Gas treatment system

Abstract

To stably control a treatment process in a gas treatment system.SOLUTION: The gas treatment system (1) comprises a separation and recovery unit (5) for separating and recovering a desired component contained in a gas discharged from a gas discharge source (10), a heat removal device (2) for removing heat from the gas, a dust removal device (3) for removing dust contained in the gas, a blower (4) for compressing and discharging the gas from which dust has been removed by the dust removal device, at least one buffer tank (6A) for pressure adjustment provided on the gas discharge source side of the separation and recovery unit and for adjusting the flow rate of the gas flow path, a recirculation flow path (112, 113) for recirculating the gas from which dust has been removed by the dust removal device to the dust removal device, and a second control valve (137) for adjusting the flow rate of the gas flowing to the buffer tank.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to gas processing systems. [Background technology]

[0002] There is known a gas treatment system that separates and recovers desired components such as CO2 contained in gas discharged from an emission source such as a combustor or a power generator. This type of gas treatment system includes a dust removal device that removes impurities such as dust contained in the discharged gas, a heat removal device that cools (removes heat from) the high-temperature discharged gas, and a recovery device that selectively separates the desired components contained in the discharged gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-5241 [Patent Document 2] International Publication No. 2019 / 135284 [Patent Document 3] Japanese Patent Application Laid-Open No. 2000-208686 [Patent Document 4] Japanese Patent Application Publication No. 10-256319 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described gas treatment system, it is difficult to stably control the gas treatment process.

[0005] One of the objects of the present invention is to enable stable control of a treatment process in a gas treatment system. [Means for solving the problem]

[0006] A gas processing system according to one embodiment of the present invention comprises a separation and recovery unit that separates and recovers desired components contained in gas discharged by a gas emission source, a heat removal device that removes heat from the gas, a dust removal device that removes dust contained in the gas, a blower that compresses and discharges the gas from which dust has been removed by the dust removal device, at least one pressure-regulating buffer tank that is installed closer to the gas emission source than the separation and recovery unit and that adjusts the pressure in the gas flow path, a first control valve that adjusts the flow of gas in the gas flow path that flows to the buffer tank, a recirculation flow path that recirculates the gas from which dust has been removed by the dust removal device to the dust removal device, and a second control valve that adjusts the flow of gas in the flow path that supplies gas to the separation and recovery unit. [Effects of the Invention]

[0007] According to the present invention, stable control of the treatment process in the gas treatment system is possible. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of the configuration of a gas processing system according to a first embodiment. [Figure 2] FIG. 2 is a block diagram illustrating an example of the functional configuration of a control panel. [Figure 3] FIG. 3A is a graph illustrating the relationship between the operating load of the gas emission source and the pressure set value of the first buffer tank, and FIG. 3B is a graph illustrating the relationship between the operating load of the gas emission source and the opening degree of the pressure control valve connected to the first buffer tank. [Figure 4] FIG. 4A is a graph illustrating the relationship between the supply flow rate to the dust remover, the opening of the dust remover inlet flow control valve, and the flow rate in the excess flow discharge line, and FIG. 4B is a graph illustrating the relationship between the supply flow rate to the dust remover and the opening of the pressure control valve of the first buffer tank. [Figure 5] FIG. 10 is a flow chart illustrating an example of a process for releasing an excess flow amount of gas in the second state from the first buffer tank. [Figure 6]FIG. 10 is a flow chart illustrating an example of a control process for absorbing the difference between the processing capacity of the dust removal device and the processing capacity of the separation and recovery unit. [Figure 7] FIG. 4 is a diagram illustrating a modified example of the gas processing system according to the first embodiment. [Figure 8] FIG. 10 is a diagram illustrating a configuration example of a gas processing system according to a second embodiment. [Figure 9] FIG. 10 is a flow chart illustrating an example of a process for adjusting the flow rate of gas recirculated to the dust remover. [Figure 10] FIG. 10 is a diagram illustrating a modified example of the gas processing system according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The gas processing system exemplified in the following description is a system that performs a treatment process to selectively separate and recover desired components from gas emitted by a gas emission source. In this specification, the system will be described as recovering CO2 (carbon dioxide), but the components to be recovered are not limited to a specific component. The components to be recovered may be, for example, CH4 (methane) contained in natural gas flowing through the system, or CH4 or CO2 contained in biogas.

[0010] [First embodiment] FIG. 1 is a diagram showing an example of the configuration of a gas processing system according to a first embodiment. The gas processing system 1 shown in FIG. 1 includes process equipment, such as a heat removal device 2, a dust removal device 3, a blower 4, a separation and recovery unit 5, a first buffer tank 6A, a second buffer tank 6B, and an open circuit 7. The gas processing system 1 further includes a plurality of control valves and a plurality of measuring instruments provided in a gas flow path from a gas outlet of a gas emission source 10 to a gas inlet of the separation and recovery unit 5. The processing process performed by the gas processing system 1 is controlled by a control panel 8. The control panel 8 is connected to the process equipment, control valves, and measuring instruments of the gas processing system 1, as well as to the gas emission source 10, via communication lines 171 and 172. The communication lines 171 and 172 in FIG. 1 merely schematically illustrate the connection of the control panel 8 to the process equipment, control valves, and measuring instruments, as well as to the gas emission source 10, and the actual connection configuration in the gas processing system 1 is not limited to a specific connection configuration. For example, each of the process equipment, control valves and instruments, and the gas emission source 10 may be connected to the control panel 8 by a separate communication line.

[0011] The gas emission source 10 may be a device that burns fossil fuels or fuels derived from fossil fuels and emits gases containing CO2 (carbon dioxide) and the like, such as a diesel engine, a gasoline engine, a gas turbine, or a gas boiler. This type of gas emission source 10 may be applied, for example, to power ships, power generation equipment, and power generation equipment in various plants. The gas emission source 10 may be, for example, an incinerator in a waste incineration facility, a device for collecting natural gas that flows naturally, or a device for generating (creating) biogas.

[0012] A gas outlet (hereinafter referred to as "outlet") of the gas emission source 10 is connected to a gas recovery system and an open circuit 7 of the gas processing system 1 via a flow path switching unit. The gas recovery system is a flow path for recovering CO2 from the gas emitted by the gas emission source 10, and is connected in this order from upstream to downstream with a heat remover 2, a dust remover 3, a blower 4, and a separation and capture unit 5. The open circuit 7 is a circuit for releasing some or all of the gas emitted by the gas emission source 10 into the atmosphere without introducing it into the separation and capture unit 5, and may be, for example, an exhaust chimney. The flow path switching unit includes a first flow path 101, a second flow path 102, a first release flow path 121, a second release flow path 122, a first switching valve 131, a second switching valve 132, and a third switching valve 133. The term "flow path" in this specification may be interpreted as a "gas pipe." The first flow path 101 is a branched flow path having one upstream end and three downstream ends, and the upstream end is connected to the outlet of the gas discharge source 10. The first of the three downstream ends is connected to the inlet (primary side) of a first switching valve 131, and the second flow path 102 that introduces gas into the heat removal device 2 is connected to the outlet (secondary side) of the first switching valve 131. The second downstream end of the first flow path 101 is connected to the inlet of a second switching valve 132, and the outlet of the second switching valve 132 is connected to the first discharge flow path 121 that introduces gas into the open circuit 7. The third downstream end of the first flow path 101 is connected to the inlet of a third switching valve 133, and the outlet of the third switching valve 133 is connected to the second discharge flow path 122 that introduces gas into the open circuit 7.

[0013] The first switching valve 131 may be a control valve capable of continuously changing its valve opening, sometimes called a continuous control valve, but may also be an ON-OFF valve such as a solenoid valve. The second switching valve 132 may be a continuous control valve, and the third switching valve 133 may be an ON-OFF valve. The opening and closing of the first switching valve 131, the second switching valve 132, and the third switching valve 133 is controlled by the control panel 8 based on the pressure P0 of the first flow path 101 measured by the pressure sensor 151 and a protection set value set for the treatment process. The pressure P0 of the first flow path 101 may be a pressure measured upstream of a branch point of the first flow path 101, which may also be called the back pressure, outlet pressure, etc. of the gas discharge source 10. The protection set value for the pressure P0 may be, for example, the allowable back pressure (critical back pressure) Pp of the gas discharge source 10. The pressure sensor 151 may be a well-known one that outputs an electrical signal corresponding to the pressure P0 in the first flow path 101, and a suitable one is selected based on, for example, the shape of the first flow path 101 (inside the gas pipe), the type of gas flowing through the first flow path 101, the temperature, etc.

[0014] When separating and recovering CO2 from the gas emitted by the gas emission source 10, the first selector valve 131 is opened and the second selector valve 132 and the third selector valve 133 are closed to introduce the gas emitted by the gas emission source 10 into the heat removal device 2. When the flow rate of gas supplied from the gas emission source 10 to the heat removal device 2 is greater than the processing capacity of the heat removal device 2, the second selector valve 132 is opened to release a portion of the gas into the atmosphere through the open circuit 7. When the pressure P0 of the first flow path 101 increases, for example, the first selector valve 131 is closed and the second selector valve 132 and the third selector valve 133 are opened to release the gas into the atmosphere through the open circuit 7, thereby preventing the pressure P0 of the first flow path 101 from exceeding a protection setting value (for example, the allowable back pressure Pp of the gas emission source 10). The third switching valve 133 and the second release flow path 122 may be used to forcibly release the gas in the first flow path 101 into the atmosphere in an emergency.

[0015] The combination of the flow path switching unit including the first switching valve 131, the second switching valve 132, and the third switching valve 133 illustrated in FIG. 1 and the open circuit 7 can be an example of an open path and release valve in the flow path connecting the gas emission source 10 and the process equipment that exhausts gas to the outside of the gas recovery system without passing it through the process equipment when a protection setting value set for the treatment process is exceeded or until the process conditions for the treatment process are met.

[0016] The gas emitted from the gas emission source 10, particularly the gas emitted from a gas emission source 10 that burns a fuel with few impurities (e.g., gaseous fuel, liquid fuel equivalent to heavy oil A or light oil, etc.), may be at a high temperature and may contain impurities such as dust. For this reason, the high-temperature gas containing impurities (hereinafter referred to as "gas in a first state") that flows from the gas emission source 10 into the gas recovery system (second flow path 102) is first subjected to heat removal (cooling) in the heat removal device 2. The heat removal device 2 may be one well known in the field of gas processing and is not limited to a specific heat removal method (cooling method) or a specific configuration. The heat removal device 2 may be a direct contact gas-liquid heat exchanger such as a spray tower or a trickle type, or an indirect contact gas-liquid heat exchanger. In the gas processing system 1, process equipment (intermediate equipment) such as a selective catalytic reduction (SCR) device that removes NOx (nitrogen oxides) such as NO (nitric oxide) and NO2 (nitrogen dioxide), an exhaust gas recirculation (EGR) system, and an economizer that recovers heat from the gas discharged by the gas emission source 10 may be arranged between the gas emission source 10 and the heat removal device 2. The gas from which heat has been removed by the heat removal device 2 (hereinafter referred to as "second state gas") is introduced into the first buffer tank 6A through a third flow path 103.

[0017] The first buffer tank 6A may be a pressure adjustment tank for preventing the pressure P0 of the first flow path 101, measured by the pressure sensor 151, from exceeding a protective set value, causing the gas emission source 10 to shut down. The first buffer tank 6A has two outlets, one of which is connected to a fourth flow path 104 for introducing the second state gas into the dust remover 3. The downstream end of the fourth flow path 104 is connected to the inlet of a flow control valve 134, and the outlet of the flow control valve 134 is connected to a fifth flow path 105 for introducing the second state gas into the dust remover 3. The fifth flow path 105 is a branched flow path having two downstream ends, one of which is connected to the inlet of the dust remover 3. The other downstream end of the fifth flow path 105 is connected to the inlet of a release valve 135, and the outlet of the release valve 135 is connected to a third release flow path 123 for releasing the second state gas to the outside of the gas recovery system. The other outlet of the first buffer tank 6A is connected to the inlet of a pressure control valve 136 directly or via a flow path. The outlet of the pressure control valve 136 is connected to a fourth release flow path 124 that releases the gas in the second state to the outside of the gas recovery system. The downstream ends of the third release flow path 123 and the fourth release flow path 124 may be connected to the open circuit 7.

[0018] The flow control valve 134 between the fourth flow path 104 and the fifth flow path 105 may be a continuous control valve. The opening degree of the flow control valve 134 is controlled by the control panel 8 based on, for example, the flow rate of the gas in the first state discharged from the gas discharge source 10 (in other words, the flow rate of the gas in the second state introduced from the heat remover 2 to the first buffer tank 6A) and the supply flow rate of the gas in the second state to the dust remover 3. The supply flow rate of the gas in the second state to the dust remover 3 may be the treatment capacity of the dust remover 3, and the control panel 8 controls the opening degree of the flow control valve 134 so that the flow rate of the fifth flow path 105 measured by the flow sensor 152 becomes a set value (for example, the treatment capacity of the dust remover 3). The pressure control valve 136 connected to the other outlet of the first buffer tank 6A may be a continuous control valve. The pressure control valve 136 controls, for example, the pressure of the first buffer tank 6A measured by the pressure sensor 153 to a pressure set value PB calculated by an arithmetic expression described later. SVThe flow rate sensor 152 may be a well-known type that outputs an electric signal corresponding to the flow rate of the gas in the second state that passes through the flow control valve 134 and flows through the fifth flow path 105, and a suitable type is selected based on, for example, the type, temperature, etc. of the gas that flows through the fifth flow path 105. The pressure sensor 153 may be a well-known type that outputs an electric signal corresponding to the pressure of the first buffer tank 6A, and a suitable type is selected based on, for example, the type, temperature, etc. of the gas that is in the second state.

[0019] In gas processing system 1 of the present embodiment, for example, in dust remover 3 and separation and recovery unit 5 downstream of flow control valve 134 in the gas recovery system, blockage by dust or the like can increase flow path resistance (causing pressure to rise) or cause instantaneous pressure fluctuations. Such pressure increases or fluctuations can increase the back pressure of gas emission source 10 (pressure P0 of first flow path 101), potentially causing gas emission source 10 to stop. For this reason, in gas processing system 1 of the present embodiment, pressure control valve 136 adjusts the pressure of first buffer tank 6A to prevent pressure P0 of first flow path 101 from exceeding a protection setting value (allowable back pressure PP of gas emission source 10).

[0020] Furthermore, in gas processing system 1 of the present embodiment, for example, the flow rate of the first state gas (the processing capacity of heat remover 2) and the processing capacity of dust remover 3 may differ, and the flow rate of the second state gas in the flow path between heat remover 2 and dust remover 3 may become greater than the supply flow rate to dust remover 3. When the flow rate of the first state gas and the supply flow rate of the second state gas to dust remover 3 differ, in order to absorb the flow rate difference, gas processing system 1 of the present embodiment can adjust the supply flow rate to dust remover 3 by flow control valve 134. At this time, the second state gas that is not supplied to dust remover 3 and remains in first buffer tank 6A is released as an excess flow rate to the outside of the gas recovery system (e.g., into the atmosphere) through fourth release flow path 124 when the pressure of first buffer tank 6A is adjusted by pressure control valve 136. Therefore, gas processing system 1 of this embodiment can also prevent the back pressure of gas discharge source 10 (pressure P0 of first flow path 101) from exceeding the protective set value due to a pressure increase caused by an excess flow rate of the second state gas. Furthermore, in gas processing system 1 of this embodiment, if it is difficult to prevent the back pressure of gas discharge source 10 from exceeding the protective set value by only adjusting the pressure of first buffer tank 6A with pressure control valve 136, release valve 135 can be opened to release the second state gas to the outside of the gas recovery system through third release flow path 123.

[0021] The dust remover 3, to which the second-state gas from the first buffer tank 6A is introduced, removes impurities such as dust from the second-state gas. The dust remover 3 may be a known device in the field of gas processing and is not limited to a specific dust removal method (dust collection method) or a specific configuration. The dust remover 3 may be a device using any one of the following methods: a filter method, a dry or wet electrostatic precipitator method, a gravity precipitator method, an inertial force precipitator method, a centrifugal force precipitator method, and a scrubbing precipitator method, or a combination of these methods. The outlet of the dust remover 3 is connected to the inlet of the blower 4 by a sixth flow path 106. The blower 4 sucks in the gas from which impurities have been removed by the dust remover 3 (hereinafter referred to as "third-state gas"), compresses it, and sends it out from the outlet. In the gas processing system 1 illustrated in Figure 1, the third state gas compressed by the blower 4 is introduced into a second buffer tank 6B installed between the blower 4 and the separation and recovery unit 5 through a seventh flow path 107 connected to the outlet of the blower 4. The blower 4 may be a compressor with a larger compression ratio. The blower 4 or compressor may be one well known in the field of gas processing, and is not limited to one of a specific compression type or one of a specific configuration.

[0022] Like the first buffer tank 6A, the second buffer tank 6B can be a pressure adjustment tank for preventing the pressure P0 of the first flow path 101 from exceeding a protective setting value and causing the gas discharge source 10 to shut down. The second buffer tank 6B has two outlets, one of which is connected to an eighth flow path 108 for introducing the third state gas into the separation and recovery unit 5. The downstream end of the eighth flow path 108 is connected to the inlet of a flow control valve 137, and the outlet of the flow control valve 137 is connected to a ninth flow path 109 for introducing the third state gas into the separation and recovery unit 5. The ninth flow path 109 is a branched flow path having two downstream ends, one of which is connected to the inlet of the separation and recovery unit 5. The other downstream end of the ninth flow path 109 is connected to the inlet of a release valve 138, and the outlet of the release valve 138 is connected to a fifth release flow path 125 for releasing the third state gas to the outside of the gas recovery system. The downstream end of the fifth discharge flow path 125 may be connected to the open circuit 7 .

[0023] The flow control valve 137 between the eighth flow path 108 and the ninth flow path 109 may be a continuous control valve similar to the flow control valve 134. The opening degree of the flow control valve 137 is controlled by the control panel 8 based on, for example, the flow rate of the gas in the third state sent from the blower 4 and the supply flow rate of the gas in the third state to the separation and recovery unit 5. The supply flow rate of the gas in the third state to the separation and recovery unit 5 may be the treatment capacity of the separation and recovery unit 5, and the control panel 8 controls the opening degree of the flow control valve 137 so that the flow rate of the gas in the ninth flow path 109 measured by the flow sensor 154 becomes a set value (e.g., the treatment capacity of the separation and recovery unit 5). The flow sensor 154 may be a well-known type that outputs an electrical signal corresponding to the flow rate of the gas in the third state passing through the flow control valve 137 and flowing through the ninth flow path 109, and a suitable type is selected based on, for example, the type, temperature, etc. of the gas flowing through the ninth flow path 109.

[0024] The other outlet of the second buffer tank 6B is connected to a flow path 112 for releasing an excess flow of the third state gas introduced into the second buffer tank 6B from the dust remover 3. The downstream end of the flow path 112 is connected to the inlet of a pressure control valve 139. The pressure control valve 139 may be a continuous control valve corresponding to the pressure control valve 136 connected to the first buffer tank 6A. The opening degree of the pressure control valve 139 is controlled by the control panel 8 based on the pressure of the second buffer tank 6B measured by a pressure sensor 156, the pressure of the ninth flow path 109 measured by a pressure sensor 155, and the rotation speed (discharge pressure) of the blower 4. In the gas processing system 1 illustrated in FIG. 1, the outlet of the pressure control valve 139 is connected to a flow path 113 that returns the third state gas to the dust remover 3 (in other words, recirculates the third state gas). The pressure sensor 156 may be a known sensor that outputs an electric signal corresponding to the pressure in the second buffer tank 6B, and a suitable sensor is selected based on, for example, the type of gas in the third state, the temperature, etc. The pressure sensor 155 may be a known sensor that outputs an electric signal corresponding to the pressure in the ninth flow path 109, and a suitable sensor is selected based on, for example, the type of gas in the third state, the temperature, etc. The pressure sensor 155 that measures the pressure in the ninth flow path 109 and the flow rate sensor 154 that measures the flow rate in the ninth flow path 109 are not limited to separate sensors, and may be sensors included in a single measuring instrument that can measure both pressure and flow rate.

[0025] The separation and capture unit 5 separates and captures a desired component (e.g., CO2) contained in the third state gas. The separation and capture unit 5 may be one well known in the field of gas processing and is not limited to a specific separation and capture method or a specific configuration. The separation and capture unit 5 may be configured to separate the introduced gas into a gas with a low CO2 concentration and a gas containing a high CO2 concentration using a separation membrane that selectively permeates CO2 contained in the gas and release the separated gas. The separation membrane may be a hollow fiber membrane, but is not limited to a specific configuration. The separation and capture unit 5 may separate the target components to be captured, such as CO2, using a physical adsorbent, a solid absorbent, a PCP (porous coordination polymer), a MOF (metal-organic framework), or a chemical absorption liquid instead of a separation membrane. The gas containing a high concentration of CO2 separated from the third state gas in the separation and capture unit 5 is recovered through the recovery flow path 110. The gas with a lower CO2 concentration is released through the release flow path 111, for example, to the outside of the gas recovery system. The gas containing a high concentration of CO2 discharged into the recovery passage 110 may be supplied to, for example, another (next stage) separation and recovery unit.

[0026] In the separation and recovery unit 5, pressure may rise or fluctuate momentarily due to blockages caused by dust or the like remaining in the third state gas. Such pressure rises or fluctuations may cause the gas emission source 10 to stop, as described above. For this reason, in the gas treatment system 1 of this embodiment, the pressure of the second buffer tank 6B is adjusted by a pressure control valve 139 connected to the outlet of the second buffer tank 6B via a flow path 112. In addition, in the gas treatment system 1 of this embodiment, the supply flow rate of the third state gas to the separation and recovery unit 5 is controlled to a set value (e.g., the processing capacity of the separation and recovery unit 5) by adjusting the opening of the flow control valve 137 and the rotation speed of the blower 4. In this case, for example, if the processing capacity of the dust remover 3 and the processing capacity of the separation and recovery unit 5 differ, the flow rate of the third state gas in the flow path between the dust remover 3 and the separation and recovery unit 5 may be greater than the processing capacity of the separation and recovery unit 5. In this case, too, the third state gas that is not supplied to the separation and recovery unit 5 and remains in the second buffer tank 6B is recirculated as an excess flow rate through the flow paths 112 and 113 when the pressure of the second buffer tank 6B is adjusted by the pressure control valve 139. This makes it possible to absorb the difference in flow rate between the treatment capacity of the dust remover 3 and the treatment capacity of the separation and recovery unit 5. Furthermore, if it is difficult to prevent the back pressure of the gas emission source 10 from exceeding the protective set value simply by adjusting the pressure of the second buffer tank 6B with the pressure control valve 139, the release valve 138 can be opened and the excess flow rate of the third state gas can be released to the outside of the gas recovery system through the fifth release flow path 125.

[0027] In the gas processing system 1 illustrated in FIG. 1, the excess flow rate of the third state gas released from the second buffer tank 6B to the flow path 113 through the pressure control valve 139 is reintroduced into the dust remover 3. In this way, by recirculating the excess flow rate of the third state gas from which dust has been removed, the amount of CO2 released outside the gas recovery system (e.g., into the atmosphere) can be reduced. Note that if it is difficult to prevent the back pressure of the gas emission source 10 from exceeding the protective set value by recirculating the excess flow rate of the third state gas, the excess flow rate of the third state gas may be released outside the gas recovery system through a separate release flow path connected to the outlet of the second buffer tank 6B via a pressure control valve, for example.

[0028] Fig. 2 is a block diagram illustrating an example of the functional configuration of a control panel 8. The control panel 8 illustrated in Fig. 2 includes a control unit 800, a storage unit 810, a communication unit (a receiving unit 821 and a transmitting unit 822), and an operation unit 830, which are interconnected by a bus 840.

[0029] The control unit 800 generates control signals for controlling the operation of the gas emission source 10, the operation of process equipment such as the heat removal device 2, the opening degree of each control valve, etc., in accordance with the programs and control information stored in the memory unit 810 and various information related to the treatment process of the gas processing system 1 acquired via the receiving unit 821. The receiving unit 821 receives the operating state of the gas emission source 10, the operating state of process equipment such as the heat removal device 2, detection signals from pressure sensors 151, 153, 155, and 156, detection signals from flow sensors 152 and 154, etc. The control unit 800 transmits the generated control signals via the transmitting unit 822 to the gas emission source 10, the process equipment such as the heat removal device 2, and the opening degree adjustment mechanisms of each control valve. The functions of the control unit 800 are provided by a processor such as a CPU (Central Processing Unit) that executes a program. The memory unit 810 stores control programs that cause the control unit 800 to execute the processes described below, setting values ​​811 referenced by the control unit 800, etc. The storage device that provides the functions of the storage unit 810 includes a ROM (Read Only Memory) and a RAM (Random Access Memory) as a main storage device. The storage device that provides the functions of the storage unit 810 may also include an auxiliary storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

[0030] Operation unit 830 accepts and displays inputs such as setting information related to the control of gas processing system 1. The functions of operation unit 830 are provided by, for example, various switches arranged on an operation panel, input devices such as a keyboard, and display devices such as a liquid crystal display, a seven-segment display, pilot lamps, etc. arranged on the operation panel. Some or all of the functions of operation unit 830 may be provided by, for example, a single piece of hardware that combines the functions of an input device, such as a touch panel display, and the functions of a display device.

[0031] Note that control panel 8 is not limited to a specific hardware configuration. Control panel 8 may be designed and manufactured as a control device dedicated to controlling gas processing system 1, or may be a combination of a general-purpose computer such as a personal computer and a control program recorded on a computer-readable recording medium. The hardware of control panel 8 may include a single piece of hardware that provides the functions shown by multiple blocks in FIG. 2, for example, hardware that integrates a processor as control unit 800 and a memory as storage unit 810. Alternatively, the hardware of control panel 8 may include multiple pieces of hardware that provide the functions shown by a single block in FIG. 2, for example, multiple separate processors that function as control unit 800.

[0032] In the gas treatment system 1, pressure increases due to blockage of the filter of the dust remover 3 or the separation membrane of the separation and recovery unit 5, as well as momentary pressure fluctuations due to other factors, may occur. If the allowable back pressure PP of the gas emission source 10 is set low, an increase in pressure in the gas recovery system may cause the back pressure of the gas emission source 10 (pressure P0 of the first flow path 101) to exceed the allowable back pressure PP, which may result in the gas emission source 10 shutting down. In the gas treatment system 1 of this embodiment, for example, when the filter of the dust remover 3 becomes clogged and flow path resistance increases, the pressure in the first buffer tank 6A can be adjusted to suppress a pressure increase in the fifth flow path 105 and thereby suppress a rise in the back pressure of the gas emission source 10. The pressure in the first buffer tank 6A is adjusted by the aperture of the pressure control valve 136.

[0033] The opening of the pressure control valve 136 is controlled by the control panel 8 so that the measured value (PV value) of the pressure of the first buffer tank 6A measured by the pressure sensor 153 does not exceed a set value (SV value). The set value is not limited to a fixed value set based on the allowable back pressure PP of the gas emission source 10, but may be a variable value that can be changed within a range that does not exceed the allowable back pressure PP of the gas emission source 10. As an example, the pressure setting value PB of the first buffer tank 6A is SV can be calculated by the following formula 1.

number

[0034] FIG. 3A is a graph illustrating the relationship between the operating load of the gas emission source and the pressure set value of the first buffer tank, and FIG. 3B is a graph illustrating the relationship between the operating load of the gas emission source and the opening degree of the pressure control valve connected to the first buffer tank.

[0035] The set pressure value PB of the first buffer tank 6A calculated by Equation 1 SV 3A, increases in proportion to the operating load of the gas exhaust source 10, and can be set so that the pressure PBmax when the operating load of the gas exhaust source 10 is at its maximum value (rated load) is equal to or less than the allowable back pressure PP of the gas exhaust source 10. The control unit 800 of the control panel 8 acquires information about the operating load of the gas exhaust source 10 via the receiving unit 821, and calculates the set value PB of the pressure of the first buffer tank 6A using Equation 1. SV Thereafter, the control unit 800 calculates the pressure of the first buffer tank 6A measured by the pressure sensor 153. SV The opening of the pressure control valve 136 is adjusted so that the pressure is equal to or greater than the pressure measured by the pressure sensor 153. The opening of the pressure control valve 136 is adjusted by a known method. For example, the control unit 800 may adjust the opening of the pressure control valve 136 by calculating the pressure measured by the pressure sensor 153 (PV value) and the calculated set value PB SV Based on the difference between the pressure in the first buffer tank 6A and the current opening of the pressure control valve 136, the pressure in the first buffer tank 6A is set to the set value PB SVand controls the opening degree of the pressure control valve 136 by deriving an opening degree (command value) of the pressure control valve 136 such that the opening degree of the pressure control valve 136 satisfies the following equation. Also, for example, the relationship between the operating load of the gas emission source 10 and the opening degree of the pressure control valve 136 as shown in FIG. 3B may be derived in advance using the calculation result of Equation 1, and stored in the storage unit 810 as one of the set values ​​811. In this case, the control unit 800 determines whether the pressure of the first buffer tank 6A is equal to or exceeds the set value PB based on the opening degree (set value) of the pressure control valve 136 derived based on the operating load of the gas emission source 10 and the relationship shown in FIG. 3B, and the current opening degree of the pressure control valve 136. SV 3B is calculated in advance and stored in the storage unit 810, the pressure setting value PB SV This can omit the process of calculating the set value PB, thereby reducing the processing load on the control unit 800. SV is varied within a range that does not exceed the allowable back pressure PP of gas exhaust source 10, thereby enabling gas processing system 1 to continue operating even when the operating load of gas exhaust source 10 varies. Note that the curve in Figure 3B merely shows a schematic example of the relationship between the operating load of gas exhaust source 10 and the aperture of pressure control valve 136. The relationship between the operating load of gas exhaust source 10 and the aperture of pressure control valve 136 can be set to be a suitable relationship depending on, for example, the conditions of the process in gas processing system 1.

[0036] Furthermore, in gas processing system 1 of the present embodiment, as described above, the flow rate of the second state gas supplied from first buffer tank 6A to dust remover 3 can be controlled by flow control valve 134. Then, an excess flow rate of the second state gas generated by this control can be discharged from first buffer tank 6A to the outside of the gas recovery system through fourth discharge flow path 124 connected to the outlet of pressure control valve 136.

[0037] Fig. 4A is a graph illustrating the relationship between the supply flow rate to the dust remover, the aperture of the dust remover supply flow control valve, and the flow rate in the excess flow rate discharge line, and Fig. 4B is a graph illustrating the relationship between the supply flow rate to the dust remover and the aperture of the pressure control valve of the first buffer tank. In Fig. 4A, the dust remover supply flow control valve is flow control valve 134 between first buffer tank 6A and dust remover 3, and the excess flow rate discharge line is fourth discharge flow path 124 connected to first buffer tank 6A via pressure control valve 136.

[0038] The supply flow rate of the second-state gas from the first buffer tank 6A to the dust remover 3 is controlled by the aperture of the flow control valve 134. The relationship between the aperture of the flow control valve 134 and the supply flow rate of the second-state gas to the dust remover 3 is, for example, as shown by the thick solid curve in FIG. 4A. The control unit 800 of the control panel 8 derives the supply flow rate to the dust remover 3 based on the processing capacity of the dust remover 3, and adjusts the aperture of the flow control valve 134 so that the flow rate of the second-state gas in the fifth flow path 105 (between the flow control valve 134 and the dust remover 3) measured by the flow sensor 152 becomes equal to the derived supply flow rate. The method for adjusting the aperture of the flow control valve 134 may be any known method and is not limited to a specific method. Note that the thick solid curve in FIG. 4A merely illustrates a schematic example of the relationship between the aperture of the flow control valve 134 and the supply flow rate of the second-state gas to the dust remover 3. The relationship between the opening degree of the flow control valve 134 and the supply flow rate of the gas in the second state to the dust removal device 3 can be set to be an appropriate relationship depending on, for example, the flow characteristics of the flow control valve 134, the process conditions in the gas processing system 1, etc.

[0039] When the flow rate of the second state gas supplied to the dust remover 3 is low, the excess amount of the second state gas remaining in the first buffer tank 6A increases, whereas when the flow rate of the second state gas supplied to the dust remover 3 is high, the excess amount of the second state gas remaining in the first buffer tank 6A decreases. Therefore, when the pressure in the first buffer tank 6A is kept constant, the relationship between the flow rate of the second state gas supplied to the dust remover 3 and the excess flow rate of the second state gas released from the first buffer tank 6A through the fourth release flow path 124 is, for example, as shown by the dotted curve in FIG. 4A . That is, when the control unit 800 of the control panel 8 adjusts the aperture of the flow rate control valve 134 according to the thick solid curve illustrated in FIG. 4A , it simultaneously adjusts the aperture of the pressure control valve 136 according to the curve illustrated in FIG. 4B . The method for adjusting the aperture of the pressure control valve 136 may be any well-known method and is not limited to a specific method. 4B merely shows a schematic example of the relationship between the flow rate of the gas in the second state supplied to the dust remover 3 and the aperture of the pressure control valve 136. The relationship between the flow rate of the gas in the second state supplied to the dust remover 3 and the aperture of the pressure control valve 136 can be set to be a suitable relationship depending on, for example, the process conditions in the gas processing system 1.

[0040] FIG. 5 is a flow chart illustrating an example of a process for releasing an excess flow amount of the second-state gas from the first buffer tank. First, the control unit 800 of the control panel 8 derives the processing flow rate Re of the heat remover 2 and the supply flow rate Ra of the second-state gas to the dust remover 3 (step S100), and determines whether the relationship between them is Re>Ra (step S101). The term "processing flow rate" in this specification refers to the flow rate of gas flowing out from the outlet of the process equipment. The processing flow rate Re of the heat remover 2 is the flow rate of the second-state gas flowing out from the outlet of the heat remover 2, and may be the supply flow rate of the first-state gas supplied to the heat remover 2. The supply flow rate Ra of the second-state gas to the dust remover 3 may be the flow rate of the second-state gas flowing through the fifth flow path 105 and supplied to the dust remover 3, which is controlled by the flow control valve 134. The method for deriving the processing flow rate Re of the heat remover 2 and the supply flow rate Ra to the dust remover 3 may be any known method and is not limited to a specific method. As an example, the control unit 800 acquires information regarding the current processing flow rate Re from the heat removal device 2 via the receiving unit 821, and also acquires the flow rate of the gas in the second state in the flow path between the first buffer tank 6A and the dust removal device 3 measured by the flow sensor 152, and derives the processing flow rate Re and the supply flow rate Ra.

[0041] If the relationship Re>Ra is satisfied (step S101; YES), the control unit 800 adjusts the aperture of the flow control valve 134 between the first buffer tank 6A and the dust remover 3 so that the supply flow rate Ra becomes the command calculation value (step S102). The method for adjusting the aperture of the flow control valve 134 in step S102 may be any well-known method, and is not limited to a specific method. In step S102, the control unit 800 can, for example, derive the command calculation value of the supply flow rate Ra based on the treatment flow rate Rb of the dust remover 3, and adjust the aperture of the flow control valve 134.

[0042] On the other hand, if the relationship Re≦Ra holds (step S101; NO), the control unit 800 reduces the operating load of the entire gas processing system 1 (i.e., the gas recovery system) (step S103). In step S103, the control unit 800 reduces the processing flow rates of the dust remover 3 and the separation and recovery unit 5, for example.

[0043] After performing the process of step S102 or S103, the control unit 800 derives a measured value (PV value) Rp of the supply flow rate Ra to the dust remover 3 (step S104), and determines whether the relationship between the derived measured value Rp and the set value (SV value) Rs is Rp=Rs (step S105). If the relationship Rp=Rs does not hold (step S105; NO), the control unit 800 performs the processes from step S100 onwards. If the relationship Rp=Rs holds (step S105; YES), the process of releasing the excess flow amount of gas in the second state illustrated in FIG. 5 is terminated.

[0044] By performing the process according to the flow chart of FIG. 5, an excess flow rate of the second state gas corresponding to the flow rate difference between the treatment flow rate Re of the heat removal device 2 and the treatment flow rate to the dust removal device 3 is released from the first buffer tank 6A to the outside of the gas recovery system through the fourth release flow path 124. Note that the start conditions of the process according to the flow chart of FIG. 5 are not limited to specific conditions. The process according to the flow chart of FIG. 5 may be performed multiple times during operation of the gas treatment system 1. Furthermore, the process according to the flow chart of FIG. 5 is merely an example of a process that absorbs the flow rate difference between the treatment flow rate Re of the heat removal device 2 and the treatment flow rate to the dust removal device 3. In other words, the process that absorbs the flow rate difference between the treatment flow rate Re of the heat removal device 2 and the treatment flow rate to the dust removal device 3 and releases the excess flow rate of the second state gas is not limited to the process according to the flow chart of FIG. 5 and can be modified as appropriate.

[0045] In the gas treatment system 1 of the present embodiment described above, by adjusting (controlling) the pressure of the first buffer tank 6A installed between the heat removal device 2 and the dust remover 3, it is possible to prevent the back pressure of the gas discharge source 10 (pressure P0 of the first flow path 101) from exceeding the allowable back pressure PP of the gas discharge source 10, and to prevent unintended shutdown of the gas discharge source 10. Furthermore, the gas treatment system 1 of the present embodiment can adjust (control) the flow rate of the second state gas supplied to the dust remover 3 by using a flow control valve 134 provided in the flow path that supplies the second state gas from the first buffer tank 6A to the dust remover 3. Furthermore, in the gas treatment system 1, excess second state gas that has been generated by controlling the flow rate of the second state gas supplied to the dust remover 3 by the flow control valve 134 can be released into the atmosphere through a fourth release flow path 124 connected to the first buffer tank 6A via a pressure control valve 136. Therefore, the flow rate difference between the flow rate of the first state gas discharged from the gas emission source 10 (the processing flow rate of the heat removal device 2) and the processing flow rate of the second state gas in the dust removal device 3 can be absorbed, and the treatment process can be carried out stably and efficiently.

[0046] 1, a second buffer tank 6B is installed between a blower (compressor) 4 that compresses and discharges gas (third state gas) from which impurities such as dust have been removed by the dust remover 3, and the separation and recovery unit 5. The gas treatment system 1 is further provided with a recirculation flow path that sends (recirculates) the third state gas that has flowed into the second buffer tank 6B from the second buffer tank 6B to the dust remover 3 through flow paths 112 and 113 that are connected via a pressure control valve 139. Therefore, in the gas treatment system 1, the difference in flow rate between the supply flow rate of the third state gas to the separation and recovery unit 5, which depends on the treatment flow rate of the dust remover 3 and the compression ratio of the blower 4, and the treatment flow rate of the separation and recovery unit 5, can be absorbed by using the recirculation flow path.

[0047] In the gas processing system 1 of this embodiment, at the start of operation or the like, the aperture of the flow control valve 137 between the second buffer tank 6B and the separation and recovery unit 5 is adjusted so that the flow rate Rd of the gas in the third state supplied to the separation and recovery unit 5 matches a command value. The control unit 800 of the control panel 8 acquires the flow rate of the ninth flow path 109 between the flow control valve 137 and the separation and recovery unit 5 measured by the flow rate sensor 154, and activates the aperture adjustment mechanism of the flow control valve 137 so that the acquired flow rate of the ninth flow path 109 matches the command value. Thereafter, the control unit 800 adjusts the aperture of the pressure control valve 139 of the recirculation flow path and the operating speed of the blower 4 so that the pressure of the second buffer tank 6B located on the secondary side of the blower 4 matches a set pressure. The control unit 800 adjusts the aperture of the pressure control valve 139 and the operating speed of the blower 4 until the pressure (measured value) of the second buffer tank 6B measured by the pressure sensor 156 matches the set pressure.

[0048] 6 is a flow chart illustrating an example of a control process for absorbing the difference between the treatment capacity of the dust remover and the treatment capacity of the separation and recovery unit. First, the control unit 800 of the control panel 8 derives the treatment flow rate Rb of the dust remover 3 and the treatment flow rate Rd of the separation and recovery unit 5 (step S200), and determines whether the relationship between them is Rb>Rd (step S201). The method for deriving the treatment flow rate Rb of the dust remover 3 and the treatment flow rate Rd of the separation and recovery unit 5 may be any well-known method, and is not limited to a specific method. As an example, the control unit 800 obtains and derives information on the current treatment flow rates Rb and Rd from the dust remover 3 and the separation and recovery unit 5 via the receiving unit 821.

[0049] If the relationship Rb>Rd is satisfied (step S201; YES), the control unit 800 calculates the recirculation flow rate Rc=Rd-Rb and adjusts the aperture of the flow control valve 137 so that the flow rate of the gas in the third state in the recirculation flow path becomes the recirculation flow rate Rc (step S202). The method for adjusting the aperture of the flow control valve 137 in step S202 may be any known method and is not limited to a specific method. In step S202, as described above, the aperture of the pressure control valve 139 of the recirculation flow path may be adjusted based on the pressure of the ninth flow path 109 measured by the pressure sensor 155, the pressure of the second buffer tank 6B measured by the pressure sensor 156, and the rotation speed of the blower 4. As a result of step S202, the relationship between the supply flow rate Ra of the gas in the second state from the first buffer tank 6A to the dust remover 3 and the treatment flow rate Rd of the separation and recovery unit 5 becomes Ra=Rd.

[0050] On the other hand, if the relationship Rb≦Rd holds (step S201; NO), the control unit 800 either reduces the discharge flow rate of the excess flow from the first buffer tank 6A to increase the supply flow rate Ra from the first buffer tank 6A to the dust remover 3, or reduces the operating load of the separation and recovery unit 5 to reduce the treatment flow rate Rd (step S203). If it is possible to increase the treatment flow rate Rb of the dust remover 3, the control unit 800 adjusts the aperture of the flow control valve 134 provided in the flow path between the first buffer tank 6A and the dust remover 3 so as to increase the supply flow rate Ra from the first buffer tank 6A to the dust remover 3 in step S203. In addition to adjusting the aperture of the flow control valve 134, the control unit 800 also adjusts the aperture of the pressure control valve 136 of the first buffer tank 6A so as to reduce the discharge flow rate of the second state gas discharged from the first buffer tank 6A through the fourth discharge flow path 124 as the excess flow rate. If it is difficult to increase the supply flow rate of the gas in the second state to the dust remover 3, the control unit 800 reduces the operating load of the separation and recovery unit 5 in step S203 to decrease the treatment flow rate Rd.

[0051] After performing the process of step S202 or S203, the control unit 800 derives a measured value (PV value) of the supply flow rate of the gas in the third state to the separation and recovery unit 5 (step S204) and determines whether the relationship between the derived measured value and the set value (SV value) Rs is Rp=Rs (step S205). In step S204, the control unit 800 acquires the flow rate of the ninth flow path 109 between the flow control valve 137 and the separation and recovery unit 5 measured by the flow sensor 154, and compares the measured value Rp with the set value Rs, assuming that the relationship between the supply flow rate Ra to the dust remover 3 and the treatment flow rate Rd of the separation and recovery unit 5 is Ra=Rd. If the relationship Rp=Rs does not hold (step S205; NO), the control unit 800 performs the process from step S200 onwards. If the relationship Rp=Rs holds (step S205; YES), the control process illustrated in FIG. 6 is terminated. Note that the start condition of the control process according to the flow of FIG. 6 is not limited to a specific condition. The control process according to the flow chart of FIG. 6 may be performed multiple times during operation of the gas processing system 1.

[0052] In this way, in gas treatment system 1 of the present embodiment, by returning (recirculating) a portion of the gas in the third state that has flowed from dust remover 3 into second buffer tank 6B to dust remover 3, it is possible to absorb the difference between the treatment capacity of dust remover 3 and the treatment capacity of separation and recovery unit 5. This makes it possible to prevent the treatment process (operation of gas treatment system 1) from becoming unstable due to the difference between the treatment capacity of dust remover 3 and the treatment capacity of separation and recovery unit 5.

[0053] In the gas processing system 1 of this embodiment, the pressure and recirculation flow path of the first buffer tank 6A and the second buffer tank 6B can absorb differences in processing capacity, response speed, and the like in the process equipment that performs processing to change the state of the gas discharged from the gas emission source 10, such as the heat removal device 2, the dust removal device 3, and the separation and capture unit 5. Therefore, it is possible to meet social needs, such as gradually increasing the CO2 capture rate in the gas processing system, simply by changing the process control settings and adding on the separation and capture unit 5.

[0054] 1, if a protective setting value set according to the treatment process is exceeded in a flow path connecting process equipment, the gas can be released from that flow path to the outside of the gas recovery system, and the supply of gas to the secondary (downstream) process equipment can be stopped. For example, if a protective setting value is exceeded in a flow path connecting the first buffer tank 6A and the dust remover 3, the release valve 135 connected to the other downstream end of the fifth flow path 105 can be opened to release the second state gas to the outside through the third release flow path 123, and the supply of the second state gas to the dust remover 3 can be stopped. Also, if a protective setting value is exceeded in a flow path connecting the second buffer tank 6B and the separation and recovery unit 5, the release valve 138 connected to the other downstream end of the ninth flow path 109 can be opened to release the third state gas to the outside through the fifth release flow path 125, and the supply of the third state gas to the separation and recovery unit 5 can be stopped. In this way, by releasing the gas outside the gas recovery system and stopping the supply of gas to the secondary process equipment, it is possible to avoid the gas emission source 10 from shutting down due to an increase in pressure, even in an emergency that is difficult to deal with by simply adjusting the pressure of the first buffer tank 6A, etc.

[0055] Furthermore, in gas processing system 1 of the present embodiment, a release flow path is connected to the flow path connecting the process equipment via a switching valve or a release valve, so that the gas discharged by gas discharge source 10 can be controlled not to be introduced into the process equipment until the process conditions are met, such as when starting up operation of gas processing system 1. For example, first switching valve 131 can be closed until the process conditions are met, and second switching valve 132 and third switching valve 133 can be opened to release the gas discharged by gas discharge source 10 from open circuit 7. Also, for example, release valve 135 can be opened until the process conditions of dust removal device 3 are met to release the gas in the second state to the outside of the gas recovery system.

[0056] FIG. 7 is a diagram illustrating a modified example of the gas processing system according to the first embodiment. FIG. 7 illustrates only the configuration of the main parts of the gas processing system 1 that are relevant to the modified example being described. In the gas processing system 1 illustrated in FIG. 7, a sixth discharge flow path 126 is connected to an outlet of a second buffer tank 6B installed on the secondary side (downstream side) of the dust removal device 3, separate from the outlets connected to the eighth flow path 108 and the recirculation flow path 112, via an additional pressure control valve 140. The additional pressure control valve 140 and the sixth discharge flow path 126 provided for the second buffer tank 6B correspond to the pressure control valve 136 and the fourth discharge flow path 124 provided for the first buffer tank 6A.

[0057] In the gas processing system 1 provided with the additional pressure control valve 140, the processing described above with reference to FIG. 6 is performed with the additional pressure control valve 140 set to an opening corresponding to a predetermined pressure, thereby absorbing the difference between the processing capacity of the dust remover 3 and the processing capacity of the separation and recovery unit 5. However, for example, if the separation and recovery unit 5 is clogged and the processing flow rate of the separation and recovery unit 5 decreases, continuing to recirculate the third state gas to the dust remover 3 may increase the excess flow rate of the third state gas, causing the pressure to rise, making it difficult to adjust the pressure using the pressure control valve 139. If it becomes difficult to adjust the pressure using the pressure control valve 139, for example, by adjusting the opening of the additional pressure control valve 140, the excess flow rate of the third state gas can be released from the second buffer tank 6B to the outside of the gas recovery system, thereby suppressing the increase in pressure in the recirculation flow path. Note that the additional pressure control valve 140 and the sixth release flow path 126 described above with reference to FIG. 7 are merely one example of a configuration for releasing the excess flow rate of the third state gas recirculated through the flow paths 112 and 113 to the outside of the gas recovery system. The gas processing system 1 may be configured in another way to release the excess flow rate of the third state gas to the outside of the gas recovery system.

[0058] [Second embodiment] FIG. 8 is a diagram illustrating an example of the configuration of a gas processing system according to a second embodiment. FIG. 8 illustrates only the configuration of parts of the gas processing system 1 according to this embodiment that are different from the gas processing system 1 (see FIG. 1) illustrated in the first embodiment. The gas processing system 1 illustrated in this embodiment does not have a buffer tank (second buffer tank 6B) between the dust remover 3 and the separation and recovery unit 5. That is, the downstream end of a seventh flow path 107 connected to the outlet of a blower (or compressor) 4 that compresses and discharges gas (third state gas) from which impurities such as dust have been removed in the dust remover 3 is connected to the upstream end of an eighth flow path 108 and the upstream end of a flow path 112 for recirculation. In other words, the seventh flow path 107 connected to the outlet of the blower 4 branches into the eighth flow path 108 that supplies the third state gas to the separation and recovery unit 5 and the flow path 112 that recirculates the third state gas to the dust remover 3. Furthermore, in gas processing system 1 of the present embodiment, the pressure in seventh flow path 107 can be measured by pressure sensor 156, which is used to measure the pressure in second buffer tank 6B in the first embodiment.

[0059] In gas processing system 1 of the present embodiment, a first buffer tank 6A is installed between heat removal device 2 and dust removal device 3. Therefore, similar to gas processing system 1 of the first embodiment, gas processing system 1 of the present embodiment can prevent the back pressure of gas emission source 10 (pressure P0 of first flow path 101) from exceeding a protective setting value such as the allowable back pressure PP of gas emission source 10 by adjusting the pressure of first buffer tank 6A. Furthermore, an excess flow amount of gas in the second state caused by the difference in flow rate between the treatment flow rate of heat removal device 2 and the treatment flow rate of dust removal device 3 can be released from first buffer tank 6A to the outside of the gas recovery system through fourth release flow path 124, thereby enabling stable operation of gas processing system 1.

[0060] 9 is a flow chart illustrating an example of a process for adjusting the flow rate of gas recirculated to the dust remover. First, the control unit 800 of the control panel 8 derives the treatment flow rate Rb of the dust remover 3 and the treatment flow rate Rd of the separation and recovery unit 5 (step S300), and determines whether the relationship between them is Rb>Rd (step S301). The method for deriving the treatment flow rate Rb of the dust remover 3 and the treatment flow rate Rd of the separation and recovery unit 5 may be any known method, and is not limited to a specific method. As an example, the control unit 800 acquires and derives information on the current treatment flow rates Rb and Rd from the dust remover 3 and the separation and recovery unit 5 via the receiving unit 821.

[0061] If the relationship Rb>Rd is satisfied (step S301; YES), the control unit 800 adjusts the aperture of the pressure control valve 139 of the recirculation flow path so that the discharge pressure of the blower 4 becomes the set value (step S302). The method for adjusting the aperture of the pressure control valve 139 in step S302 may be any well-known method, and is not limited to a specific method. In step S302, the aperture of the pressure control valve 139 of the recirculation flow path may be adjusted based on, for example, the pressure of the seventh flow path 107 measured by the pressure sensor 156 and the rotation speed of the blower 4.

[0062] After step S302, the control unit 800 derives a measured value (PV value) Rp of the supply flow rate Ra to the dust remover 3 (step S303) and determines whether the relationship between the derived measured value Rp and the set value (SV value) Rs is Rp = Rs (step S304). The supply flow rate Ra to the dust remover 3 is the flow rate of the gas in the second state supplied from the heat remover 2 to the dust remover 3 via the first buffer tank 6A, and may be the flow rate of the fifth flow path 105 between the first buffer tank 6A and the dust remover 3. The control unit 800 acquires the flow rate of the gas in the second state in the fifth flow path 105 measured by the flow sensor 152 and derives a measured value of the supply flow rate Ra to the dust remover 3. If the relationship Rp = Rs is met (step S304; YES), the process of adjusting the flow rate of the gas in the third state to be recirculated to the dust remover 3 is terminated. If the relationship Rp=Rs does not hold (step S304; NO), the control unit 800 performs the processes from step S300 onwards.

[0063] On the other hand, if the relationship Rb≦Rd holds (step S301; NO), the control unit 800 at least one of increasing the rotation speed of the blower 4 and increasing the supply flow rate Ra to the dust remover 3 (step S305), and then performs the processes from step S300 onwards. In step S305, in order to increase the supply flow rate Ra to the dust remover 3, the control unit 800 can increase the aperture of the flow control valve 134 between the first buffer tank 6A and the dust remover 3, and / or adjust the aperture of the pressure control valve 136 connected to the first buffer tank 6A to reduce the flow rate of the second state gas released from the first buffer tank 6A to the outside of the gas recovery system via the fourth release flow path 124.

[0064] As described above, in the gas processing system 1 of the present embodiment, an excess flow rate of the third state gas, from which impurities such as dust have been removed in the dust remover 3, can be recirculated to the dust remover 3 with a simple configuration that omits the buffer tank (second buffer tank 6B). That is, the gas processing system 1 of the present embodiment can absorb the flow rate difference between the treatment flow rate of the dust remover 3 and the treatment flow rate of the separation and recovery unit 5 with a simple configuration that omits the buffer tank (second buffer tank 6B). Note that the start conditions for the process according to the flow of FIG. 9 are not limited to specific conditions. The process according to the flow of FIG. 9 may be performed multiple times during operation of the gas processing system 1. Furthermore, the process according to the flow of FIG. 9 is merely one example of a process for adjusting the flow rate of the third state gas to be recirculated to the dust remover 3.

[0065] FIG. 10 is a diagram illustrating a modified example of the gas processing system according to the second embodiment. FIG. 10 illustrates only the configuration of the main parts of the gas processing system 1 that are relevant to the modified example being described. In the gas processing system 1 illustrated in FIG. 10, a sixth discharge flow path 126 is connected to a seventh flow path 107, through which the gas in the third state delivered from the blower 4 flows, via an additional pressure control valve 140. Specifically, the seventh flow path 107 is branched, and one downstream end thereof is further branched into an eighth flow path 108 and a recirculation flow path 112, and the other downstream end thereof is connected to the inlet of the additional pressure control valve 140. The sixth discharge flow path 126 is connected to the outlet of the additional pressure control valve 140.

[0066] The additional pressure control valve 140 illustrated in FIG. 10 may correspond to the additional pressure control valve 140 for adjusting the pressure of the second buffer tank 6B described with reference to FIG. 7 in the first embodiment. In the gas processing system 1 of this embodiment, which is provided with the additional pressure control valve 140, the process of adjusting the flow rate of the third state gas in the recirculation flow path, described above with reference to FIG. 9, is started with the additional pressure control valve 140 set to an aperture corresponding to a predetermined pressure. Thereafter, for example, if the separation and recovery unit 5 is clogged and the treatment flow rate of the separation and recovery unit 5 decreases, continuing to recirculate the third state gas to the dust remover 3 may increase the excess flow rate of the third state gas, causing the pressure to rise, making it difficult to adjust the pressure using the pressure control valve 139. If it becomes difficult to adjust the pressure using the pressure control valve 139, for example, the aperture of the additional pressure control valve 140 may be adjusted to release the excess flow rate of the third state gas to the outside of the gas recovery system, thereby suppressing the increase in pressure in the recirculation flow path. 10 is merely one example of a configuration for discharging the excess flow rate of the third state gas recirculated through the flow paths 112 and 113 to the outside of the gas recovery system. Gas processing system 1 may be configured differently to be able to discharge the excess flow rate of the third state gas to the outside of the gas recovery system.

[0067] The embodiments of the gas processing system 1 according to the present invention are not limited to the above-described embodiments, and may be variously modified, substituted, or altered without departing from the spirit of the technical idea. Furthermore, if the technical idea can be realized in a different way due to technological advances or other derived technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea.

[0068] The features of the above-described embodiment will be summarized below. The gas processing system according to the above-described embodiment includes a separation and recovery unit that separates and recovers desired components contained in gas discharged by a gas emission source, a heat removal device that removes heat from the gas, a dust removal device that removes dust contained in the gas, a blower that compresses and discharges the gas from which dust has been removed by the dust removal device, at least one pressure-regulating buffer tank that is installed closer to the gas emission source than the separation and recovery unit and that adjusts the pressure of the gas flow path, a first control valve that adjusts the flow of gas in the gas flow path that flows to the buffer tank, a recirculation flow path that recirculates the gas from which dust has been removed by the dust removal device to the dust removal device, and a second control valve that adjusts the flow of gas in the flow path that supplies gas to the separation and recovery unit.

[0069] The gas processing system further includes a control unit that controls the aperture of the first control valve, the first control valve being a pressure control valve that adjusts the pressure in the buffer tank, and the control unit controls the aperture of the pressure control valve to adjust the pressure in the buffer tank in response to at least one of an increase and a fluctuation in pressure in the dust removal device or the separation and recovery unit, so that the back pressure of the gas discharged from the gas discharge source is below an allowable value.

[0070] The gas treatment system further includes a flow control valve that adjusts the flow rate of gas supplied to the dust removal device, and the control unit controls the aperture of the flow control valve in accordance with the flow rate difference between the flow rate of gas discharged from the gas emission source and the flow rate of the gas supplied to the dust removal device, and controls the aperture of the pressure control valve so that an excess flow rate of gas in excess of the supply to the dust removal device is released from the buffer tank to the outside through the pressure control valve.

[0071] The gas processing system further includes a pressure control valve that controls the pressure in the recirculation flow path, and a control unit that controls the opening degree of the second control valve and the opening degree of the pressure control valve, wherein the second control valve is a flow rate control valve that controls the flow rate of the gas in the flow path that supplies the gas from which dust has been removed by the dust removal device to the separation and recovery unit, and when the processing capacity of the dust removal device is different from the processing capacity of the separation and recovery unit, the control unit controls the opening degree of the second control valve to adjust the flow rate of the gas to the separation and recovery unit, and controls the opening degree of the pressure control valve to adjust the pressure at the inlet of the separation and recovery unit.

[0072] The gas processing system further comprises a discharge flow path that discharges the gas from which dust has been removed by the dust removal device to the outside of the gas processing system, a pressure control valve that controls the pressure of the discharge flow path, and a control unit that controls the opening degree of the second control valve and the opening degree of the pressure control valve, wherein the second control valve is a flow rate control valve that controls the flow rate of the gas in a flow path that supplies the gas from which dust has been removed by the dust removal device to the separation and recovery unit, and when the processing capacity of the dust removal device is different from the processing capacity of the separation and recovery unit, the control unit controls the opening degree of the second control valve to adjust the flow rate of the gas to the separation and recovery unit and controls the opening degree of the pressure control valve to adjust the pressure at the inlet of the separation and recovery unit.

[0073] In the above gas treatment system, the blower is installed between the dust removal device and the separation and recovery unit, and the control unit controls the rotation speed of the blower and the opening degree of the pressure control valve so that the pressure at the inlet of the separation and recovery unit becomes a set value.

[0074] In the above gas processing system, the control unit controls the opening of the flow control valve and the rotation speed of the blower installed between the dust removal device and the separation and recovery unit so that the flow rate at the inlet of the separation and recovery unit becomes a set value, and then controls the opening of the pressure control valve.

[0075] The gas processing system further includes an open flow path that releases the gas discharged by the gas discharge source to the outside of the gas processing system until a process condition for the treatment process by the gas processing system is met, and a flow path switching valve.

[0076] The gas processing system further includes an open flow path in the flow path connecting the heat removal device and the dust removal device, which releases the gas whose heat has been removed by the heat removal device to the outside of the gas processing system until the process conditions for supplying gas to the dust removal device are met, and a flow path switching valve.

[0077] The gas processing system further includes an open flow path in the flow path connecting the dust removal device and the separation and recovery unit, which releases the gas from which dust has been removed by the dust removal device to the outside of the gas processing system until the process conditions for supplying gas to the separation and recovery unit are met, and a flow path switching valve.

[0078] The gas processing system further includes a control unit that controls the switching of flow paths by the flow path switching valve, and when a value related to the treatment process measured at the inlet of the heat removal device, the inlet of the dust removal device, or the inlet of the separation and recovery unit exceeds a protection setting value, the control unit switches the flow path switching valve located on the primary side of the heat removal device, the dust removal device, or the separation and recovery unit where the excess value is measured so that the gas flow path becomes the open flow path.

[0079] The gas treatment system further includes a flow path switching valve that switches the flow path of the gas emitted by the gas emission source between a gas recovery system that separates and recovers the desired components from the gas, and a discharge flow path that releases the gas outside the gas recovery system, and the gas recovery system is installed so that the gas passes through the heat removal device, the buffer tank, the dust removal device, the blower, and the separation and recovery unit in that order.

[0080] In the above gas processing system, an additional buffer tank is installed between the blower and the separation and recovery unit, and the recirculation flow path recirculates the gas from the additional buffer tank to the dust removal device. [Industrial Applicability]

[0081] As described above, the present invention enables stable control of the treatment process in a gas treatment system, and is particularly useful in a system that separates and recovers desired components such as CO2 from high-temperature gas containing impurities such as dust emitted from a gas emission source. [Explanation of symbols]

[0082] DESCRIPTION OF SYMBOLS 1...gas treatment system, 2...heat removal device, 3...dust removal device, 4...blower, 5...separation and recovery unit, 6A, 6B...buffer tank, 7...open circuit, 8...control panel, 101-113...flow path, 121-126...discharge path, 131-133...switching valve, 134, 137...flow control valve, 135, 138...discharge valve, 136, 139, 140...pressure control valve

Claims

1. a separation and recovery unit that separates and recovers desired components contained in the gas discharged from the gas discharge source; a heat removal device for removing heat from the gas; a dust removal device for removing dust contained in the gas; a blower that compresses and discharges the gas from which dust has been removed by the dust removal device; at least one pressure-adjusting buffer tank that is installed closer to the gas discharge source than the separation and recovery unit and adjusts the pressure of the gas flow path; a first control valve that adjusts the flow of the gas in the gas flow path that flows to the buffer tank; a recirculation flow path that recirculates the gas from which dust has been removed by the dust remover to the dust remover; a second control valve for adjusting the flow of the gas in a flow path for supplying the gas to the separation and recovery unit; A gas treatment system comprising:

2. a control unit that controls an opening degree of the first control valve; the first control valve is a pressure control valve that adjusts the pressure of the buffer tank, the control unit controls the aperture of the pressure control valve to adjust the pressure of the buffer tank in response to at least one of an increase and a fluctuation in pressure in the dust removal device or the separation and recovery unit so that the back pressure of the gas discharged from the gas discharge source is equal to or less than an allowable value. The gas processing system of claim 1 .

3. a flow control valve for adjusting the flow rate of gas supplied to the dust removal device; the control unit controls the aperture of the flow control valve in accordance with the flow rate difference between the flow rate of the gas discharged from the gas discharge source and the flow rate of the gas supplied to the dust remover, and controls the aperture of the pressure control valve so that the excess flow rate of gas that is excessive with respect to the supply to the dust remover is released from the buffer tank to the outside through the pressure control valve. The gas processing system of claim 2 .

4. a pressure control valve that controls the pressure in the recirculation flow path; and a control unit that controls the opening degree of the second control valve and the opening degree of the pressure control valve, the second control valve is a flow rate control valve that controls a flow rate of the gas in a flow path through which the gas from which dust has been removed by the dust removal device is supplied to the separation and recovery unit, when the processing capacity of the dust removal device is different from the processing capacity of the separation and recovery unit, the control unit controls the aperture of the second control valve to adjust the flow rate of the gas to the separation and recovery unit, and controls the aperture of the pressure control valve to adjust the pressure at the inlet of the separation and recovery unit. The gas processing system of claim 1 .

5. a discharge flow path that discharges the gas from which dust has been removed by the dust removal device to the outside of the gas processing system, a pressure control valve that controls the pressure of the discharge flow path, and a control unit that controls the opening degree of the second control valve and the opening degree of the pressure control valve, the second control valve is a flow rate control valve that controls a flow rate of the gas in a flow path through which the gas from which dust has been removed by the dust removal device is supplied to the separation and recovery unit, when the processing capacity of the dust removal device is different from the processing capacity of the separation and recovery unit, the control unit controls the aperture of the second control valve to adjust the flow rate of the gas to the separation and recovery unit, and controls the aperture of the pressure control valve to adjust the pressure at the inlet of the separation and recovery unit. The gas processing system of claim 1 .

6. The blower is installed between the dust removal device and the separation and recovery unit, the control unit controls the rotation speed of the blower and controls the opening degree of the pressure control valve so that the pressure at the inlet of the separation and recovery unit becomes a set value.

6. A gas processing system according to claim 4 or 5.

7. the control unit controls the opening degree of the flow control valve and the rotation speed of the blower installed between the dust removal device and the separation and recovery unit so that the flow rate at the inlet of the separation and recovery unit becomes a set value, and then controls the opening degree of the pressure control valve.

6. A gas processing system according to claim 4 or 5.

8. an open flow path that releases the gas discharged from the gas discharge source to the outside of the gas processing system until a process condition for the treatment process by the gas processing system is met, and a flow path switching valve. The gas processing system of claim 1 .

9. a flow path connecting the heat removal device and the dust removal device, the flow path further comprising an open flow path for releasing the gas from which heat has been removed by the heat removal device to the outside of the gas processing system until a process condition for supplying gas to the dust removal device is satisfied, and a flow path switching valve; The gas processing system of claim 1 .

10. a flow path connecting the dust remover and the separation and recovery unit, the flow path further comprising an open flow path for releasing the gas from which dust has been removed by the dust remover to the outside of the gas processing system until a process condition for supplying gas to the separation and recovery unit is met, and a flow path switching valve; The gas processing system of claim 1 .

11. The system further includes a control unit that controls switching of the flow paths by the flow path switching valves, and when a value related to the treatment process measured at any one of the inlet of the heat removal device, the inlet of the dust removal device, and the inlet of the separation and recovery unit exceeds a protection setting value, the control unit switches the flow path switching valves located on the primary side of the heat removal device, the dust removal device, and the separation and recovery unit where the excess value is measured so that the gas flow path becomes the open flow path. A gas processing system according to any one of claims 8 to 10.

12. a flow path switching valve that switches a flow path of the gas discharged from the gas discharge source between a gas recovery system that separates and recovers the desired components from the gas and a discharge flow path that discharges the gas to the outside of the gas recovery system, the gas recovery system is installed so that the gas passes through the heat removal device, the buffer tank, the dust removal device, the blower, and the separation and recovery unit in this order; The gas processing system of claim 1 .

13. an additional buffer tank is installed between the blower and the separation and recovery unit, and the recirculation flow path recirculates the gas from the additional buffer tank to the dust removal device; The gas processing system of claim 12.

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