Control device, exhaust gas supply system, and control method

Abstract

Provided is technology for suppressing exhaust gas pressure fluctuation when the amount of exhaust gas being supplied suddenly decreases. This control device, for a system that draws in exhaust gas by means of a blower provided in an exhaust gas system for guiding exhaust gas, discharged by a facility, to a CO2 recovery device, and supplies the exhaust gas to the CO2 recovery device, comprises: a detection unit for detecting a sudden decrease in the flow rate of the exhaust gas discharged by the facility; and a control unit that, when a sudden decrease in the flow rate of the exhaust gas is detected, reduces the opening degree of a rotor blade of the blower to a target value, and simultaneously controls a means for suppressing a pressure drop in the exhaust gas system, thereby suppressing a pressure drop in the exhaust gas system for a certain period of time.

Description

Control device, exhaust gas supply system, and control method

[0001] The present disclosure provides ２ This disclosure claims priority to Japanese Patent Application No. 2024-091586, filed on June 5, 2024, the contents of which are incorporated herein by reference.

[0002] CO ２ The application of recovery equipment to various upstream facilities such as gas turbines and GTCCs (Gas Turbine Combined Cycles) is being considered. For example, ２ A blower is installed between the recovery devices to draw in exhaust gases emitted by GTCC, etc., and ２ Patent Document 1 describes a chimney that discharges exhaust gas emitted from an upstream industrial facility to the outside, a blower that is installed downstream of the chimney and draws in the exhaust gas, and a CO recovery device that recovers the CO from the exhaust gas drawn in by the blower. ２ CO2 recovery ２ The CO2 recovery system is equipped with a blower and is operated until the exhaust flow rate of the flue gas from the chimney becomes zero. ２ The amount of exhaust gas drawn into the recovery device is increased, and when the amount of exhaust gas discharged from the chimney becomes zero, the CO in the exhaust gas is extracted while drawing in the exhaust gas at a substantially constant rate. ２ CO to be recovered ２ A recovery system is disclosed.

[0003] Such CO ２ In a recovery system, if a sudden change in load occurs in an upstream GTCC or the like, the flow rate of the exhaust gas supplied from the upstream side changes significantly, affecting plant equipment such as piping and blowers. For example, if a load shedding occurs and the exhaust gas flow rate drops sharply, the exhaust gas pressure drops and deviates significantly from the allowable range. Such pressure fluctuations can cause CO ２ This could result in the shutdown of recovery equipment and damage to plant equipment.

[0004] Japanese Patent No. 5039651

[0005] There is a need for a control method that can suppress fluctuations in exhaust gas pressure when the amount of exhaust gas supplied from the upstream equipment suddenly decreases. However, Patent Document 1 does not disclose such a control method.

[0006] The present disclosure provides a control device, an exhaust gas supply system, and a control method that can solve the above-mentioned problems.

[0007] According to one aspect of the present disclosure, the control device converts the exhaust gas emitted by the equipment into CO ２ The exhaust gas is drawn in by a blower provided in the exhaust gas system leading to the recovery device, and the CO ２ The control device for the system that supplies exhaust gas to the recovery device includes: a detection unit that detects a sudden decrease in the flow rate of exhaust gas discharged by the facility; and a control unit that, when the detection unit detects a sudden decrease in the flow rate of the exhaust gas, reduces the opening of the blower's rotor blades to a target value and controls a means for suppressing a pressure decrease in the exhaust gas system, thereby suppressing a pressure decrease in the exhaust gas system.

[0008] According to one aspect of the present disclosure, the exhaust gas supply system converts exhaust gas emitted from a facility into CO ２ The exhaust gas recovery system includes an exhaust gas system that leads the exhaust gas to a recovery device, a blower provided in the exhaust gas system, a means for suppressing a pressure drop provided in the exhaust gas system, and the above-mentioned control device.

[0009] According to one aspect of the present disclosure, a control method includes: ２ The exhaust gas is drawn in by a blower provided in the exhaust gas system leading to the recovery device, and the CO ２ A control method for a system that supplies exhaust gas to a recovery device, comprising: a step of detecting a sudden decrease in the flow rate of exhaust gas discharged by the facility; and a step of, upon detecting a sudden decrease in the flow rate of the exhaust gas, reducing the opening of the rotor blades of the blower to a target value and controlling a means for suppressing a pressure decrease in the exhaust gas system, thereby suppressing a pressure decrease in the exhaust gas system.

[0010] According to the above-described control device, exhaust gas supply system, and control method, fluctuations in exhaust gas pressure can be suppressed when the amount of exhaust gas supplied decreases suddenly.

[0011] CO according to the first embodiment ２ 1 is a schematic diagram of a recovery system; FIG. 2 is a time chart showing an example of exhaust gas pressure under general control; FIG. 3 is a time chart showing an example of exhaust gas pressure under control of a first embodiment; FIG. 4 is a flowchart showing an example of control according to the first embodiment; FIG. 5 is a CO ２ 1 is a schematic diagram of a recovery system; FIG. 2 is a time chart showing an example of exhaust gas pressure under control of a second embodiment; FIG. 3 is a flowchart showing an example of control according to the second embodiment; FIG. 4 is a CO ２ Fig. 10 is a schematic diagram of a recovery system; Fig. 11 is a time chart showing an example of exhaust gas pressure under control of a third embodiment; Fig. 12 is a flowchart showing an example of control according to the third embodiment; Fig. 13 is a diagram showing an example of the hardware configuration of a control device according to each embodiment;

[0012] Hereinafter, the CO ２ The control of exhaust gas pressure when the load in the recovery system suddenly changes (drops) will be described with reference to Figs. 1 to 11. <First embodiment> (Configuration) Fig. 1 shows a CO ２ 1 is a schematic diagram of a recovery system 100. ２ The recovery system 100 includes an upstream facility 1, a stack (chimney) 4, a cooling tower 5, a blower 6, and a CO ２ The system includes a recovery device 7 and a control device 10. The upstream facility 1 is, for example, a power generation plant such as a gas turbine or a GTCC. In this embodiment, the upstream facility 1 is described as a GTCC 3 as an example. An IGV (inlet guide vane) 2 is provided on the inlet side of the GTCC 3. By adjusting the opening of the IGV 2, the flow rate of air taken into the GTCC 3 changes. For example, when the load of the GTCC 3 is high, the flow rate of air taken in also increases, and the opening of the IGV 2 is controlled according to the required air intake amount. The GTCC 3, a cooling tower 5, a blower 6, and a CO ２The recovery device 7 is disposed on the exhaust gas system L1, and each device is connected by pipes, ducts, etc. Between the GTCC 3 and the cooling tower 5, there is a branch point that connects to the system L2, and a stack 4 is provided at the end of the system L2. A stack damper D1 is provided on the system L2. Between the branch point of the system L1 with the system L2 and the cooling tower 5, CCPs (Carbon Capture Plants: CO ２ The CCP inlet damper D2 and pressure sensor PT are provided. The pressure sensor PT is provided upstream of the CCP inlet damper D2 and measures the pressure of the exhaust gas flowing through the system L1. In the control described below, the CCP inlet damper D2 is open. During normal operation, the stack damper D1 is closed, and the exhaust gas discharged from the GTCC 3 is ２ The exhaust gas is supplied to the CO recovery device 7. ２ When the exhaust gas is not to be supplied to the recovery device 7, the damper D1 is opened and the exhaust gas is discharged outside the system. Normally, the pressure in the lines L1 and L2 is higher than that outside the system, so when the stack damper D1 is opened, the exhaust gas in the line L1 is discharged outside the system from the stack 4 through the line L2. However, when the stack damper D1 is opened in a situation where the outside air has a higher pressure than the line L1, the outside air is taken in from the stack 4 and the air is taken into the line L1 through the line L2. ２ A blower 6 is provided between the recovery devices 7. The blower 6 has a shaft to which rotor blades are attached, and by rotating the shaft, exhaust gas from the line L1 is drawn in and CO ２ The exhaust gas is sent to the recovery device 7. The mounting angle (opening) of the moving blades of the blower 6 is variable, and the volume and pressure of the exhaust gas can be controlled by adjusting the opening of the moving blades. The control device 10 feedback-controls the opening of the moving blades of the blower 6 so that the exhaust gas pressure measured by the pressure sensor PT becomes a predetermined target pressure. The control device 10 controls the opening and closing of the stack damper D1, the opening and closing of the CCP inlet damper D2, the start and stop of the blower 6, the opening of the moving blades, etc.

[0013] The control device 10 includes a detection unit 11 and a control unit 12. The detection unit 11 acquires information indicating the operating state of the upstream equipment 1. For example, the detection unit 11 acquires the aperture of the IGV 2, the output of the GTCC 3, a signal indicating a sudden change in the load of the GTCC 3 (e.g., a load shedding signal), and the like. The detection unit 11 acquires the pressure of the exhaust gas measured by the pressure sensor PT. The control unit 12 controls the opening and closing of the stack damper D1, the aperture of the rotor blades of the blower 6, and the like based on the information acquired by the detection unit 11. For example, the control unit 12 feedback-controls the aperture of the rotor blades of the blower 6 so that the pressure of the exhaust gas reaches a predetermined target pressure. When the flow rate of the exhaust gas discharged from the upstream equipment 1 suddenly decreases, the control unit 12 reduces the aperture of the rotor blades of the blower 6 to a predetermined target value. By reducing the aperture of the rotor blades of the blower 6, a pressure drop in the exhaust gas system L1 can be suppressed even when the amount of exhaust gas supplied from the upstream equipment 1 decreases.

[0014] (Control when load suddenly drops) Next, control during load rejection will be described with reference to Figures 2 and 3. Figure 2 is a time chart showing an example of exhaust gas pressure under general control. Figure 3 is a time chart showing an example of exhaust gas pressure under control of the first embodiment. First, general control will be described with reference to Figure 2.

[0015] (Time t0) When load shedding occurs at time t0 in the GTCC 3 operating at rated load, the GTCC 3 transmits a load shedding signal to the control device 10. The detection unit 11 acquires the load shedding signal. When the detection unit 11 acquires the load shedding signal, the control unit 12 reduces the rotor blade opening of the blower 6. The stack damper D1 remains closed, and the CCP inlet damper D2 remains open. Due to the load shedding, the flow rate of the exhaust gas supplied from the GTCC 3 drops sharply. Because the rate at which the rotor blade opening of the blower 6 drops is slower than the drop in the exhaust gas flow rate, pressure control cannot keep up, and the exhaust gas pressure measured by the pressure sensor PT also drops sharply.

[0016] At time t1, the opening of the blower 6 reaches the predetermined target value, but the exhaust gas pressure drops below the predetermined range and further drops below the lower limit of the control range. When the opening of the blower 6 is fully closed, the control unit 12 performs feedback control so that the exhaust gas pressure measured by the pressure sensor PT reaches the target pressure. However, the exhaust gas pressure is unstable and repeatedly remains within the predetermined range and then overshoots.

[0017] In this way, in conventional control, a sudden drop in the exhaust gas flow rate is addressed by proactively reducing the opening of the blower 6 based on the load shedding signal, but it is difficult to control the exhaust gas pressure within a control range. Next, the control of this embodiment will be described with reference to Figure 3.

[0018] (Time t0) When load shedding occurs at time t0, the GTCC 3 transmits a load shedding signal to the control device 10. The detection unit 11 acquires this load shedding signal. Upon acquiring the load shedding signal, the control unit 12 stops feedback control of the rotor blade opening of the blower 6, reduces the opening of the blower 6 to a predetermined opening based on the load shedding signal, and opens the stack damper D1, thereby increasing the opening of the stack damper D1. When the stack damper D1 opens in a situation where the exhaust gas pressure is decreasing, air is taken in from the stack 4. This air flow rate is referred to as the stack damper flow rate. In FIG. 3 , the side below the reference line of the stack damper flow rate is represented as air intake, and the side above is represented as air discharge to the outside of the system. Because air is taken in from outside the system through line L2, the decrease in the exhaust gas pressure measured by the pressure sensor PT (more precisely, the pressure of the gas obtained by mixing the exhaust gas with outside air taken in from outside the system) is more gradual than in the example of FIG. 2 .

[0019] (Time t1) At time t1, stack damper D1 is fully open. Until time t1, the exhaust gas flow rate drops to 10-30%, and the pressure measured by pressure sensor PT also drops below the specified range, but remains within the lower limit of the control range. At time t1, the drop in exhaust gas pressure stops, and the flow rate of outside air taken in from stack 4 begins to decrease.

[0020] (Time t2) At time t2, the opening of the blower 6 decreases to a predetermined target value. When the opening of the blower 6 reaches the target value, the control unit 12 performs feedback control so that the exhaust gas pressure measured by the pressure sensor PT reaches the target pressure. Compared to the example in FIG. 2, the stack damper D1 is fully open, so pressure fluctuations are small, and fluctuations in the rotor blade opening due to feedback control are also small. Because the pressure is stabilized by feedback control of the rotor blade opening of the blower 6, the stack damper flow rate also gradually decreases.

[0021] (After time t3) At time t3, the control unit 12 reduces the opening degree of the stack damper D1, which is fully open, and fully closes it at time t4. At time t4, the exhaust gas pressure has stabilized at the target value. Here, time t3 can be determined, for example, as follows: (a) A certain amount of time has passed since the exhaust gas pressure became capable of operating within a predetermined range. In the example of FIG. 3, the exhaust gas pressure became capable of operating within the predetermined range at time t2. At time t3, which is a certain amount of time that has passed since time t2, the control unit 12 closes the stack damper D1. (b) A certain amount of time has passed since the rotor blade opening degree of the blower 6 was able to be closed to the target value. In the example of FIG. 3, the rotor blade opening degree of the blower 6 reaches the target value at time t2. At time t3, which is a certain amount of time that has passed since time t2, the control unit 12 closes the stack damper D1. (c) A certain amount of time has passed since the load shedding signal was acquired. In the example of Figure 3, a load shedding signal is acquired at time t0. When a certain time has elapsed from time t0, at time t3, the control unit 12 closes the stack damper D1. The certain times (a) to (c) can be set arbitrarily.

[0022] As described above, in this embodiment, the opening degree of the blower 6 is proactively reduced to a predetermined target value and the stack damper D1 is opened based on the load shedding signal. This allows outside air to be taken in and fluctuations in the exhaust gas pressure in the system L1 to be suppressed. Then, by feedback controlling the rotor blade opening degree of the blower 6, the exhaust gas pressure can be controlled within a predetermined range based on the target pressure. Due to mechanical constraints, controlling the rotor blade opening degree of the blower 6 alone often fails to reduce the rotor blade opening degree to the target value quickly enough to keep up with the rate at which the exhaust gas pressure decreases due to load shedding, resulting in a sudden drop in exhaust gas pressure. However, in this embodiment, by reducing the rotor blade opening degree and opening the stack damper D1, air is taken in from outside the system, preventing a drop in exhaust gas pressure.

[0023] (Operation) Next, referring to FIG. 4, the CO ２The operation of the recovery system 100 will now be described. FIG. 4 is a flowchart illustrating an example of control according to the first embodiment. The detector 11 receives a load shedding signal (step S1). When the detector 11 receives the load shedding signal, the controller 12 stops the feedback control, reduces the blade opening of the blower 6 toward a predetermined target value, and opens the stack damper D1 toward full opening (step S2). It takes approximately 10 seconds for the blade opening to reach the target value, and the stack damper D1 fully opens even earlier. Next, the controller 12 determines whether the blade opening of the blower 6 has been reduced to the target value (step S3). If the blade opening has not been reduced to the target value (step S3; No), the controller 12 continues reducing the blade opening. If the blade opening has been reduced to the target value (step S3; Yes), the controller 12 stops reducing the blade opening and starts feedback control of the blade opening (step S4). The controller 12 continues feedback control of the blade opening thereafter. Next, the control unit 12 determines whether the closing condition for the stack damper D1 is satisfied (step S5). For example, the control unit 12 determines that the closing condition is satisfied when a certain time has elapsed since the pressure measured by the pressure sensor PT fell within a predetermined range. Alternatively, the control unit 12 may determine that the closing condition is satisfied when a certain time has elapsed since the rotor blade opening of the blower 6 decreased to a target value, or when a certain time has elapsed since the detection unit 11 acquired a load shedding signal. If the closing condition is not satisfied (step S5; No), the control unit 12 maintains the stack damper D1 fully open until the closing condition is satisfied. If the closing condition is satisfied (step S5; Yes), the control unit 12 fully closes the stack damper D1 (step S6).

[0024] (Effects) As described above, according to this embodiment, when the flow rate of the exhaust gas supplied from the upstream equipment 1 suddenly decreases, a control signal is acquired, the degree of opening of the moving blades of the blower 6 is reduced, and the stack damper D1 is suddenly opened. After the stack damper D1 is opened, it is kept open for a certain period of time, and then it is fully closed. This makes it possible to suppress fluctuations in the exhaust gas pressure and control it within a control range, thereby avoiding damage to plant equipment such as piping and the blower, and reducing CO ２The recovery equipment can continue to operate. A sudden drop in load can be accommodated without adding valves or other equipment.

[0025] In the second embodiment, a circulation system L3 is provided in the blower 6, and when the amount of exhaust gas supplied from the upstream equipment 1 (GTCC 3) suddenly drops, the exhaust gas flow rate is ensured by circulating the exhaust gas through the circulation system L3, and fluctuations in the pressure measured by the pressure sensor PT are suppressed. ２ An example of a recovery system 100a is shown. As shown in FIG. 5 , a circulation system L3 is provided connecting the upstream side of the blower 6 with the outlet side of the blower 6, and a circulation damper V1 is provided in the circulation system L3. The upstream location of the circulation system L3 connected to the exhaust gas system L1 is preferably upstream of the pressure sensor PT and downstream of the branch point between the system L1 and the system L2, as shown in the figure. However, other locations are acceptable as long as the system L1 can be connected to the system. For example, the system L3 may be located between the cooling tower 5 and the blower 6, or upstream of the branch point. A control device 10a is provided instead of the control unit 10. The control device 10a is provided instead of the control unit 12. The control unit 12a opens the circulation damper V1 instead of the stack damper D1 when the load suddenly changes. The other configurations are the same as those of the first embodiment. When the circulation damper V1 is opened, a portion of the exhaust gas drawn in by the blower 6 is returned through the circulation system L3 to the upstream side of the pressure sensor PT in the exhaust gas system L1. Even if the amount of exhaust gas supplied from the upstream equipment 1 suddenly decreases due to load shedding or the like, this can be compensated for by the exhaust gas supplied to the exhaust gas system L1 through the circulation system L3, thereby suppressing pressure fluctuations in the exhaust gas system L1.

[0026] (Control When Load Drops Suddenly) Next, control when a load is cut off will be described with reference to Fig. 6. Fig. 6 is a time chart showing an example of exhaust gas pressure under control in the second embodiment.

[0027] (Time t0) When load shedding occurs at time t0, the GTCC 3 transmits a load shedding signal to the control device 10. The detection unit 11 acquires this load shedding signal. Upon acquiring the load shedding signal, the control unit 12a stops feedback control of the rotor blade opening of the blower 6, reduces the opening of the blower 6 to a predetermined opening based on the load shedding signal, opens the circulation damper V1, and increases the opening of the circulation damper V1. By opening the circulation damper V1, a portion of the exhaust gas that has passed through the blower 6 is returned to the upstream side of the exhaust gas system L1 via the circulation system L3. The flow rate of the exhaust gas flowing through the circulation system L3 is shown as "circulation damper flow rate" in FIG. 4. Due to the circulation of the exhaust gas, the decrease in the exhaust gas pressure measured by the pressure sensor PT (more precisely, the pressure of the gas obtained by mixing the exhaust gas with outside air taken in from outside the system) is more gradual than in the example of FIG. 2.

[0028] (Time t1) At time t1, the circulation damper V1 is fully open. By time t1, the exhaust gas flow rate drops to 10-30%, and the pressure measured by the pressure sensor PT also drops below the specified range, but remains within the lower limit of the control range. At time t1, the drop in exhaust gas pressure stops, and the flow rate of exhaust gas flowing through the circulation system L3 (circulation damper flow rate) begins to decrease.

[0029] (Time t2) At time t2, the aperture of the blower 6 reaches a predetermined target value. When the aperture of the blower 6 reaches the target value, the control unit 12a performs feedback control so that the exhaust gas pressure measured by the pressure sensor PT reaches the target pressure. By circulating the exhaust gas through the circulation system L3, fluctuations in the exhaust gas pressure are smaller than in the example of FIG. 2, and fluctuations in the rotor blade aperture due to feedback control are also smaller. Because the pressure is stabilized by the feedback control of the rotor blade aperture of the blower 6, the flow rate of the exhaust gas circulating through the circulation system L3 also gradually decreases.

[0030] (After time t3) At time t3, the control unit 12a reduces the opening of the circulation damper V1, which is fully open, and fully closes the circulation damper V1 at time t4. At time t4, the exhaust gas pressure has stabilized at the target pressure. Here, time t3 can be determined as follows, as in the first embodiment: (a) A certain amount of time has elapsed since operation can be performed with the exhaust gas pressure within a predetermined range. (b) A certain amount of time has elapsed since the exhaust gas blower rotor blade opening can be closed to the target value. (c) A certain amount of time has elapsed since a load shedding signal was obtained.

[0031] In this embodiment, the opening of the blower 6 is reduced to a predetermined target value in advance based on the load shedding signal, and the circulation damper V1 is opened. As a result, a portion of the exhaust gas that has passed through the blower 6 is returned to the upstream side of the exhaust gas system L1 through the circulation system L3 and circulated. Fluctuations in the exhaust gas pressure are suppressed by circulating the exhaust gas, and the exhaust gas pressure is controlled to the target pressure by feedback control of the rotor blade opening of the blower 6.

[0032] (Operation) Next, referring to FIG. 7, the CO ２The operation of the recovery system 100a will now be described. FIG. 7 is a flowchart illustrating an example of control according to the second embodiment. The detector 11 receives a load shedding signal (step S11). When the detector 11 receives the load shedding signal, the controller 12a stops the feedback control, reduces the rotor blade opening of the blower 6 toward a predetermined target value, and opens the circulation damper V1 of the circulation system L3 toward full opening (step S12). It takes approximately 10 seconds for the rotor blade opening to reach the target value, and the circulation damper V1 fully opens even earlier. Next, the controller 12a determines whether the rotor blade opening of the blower 6 has been reduced to the target value (step S13; No). If the rotor blade opening has not been reduced to the target value (step S13; No), the controller 12a continues to reduce the rotor blade opening. If the rotor blade opening has been reduced to the target value (step S13; Yes), the controller 12a stops reducing the rotor blade opening and starts feedback control of the rotor blade opening (step S14). The control unit 12a then continues the feedback control of the rotor blade opening. Next, the control unit 12a determines whether the closing condition for the circulation damper V1 is satisfied (step S15). For example, the control unit 12a determines that the closing condition is satisfied when a certain time has elapsed since the pressure measured by the pressure sensor PT fell within a predetermined range. Alternatively, the control unit 12a may determine that the closing condition is satisfied when a certain time has elapsed since the rotor blade opening of the blower 6 decreased to a target value, or when a certain time has elapsed since the detection unit 11 acquired a load shedding signal. If the closing condition is not satisfied (step S15; No), the control unit 12a maintains the circulation damper V1 fully open until the closing condition is satisfied. If the closing condition is satisfied (step S15; Yes), the control unit 12a fully closes the circulation damper V1 of the circulation system L3 (step S16).

[0033] (Effects) As described above, according to this embodiment, when the flow rate of the exhaust gas supplied from the upstream equipment 1 suddenly decreases, a control signal is acquired, the rotor blade opening of the blower 6 is reduced, and the circulation damper V1 of the circulation system L3 is suddenly opened. After the circulation damper V1 is opened, it is kept open for a certain period of time, and then it is fully closed. This makes it possible to suppress fluctuations in the exhaust gas pressure and control the exhaust gas pressure within a control range. If the flow rate of the blower 6 cannot be adjusted quickly due to mechanical constraints, it is unable to keep up with the sudden decrease in the exhaust gas flow rate, resulting in a decrease in the exhaust gas pressure. However, according to this embodiment, the decrease in exhaust gas pressure can be suppressed by opening the circulation damper V1. In the first embodiment, outside air is taken in to maintain the exhaust gas pressure, which causes changes in the properties of the exhaust gas, but in the second embodiment, outside air is not taken in, so CO ２ Fluctuations in the properties of the exhaust gas supplied to the recovery device 7 can be suppressed.

[0034] Third Embodiment FIG. 8 shows a CO ２An example of a recovery system 100b is shown. As shown in FIG. 8 , in the third embodiment, a vacuum breaker VB is provided upstream of the branch point connecting the exhaust gas line L1 to the line L2. The vacuum breaker VB functions to quickly draw in outside air when pressure at the installation location drops. In the third embodiment, rather than controlling the opening and closing of the stack damper D1 and the circulation damper V1 based on a load shedding signal, the vacuum breaker VB is responsible for responding to sudden pressure fluctuations in the exhaust gas line L1 (though it does control the reduction of the rotor blade opening of the blower 6). Specifically, when the exhaust gas flow rate suddenly decreases and the exhaust gas pressure drops, the vacuum breaker VB activates and draws in air from outside the system. When the exhaust gas pressure returns, the vacuum breaker VB stops drawing air. While a mechanical vacuum breaker VB is preferable, an electro-pneumatic valve may also be used. A control device 10b is provided instead of the control device 10. The control device 10b includes a control unit 12b instead of the control unit 12. The control unit 12b controls the blade opening of the blower 6 without opening the stack damper D1 when the load suddenly changes. The other configurations are the same as those of the first embodiment. Even if the amount of exhaust gas supplied from the upstream equipment 1 suddenly decreases due to load shedding or the like, the vacuum breaker VB functions to take in air, thereby suppressing pressure fluctuations in the exhaust gas line L1.

[0035] (Control When Load Drops Suddenly) Next, control when a load is cut off will be described with reference to Fig. 9. Fig. 9 is a time chart showing an example of exhaust gas pressure under control in the third embodiment.

[0036] (Time t0) When load shedding occurs at time t0, the GTCC 3 transmits a load shedding signal to the control device 10. The detection unit 11 acquires this load shedding signal. Upon acquiring the load shedding signal, the control unit 12b stops feedback control of the rotor blade opening of the blower 6 and reduces the opening of the blower 6 to a predetermined opening based on the load shedding signal. After a while, the pressure in the exhaust gas line L1 decreases to the point where the vacuum breaker VB activates (time t0'). Because the vacuum breaker VB activates at time t0' and air is taken in from outside the system, the decrease in the exhaust gas pressure measured by the pressure sensor PT (more precisely, the pressure of the gas obtained by mixing the exhaust gas with the outside air taken in from outside the system) becomes more gradual compared to the example in FIG. 2 .

[0037] (Time t1) At time t1, the vacuum breaker VB is fully open. By time t1, the exhaust gas flow rate has decreased to 10-30%, and the pressure measured by the pressure sensor PT has also decreased beyond the specified range, but remains within the lower limit of the control range. At time t1, the decrease in exhaust gas pressure stops, and the flow rate of air taken in by the vacuum breaker VB begins to decrease.

[0038] (Time t2) At time t2, the aperture of the blower 6 reaches a predetermined target value. When the aperture of the blower 6 reaches the target value, the control unit 12b performs feedback control so that the exhaust gas pressure measured by the pressure sensor PT falls within a predetermined range. As the vacuum breaker VB takes in air, the pressure fluctuations of the exhaust gas are smaller than in the example of FIG. 2, and the fluctuations in the rotor blade aperture due to feedback control are also smaller. Because the pressure is stabilized by the feedback control of the rotor blade aperture of the blower 6, the flow rate of air taken in by the vacuum breaker VB also gradually decreases.

[0039] (After time t3) At time t3, the vacuum breaker VB changes from the fully open state to the closed state, and reaches the fully closed state at time t4. At time t4, the exhaust gas pressure has stabilized at the target pressure.

[0040] In this way, in this embodiment, the opening of the blower 6 is proactively reduced to a predetermined target value based on the load shedding signal, and the vacuum breaker VB takes in air from outside the system. This suppresses fluctuations in exhaust gas pressure, and by feedback-controlling the blade opening of the blower 6, the exhaust gas pressure is controlled within a predetermined range.

[0041] (Operation) Next, referring to FIG. 10, the CO ２ The operation of the recovery system 100b will now be described. FIG. 10 is a flowchart illustrating an example of control according to the third embodiment. The detector 11 receives a load shedding signal (step S21). When the detector 11 receives the load shedding signal, the controller 12b stops feedback control and reduces the blade opening of the blower 6 toward a predetermined target value (step S22). When the vacuum breaker VB detects a pressure drop in the exhaust gas system L1, it automatically opens (step S23) and takes in air. Next, the controller 12b determines whether the blade opening of the blower 6 has decreased to the target value (step S24). If the blade opening has not decreased to the target value (step S24; No), the controller 12b continues to reduce the blade opening. When the blade opening has decreased to the target value (step S24; Yes), the controller 12b stops reducing the blade opening and starts feedback control of the blade opening (step S25). From this point on, the controller 12b continues feedback control of the blade opening. When the pressure in the exhaust gas line L1 returns to a predetermined value, the vacuum breaker VB is automatically closed (step S26).

[0042] (Effects) As described above, according to this embodiment, when the flow rate of the exhaust gas supplied from the upstream equipment 1 suddenly decreases, a control signal is acquired and the blade opening of the blower 6 is reduced. When the vacuum breaker VB detects a pressure drop, it takes in air from outside the system. This suppresses fluctuations in the exhaust gas pressure and controls the exhaust gas pressure within a control range. Because the vacuum breaker VB responds to a pressure drop without relying on a control signal such as a load shedding signal, it can also respond to a drop in exhaust gas pressure caused by factors other than changes in the exhaust gas flow rate. Since the stack damper D1 of the first embodiment and the circulation damper V1 of the second embodiment are also used in situations such as startup and shutdown, equipment that meets the required specifications (opening / closing speed, etc.) can be expensive. However, the vacuum breaker VB used in the third embodiment requires only a small flow rate, thereby reducing costs.

[0043] In the configuration example of FIG. 8 , the vacuum breaker VB is added to the configuration of the first embodiment. However, the vacuum breaker VB may be added to the configuration of the second embodiment illustrated in FIG. 5 to perform the control described in FIGS. 9 and 10 . In addition to the configuration, the control of the first or second embodiment may be combined with the control of the third embodiment. For example, when combined with the control of the first embodiment, upon receiving a load shedding signal, the control unit 12b opens the stack damper D1. Independently, when the pressure in the exhaust gas line L1 drops, the vacuum breaker VB activates, allowing air to be drawn in from outside the system. When the closing condition for the stack damper D1 is met, the control unit 12b closes the stack damper D1. Independently, when the pressure in the exhaust gas line L1 returns to a predetermined value, the vacuum breaker VB closes. The same applies to the second embodiment. Upon receiving a load shedding signal, the control unit 12b opens the circulation damper V1. Independently of this, when the pressure in the exhaust gas line L1 drops, the vacuum breaker VB is activated, and air is drawn in from outside the system. When the closing condition for the circulation damper V1 is met, the control unit 12b closes the circulation damper V1. Independently of this, when the pressure in the exhaust gas line L1 returns to a predetermined value, the vacuum breaker VB is closed.

[0044] 11 is a diagram showing an example of the hardware configuration of a control device according to each embodiment. A computer 900 includes a CPU 901, a main storage device 902, an auxiliary storage device 903, an input / output interface 904, and a communication interface 905. The above-described control device 10 is implemented in the computer 900. The above-described functions are stored in the auxiliary storage device 903 in the form of a program. The CPU 901 reads the program from the auxiliary storage device 903, loads it into the main storage device 902, and executes the above-described processing in accordance with the program. The CPU 901 allocates a storage area in the main storage device 902 in accordance with the program. The CPU 901 allocates a storage area in the auxiliary storage device 903 for storing data being processed in accordance with the program.

[0045] A program for implementing all or part of the functions of the control device 10 may be recorded on a computer-readable recording medium, and the program may be loaded into a computer system and executed to perform processing by each functional unit. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. If a WWW system is used, the term "computer system" also includes the homepage provision environment (or display environment). The term "computer-readable recording medium" refers to portable media such as CDs, DVDs, and USBs, as well as storage devices such as hard disks built into the computer system. If the program is distributed to the computer 900 via a communication line, the computer 900 may load the program into the main storage device 902 and execute the processing described above. The program may be for implementing part of the functions described above, or may be capable of implementing the functions described above in combination with a program already stored in the computer system.

[0046] As described above, several embodiments according to the present disclosure have been described, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as defined in the claims, as well as in the scope and spirit of the invention.

[0047] <Additional Notes> The control device, exhaust gas supply system, control method, and program described in each embodiment can be understood, for example, as follows.

[0048] (1) The control device according to the first aspect converts exhaust gas emitted from the equipment into CO ２ The exhaust gas is drawn in by a blower provided in the exhaust gas system leading to the recovery device, and the CO ２ The control device for the system that supplies exhaust gas to the recovery device includes a detection unit that detects a sudden decrease in the flow rate of exhaust gas discharged from the facility, and a control unit that, when the detection unit detects a sudden decrease in the flow rate of the exhaust gas, reduces the opening degree of the rotor blades of the blower to a target value and controls a means for suppressing a pressure decrease in the exhaust gas system to suppress a pressure decrease in the exhaust gas system. This makes it possible to suppress fluctuations in exhaust gas pressure when the supply amount of exhaust gas decreases suddenly.

[0049] (2) A control device according to a second aspect is the control device of (1), wherein the means for suppressing a pressure drop in the exhaust gas system is a damper provided in a system leading to a stack provided upstream of the blower in the exhaust gas system, and the control unit opens the damper for a certain period of time when the detection unit detects a sudden drop in the flow rate of the exhaust gas (first embodiment). This makes it possible to suppress fluctuations in exhaust gas pressure when the supply amount of exhaust gas suddenly decreases.

[0050] (3) A third aspect of the control device is the control device of (1), wherein the means for suppressing a pressure drop in the exhaust gas system includes a circulation system that connects the downstream side of the blower in the exhaust gas system with the upstream side of the blower so as to bypass the blower, and a damper provided in the circulation system, and the control unit opens the damper for a certain period of time when the detection unit detects a sudden drop in the flow rate of the exhaust gas (second embodiment). This makes it possible to suppress fluctuations in exhaust gas pressure when the supply amount of exhaust gas suddenly decreases.

[0051] (4) The control device according to the fourth aspect converts exhaust gas emitted by the equipment into CO ２ A blower and a vacuum breaker are provided in the exhaust gas system leading to the recovery device, and the exhaust gas is drawn in by the blower, and the CO ２ A control device for a system that supplies exhaust gas to a recovery device includes a detection unit that detects a sudden decrease in the flow rate of exhaust gas discharged from the facility, and a control unit that reduces the opening degree of the rotor blades of the blower to a target value when the detection unit detects a sudden decrease in the flow rate of the exhaust gas (third embodiment). This makes it possible to suppress fluctuations in exhaust gas pressure when the supply rate of exhaust gas suddenly decreases.

[0052] (5) A fifth aspect of the control device is the control device of (2) to (3), wherein the control unit closes the damper when a predetermined time has elapsed since the pressure in the exhaust gas system reached a predetermined range, or when a predetermined time has elapsed since the opening degree of the rotor blades of the blower decreased to a target value, or when a predetermined time has elapsed since the detection unit detected a sudden decrease in the flow rate of the exhaust gas. This makes it possible to suppress fluctuations in exhaust gas pressure and then return to the original operating state.

[0053] (6) The exhaust gas supply system according to the sixth aspect is a system for converting exhaust gas emitted from a facility into CO ２The exhaust gas recovery system includes an exhaust gas system that leads the exhaust gas to a recovery device, a blower provided in the exhaust gas system, a system that leads to a stack provided upstream of the blower in the exhaust gas system, a damper provided in the system that leads to the stack, and the control device described in (2) (first embodiment). This makes it possible to suppress fluctuations in exhaust gas pressure when the supply amount of exhaust gas suddenly decreases.

[0054] (7) The exhaust gas supply system according to the seventh aspect converts exhaust gas discharged from a facility into CO ２ The exhaust gas recovery system includes an exhaust gas system that leads exhaust gas to a recovery device, a blower provided in the exhaust gas system, a bypass system that bypasses the blower in the exhaust gas system, a damper provided in the bypass system, and the control device described in (3) (second embodiment). This makes it possible to suppress fluctuations in exhaust gas pressure when the supply amount of exhaust gas suddenly decreases.

[0055] (8) An exhaust gas supply system according to an eighth aspect is a system for converting exhaust gas emitted from a facility into CO ２ The third embodiment includes an exhaust gas system that leads exhaust gas to a recovery device, a blower provided in the exhaust gas system, a vacuum breaker provided in the exhaust gas system upstream of the blower, and the control device described in (4). This makes it possible to suppress fluctuations in exhaust gas pressure when the amount of exhaust gas supply suddenly decreases.

[0056] (9) A control method according to a ninth aspect is a method for controlling exhaust gas emitted from a facility to CO ２ The exhaust gas is drawn in by a blower provided in the exhaust gas system leading to the recovery device, and the CO ２ A control method for a system that supplies exhaust gas to a recovery device, comprising: a step of detecting a sudden decrease in the flow rate of exhaust gas discharged by the facility; and a step of, upon detecting a sudden decrease in the flow rate of the exhaust gas, reducing the opening of the rotor blades of the blower to a target value and controlling a means for suppressing a pressure decrease in the exhaust gas system, thereby suppressing a pressure decrease in the exhaust gas system.

[0057] (10) A control method according to a tenth aspect is a method for controlling exhaust gas emitted from a facility to CO ２A blower and a vacuum breaker are provided in the exhaust gas system leading to the recovery device, and the exhaust gas is drawn in by the blower, and the CO ２ A control method for a system that supplies exhaust gas to a recovery device, comprising the steps of: detecting a sudden decrease in the flow rate of exhaust gas discharged from the equipment; reducing the opening of the blower's rotor blades to a target value when the sudden decrease in the flow rate of the exhaust gas is detected; and taking in outside air into the exhaust gas system through the vacuum breaker.

[0058] According to the above-described control device, exhaust gas supply system, and control method, fluctuations in exhaust gas pressure can be suppressed when the amount of exhaust gas supplied decreases suddenly.

[0059] 1...Upstream equipment 2...IGV 3...GTCC 4...Stack 5...Cooling tower 6...Blower 7...CO ２ Recovery device 10, 10a, 10b...controller 11...detector 12, 12a, 12b...controller D1, D2...damper L1, L2, L3...system V1...circulation damper VB...vacuum breaker 100, 100a, 100b...CO ２ Collection system 900: Computer 901: CPU 902: Main storage device 903: Auxiliary storage device 904: Input / output interface 905: Communication interface

Claims

1. CO2 emissions from equipment ２ The exhaust gas is drawn in by a blower provided in the exhaust gas system leading to the recovery device, and the CO ２ A control device for a system that supplies exhaust gas to a recovery device, comprising: a detection unit that detects a sudden decrease in the flow rate of exhaust gas discharged from the facility; and a control unit that, when the detection unit detects a sudden decrease in the flow rate of the exhaust gas, reduces the opening of the rotor blades of the blower to a target value and controls a means for suppressing a pressure decrease in the exhaust gas system, thereby suppressing the pressure decrease in the exhaust gas system.

2. The control device described in claim 1, wherein the means for suppressing a pressure drop in the exhaust gas system is a damper provided in a system leading to a stack provided upstream of the blower in the exhaust gas system, and the control unit opens the damper for a certain period of time when the detection unit detects a sudden drop in the flow rate of the exhaust gas.

3. The control device according to claim 1, wherein the means for suppressing a pressure drop in the exhaust gas system comprises a circulation system that connects the downstream side of the blower in the exhaust gas system with the upstream side of the blower so as to bypass the blower, and a damper provided in the circulation system, and the control unit opens the damper for a certain period of time when the detection unit detects a sudden drop in the flow rate of the exhaust gas.

4. CO2 emissions from equipment ２ A blower and a vacuum breaker are provided in the exhaust gas system leading to the recovery device, and the exhaust gas is drawn in by the blower, and the CO ２ A control device for a system that supplies exhaust gas to a recovery device, the control device comprising: a detection unit that detects a sudden decrease in a flow rate of exhaust gas discharged from the facility; and a control unit that reduces an opening degree of the rotor blades of the blower to a target value when the detection unit detects a sudden decrease in the flow rate of the exhaust gas.

5. A control device as described in claim 2 or claim 3, wherein the control unit closes the damper when a certain time has passed since the pressure in the exhaust gas system has reached a predetermined range, or when a certain time has passed since the opening of the blower's rotor blades has decreased to a target value, or when a certain time has passed since the detection unit detected a sudden decrease in the flow rate of the exhaust gas.

6. CO2 emissions from equipment ２ 10. An exhaust gas supply system comprising: an exhaust gas system that leads to a recovery device; a blower provided in the exhaust gas system; a system that leads to a stack provided upstream of the blower in the exhaust gas system; a damper provided in the system that leads to the stack; and the control device according to claim 2.

7. CO2 emissions from equipment ２ 4. An exhaust gas supply system comprising: an exhaust gas system that leads exhaust gas to a recovery device; a blower provided in the exhaust gas system; a bypass system that bypasses the blower in the exhaust gas system; a damper provided in the bypass system; and the control device according to claim 3.

8. CO2 emissions from equipment ２ 5. An exhaust gas supply system comprising: an exhaust gas line that leads exhaust gas to a recovery device; a blower provided in the exhaust gas line; a vacuum breaker provided upstream of the blower in the exhaust gas line; and the control device according to claim 4.

9. CO2 emissions from equipment ２ The exhaust gas is drawn in by a blower provided in the exhaust gas system leading to the recovery device, and the CO ２ A control method for a system that supplies exhaust gas to a recovery device, comprising: a step of detecting a sudden decrease in the flow rate of exhaust gas discharged from the facility; and a step of reducing the opening of the rotor blades of the blower to a target value when a sudden decrease in the flow rate of the exhaust gas is detected, and controlling a means for suppressing a pressure decrease in the exhaust gas system, thereby suppressing a pressure decrease in the exhaust gas system.

10. CO2 emissions from equipment ２ A blower and a vacuum breaker are provided in the exhaust gas system leading to the recovery device, and the exhaust gas is drawn in by the blower, and the CO ２ A control method for a system that supplies exhaust gas to a recovery device, comprising: a step of detecting a sudden decrease in the flow rate of exhaust gas discharged from the facility; a step of decreasing the opening of the rotor blades of the blower to a target value when the sudden decrease in the flow rate of the exhaust gas is detected; and a step of taking in outside air into the exhaust gas system through the vacuum breaker.

Images