Thermal storage power plant

Abstract

To provide a heat storage power generation system capable of efficiently performing heat storage power generation.SOLUTION: A heat storage power generation system includes a heat accumulator which stores thermal energy supplied from a heating portion and heats a thermal medium by the thermal energy, and a vapor generator which generates vapor by using the thermal medium heated by the heat accumulator. The system further includes a first channel for transferring the thermal medium from the heat accumulator to the vapor generation part to the heat accumulator and a second channel for transferring the thermal medium to the heat accumulator from the vapor generation part. The system furthermore includes an auxiliary part provided on the first channel and a bypass channel which transfers the thermal medium flowing through the second channel to the auxiliary part while bypassing the heat accumulator. Therein, a first thermal medium is supplied as the thermal medium from the heat accumulator and a second thermal medium is supplied as the thermal medium via the bypass channel from the second channel, and the auxiliary part supplies a third thermal medium to the vapor generator as the thermal medium.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a thermal energy storage power plant. [Background technology]

[0002] FIG. 1 is a schematic diagram showing the configuration of a conventional thermal storage power generation plant.

[0003] The thermal energy storage power generation plant of Figure 1 comprises a heating section 1, a thermal energy storage unit 2, a thermal energy storage inlet fan 3, a steam generator 4, a generator 5, a steam turbine 6, a turbine control valve 7, a turbine bypass valve 8, a condenser 9, and a condenser pump 10.

[0004] The operation of the thermal energy storage power plant in Figure 1 can be divided into two processes: the first process is the heat storage process, and the second process is the heat release process.

[0005] The heating section 1 is a section that generates thermal energy. The heating section 1 supplies sufficient thermal energy to the heat accumulator 2 to operate the thermal energy storage power plant. The heat accumulator 2 stores the thermal energy supplied from the heating section 1. In this way, the heat storage process is carried out by the heating section 1 and the heat accumulator 2.

[0006] On the other hand, the heat dissipation process is carried out by the heat accumulator 2, the heat storage inlet fan 3, and the steam generator 4 using a heat medium. The heat accumulator 2 heats the heat medium with the thermal energy stored in the heat accumulator 2 and supplies this heat medium to the steam generator 4. The steam generator 4 heats water with the thermal energy of the heat medium supplied from the heat accumulator 2 and generates steam from the water. As a result, the temperature of this heat medium drops in the steam generator 4 and it is discharged from the steam generator 4 together with waste heat. The heat storage inlet fan 3 returns the heat medium discharged from the steam generator 4 to the heat accumulator 2. In this way, the thermal energy stored in the heat accumulator 2 is dissipated to the steam generator 4.

[0007] The steam turbine 6 is supplied with steam (main steam) generated in the steam generator 4 and is rotationally driven by this steam. This steam is discharged from the steam turbine 6 together with waste heat and flows into the condenser 9. The generator 5 is rotationally driven by the steam turbine 6 to generate electricity, that is, converts kinetic energy into electrical power. The condenser 9 receives the steam discharged from the steam turbine 6 and converts this steam back into water. The condenser pump 10 sends the water (feedwater) discharged from the condenser 9 to the steam generator 4. In this way, water and steam circulate among the steam generator 4, steam turbine 6, condenser 9, and condenser pump 10.

[0008] The turbine control valve 7 is used to adjust the flow rate of steam supplied from the steam generator 4 to the steam turbine 6. The turbine bypass valve 8 is used to bypass the steam turbine 6 and discard the steam supplied from the steam generator 4 to a condenser 9. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 5461666 [Patent Document 2] European Patent Publication No. EP3327399 Summary of the Invention [Problem to be solved by the invention]

[0010] The thermal energy storage plant shown in Figure 1 has the following problems, making it difficult to achieve efficient operation of the plant.

[0011] First, the load control of the thermal energy storage power generation plant in Fig. 1 is performed by controlling the amount of thermal energy flowing into the steam turbine 6 with the control valve 7. When the set value of the plant load is lower than the thermal energy flowing into the steam turbine 6, excess thermal energy is supplied from the steam generator 4. In this case, the control valve 7 is closed, the turbine bypass valve 8 is opened, and this thermal energy is discarded to the condenser 9. As a result, the efficiency of the plant decreases.

[0012] Furthermore, the temperature of the heat medium sent from the regenerator 2 to the steam generator 4 must satisfy the design conditions of the steam generator 4. The temperature of the heat medium sent from the regenerator 2 to the steam generator 4 depends on the amount of thermal energy radiated from the regenerator 2. If the amount of thermal energy radiated is large and the temperature of the heat medium becomes high, the temperature of the heat medium may exceed the design conditions of the steam generator 4, which may have an adverse effect on the steam generator 4.

[0013] Furthermore, the heat quantity Q of the heat storage material in the heat storage device 2 is proportional to the weight M of the heat storage material, the specific heat Cp of the heat storage material, and the temperature difference ΔT (= T1 - T2) between the heat input temperature T1 and the heat output temperature T2 to the heat storage device 2 (Q = M × Cp × ΔT). Therefore, if the heat storage device 2 cannot store heat at a high temperature due to the influence of the design conditions of the steam generator 4, the heat input temperature T1 to the heat storage device 2 will be low. As a result, the weight M of the heat storage material needs to be large to achieve the target heat storage quantity Q, and a large space is required to install the heat storage device 2.

[0014] Furthermore, if there is a restriction on the heat input temperature T1 to the heat storage device 2, latent heat storage materials (e.g., alloy PCM (Phase Change Material)) and chemical heat storage materials (e.g., LiSiO4) that can store heat at higher temperatures cannot be used as heat storage materials, and the type of heat storage material in the heat storage device 2 is limited.

[0015] Furthermore, since the thermal storage power generation plant of FIG. 1 does not have a configuration for forcibly cooling the steam generator 4 during maintenance of the plant, it takes a long time to start maintenance of the steam generator 4.

[0016] Therefore, an embodiment of the present invention provides a thermal storage power generation plant that can save space in the thermal storage device 2, flexibly select the type of thermal storage material in the thermal storage device 2, or efficiently perform thermal storage power generation using the thermal storage device 2. [Means for solving the problem]

[0017] According to one embodiment, a thermal energy storage power generation plant includes a heat accumulator that stores thermal energy supplied from a heating section and heats a heat medium with the thermal energy, and a steam generator that generates steam using the heat medium heated by the heat accumulator. The device further includes a first flow path that transports the heat medium from the heat accumulator to the steam generating section and a second flow path that transports the heat medium from the steam generating section to the heat accumulator. The device further includes an auxiliary section provided on the first flow path and a bypass flow path that transports the heat medium flowing through the second flow path to the auxiliary section, bypassing the heat accumulator. The auxiliary section receives a first heat medium as the heat medium from the heat accumulator via the first flow path, a second heat medium as the heat medium from the second flow path via the bypass flow path, and supplies a third heat medium as the heat medium to the steam generator via the first flow path. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a conventional thermal storage power generation plant. [Figure 2] 1 is a schematic diagram showing the configuration of a thermal storage power generation plant according to a first embodiment. [Figure 3] FIG. 2 is a schematic diagram showing the configuration of an auxiliary system of the first embodiment. [Figure 4] FIG. 3 is another schematic diagram showing the configuration of the thermal storage power generation plant of the first embodiment. [Figure 5] FIG. 4 is another schematic diagram showing the configuration of the auxiliary system of the first embodiment. [Figure 6] FIG. 2 is a functional block diagram showing the configuration of a control device according to the first embodiment. [Figure 7] FIG. 4 is a schematic diagram showing the configuration of a thermal storage power generation plant according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. In Figures 1 to 7, the same components are denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0020] (First embodiment) FIG. 2 is a schematic diagram showing the configuration of the thermal storage power generation plant of the first embodiment.

[0021] The thermal energy storage power generation plant of Fig. 2, like the thermal energy storage power generation plant of Fig. 1, includes a heating section 1, a thermal accumulator 2, a thermal storage inlet fan 3, a steam generator 4, a power generator 5, a steam turbine 6, a turbine control valve 7, a turbine bypass valve 8, a condenser 9, and a condenser pump 10. The functions and operations of these components are as described with reference to Fig. 1. The heating section 1 is, for example, an electric heater. The thermal accumulator 2 is, for example, a thermal storage tank using crushed stone.

[0022] 2 further includes an auxiliary system 11, a bypass line 12, a control device 13, a power generation amount detector 14, and a pressure detector 15. The auxiliary system 11 is an example of an auxiliary part, and the bypass line 12 is an example of a bypass flow path. The power generation amount detector 14 is an example of a power generation detector, and the pressure detector 15 is an example of a steam detector.

[0023] FIG. 2 further shows the following heat medium flow paths: a line P1 from the heat storage device 2 to the auxiliary system 11; a line P2 from the auxiliary system 11 to the steam generator 4; a line P3 from the steam generator 4 to the heat storage inlet fan 3; and a line P4 from the heat storage inlet fan 3 to the heat storage device 2. The heat medium is, for example, air. The heat storage inlet fan 3 can circulate the heat medium between the heat storage device 2 and the steam generator 4 via these lines P1 to P4. In FIG. 2, the heat storage inlet fan 3 is disposed between the line P3 and the line P4 on the flow path from the steam generator 4 to the heat storage device 2; however, it may alternatively be disposed on the line P1 or the line P2 on the flow path from the heat storage device 2 to the steam generator 4. The lines P1 and P2 are examples of a first flow path, and the lines P3 and P4 are examples of a second flow path. The heat storage inlet fan 3 is an example of a rotating device.

[0024] The auxiliary system 11 is arranged between the line P1 and the line P2 on the flow path from the heat accumulator 2 to the steam generator 4. The bypass line 12 is connected to the line P4 and the auxiliary system 11, and the heat medium flowing through the line P4 can be transported to the auxiliary system 11, bypassing the heat accumulator 2. In this embodiment, the connection point between the line P4 and the bypass line 12 is located upstream of the heat accumulator 2, the auxiliary system 11 is located downstream of the heat accumulator 2, and the entire bypass line 12 is laid outside the heat accumulator 2. Note that the bypass line 12 may be connected to the line P3 and the auxiliary system 11, and the heat medium flowing through the line P3 may be transported to the auxiliary system 11, bypassing the heat accumulator 2.

[0025] The auxiliary system 11 is supplied with a heat medium (first heat medium) from the heat accumulator 2 via a line P1, and is supplied with a heat medium (second heat medium) from a line P4 via a bypass line 12. The first heat medium is a high-temperature heat medium heated in the heat accumulator 2, and the second heat medium is a low-temperature heat medium that is not heated in the heat accumulator 2.

[0026] The auxiliary system 11 further supplies a heat medium (third heat medium) to the steam generator 4 via line P2. When the first or second heat medium is supplied to the auxiliary system 11, the auxiliary system 11 discharges the first or second heat medium as the third heat medium. On the other hand, when the first and second heat medium are supplied to the auxiliary system 11, the auxiliary system 11 discharges a heat medium obtained by mixing the first and second heat medium as the third heat medium. This allows a heat medium that is lower in temperature than the first heat medium but higher in temperature than the second heat medium to be discharged as the third heat medium. The temperature of this third heat medium can be adjusted by controlling the ratio between the flow rate of the first heat medium and the flow rate of the second heat medium. The third heat medium discharged from the auxiliary system 11 is supplied to the steam generator 4 via line P2.

[0027] The control device 13 controls various operations of the thermal storage power generation plant shown in Fig. 2. For example, the control device 13 controls the rotation speed of the thermal storage inlet fan 3, the opening and closing of the turbine control valve 7, the opening and closing of the turbine bypass valve 8, and the operation of the auxiliary system 11. Further details of the control device 13 will be described later.

[0028] The power generation output detector 14 detects the power generation output of the generator 5 and outputs the power generation output detection result to the control device 13. The pressure detector 15 detects the pressure of the steam (main steam pressure) flowing from the steam generator 4 to the turbine control valve 7 and the turbine bypass valve 8 and outputs the pressure detection result to the control device 13. For example, when the turbine control valve 7 is open and the turbine bypass valve 8 is closed, the pressure detector 15 detects the pressure of the steam supplied to the steam turbine 6. On the other hand, when the turbine control valve 7 is closed and the turbine bypass valve 8 is open, the pressure detector 15 detects the pressure of the steam flowing into the condenser 9. The thermal energy storage power generation plant in FIG. 2 is provided with two lines that supply steam from the steam generator 4 to the steam turbine 6, and the pressure detector 15 is provided on one of these lines.

[0029] Fig. 3 is a schematic diagram showing the configuration of the auxiliary system 11 of the first embodiment. In Fig. 3, system lines are shown by solid lines and control lines are shown by dashed lines. This also applies to other figures described later.

[0030] As shown in Fig. 3, the auxiliary system 11 includes a bypass damper 11a, a temperature detector 11b, a steam generator inlet damper 11c, a flow rate detector 11d, a mixer 11e, a heat accumulator shutoff damper 11f, and a pressure detector 11g. The heat accumulator shutoff damper 11f is an example of a first adjustment unit. The bypass damper 11a is an example of a second adjustment unit. The steam generator inlet damper 11c is an example of a third adjustment unit.

[0031] In the auxiliary system 11, flow paths for the heat medium extend from the line P1, the line P2, and the bypass line 12 to the mixer 11e. In the description of this embodiment, these flow paths will also be referred to as the line P1, the line P2, and the bypass line 12, respectively.

[0032] The mixer 11e is disposed between the line P1 and the line P2 on the flow path from the heat accumulator 2 to the steam generator 4, and is connected to the bypass line 12. Thus, the mixer 11e is supplied with a heat medium (first heat medium) from the heat accumulator 2 via the line P1, is supplied with a heat medium (second heat medium) from the line P4 via the bypass line 12, and supplies a heat medium (third heat medium) to the steam generator 4 via the line P2. When the first or second heat medium is supplied to the mixer 11e, the mixer 11e discharges the first or second heat medium as the third heat medium. On the other hand, when the first and second heat media are supplied to the mixer 11e, the mixer 11e mixes the first heat medium and the second heat medium and discharges the heat medium obtained by mixing them as the third heat medium. The third heat medium discharged from the mixer 11e is supplied to the steam generator 4 via the line P2.

[0033] The bypass damper 11a is provided on the bypass line 12 in the auxiliary system 11 and is used to adjust the flow rate of the second heat medium flowing through the bypass line 12. The temperature detector 11b is provided on the line P2 in the auxiliary system 11 and detects the temperature of the third heat medium flowing through the line P2 and outputs the temperature detection result to the control device 13. This temperature corresponds to the temperature of the heat medium at the inlet of the steam generator 4. As will be described later, the control device 13 can control the temperature of the third heat medium flowing through the line P2 by controlling the bypass damper 11a based on the temperature detected by the temperature detector 11b.

[0034] The steam generator inlet damper 11c is provided on the line P2 in the auxiliary system 11 and is used to adjust the flow rate of the third heat medium flowing through the line P2. The flow rate detector 11d is provided on the line P2 in the auxiliary system 11 and detects the flow rate of the third heat medium flowing through the line P2 and outputs the flow rate detection result to the control device 13. This flow rate corresponds to the flow rate of the heat medium at the inlet of the steam generator 4. As will be described later, the control device 13 can control the flow rate of the third heat medium flowing through the line P2 by controlling the steam generator inlet damper 11c based on the flow rate detected by the flow rate detector 11d.

[0035] The heat accumulator shutoff damper 11f is provided on the line P1 in the auxiliary system 11 and is used to adjust the flow rate of the first heat medium flowing through the line P1. The thermal energy storage power generation plant of FIG. 2 requires forced cooling of the plant during maintenance, etc. The control device 13 fully closes the heat accumulator shutoff damper 11f during forced cooling of the plant. As a result, the supply of heat medium to the heat accumulator 2 is stopped, and the heat medium heated by the heat accumulator 2 is no longer supplied to the steam generator 4, so the heat medium does not pass through the heat accumulator 2. Therefore, the heat medium is supplied to the steam generator 4 at a low temperature. This allows the steam generator 4 to be cooled quickly and shut down in a short time. When the heat accumulator shutoff damper 11f is fully closed, all of the heat medium that flows into the connection point between the line P4 and the bypass line 12 flows into the bypass line 12. The heat accumulator cutoff damper 11f may be capable of taking only two states, an open state and a closed state, or may be capable of taking a plurality of opening degrees.

[0036] The pressure detector 11g is provided on the line P1 in the auxiliary system 11, detects the pressure of the first heat medium flowing through the line P1, and outputs the pressure detection result to the control device 13. This pressure corresponds to the pressure of the heat medium at the outlet of the heat accumulator 2. As will be described later, the control device 13 can control the pressure of the first heat medium flowing through the line P1 by controlling the heat storage inlet fan 3 based on the pressure detected by the pressure detector 11g.

[0037] According to this embodiment, it is possible to independently control the temperature of the heat medium at the inlet of the steam generator 4 and the flow rate of the heat medium at the inlet of the steam generator 4. Unless these are independently controlled, it takes time for the control of the adjustment unit that controls the temperature of the heat medium at the inlet of the steam generator 4 and the control of the adjustment unit that controls the flow rate of the heat medium at the inlet of the steam generator 4 to converge.

[0038] Specifically, in this embodiment, the temperature of the heat medium at the inlet of the steam generator 4 can be controlled by the bypass damper 11a, and the flow rate of the heat medium at the inlet of the steam generator 4 can be controlled by the steam generator inlet damper 11c.

[0039] On the other hand, for example, if a control unit that controls the flow rate of the heat medium at the inlet of the steam generator 4 is provided on line P1 instead of line P2, the operation of the adjustment unit will change the ratio between the flow rate of the heat medium flowing through bypass line 12 and the flow rate of the heat medium flowing through line P1, and accordingly, the temperature of the heat medium at the inlet of the steam generator 4 will change. Accordingly, the adjustment unit (bypass damper 11a) that controls the temperature of the heat medium at the inlet of the steam generator 4 will operate, and accordingly, the flow rate of the heat medium at the inlet of the steam generator 4 will change. Accordingly, the adjustment unit that controls the flow rate of the heat medium at the inlet of the steam generator 4 will operate, and this interlocking will be repeated until the operations of both adjustment units converge, and it will take time for the temperature and flow rate of the heat medium at the inlet of the steam generator 4 to converge.

[0040] In contrast to this, according to this embodiment, if the control unit that controls the flow rate of the heat medium at the inlet of the steam generator 4 is provided on line P2, it becomes possible to suppress interference between these controls, and the time required for the temperature and flow rate of the heat medium at the inlet of the steam generator 4 to converge is shortened.

[0041] FIG. 4 is another schematic diagram showing the configuration of the thermal storage power generation plant of the first embodiment.

[0042] Fig. 4 shows details of the control device 13 in addition to the contents shown in Fig. 2. As shown in Fig. 4, the control device 13 includes a unit master control unit 21, a turbine control unit 22, and an auxiliary system control unit 23.

[0043] The unit master control unit 21 receives a signal S1 indicating the amount of power generation required for the plant from the central load dispatching center of the thermal storage power generation plant of this embodiment. The amount of power generation required may be input to the control device 13 by an operator of the control device 13. The unit master control unit 21 further outputs a signal S2 indicating a unit load set value (MWD) based on the signal S1. The signal S2 is output to the turbine control unit 22 and the auxiliary system control unit 23.

[0044] The turbine control unit 22 performs load control of the thermal storage power generation plant of this embodiment based on the signal S2. Specifically, the turbine control unit 22 calculates a command value for the turbine control valve 7 based on the signal S2, and outputs a signal S3 indicating this designated value to the turbine control valve 7. In this way, the turbine control unit 22 can control the flow rate of steam supplied from the turbine control valve 7 to the steam turbine 6.

[0045] The auxiliary system control unit 23 controls the auxiliary system 11 based on the signal S2, and further controls the thermal storage inlet fan 3 based on the signal S2. Specifically, the auxiliary system control unit 23 calculates command values ​​for the bypass damper 11a, the steam generator inlet damper 11c, and the thermal storage inlet fan 3 based on the signal S2, and outputs signals S4, S5, and S6 indicating these command values ​​to the bypass damper 11a, the steam generator inlet damper 11c, and the thermal storage inlet fan 3, respectively. In this way, the auxiliary system control unit 23 can control the temperature, flow rate, and pressure of the heat medium.

[0046] As will be described later, the operation of the auxiliary system control unit 23 is linked to the operation of the turbine control unit 22 due to various factors. Therefore, the control device 13 can integrate the steam turbine 6 and the auxiliary system 11 into a single unit and operate the steam turbine 6 and the auxiliary system 11 in coordination. For example, when the amount of power generation requested by the central load dispatching center decreases, the thermal energy supplied from the regenerator 2 to the steam generator 4 may be reduced instead of discarding steam to the condenser 9. This makes it possible, for example, to quickly respond to changes in the amount of power generation requested and to prevent a deterioration in plant efficiency due to the discarding of steam.

[0047] FIG. 5 is another schematic diagram showing the configuration of the auxiliary system 11 of the first embodiment.

[0048] In addition to the contents shown in Fig. 3, Fig. 5 shows details of the control device 13. As shown in Fig. 5, the auxiliary system control unit 23 of the control device 13 includes a temperature control unit 23a, a flow rate control unit 23b, and a pressure control unit 23c.

[0049] The temperature control unit 23a controls the bypass damper 11a with a signal S4 based on the temperature detected by the temperature detector 11b, thereby controlling the temperature of the third heat medium flowing through the line P2. The flow rate control unit 23b controls the steam generator inlet damper 11c with a signal S5 based on the flow rate detected by the flow rate detector 11d, thereby controlling the flow rate of the third heat medium flowing through the line P2. The pressure control unit 23c controls the thermal storage inlet fan 3 with a signal S6 based on the pressure detected by the pressure detector 11g, thereby controlling the pressure of the first heat medium flowing through the line P1. These controls are performed based on a signal S2 indicating the MWD. ​​Further details of these controls will be described later.

[0050] FIG. 6 is a functional block diagram showing the configuration of the control device 13 of the first embodiment.

[0051] The unit master control unit 21 includes a load change rate calculator 31, an adder 32, and a load setting upper and lower limiter 33. The turbine control unit 22 includes a subtractor 41 and a PID (Proportional Integral Derivative) control unit 42. The auxiliary system control unit 23 includes a temperature control unit 23a, a flow rate control unit 23b, a pressure control unit 23c, and a master logic unit 23d. The master logic unit 23d is an example of a calculation unit.

[0052] Furthermore, the master logic unit 23d includes a function generator 51, a subtractor 52, a PID control unit 53, and an adder 54. The temperature control unit 23a includes a function generator 61, a subtractor 62, and a PID control unit 63. The flow rate control unit 23b includes a function generator 71, a subtractor 72, and a PID control unit 73. The pressure control unit 23c includes a function generator 81, a subtractor 82, a PID control unit 83, an adder 84, and a function generator 85.

[0053] The unit master control unit 21 operates as follows. The load change rate calculator 31 receives a signal S1 indicating the amount of power required for the thermal storage power generation plant of this embodiment, and limits the rate of change of the MWD calculated from the amount of power required. The adder 32 receives a signal S7 indicating a correction value due to frequency changes, etc., and calculates the corrected MWD by adding the correction value to the MWD before correction. The load setting upper and lower limiter 33 limits the value of the corrected MWD by upper and lower limits based on the capacity or limitations of the plant. The unit master control unit 21 outputs a signal S2 indicating the MWD output from the load setting upper and lower limiter 33.

[0054] The turbine control unit 22 operates as follows. The subtractor 41 receives a signal S2 indicating the MWD from the unit master control unit 21, and also receives the power generation amount of the generator 5 detected by the power generation amount detector 14, and subtracts the power generation amount from the MWD. ​​The PID control unit 42 receives the deviation between the MWD and the power generation amount from the subtractor 41 and controls the opening of the turbine control valve 7 by feedback control (PID control) based on this deviation. Specifically, the PID control unit 42 calculates a command value for the turbine control valve 7 so as to bring this deviation closer to zero, and outputs a signal S3 indicating this command value to the turbine control valve 7. In this way, the turbine control unit 22 can control the flow rate of steam supplied from the turbine control valve 7 to the steam turbine 6, thereby controlling the power generation amount of the generator 5. Note that the turbine control unit 22 may receive a value related to the generator 5 other than the power generation amount from a predetermined detector and control the turbine control valve 7 based on this value.

[0055] The auxiliary system control unit 23 includes a master logic unit 23d that performs upstream control, and a flow rate control unit 23b, a pressure control unit 23c, and the master logic unit 23d that perform downstream control (local control) based on the upstream control.

[0056] The master logic unit 23d operates as follows. The function generator 51 receives a signal S2 indicating the MWD from the unit master control unit 21 and calculates the set value of the main steam pressure from the MWD using the function generated by the function generator 51. The subtractor 52 receives the measured value of the main steam pressure from the pressure detector 15 and subtracts the measured value of the main steam pressure from the set value of the main steam pressure. The PID control unit 53 receives the deviation between the set value and the measured value from the subtractor 52 and determines a correction signal for the thermal storage outlet set value by feedback control (PID control) based on this deviation. Specifically, the PID control unit 53 calculates a correction signal for the thermal storage outlet set value so as to bring this deviation closer to zero. The adder 54 receives the MWD, which is a base signal for the thermal storage outlet set value, from the unit master control unit 21, receives a correction signal for the thermal storage outlet set value from the PID control unit 53, and adds the correction signal for the thermal storage outlet set value to the base signal for the thermal storage outlet set value. The master logic unit 23d outputs a signal S8 indicating the thermal storage outlet set value obtained by adding the correction signal to the base signal. MWD, which is the base signal for the thermal storage outlet set value, is an example of a first set value, and the thermal storage outlet set value is an example of a second set value.

[0057] The thermal storage outlet set value in this embodiment is used to control the temperature, flow rate, and pressure of the heat medium at the outlet of the thermal storage device 2. For example, the temperature control unit 23a controls the temperature of the third heat medium flowing through the line P2 based on the thermal storage outlet set value. Furthermore, the flow rate control unit 23b controls the flow rate of the third heat medium flowing through the line P2 based on the thermal storage outlet set value. Furthermore, the pressure control unit 23c controls the pressure of the first heat medium flowing through the line P1 based on the thermal storage outlet set value. According to this embodiment, it is possible to unify the set values ​​for controlling the bypass damper 11a, the steam generator inlet damper 11c, and the thermal storage inlet fan 3, which are the control terminals of the thermal storage device 2, to the thermal storage outlet set value, thereby enabling these control terminals to operate in a coordinated manner.

[0058] In this embodiment, the thermal storage outlet setting value is set based on the MWD in order to supply a thermal storage output that corresponds to the amount of power generated by the generator 5. The thermal storage output is the thermal energy released from the thermal accumulator 2. The thermal storage outlet setting value in this embodiment is calculated by adding a correction signal for the thermal storage outlet setting value to the MWD, which is a base signal for the thermal storage outlet setting value, and therefore changes according to changes in the MWD.

[0059] Even if the thermal storage outlet setting value is set to MWD, the balance between the amount of power generation and the thermal storage output is usually maintained. However, if the thermal storage outlet setting value is set to MWD, an imbalance between the amount of power generation and the thermal storage output may occur when the efficiency of the steam turbine 6 changes or when the load on the thermal storage power generation plant changes. Therefore, in this embodiment, the thermal storage outlet setting value is set to the sum of the MWD, which is the base signal, and a correction signal. The correction signal is calculated based on the main steam pressure detected by the pressure detector 15. Therefore, according to this embodiment, by using such a thermal storage outlet setting value, it is possible to prevent an imbalance between the amount of power generation and the thermal storage output.

[0060] The master logic unit 23d may receive a value related to the main steam other than the main steam pressure from a predetermined detector and calculate the thermal storage outlet set value based on this value. In this embodiment, the master logic unit 23d calculates a thermal storage outlet set value having the same dimension as the MWD, but may also calculate a thermal storage outlet set value having a dimension different from the MWD.

[0061] The temperature control unit 23a operates as follows. The function generator 61 receives a signal S8 indicating the thermal storage outlet set value from the master logic unit 23d and calculates a set value for the steam generator inlet temperature from the thermal storage outlet set value using the function generated by the function generator 61. The steam generator inlet temperature is the temperature of the heat medium at the inlet of the steam generator 4 and is measured by the temperature detector 11b. The subtractor 62 receives the measured value of the steam generator inlet temperature from the temperature detector 11b and subtracts the measured value of the steam generator inlet temperature from the set value of the steam generator inlet temperature. The PID control unit 63 receives the deviation between the set value and the measured value from the subtractor 62 and controls the opening of the bypass damper 11a by feedback control (PID control) based on this deviation. Specifically, the PID control unit 63 calculates a command value for the bypass damper 11a so as to bring this deviation closer to zero and outputs a signal S4 indicating this specified value to the bypass damper 11a.

[0062] In this way, the temperature control section 23a of this embodiment can control the temperature of the third heat medium flowing through the line P2, and thereby the temperature of the heat medium at the outlet of the heat accumulator 2 can be controlled.

[0063] The flow rate control unit 23b operates as follows. The function generator 71 receives a signal S8 indicating the thermal storage outlet set value from the master logic unit 23d, and calculates a set value for the steam generator inlet flow rate from the thermal storage outlet set value using the function generated by the function generator 71. The steam generator inlet flow rate is the flow rate of the heat medium at the inlet of the steam generator 4, and is measured by the flow rate detector 11d. The subtractor 72 receives the measured value of the steam generator inlet flow rate from the flow rate detector 11d, and subtracts the measured value of the steam generator inlet flow rate from the set value of the steam generator inlet flow rate. The PID control unit 73 receives the deviation between the set value and the measured value from the subtractor 72, and controls the opening of the steam generator inlet damper 11c using feedback control (PID control) based on this deviation. Specifically, the PID control unit 73 calculates a command value for the steam generator inlet damper 11c so as to bring this deviation closer to zero, and outputs a signal S5 indicating this designated value to the steam generator inlet damper 11c.

[0064] In this way, the flow rate control unit 23b of this embodiment can control the flow rate of the third heat medium flowing through the line P2, and thereby the flow rate of the heat medium at the outlet of the heat accumulator 2 can be controlled.

[0065] The pressure control unit 23c operates as follows. The function generator 85 receives a signal S8 indicating the thermal storage outlet set value from the master logic unit 23d and calculates a correction value for the command value of the thermal storage inlet fan 3 from the thermal storage outlet set value using the function generated by the function generator 85. The thermal storage outlet pressure is the pressure of the heat medium at the outlet of the thermal storage device 2 and is measured by the pressure detector 11g. The function generator 81 receives the measured value of the steam generator inlet flow rate from the flow rate detector 11d and calculates the set value of the thermal storage outlet pressure corresponding to the measured value of the steam generator inlet flow rate using the function generated by the function generator 81. The subtractor 82 receives the measured value of the thermal storage outlet pressure from the pressure detector 11g and subtracts the measured value of the thermal storage outlet pressure from the set value of the thermal storage outlet pressure. The PID control unit 83 receives the deviation between the set value and the measured value from the subtractor 82 and determines the rotation speed of the thermal storage inlet fan 3 using feedback control (PID control) based on this deviation. Specifically, the PID control unit 83 calculates a command value for the thermal storage inlet fan 3 so as to bring this deviation closer to zero. The adder 84 adds the correction value calculated by the function generator 85 to the command value calculated by the PID control unit 83. The adder 84 outputs a signal S6 to the thermal storage inlet fan 3, which indicates a corrected command value obtained by adding the correction value to the command value before correction.

[0066] In this way, the pressure control unit 23c of this embodiment can control the pressure of the first heat medium flowing through the line P1, and thereby control the pressure of the heat medium at the outlet of the heat accumulator 2. In the pressure control unit 23c of this embodiment, it is difficult to sufficiently improve the operating performance of the thermal storage power generation plant when the load changes rapidly using only feedback control by the PID control unit 83. For this reason, the pressure control unit 23c of this embodiment corrects the command value obtained by feedback control using feedforward control by the adder 84. This makes it possible to sufficiently improve the operating performance of the thermal storage power generation plant even when the load changes rapidly.

[0067] As described above, the thermal energy storage power generation plant of this embodiment includes the auxiliary system 11 provided between the line P1 and the line P2, and the bypass line 12 that supplies the heat medium from the line P4 to the auxiliary system 11, bypassing the heat accumulator 2. This makes it possible to perform load control in this embodiment not only using the regulator valve 7 but also using the auxiliary system 11, and it becomes possible for the auxiliary system 11 to assist the load control by the regulator valve 7. Conventionally, when it was desired to reduce the amount of steam supply, unnecessary steam was discarded to the condenser 9. However, according to this embodiment, thermal energy storage power generation can be performed efficiently by controlling the supply of steam from the steam generator 4 using the auxiliary system 4. According to this embodiment, such efficient thermal energy storage power generation can be achieved by controlling the auxiliary system 11 and the like using the control device 13.

[0068] As described above, the calorific value Q of the heat storage material in the heat storage device 2 is proportional to the weight M of the heat storage material, the specific heat Cp of the heat storage material, and the temperature difference ΔT (=T1-T2) between the heat input temperature T1 and the heat output temperature T2 to the heat storage device 2 (Q=M×Cp×ΔT). According to this embodiment, the heat supply to the steam generator 4 can be controlled by the auxiliary system 11, so that the heat storage device 2 can store heat at a high temperature, and it becomes possible to increase the heat input temperature T1 to the heat storage device 2 in the above formula. Therefore, a large calorific value Q can be obtained with a small weight M, and the size of the heat storage device 2 can be made compact.

[0069] Furthermore, by increasing the heat input temperature T1 to the heat storage device 2, it is possible to eliminate the constraints on the heat medium temperature. Therefore, the type of heat storage material in the heat storage device 2 can be not only crushed stone, concrete, ceramics, etc., but also latent heat storage materials (e.g., alloy PCM) and chemical heat storage materials (e.g., LiSiO4) that can store heat at higher temperatures and higher densities. As described above, according to this embodiment, the type of heat storage material in the heat storage device 2 can be flexibly selected, it is possible to reduce the space required for the heat storage device 2, and it is possible to achieve heat storage power generation that can maintain high power generation thermal efficiency.

[0070] Furthermore, in this embodiment, a heat accumulator shutoff damper 11f is provided to forcibly cool the steam generator 4 during maintenance of the steam generator 4, and when the heat accumulator shutoff damper 11f is shut off, the heat medium attempting to return from the steam generator 4 to the heat accumulator 2 does not return to the heat accumulator 2, but instead circulates to the steam generator 4 through the bypass line 12. Therefore, the heat medium that does not pass through the heat accumulator 2 is circulated between the heat accumulator 2 and the steam generator 4, which quickly cools the steam generator 4, and as a result, the time until maintenance of the steam generator 4 can be started can be shortened.

[0071] (Second embodiment) FIG. 7 is a schematic diagram showing the configuration of a thermal storage power generation plant according to the second embodiment.

[0072] The thermal storage power generation plant in Fig. 7 has a configuration similar to that of the thermal storage power generation plant in Fig. 2. However, the thermal storage power generation plant in Fig. 7 includes a thermal storage shut-off damper 16 instead of or in addition to the thermal storage shut-off damper 11f. The thermal storage shut-off damper 16 is an example of a fourth adjustment unit.

[0073] The heat storage shutoff damper 16 is provided on the line P4 and is used to adjust the flow rate of the heat medium flowing through the line P4. In FIG. 7, the heat storage shutoff damper 16 is located downstream of the connection point between the line P4 and the bypass line 12. The heat storage power generation plant of FIG. 7 requires forced cooling of the plant during maintenance, etc. The control device 13 fully closes the heat storage shutoff damper 16 during forced cooling of the plant. As a result, the supply of heat medium to the heat storage device 2 is stopped, and the heat medium heated by the heat storage device 2 is no longer supplied to the steam generator 4. This allows the steam generator 4 to be cooled quickly and shut down in a short time. When the heat storage shutoff damper 16 is fully closed, all of the heat medium flowing into the connection point between the line P4 and the bypass line 12 flows into the bypass line 12. The heat storage shutoff damper 16 may be capable of being opened only in two states, an open state and a closed state, or may be capable of being opened to multiple degrees.

[0074] Here, the heat stor- age shut-off damper 11f and the heat stor- age shut-off damper 16 will be compared. Since the heat stor- age shut-off damper 11f is arranged downstream of the heat stor- age 2, the high-temperature heat medium after being heated in the heat stor- age 2 flows into the heat stor- age shut-off damper 11f. On the other hand, since the heat stor- age 2 is arranged upstream of the heat stor- age 2, the low-temperature heat medium before being heated in the heat stor- age 2 flows into the heat stor- age shut-off damper 16. Therefore, using the heat stor- age shut-off damper 16 has the advantage that thermal deterioration of the heat stor- age stor- age shut-off damper 16 can be suppressed, and that a heat stor- age shut-off damper 16 with low heat resistance can be employed, for example.

[0075] Similarly, the thermal energy storage power generation plant of Fig. 7 may include a flow rate adjustment damper on the line P4 instead of or in addition to the steam generator inlet damper 11c. This damper is, for example, located upstream of the connection point between the line P4 and the bypass line 12 and is controlled by the control device 13 using the same control method as the steam generator inlet damper 11c. The use of such a damper has the advantages of suppressing thermal deterioration of the damper and allowing the use of a damper with low heat resistance. On the other hand, the use of the steam generator inlet damper 11c has the advantage of improving the responsiveness of the flow rate control, for example, because the steam generator inlet damper 11c and the flow rate detector 11d can be located close to each other.

[0076] Although several embodiments have been described above, these embodiments are presented only as examples and are not intended to limit the scope of the invention. The novel plant described in this specification can be embodied in various other forms. Furthermore, various omissions, substitutions, and modifications can be made to the plant forms described in this specification without departing from the spirit of the invention. The appended claims and their equivalents are intended to cover such forms and modifications that fall within the scope and spirit of the invention. [Explanation of symbols]

[0077] 1: heating section, 2: heat storage unit, 3: heat storage inlet fan, 4: steam generator, 5: Generator, 6: Steam turbine, 7: Turbine control valve, 8: turbine bypass valve, 9: condenser, 10: condenser pump, 11: auxiliary system, 11a: bypass damper, 11b: temperature detector, 11c: steam generator inlet damper, 11d: flow rate detector, 11e: mixer, 11f: heat storage shutoff damper, 11g: pressure detector, 12: bypass line, 13: control device, 14: power generation amount detector, 15: pressure detector, 16: heat storage shutoff damper, 21: unit master control unit, 22: turbine control unit, 23: auxiliary system control unit, 23a: temperature control section, 23b: flow rate control section, 23c: Pressure control unit, 23d: Master logic unit, 31: Load change rate calculator, 32: Adder, 33: Load setting upper and lower limiter, 41: subtractor, 42: PID control unit, 51: Function generator, 52: Subtractor, 53: PID control unit, 54: Adder, 61: Function generator, 62: Subtractor, 63: PID control unit, 71: Function generator, 72: Subtractor, 73: PID control unit, 81: Function generator, 82: Subtractor, 83: PID control unit, 84: Adder, 85: Function generator

Claims

1. a heat accumulator that stores thermal energy supplied from the heating portion and heats a heat medium with the thermal energy; a steam generator that generates steam using the heat medium heated by the heat accumulator; a first flow path that transports the heat medium from the heat accumulator to the steam generator; a second flow path that transports the heat medium from the steam generator to the heat accumulator; an auxiliary portion provided on the first flow path; a bypass flow path that transports the heat medium flowing through the second flow path to the auxiliary section, bypassing the heat accumulator; A thermal storage power generation plant comprising: the auxiliary unit receives a first heat medium as the heat medium from the heat accumulator via the first flow path, receives a second heat medium as the heat medium from the second flow path via the bypass flow path, and supplies a third heat medium as the heat medium to the steam generator via the first flow path, the auxiliary unit includes a first adjusting unit that adjusts the flow rate of the first heat medium, The first adjustment unit stops the supply of the heat medium to the heat accumulator when the heat storage power generation plant is forcedly cooled.

2. a fourth adjusting unit provided on the second flow path and configured to adjust the flow rate of the heat medium; The thermal energy storage power generation plant according to claim 1 , wherein the fourth adjustment unit stops the supply of the heat medium to the heat accumulator when the thermal energy storage power generation plant is forcedly cooled.

3. a heat accumulator that stores thermal energy supplied from the heating portion and heats a heat medium with the thermal energy; a steam generator that generates steam using the heat medium heated by the heat accumulator; a first flow path that transports the heat medium from the heat accumulator to the steam generator; a second flow path that transports the heat medium from the steam generator to the heat accumulator; an auxiliary portion provided on the first flow path; a bypass flow path that transports the heat medium flowing through the second flow path to the auxiliary section, bypassing the heat accumulator; A thermal storage power generation plant comprising: the auxiliary unit receives a first heat medium as the heat medium from the heat accumulator via the first flow path, receives a second heat medium as the heat medium from the second flow path via the bypass flow path, and supplies a third heat medium as the heat medium to the steam generator via the first flow path, a fourth adjusting unit provided on the second flow path and configured to adjust the flow rate of the heat medium; The fourth adjustment unit stops the supply of the heat medium to the heat accumulator when the heat storage power generation plant is forcedly cooled.

4. the auxiliary unit includes a first adjusting unit that adjusts the flow rate of the first heat medium, The thermal energy storage power generation plant according to claim 3 , wherein the first adjustment unit stops the supply of the heat medium to the heat accumulator when the thermal energy storage power generation plant is forcibly cooled.

5. The thermal storage power generation plant according to claim 1 , wherein the auxiliary unit includes a mixer that mixes the first heat medium and the second heat medium, and discharges the third heat medium from the mixer.

6. The thermal energy storage power generation plant according to claim 1 , wherein the auxiliary unit includes a second adjusting unit that adjusts a flow rate of the second heat medium.

7. The thermal energy storage power generation plant according to claim 1 , wherein the auxiliary unit includes a third adjusting unit that adjusts a flow rate of the third heat medium.

8. 8. The thermal energy storage power generation plant according to claim 1, further comprising a rotating device provided on the first flow path or the second flow path, the rotating device circulating the heat medium between the heat accumulator and the steam generator.

9. a heat accumulator that stores thermal energy supplied from the heating portion and heats a heat medium with the thermal energy; a steam generator that generates steam using the heat medium heated by the heat accumulator; a first flow path that transports the heat medium from the heat accumulator to the steam generator; a second flow path that transports the heat medium from the steam generator to the heat accumulator; an auxiliary portion provided on the first flow path; a bypass flow path that transports the heat medium flowing through the second flow path to the auxiliary section, bypassing the heat accumulator; a steam turbine driven by steam supplied from the steam generator; a generator driven by the steam turbine; a steam detector that detects a value related to steam supplied from the steam generator; a control device that controls the auxiliary unit based on a value detected by the steam detector, the auxiliary unit supplies a first heat medium as the heat medium from the heat accumulator via the first flow path, a second heat medium as the heat medium from the second flow path via the bypass flow path, and a third heat medium as the heat medium to the steam generator via the first flow path.

10. The thermal energy storage power generation plant according to claim 9, wherein the steam detector detects the pressure of the steam supplied from the steam generator.

11. a regulator valve for controlling the supply of steam from the steam generator to the steam turbine; a power generation detector that detects a value related to the power generator; 11. The thermal energy storage power generation plant according to claim 9, wherein the control device further controls the regulator valve based on a value detected by the power generation detector.

12. The thermal energy storage power generation plant according to claim 11, wherein the power generation detector detects the amount of power generated by the generator.

13. The control device a calculation unit that acquires a first setting value for controlling the auxiliary unit, and calculates a second setting value for controlling the auxiliary unit based on the value detected by the steam detector and the first setting value; a temperature control unit that controls the temperature of the third heat medium based on the second set value; a flow rate control unit that controls a flow rate of the third heat medium based on the second set value; a pressure control unit that controls the pressure of the first heat medium based on the second set value; The heat storage power generation plant according to any one of claims 9 to 12, comprising:

14. the auxiliary unit includes a temperature detector that detects a temperature of the third heat medium and a second adjustment unit that adjusts a flow rate of the second heat medium; The thermal storage power generation plant according to claim 13 , wherein the temperature control unit controls the second adjustment unit based on the temperature detected by the temperature detector, thereby controlling the temperature of the third heat medium.

15. the auxiliary unit includes a flow rate detector that measures a flow rate of the third heat medium, and a third adjustment unit that adjusts the flow rate of the third heat medium; The thermal storage power generation plant according to claim 13 , wherein the flow rate control unit controls the third adjustment unit based on the flow rate detected by the flow rate detector, thereby controlling the flow rate of the third heat medium.

16. a rotating device provided on the first flow path or the second flow path and configured to circulate the heat medium between the heat accumulator and the steam generator; the auxiliary unit includes a pressure detector that measures the pressure of the first heat medium, The thermal energy storage power generation plant according to claim 13 , wherein the pressure control unit controls the rotating equipment based on the pressure detected by the pressure detector, thereby controlling the pressure of the first heat medium.

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