Steam generation system for co2 recovery device, co2 recovery device provided with same, and method for generating steam for co2 recovery device

Abstract

Provided is a steam generation system for a CO2 recovery device, the steam generation system making it possible to supply thermal energy to a CO2 recovery device by using heat of less than 100°C. A steam generation system (9) comprises: a steam generator (27) that generates negative-pressure steam by heating negative-pressure water using hot water at less than 100°C; a steam supply path (31) via which the negative-pressure steam generated by the steam generator (27) is supplied to a CO2 recovery device (7); a water supply path (29) via which water is supplied to the steam generator (27); and a pressure reduction valve (35) provided to the water supply path (29), the pressure reduction valve (35) reducing the pressure of the supplied water to atmospheric pressure or less.

Description

Steam generation system for CO2 capture device, CO2 capture device equipped with the same, and steam generation method for CO2 capture device

[0001] The present disclosure relates to a steam generation system for a CO2 capture device, a CO2 capture device including the same, and a steam generation method for a CO2 capture device.

[0002] A CO2 capture device that captures CO2 from exhaust gas emitted from an internal combustion engine is known (see, for example, Patent Document 1). The CO2 capture device described in Patent Document 1 uses a portion of the exhaust gas as a heat source for desorbing CO2 adsorbed in an adsorbent.

[0003] International Publication No. 2016 / 076041

[0004] However, exhaust gas often reaches high temperatures of 300 to 400°C, and if part of the exhaust gas is used as a heat source for desorbing CO2, as in the CO2 recovery device described in Patent Document 1, the amount of exhaust gas that can be used for high-temperature applications such as exhaust heat recovery boilers will be relatively reduced.

[0005] Since steam is often used as a heat source for CO2 capture devices, it is advantageous to generate steam and supply it to the CO2 capture device. However, although there is heat below 100°C around the CO2 capture device, it is discarded without being used for heat, which is a problem in that thermal energy is not being used effectively.

[0006] The present disclosure has been made in consideration of the above circumstances, and aims to provide a steam generation system for a CO2 recovery device that can supply thermal energy to a CO2 recovery device using warm heat of less than 100°C, a CO2 recovery device equipped with the same, and a steam generation method for a CO2 recovery device.

[0007] A steam generation system for a CO2 capture device according to one embodiment of the present disclosure includes a steam generator that generates steam by heating negative pressure water with a heat medium, and a steam supply unit that supplies the steam generated by the steam generator to a CO2 capture device, wherein the heat medium is cooling water from a source of CO2 to be captured by the CO2 capture device, or a heat medium heated by the cooling water.

[0008] A CO2 capture apparatus according to one aspect of the present disclosure includes the above-described steam generation system for a CO2 capture apparatus.

[0009] A steam generation method for a CO2 capture device according to one embodiment of the present disclosure includes a steam generation process for generating steam by heating negative pressure water with a heat medium, and a steam supply process for supplying the steam generated in the steam generation process to a CO2 capture device, wherein the heat medium is cooling water from a source of CO2 to be captured by the CO2 capture device, or a heat medium heated by the cooling water.

[0010] Heat below 100°C can be used to provide thermal energy to the CO2 capture device.

[0011] 1 is a schematic configuration diagram showing a cogeneration system including a steam generation system for a CO2 capture device according to a first embodiment of the present disclosure. FIG. 2 is a schematic configuration diagram showing a cogeneration system including a steam generation system for a CO2 capture device according to a second embodiment of the present disclosure. FIG. 3 is a partially enlarged plan view showing an enlarged portion of the variable nozzle assembly of FIG.

[0012] [First Embodiment] A first embodiment according to the present disclosure will be described below with reference to Fig. 1. Fig. 1 shows a combined heat and power supply system 1A according to this embodiment. The combined heat and power supply system 1A includes a gas engine (power generation engine) 3, an exhaust gas boiler (exhaust heat recovery boiler) 5, a CO2 capture device 7, and a steam generator (steam generation system for the CO2 capture device) 9.

[0013] The gas engine 3 is operated using gas fuel such as city gas as fuel. The gas engine 3 drives a generator (not shown) to generate electric power. The electric power generated by the generator is supplied to a consumer. Note that instead of the gas engine 3, other power generation engines (internal combustion engines), such as a gas turbine engine or a diesel engine that uses oil fuel, may be used. Also, multiple gas engines 3 may be used.

[0014] The exhaust gas boiler 5 generates steam from the exhaust gas discharged from the gas engine 3. The exhaust gas that has completed heat exchange in the exhaust gas boiler 5 passes through an exhaust gas flow path 11 and is led to the CO2 recovery device 7. The steam generated in the exhaust gas boiler 5 is led to a boiler steam supply path 13 and supplied to an external demand destination.

[0015] The CO2 recovery device 7 recovers CO2 (carbon dioxide) from the exhaust gas guided from the gas engine 3. The CO2 recovery device 7 employs a chemical absorption method using an absorption liquid such as an amine absorption liquid (adsorbent) that chemically absorbs CO2.

[0016] The CO2 recovery system 7 includes an absorption tower 15 and a regeneration tower 16. In the absorption tower 15, an amine absorbing solution is brought into contact with the flue gas to absorb CO2 in the flue gas. A lean solution supply unit 15a is connected to the absorption tower 15, which supplies a lean solution from which CO2 has been desorbed and whose CO2 concentration has been made lean. The amine absorbing solution (lean solution) supplied from the lean solution supply unit 15a absorbs CO2 in the flue gas while flowing through the absorption tower 15. The rich solution, which has absorbed CO2 in the absorption tower 15 and whose CO2 concentration has been made rich, is sent to the rich solution supply unit 16a via a heat exchanger 20 by an absorption tower pump 22.

[0017] The heat exchanger 20 is a non-contact heat exchanger, and exchanges heat between the lean solution supplied from the regeneration tower pump 18 and the rich solution supplied from the absorption tower pump 22 .

[0018] The exhaust gas from which CO2 has been removed by the amine absorbent is discharged to the outside from the absorption tower 15.

[0019] In the regeneration tower 16, CO2 is desorbed from the rich solution that has absorbed CO2. The amine absorbing solution (rich solution) supplied from the rich solution supply unit 16a into the regeneration tower 16 is heated by the heat exchanger 20, thereby providing the amount of heat required for the endothermic reaction of desorbing CO2. CO2 is desorbed from the rich solution while the amine absorbing solution (rich solution) supplied from the rich solution supply unit 16a flows through the regeneration tower 16. The CO2 desorbed from the rich solution is discharged from the regeneration tower 16 and led to a CO2 storage unit (not shown).

[0020] A reboiler 17 that heats the amine absorption solution is connected to the regeneration tower 16. The reboiler 17 heats the amine absorption solution extracted from the regeneration tower 16 via an absorption solution recovery line 16b. Steam introduced from a boiler steam branch line (steam supply section) 13a branched from the boiler steam supply line 13 is used as a heat source for the reboiler 17. The amine absorption solution heated by the reboiler 17 is returned to the regeneration tower 16 via an absorption solution return line 16c. The heated amine absorption solution (lean solution) is extracted from the bottom of the regeneration tower 16 and sent to a heat exchanger 20 by a regeneration tower pump 18.

[0021] The steam generating system 9 is connected to the gas engine 3. The steam generating system 9 includes a hot water circuit 25 through which hot water (heat medium) circulates between the gas engine 3 and the steam generating system 9, and a steam generator 27 to which the hot water circuit 25 is connected.

[0022] In this embodiment, the heat medium is the cooling water that cools the gas engine 3, which is the source of CO2 captured by the CO2 capture device 7, or a heat medium heated by the cooling water. More specifically, the system may be configured as follows: The hot water circuit 25 is a closed-loop flow path for circulating hot water guided from the gas engine 3. The hot water is heated by heat exchange with the cooling water that cools the gas engine 3, and is heated to a temperature of, for example, less than 100°C. The hot water circuit 25 is provided with a hot water pump 33. The operation of the hot water pump 33 is controlled by a control unit (not shown). The cooling water that cooled the gas engine 3 may be directly supplied to the hot water circuit 25, or the hot water circuit 25 may be formed by the cooling water circulation path itself. Here, the cooling water that cools the gas engine 3 also includes the cooling water that cools the oil circulating or passing through the gas engine 3. In addition, the configuration in which the cooling water that cools the gas engine 3 heats the hot water circuit 25 may be such that the cooling water is drawn outside the gas engine 3 through a water supply pipe, and the hot water inside the hot water circuit 25 is heated by a heat exchanger provided outside the gas engine 3.

[0023] The steam generator 27 is a non-contact heat exchanger in which hot water and feed water exchange heat without contact, and a partition-type heat exchanger such as a plate-type heat exchanger, a shell-and-plate heat exchanger, or a shell-and-tube heat exchanger can be used.

[0024] A water supply line (water supply unit) 29 that supplies water to be heated is connected to the steam generator 27. A pressure reducing valve 35 is provided in the water supply line 29. The pressure reducing valve 35 reduces the pressure of the water supply, which is at atmospheric pressure at room temperature (e.g., 20°C), to produce negative pressure water. The opening of the pressure reducing valve 35 is controlled by a control unit (not shown). The pressure reducing valve 35 is controlled as necessary in coordination with the operation of each steam compressor 37 so that the interior of the steam generator 27 is at a desired pressure.

[0025] A steam supply path (steam supply unit) 31 through which negative pressure steam generated by the steam generator 27 flows out is connected to the steam generator 27. The negative pressure steam generated by the steam generator 27 is generated by hot water of less than 100°C supplied from the hot water circuit 25. For example, when the pressure of the feed water is −0.054 MPaG, saturated steam is at 80°C, so negative pressure steam can be generated with hot water of about 85°C.

[0026] The steam supply path 31 is provided with a plurality of steam compressors 37 and a supply rate adjusting unit 39. Each steam compressor 37 compresses the negative pressure steam to a pressure equal to or higher than atmospheric pressure. Examples of the steam compressor 37 include positive displacement compressors such as screw compressors and claw compressors, as well as turbo compressors. Operation of the steam compressor 37 reduces the pressure in the flow path from its upstream side to the downstream side of the pressure reducing valve 35. The steam compressor 37 is driven by, for example, an electric motor, and its rotation speed is controlled by a control unit (not shown). While the present embodiment shown in FIG. 1 has four steam compressors 37 arranged in series, the number is not limited thereto and may be one, two, three, five, or more.

[0027] The supply amount adjusting unit 39 separates the pressurized steam into gas and liquid and adjusts the flow rate of the steam to be discharged. The flow rate of the steam discharged from the supply amount adjusting unit 39 is controlled by a control unit (not shown).

[0028] A portion of the feed water is guided from the water supply passage 29 to the downstream side of each steam compressor 37 and the supply amount adjustment unit 39 via a water injection pipe 41. The feed water guided from the water injection pipe 41 is injected to cool the pressurized steam and the steam guided to the supply amount adjustment unit 39. The water injection pipe 41 may be provided with a pressure boosting means (such as a pump) to obtain the pressure required for injection.

[0029] The pressurized steam flowing out from the supply amount adjustment unit 39 passes through the steam supply path 31 and merges with the boiler steam branch path 13a. In this way, the steam guided from the supply amount adjustment unit 39 merges with the boiler steam branch path 13a and is guided to the reboiler 17 of the CO2 recovery device 7.

[0030] A turbine 14 is provided in the boiler steam branch passage 13a upstream of a junction position P1 where the boiler steam branch passage 13a joins the steam supply passage 31. The turbine 14 reduces the pressure of the steam and recovers pressure energy. Note that an expansion valve may be provided instead of the turbine 14.

[0031] The control unit is composed of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium, for example, in the form of a program. The CPU reads this program into RAM and executes information processing and arithmetic operations to realize various functions. The program may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories.

[0032] The above-described cogeneration system 1A operates as follows. Electricity is generated by operating the gas engine 3, and exhaust gas discharged from the gas engine 3 is passed through the exhaust gas boiler 5 and guided to the CO2 recovery unit 7. Steam generated in the exhaust gas boiler 5 passes through the boiler steam supply path 13 and is supplied to a demand destination. A portion of the steam generated in the exhaust gas boiler 5 is branched off at the boiler steam branch path 13a, depressurized by the turbine 14, and then guided to the reboiler 17 of the CO2 recovery unit 7. Steam generated in the steam generator 27 and pressurized by each steam compressor 37 also flows into the boiler steam branch path 13a.

[0033] Hot water below 100°C, heated by the cooling water that cooled the gas engine 3, circulates through the hot water circuit 25. The hot water below 100°C is reduced in pressure by a pressure reducing valve 35 to a negative pressure, and is then heated in a steam generator 27 to generate negative pressure steam. The negative pressure steam generated by the steam generator 27 passes through a steam supply path 31, is pressurized to atmospheric pressure or higher by a plurality of steam compressors 37, and is then guided to a supply amount adjustment unit 39. The steam, the flow rate of which is adjusted by the supply amount adjustment unit 39, passes through the steam supply path 31 and merges with the boiler steam branch path 13a. The steam that has merged at the boiler steam branch path 13a is guided to the reboiler 17 and used as a heat source.

[0034] In the CO2 recovery unit 7, CO2 is recovered from the exhaust gas guided from the gas engine 3 in an absorption tower 15, and the exhaust gas after CO2 absorption is released to the outside. In the regeneration tower 16, the amine absorption solution is heated by a reboiler 17. CO2 desorbed from the amine absorption solution is discharged from the regeneration tower 16 and sent to a CO2 storage section.

[0035] The effects of the present embodiment described above are as follows. Negative pressure water is heated using hot water below 100°C to generate steam. This makes it possible to generate steam even from hot water below 100°C, which has a relatively low thermal utility value. In other words, even if the thermal energy generated by the CO2 generation source captured in the CO2 capture device 7 is relatively low-temperature, such as hot water below 100°C, it can be effectively utilized in the CO2 capture process. Therefore, CO2 can be desorbed from the amine absorption solution by supplying steam generated in the steam generator 27 to the CO2 capture device 7 as a heat source, without using a heat source or steam generation means other than the CO2 generation source.

[0036] A pressure reducing valve 35 is provided in the water supply line 29 that supplies water to the steam generator 27, and the water is made to be negative pressure water below atmospheric pressure. This makes it possible to supply negative pressure water to the steam generator 27 even when the water pressure is above atmospheric pressure.

[0037] Even when the negative-pressure steam generated by the steam generator 27 is directly supplied to the CO2 capture device 7, the sensible heat of the negative-pressure steam can be utilized, and heat can be supplied to the CO2 capture device 7 with equipment that is less costly than installing hot water piping. Alternatively, the negative-pressure steam may be pressurized to atmospheric pressure or higher by the steam compressor 37 and then supplied to the CO2 capture device 7. This allows for flexible response to the pressure required by the CO2 capture device 7. In this case, the pressure reducing valve 35 is controlled by a control unit (not shown) in coordination with the operation of each steam compressor 37 as needed, allowing steam at a desired temperature, pressure, or flow rate to be supplied to the CO2 capture device 7. Furthermore, this control unit can suppress fluctuations in the temperature, pressure, or flow rate of the steam supplied to the CO2 capture device 7, regardless of fluctuations in the amount of heat per hour supplied by the hot water circuit 25.

[0038] Negative pressure steam is generated in the steam generator 27 using hot water heated by the cooling water of the gas engine 3 that generates electricity. This makes it possible to configure a system capable of cogeneration. In particular, when the source of CO2 to be captured is an engine generator, the thermal energy of engine cooling water below 100°C, which has a large total energy content but could not be effectively utilized in the past due to its low temperature, can now be utilized in the CO2 capture process. Therefore, high-temperature, high-pressure steam energy, such as steam generated in an exhaust gas boiler using engine exhaust gas, can be effectively utilized for other industrial purposes.

[0039] Second Embodiment A second embodiment of the present disclosure will be described below. This embodiment is similar to the first embodiment except for the configuration of the turbine and steam compressor. Therefore, in the following description, the same components will be denoted by the same reference numerals and the description thereof will be omitted.

[0040] Fig. 2 shows a combined heat and power supply system 1B according to this embodiment. Although the CO2 recovery device 7 shown in Fig. 1 is omitted in Fig. 2, the combined heat and power supply system 1B according to this embodiment includes the CO2 recovery device 7 as in Fig. 1.

[0041] 2, the final stage (fourth stage) steam compressor 37A (37) located at the most downstream of the four steam compressors 37 is connected to the turbine 14 by a common rotating shaft 44. As a result, the power recovered by the turbine 14 is transmitted to the impeller of the steam compressor 37A.

[0042] The upstream side of the turbine 14 is provided with a plurality of variable nozzle assemblies 45 that control the steam flow rate. As shown in FIG. 3 , the variable nozzle assembly 45 includes a plurality of variable nozzles 45a spaced at predetermined intervals in the circumferential direction on the upstream side (outside) of the outer periphery of the turbine 14. The variable nozzles 45a rotate synchronously around a rotation shaft 45b. The angle of each variable nozzle 45a is controlled by a control unit (not shown). By changing the angle of each variable nozzle 45a to change the flow path area, the flow rate of steam flowing into the turbine 14 is variably adjusted. The provision of the variable nozzle assemblies 45 makes the turbine 14 a variable geometry (VG) turbine.

[0043] A pressure equalizing pipe 46 is provided between the outlet of the steam compressor 37A and the outlet of the turbine 14. The pressure equalizing pipe 46 makes the outlet pressure of the steam compressor 37A and the outlet pressure of the turbine 14 approximately equal. Note that instead of the pressure equalizing pipe 46, a pressure equalizing flow path may be provided inside the main body of the turbocharger in which the steam compressor 37A and the turbine 14 are configured as an integral unit.

[0044] According to this embodiment, the following advantageous effects are achieved: Since the power is recovered by the turbine 14 from the boiler steam generated in the exhaust gas boiler 5 to drive the steam compressor 37A, it is possible to improve energy efficiency.

[0045] The steam compressor 37A and the turbine 14 are connected by a common rotating shaft 44, and the outlet steam of the steam compressor 37A and the outlet steam of the turbine 14 are pressure-equalized by a pressure equalizing pipe 46. This cancels out the thrust force of the outlet steam applied to the steam compressor 37A and the thrust force of the outlet steam applied to the turbine 14, thereby reducing the thrust force acting on the rotating shaft 44.

[0046] Since the turbine 14 is a variable capacity turbine equipped with a variable nozzle assembly 45, power can be recovered with little loss even if the pressure of the boiler steam from which the turbine 14 recovers power fluctuates.

[0047] A motor-generator may be applied to the rotating shaft 44 connecting the steam compressor 37A and the turbine 14. The motor-generator is controlled by a control unit (not shown), and is used as a generator when the power recovered by the turbine 14 is greater than the power required by the steam compressor 37A, and is used as a motor (electric motor) when the power recovered by the turbine 14 is less than the power required by the steam compressor 37A. This allows the steam compressor 37A to operate flexibly even if the pressure of the boiler steam from which the turbine 14 recovers power fluctuates.

[0048] Furthermore, although the final stage steam compressor 37A is connected to the turbine 14, the steam compressor 37 that provides the recovered power for the turbine 14 may be a compressor of another stage (first, second, or third stage).

[0049] Furthermore, foil-type gas bearings may be used as bearings for the turbine 14 in each of the above-described embodiments, and oil-free may be used.

[0050] The steam generation system for a CO2 capture apparatus, the CO2 capture apparatus including the same, and the steam generation method for a CO2 capture apparatus described in each of the above-described embodiments can be understood, for example, as follows.

[0051] The steam generation system for a CO2 capture device according to the first aspect of the present disclosure comprises a steam generator (27) that generates steam by heating negative pressure water with a heat medium, and a steam supply unit (31) that supplies the steam generated by the steam generator to the CO2 capture device, wherein the heat medium is cooling water from a source of CO2 to be captured by the CO2 capture device, or a heat medium heated by the cooling water.

[0052] Negative pressure steam is generated by heating negative pressure water using a heat medium below 100°C. This makes it possible to generate steam even with a heat medium below 100°C, which has relatively low thermal utility value. By supplying the negative pressure steam generated by the steam generator to the CO2 capture device as a heat source, CO2 can be desorbed from the adsorbent.

[0053] The steam generation system for a CO2 capture apparatus according to the second aspect of the present disclosure is the same as that of the first aspect, and includes a water supply unit (29) that supplies water to the steam generator, and a pressure reducing valve (35) that is provided in the water supply unit and reduces the pressure of the water to below atmospheric pressure.

[0054] A pressure reducing valve is installed in the water supply section that supplies water to the steam generator, and the water is kept at a negative pressure below atmospheric pressure. This allows negative pressure water to be supplied to the steam generator even when the pressure is above atmospheric pressure.

[0055] In the steam generation system for a CO2 capture apparatus according to a third aspect of the present disclosure, in the first or second aspect, the steam supply unit includes a steam compressor (37) that increases the pressure of negative pressure steam to atmospheric pressure or higher.

[0056] The steam compressor boosts the negative pressure steam above atmospheric pressure before supplying it to the CO2 capture device, allowing for flexible response to the pressure requirements of the CO2 capture device.

[0057] A steam generation system for a CO2 capture apparatus according to a fourth aspect of the present disclosure is in any one of the first to third aspects, and includes a turbine (14) that recovers power from boiler steam generated by the boiler, and the steam compressor is driven by the turbine.

[0058] The steam compressor is driven by a turbine that recovers power from the boiler steam generated in the boiler, thereby improving energy efficiency. The boiler may be, for example, a heat recovery boiler that generates steam using exhaust gas discharged from an internal combustion engine (such as a power generation engine).

[0059] A steam generation system for a CO2 capture apparatus according to a fifth aspect of the present disclosure is the fourth aspect, wherein the steam compressor and the turbine are connected by a common rotating shaft (44), and the outlet steam of the steam compressor and the outlet steam of the turbine are pressure-equalized.

[0060] The steam compressor and turbine are connected by a common rotating shaft, and the steam at the outlet of the steam compressor and the steam at the outlet of the turbine are pressure-equalized, which reduces the thrust force acting on the rotating shaft.

[0061] A sixth aspect of the present disclosure provides a steam generation system for a CO2 capture apparatus according to the fourth or fifth aspect, wherein the steam compressor and the turbine are connected to a motor generator.

[0062] The steam compressor and turbine are connected to a motor-generator, so that when the power recovered by the turbine is greater than the power required by the steam compressor, the motor-generator is used as a generator, and when the power recovered by the turbine is less than the power required by the steam compressor, the motor-generator is used as a motor. This allows the steam compressor to operate flexibly even if the pressure of the boiler steam from which the turbine recovers power fluctuates.

[0063] A seventh aspect of the present disclosure provides a steam generation system for a CO2 capture system in any one of the fourth to sixth aspects, wherein the turbine is a variable geometry turbine.

[0064] Since the turbine is a variable geometry (VG) turbine, power can be recovered with little loss even if the pressure of the boiler steam from which the turbine recovers power fluctuates.

[0065] According to an eighth aspect of the present disclosure, in the steam generation system for a CO2 capture system of any one of the first to seventh aspects, the temperature of the heat medium is obtained from cooling water that cools a power generation engine (3).

[0066] The heat medium temperature of less than 100° C. is obtained from the cooling water of the power generation engine. This makes it possible to configure a system capable of cogeneration of heat and power.

[0067] A CO2 capture apparatus according to a first aspect of the present disclosure includes any one of the steam generation systems for a CO2 capture apparatus described above.

[0068] A steam generation method for a CO2 capture device according to a first aspect of the present disclosure includes a steam generation process for heating negative pressure water with a heat medium to generate steam, and a steam supply process for supplying the steam generated in the steam generation process to a CO2 capture device, wherein the heat medium is cooling water from a source of CO2 to be captured by the CO2 capture device, or a heat medium heated by the cooling water.

[0069] DESCRIPTION OF SYMBOLS 1A, 1B Combined heat and power supply system 3 Gas engine (power generation engine) 5 Exhaust gas boiler (exhaust heat recovery boiler) 7 CO2 recovery device 9 Steam generation system (steam generation system for CO2 recovery device) 11 Exhaust gas flow path 13 Boiler steam supply path 13a Boiler steam branch path (steam supply section) 14 Turbine 15 Absorber 15a Lean solution supply section 16 Regenerator 16a Rich solution supply section 16b Absorbent solution recovery path 16c Absorbent solution return path 17 Reboiler 18 Regenerator pump 20 Heat exchanger 22 Absorber pump 25 Hot water circuit 27 Steam generator 29 Water supply path (water supply section) 31 Steam supply path (steam supply section) 33 Hot water pump 35 Pressure reducing valve 37 Steam compressor 39 Supply amount adjustment section 41 Water injection pipe 44 Rotating shaft 45 Variable nozzle assembly 45a Variable nozzle 45b Rotating shaft 46 Pressure equalizing pipe

Claims

1. A steam generation system for a CO2 capture device, comprising: a steam generator that generates steam by heating negative pressure water with a heat medium; and a steam supply unit that supplies the steam generated by the steam generator to a CO2 capture device, wherein the heat medium is cooling water from the source of CO2 captured by the CO2 capture device, or a heat medium heated by the cooling water.

2. The steam generation system for a CO2 recovery apparatus according to claim 1, comprising: a water supply unit that supplies water to the steam generator; and a pressure reducing valve that is provided in the water supply unit and reduces the pressure of the water to below atmospheric pressure.

3. A steam generating system for a CO2 recovery device according to claim 1, wherein the steam supply unit is provided with a steam compressor that increases the pressure of negative pressure steam to atmospheric pressure or higher.

4. A steam generation system for a CO2 capture device according to claim 3, further comprising a turbine that recovers power from boiler steam generated by the boiler, and the steam compressor is driven by the turbine.

5. A steam generation system for a CO2 recovery unit according to claim 4, wherein the steam compressor and the turbine are connected by a common rotating shaft, and the outlet steam of the steam compressor and the outlet steam of the turbine are pressure-equalized.

6. The steam generating system for a CO2 capture device according to claim 4, wherein the steam compressor and the turbine are connected to a motor-generator.

7. A steam generating system for a CO2 recovery unit according to claim 4, wherein the turbine is a variable geometry turbine.

8. A steam generation system for a CO2 capture device according to claim 1, wherein the temperature of the heat transfer medium is obtained from the cooling water that cools the power generation engine.

9. A CO2 recovery system comprising the steam generation system for a CO2 recovery system according to any one of claims 1 to 8.

10. A steam generation method for a CO2 recovery system, comprising: a steam generation process for heating negative pressure water with a heat transfer medium to generate steam; and a steam supply process for supplying the steam generated in the steam generation process to a CO2 recovery system, wherein the heat transfer medium is cooling water from a source of CO2 to be recovered by the CO2 recovery system, or a heat transfer medium heated by the cooling water.

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