gas pressure increasing facility; Supply the carbon dioxide pressurized by the first acid gas pressurization facility between the power generation turbine and the ２ first compressor, and mix it with the carbon dioxide fluid. A carbon dioxide recovery method characterized by this is provided. ２ A carbon dioxide recovery method characterized by supplying the carbon dioxide pressurized by the first acid gas pressurization facility between the power generation turbine and the first compressor and mixing it with the carbon dioxide fluid.

2. A turbine for power generation using carbon dioxide fluid as a driving fluid, and a CO that boosts the carbon dioxide fluid after driving the power generation turbine ２ first compressor, and the CO ２ CO that heats the carbon dioxide fluid pressurized by the first compressor ２ heat exchanger, and the CO ２ A carbon dioxide cycle power generation facility comprising: a combustor that mixes and burns and heats the carbon dioxide fluid heated by the heat exchanger, oxygen supplied from an air separation device, and a light hydrocarbon gas mainly composed of methane, and the combustion gas heated by the combustor is supplied as the driving fluid to the power generation turbine A carbon dioxide recovery method using a carbon dioxide recovery system including a carbon dioxide recovery facility that recovers carbon dioxide from exhaust gas containing carbon dioxide discharged by combustion of fuel in an external combustion facility, comprising: supplying a part of the carbon dioxide fluid discharged from the carbon dioxide cycle power generation facility and the carbon dioxide recovered by the carbon dioxide recovery facility to a carbon dioxide receiving facility capable of receiving carbon dioxide, and supplying the energy obtained by the carbon dioxide cycle power generation facility to the carbon dioxide recovery facility; the energy supplied from the carbon dioxide cycle power generation facility to the carbon dioxide recovery facility includes the heat possessed by the carbon dioxide fluid; the carbon dioxide recovery facility includes a first acid gas removal facility that recovers carbon dioxide contained in the exhaust gas from the external combustion facility, and a first acid gas pressure increasing facility that increases the pressure of the carbon dioxide recovered by the first acid gas removal facility, and the heat possessed by the carbon dioxide fluid is supplied to the first acid gas removal facility by heat exchange; The carbon dioxide pressurized by the first acid gas pressurizing facility is supplied between the power generation turbine and the ２ first compressor and mixed with the carbon dioxide fluid, characterized in that it is a carbon dioxide recovery method.

3. A turbine for power generation using carbon dioxide fluid as a driving fluid, and a CO that boosts the carbon dioxide fluid after driving the power generation turbine ２ first compressor, and the CO ２ CO that heats the carbon dioxide fluid pressurized by the first compressor ２ heat exchanger, and the CO ２ A carbon dioxide cycle power generation facility comprising a combustor that mixes and burns and heats the carbon dioxide fluid heated by the heat exchanger, oxygen supplied from an air separation device, and a light hydrocarbon gas mainly composed of methane, and the combustion gas heated by the combustor is supplied as the driving fluid to the power generation turbine A carbon dioxide recovery method using a carbon dioxide recovery system including a carbon dioxide recovery facility that recovers carbon dioxide from exhaust gas containing carbon dioxide discharged by combustion of fuel in an external combustion facility, comprising: A part of the carbon dioxide fluid discharged from the carbon dioxide cycle power generation facility and the carbon dioxide recovered by the carbon dioxide recovery facility are supplied to a carbon dioxide receiving facility capable of receiving carbon dioxide, and the energy obtained in the carbon dioxide cycle power generation facility is supplied to the carbon dioxide recovery facility. The heat of the exhaust gas from the external combustion facility is supplied to the carbon dioxide fluid circulating in the carbon dioxide cycle power generation facility, which is at a lower temperature than the exhaust gas, by heat exchange. A carbon dioxide recovery method characterized by this.

4. The energy supplied from the carbon dioxide cycle power generation facility to the carbon dioxide recovery facility includes the electric power obtained by the power generation turbine. The carbon dioxide recovery method according to claim 2 or 3, characterized by this.

5. The energy supplied from the carbon dioxide cycle power generation facility to the carbon dioxide recovery facility includes the heat possessed by the carbon dioxide fluid. The carbon dioxide recovery method according to any one of claims 1, 3, and 4, characterized by this.

6. The energy supplied from the carbon dioxide cycle power generation facility to the carbon dioxide recovery facility includes the mechanical power obtained from the combustion gas obtained in the combustor. The carbon dioxide recovery method according to any one of claims 1 to 5, characterized by this.

7. The carbon dioxide recovery facility includes a first acid gas removal facility for recovering carbon dioxide contained in the exhaust gas from the external combustion facility, and a first acid gas pressure boosting facility for boosting the carbon dioxide recovered by the first acid gas removal facility. The electric power obtained by the power generation turbine is supplied to the first acid gas pressure boosting facility. The carbon dioxide recovery method according to any one of claims 2 to 6, characterized by this.

8. The carbon dioxide recovery facility includes a first acid gas removal facility for recovering carbon dioxide contained in the exhaust gas from the external combustion facility, and a first acid gas pressure boosting facility for boosting the carbon dioxide recovered by the first acid gas removal facility. The heat possessed by the carbon dioxide fluid is supplied to the first acid gas removal facility by heat exchange. The carbon dioxide recovery method according to any one of claims 1, and 3 to 7, characterized by this.

9. The carbon dioxide recovery facility includes a first acid gas removal facility that recovers carbon dioxide contained in the exhaust gas from the external combustion facility, and a first acid gas pressure boosting facility that boosts the pressure of the carbon dioxide recovered by the first acid gas removal facility. The energy supplied from the carbon dioxide cycle power generation facility to the carbon dioxide recovery facility includes the electric power obtained by the power generation turbine and the heat possessed by the carbon dioxide fluid, and the electric power obtained by the power generation turbine is supplied to the first acid gas pressure boosting facility. The carbon dioxide recovery method according to any one of claims 1 to 8, characterized in that.

10. The carbon dioxide recovery facility includes a first acid gas removal facility that recovers carbon dioxide contained in the exhaust gas from the external combustion facility, and a first acid gas pressure boosting facility that boosts the pressure of the carbon dioxide recovered by the first acid gas removal facility. The first acid gas removal facility performs a recovery step of absorbing carbon dioxide contained in the exhaust gas from the external combustion facility into a carbon dioxide absorbent to recover carbon dioxide, and a regeneration step of heating the carbon dioxide absorbent to release carbon dioxide. The heat possessed by the carbon dioxide fluid is supplied to the regeneration step by heat exchange. The carbon dioxide recovery method according to any one of claims 1 to 9, characterized in that.

11. The carbon dioxide recovery facility includes a first acid gas removal facility that recovers carbon dioxide contained in the exhaust gas from the external combustion facility, and a first acid gas pressure boosting facility that boosts the pressure of the carbon dioxide recovered by the first acid gas removal facility. The first acid gas pressure boosting facility boosts the pressure of the carbon dioxide-containing gas recovered from the exhaust gas from the external combustion facility by the first acid gas removal facility, together with the carbon dioxide-containing gas recovered from a second acid gas removal facility, which is an acid gas removal facility other than the first acid gas removal facility. The carbon dioxide recovery method according to any one of claims 1 to 10, characterized in that.

12. The heat possessed by the exhaust gas from the external combustion facility is supplied by heat exchange to the carbon dioxide fluid that circulates through the carbon dioxide cycle power generation facility and has a lower temperature than the exhaust gas. The carbon dioxide recovery method according to any one of claims 1 to 11, characterized in that.

13. The external combustion equipment includes a combustion furnace, the carbon dioxide recovery system includes an air separation device for separating oxygen supplied to the carbon dioxide cycle power generation equipment from air, and a part of the oxygen obtained by the air separation device is supplied to the combustion furnace. The carbon dioxide recovery method according to any one of claims 1 to 12, characterized in that.

14. The carbon dioxide recovery method according to any one of claims 1 to 13, characterized in that heat possessed by the carbon dioxide fluid from the carbon dioxide cycle power generation equipment is supplied outside the carbon dioxide cycle power generation equipment.

15. A turbine for power generation using carbon dioxide fluid as a driving fluid, and a CO that boosts the carbon dioxide fluid after driving the power generation turbine ２ first compressor, and the CO ２ A CO that heats the carbon dioxide fluid pressurized by the first compressor ２ heat exchanger, and the CO ２ A carbon dioxide cycle power generation facility comprising a combustor that mixes and burns and heats the carbon dioxide fluid heated by the heat exchanger, oxygen supplied from an air separation device, and a light hydrocarbon gas mainly composed of methane, and the combustion gas heated by the combustor is supplied to the power generation turbine as the driving fluid A carbon dioxide recovery system including a carbon dioxide recovery facility for recovering carbon dioxide from exhaust gas containing carbon dioxide discharged by combustion of fuel in external combustion equipment, A part of the carbon dioxide fluid discharged from the carbon dioxide cycle power generation equipment and the carbon dioxide recovered by the carbon dioxide recovery equipment are supplied to a carbon dioxide receiving facility capable of receiving carbon dioxide, and the energy obtained by the carbon dioxide cycle power generation equipment is supplied to the carbon dioxide recovery equipment, The energy supplied from the carbon dioxide cycle power generation equipment to the carbon dioxide recovery equipment includes electric power obtained by the power generation turbine, The carbon dioxide recovery equipment includes a first acid gas removal facility for recovering carbon dioxide contained in the exhaust gas from the external combustion equipment, and a first acid gas pressure increasing facility for increasing the pressure of the carbon dioxide recovered by the first acid gas removal facility. The electric power obtained by the power generation turbine is supplied to the first acid gas pressure increasing facility, The carbon dioxide pressurized by the first acid gas pressurizing facility is supplied between the power generation turbine and the ２ ２ first compressor and mixed with the carbon dioxide fluid, and a carbon dioxide recovery system characterized by this.

16. A turbine for power generation using carbon dioxide fluid as a driving fluid, and a CO that boosts the carbon dioxide fluid after driving the turbine for power generation ２ First compressor, and the CO ２ A CO that heats the carbon dioxide fluid pressurized by the first compressor ２ Heat exchanger, and the CO ２ A combustion device that mixes and burns and heats the carbon dioxide fluid heated by the heat exchanger, oxygen supplied from an air separation device, and a light hydrocarbon gas mainly composed of methane, and a carbon dioxide cycle power generation facility in which the combustion gas heated by the combustion device is supplied to the power generation turbine as the driving fluid A carbon dioxide recovery system including a carbon dioxide recovery facility for recovering carbon dioxide from exhaust gas containing carbon dioxide discharged by combustion of fuel in external combustion equipment, A part of the carbon dioxide fluid discharged from the carbon dioxide cycle power generation equipment and the carbon dioxide recovered by the carbon dioxide recovery equipment are supplied to a carbon dioxide receiving facility capable of receiving carbon dioxide, and the energy obtained by the carbon dioxide cycle power generation equipment is supplied to the carbon dioxide recovery equipment, The heat possessed by the exhaust gas from the external combustion equipment is supplied to the carbon dioxide fluid circulating in the carbon dioxide cycle power generation equipment, which has a lower temperature than the exhaust gas, by heat exchange. A carbon dioxide recovery system characterized by this.

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