JP2020008132A - Liquid air energy storage device, power generation device, and multi-fuel thermal power generation system - Google Patents

Abstract

To ensure that power needed to store liquid air as energy can be reduced.SOLUTION: A multi-fuel thermal power generation system 10 comprises a liquid air energy storage device 12 and a multi-fuel thermal power generation facility 14. The liquid air energy storage device 12 comprises a first heat exchanger 33 for precooling air by using liquefied natural gas, a second heat exchanger 35 for cooling and liquefying the air precooled by the first heat exchanger 33, by using liquid hydrogen, and a tank 16 for storing the liquid air liquefied by the second heat exchanger 35. The power generation facility 14 generates electric power by using a vaporizer 42 for vaporizing the liquid air stored in the tank 16, the air vaporized by the vaporizer 42, the liquefied natural gas passed through the first heat exchanger 33, and the liquid hydrogen passed through the second heat exchanger 35.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid air energy storage device, a power generation device, and a co-firing thermal power generation system.

  BACKGROUND ART Conventionally, as disclosed in Patent Document 1 below, a liquid air energy storage device that cools air and stores it as liquid air is known. Specifically, as shown in FIG. 7, the apparatus disclosed in Patent Document 1 includes a liquefaction facility 81 for liquefying air in the atmosphere, and a storage tank 82 for storing liquefied air liquefied by the liquefaction facility 81. , Is provided. The liquefaction facility 81 includes a first heat exchanger 81a that cools air to about −150 ° C. using cold heat of liquefied natural gas (LNG), and a compressor that compresses the cooled air to about 80 atm. 81b, a plurality of heat exchangers 81c for further cooling the compressed air to about -160 ° C. while maintaining a high pressure, and an expansion mechanism 81d for freely expanding the cooled air. The air that has become low temperature in the heat exchanger 81c is rapidly and freely expanded by the expansion mechanism 81d, so that part of the air is liquefied and stored in the storage tank 82. The liquid air stored in the storage tank 82 is supplied to the power generation equipment 83 and used for power generation.

JP-A-4-127850

  The liquid air energy storage device disclosed in Patent Document 1 has a configuration in which air is cooled using only liquefied natural gas, and thus requires compression of air by the compressor 81b. That is, while LNG is about -160 ° C, the air condensing temperature is about -190 ° C, so that air cannot be liquefied at normal pressure. For this reason, in order to liquefy air with the cold heat of LNG, it is necessary to compress the air to a high pressure. Therefore, there is a problem that an enormous amount of power is required to generate energy and store liquid air using LNG as a cold heat source.

  Therefore, an object of the present invention is to reduce the power required to store liquid air as energy.

  In order to achieve the above object, the present invention provides a first heat exchanger for pre-cooling air with liquefied natural gas, and a second heat exchanger for cooling and liquefying the air pre-cooled in the first heat exchanger with liquid hydrogen. A liquid air energy storage device comprising: an exchanger; and a tank for storing the liquid air liquefied by the second heat exchanger.

  In the present invention, the air cooled by the liquefied natural gas in the first heat exchanger is further cooled by the liquid hydrogen in the second heat exchanger. As a result, the air becomes liquid air and is stored in the tank. That is, energy can be stored as liquid air. In the present invention, when liquefying air, liquid hydrogen having a temperature lower than the condensation temperature of air is used, so it is not necessary to compress air, or even if air may be compressed, air may be compressed using only liquefied natural gas. Power required for compressing air can be reduced as compared with the case of liquefaction. Therefore, it is possible to store more energy in the tank than power required for storage. When, for example, liquid air is used for power generation, the charge / discharge efficiency can be increased.

  The liquid air energy storage device may further include a compressor that compresses air before being liquefied in the second heat exchanger.

  In this aspect, since the air cooled to liquid hydrogen in the second heat exchanger is in a compressed and pressurized state, the boiling point of liquid air is higher than that of liquid air at normal pressure. For this reason, it is possible not only to liquefy the air in the second heat exchanger but also to partially liquefy the air in the first heat exchanger. Therefore, although more compression power is required, the amount of liquid air obtained can be increased. In addition, a part of the air can be liquefied by the cold heat of the liquid hydrogen. Therefore, the power required for compressing air can be reduced as compared with the case where air is liquefied only with liquefied natural gas. When, for example, liquid air is used for power generation, the charge / discharge efficiency decreases, but the power generation amount can be increased.

  The liquid-air energy storage device monitors a flow rate of the liquid hydrogen and a required filling amount of the liquid air, and a flow rate that determines a flow rate of the air flowing toward the tank based on a monitoring result by the monitoring section. A determination unit may be provided, and a flow rate adjustment unit that adjusts a flow rate of the air flowing toward the tank according to a determination result of the flow rate determination unit.

  In this aspect, an appropriate air flow rate can be obtained according to the flow rate of liquid hydrogen and the required filling amount of liquid air. That is, the flow rate determination unit determines the flow rate of the air flowing toward the tank to be a flow rate corresponding to the required filling amount of the liquid air, or the flow rate of the liquid hydrogen supplied to the second heat exchanger. The flow rate is determined according to Then, the flow rate adjusting unit adjusts the flow rate of the air according to the result. Therefore, it can be adjusted to an appropriate air flow rate. In addition, as a flow-rate adjustment part, the blower which can adjust a rotation speed, the compressor which can adjust a rotation speed, etc. can be used. Therefore, in the configuration including the compressor that compresses the air before being liquefied by the second heat exchanger, the compressor used for adjusting the temperature at which the air is liquefied or the condensing temperature of the air is used as the flow rate adjusting unit. Can also function.

  The liquid-air energy storage device has a plurality of compression stages, a compressor that compresses air before being liquefied by the second heat exchanger, and a bypass that bypasses a compression stage on a subsequent stage in the compressor. A line, a pressure sensor for monitoring the internal pressure of the tank, a pressure regulating valve for adjusting the internal pressure of the tank, and a switching mechanism for switching whether or not to bypass the compression stage at the subsequent stage may be provided.

  In this aspect, since the air before being liquefied by the second heat exchanger is compressed by the compressor, it is possible to increase the temperature at which the air is liquefied. For this reason, it is possible not only to liquefy the air in the second heat exchanger but also to partially liquefy the air in the first heat exchanger. Moreover, since the pressure in the tank can be adjusted by the pressure adjusting valve, the pressure in the tank is adjusted by opening and closing the pressure adjusting valve, thereby adjusting the pressure in the air line. Since the switching mechanism is provided, it is possible to appropriately cope with the set pressure while considering the characteristics of each compression stage.

  The liquid air energy storage device, a monitoring unit that monitors a required filling amount of the liquid air, a pressure determination unit that determines a pressure of the liquid air to be filled into the tank based on a monitoring result by the monitoring unit, A pressure adjusting unit that controls the switching mechanism and the pressure regulating valve according to a determination result of the pressure determining unit may be provided.

  In this aspect, the pressure determination unit determines the pressure of the liquid air filled in the tank based on the monitoring result by the monitoring unit. That is, if the pressure of the liquid air filled in the tank is increased, the temperature at which the air is liquefied increases. For this reason, in the first heat exchanger, it is possible to liquefy a part of the air with the liquefied natural gas. Therefore, the pressure determination unit can set an appropriate liquefied amount by determining the pressure of the liquid air to be charged into the tank based on the monitoring result of the required charged amount of liquid air. Then, by controlling the switching mechanism and the pressure regulating valve, the pressure of the liquid air filled in the tank can be adjusted.

  The present invention is a power generation device comprising: the liquid air energy storage device; and a power generation unit that vaporizes the liquid air stored in the tank according to a power generation request and generates power using the vaporized air. . According to the present invention, the energy of the liquefied air stored in the tank can be extracted as electric power.

  The present invention provides the liquid air energy storage device, a vaporizer for vaporizing the liquid air stored in the tank, air vaporized by the vaporizer, and liquefied natural gas that has passed through the first heat exchanger. A mixed-fired thermal power generation system including: a mixed-fired thermal power generation facility configured to generate power using liquid hydrogen that has passed through the second heat exchanger. According to the present invention, the energy of the liquefied air stored in the tank can be extracted as electric power. Moreover, since liquefied natural gas and liquid hydrogen used for liquefying air can be used as fuel, efficient operation of the entire system is possible.

  As described above, according to the present invention, the power required to store liquid air as energy can be reduced.

It is a figure showing roughly composition of a mixed combustion power generation system concerning a 1st embodiment. It is a figure which shows schematically the structure of the co-firing thermal power generation system concerning 2nd Embodiment. It is a figure for explaining the operation operation of the mixed combustion power generation system concerning a 2nd embodiment. It is a figure showing roughly composition of a co-fired thermal power generation system concerning a 3rd embodiment. It is a figure which shows roughly the structure of the co-firing thermal power generation system concerning 4th Embodiment. It is a figure for explaining the operation operation of the mixed combustion power generation system concerning a 4th embodiment. It is a figure showing the composition of the conventional liquid air energy storage device.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

(1st Embodiment)
As shown in FIG. 1, the co-firing thermal power generation system 10 according to the first embodiment is a thermal power generation system using liquefied natural gas (LNG) and liquid hydrogen (LH2) as fuels, and the system 10 includes liquid air energy. A storage device (hereinafter, simply referred to as a storage device) 12 and a co-firing thermal power generation facility (hereinafter, simply referred to as a power generation facility) 14 are provided. The storage device 12 cools air using liquefied natural gas and liquid hydrogen to produce liquid air. The power generation facility 14 generates high-pressure steam by burning the liquefied natural gas and liquid hydrogen used in the storage device 12, and drives the turbine 14a with the high-pressure steam to generate power.

  The storage device 12 includes a tank 16 for storing liquid air, an air line 17 for liquefying air, an LNG line 18 for flowing liquefied natural gas, and a liquid hydrogen line 19 for flowing liquid hydrogen. . One end of the LNG line 18 is connected to an LNG tank 21 in which liquefied natural gas is stored. One end of the liquid hydrogen line 19 is connected to an LH2 tank 23 storing liquid hydrogen. The LNG line 18 and the liquid hydrogen line 19 are provided with pumps 18a and 19a, respectively. The pump 18 a of the LNG line 18 sucks the liquefied natural gas from the LNG tank 21 and causes the liquefied natural gas to flow in the LNG line 18. The pump 19 a of the liquid hydrogen line 19 sucks the liquid hydrogen from the LH2 tank 23 and causes the liquid hydrogen to flow in the liquid hydrogen line 19.

  One end of the air line 17 is open so that air (air) can be introduced. The other end of the air line 17 is connected to the tank 16. In the air line 17, a blower 31, a first heat exchanger 33, and a second heat exchanger 35 are provided in this order.

  The blower 31 is a pressurizer that pressurizes air so that the air flows toward the air line 17 toward the tank 16. In the first embodiment, since the pressure in the tank 16 is set to about the atmospheric pressure, the blower 31 may pressurize the air to about the pressure obtained by adding the pressure loss to the atmospheric pressure.

  The first heat exchanger 33 is also connected to the LNG line 18 and cools the air flowing through the air line 17 with the liquefied natural gas flowing through the LNG line 18. The temperature of liquefied natural gas is about -160C, which is higher than the condensation temperature of air under atmospheric pressure (-190C). Therefore, in the first heat exchanger 33, air does not condense.

  The second heat exchanger 35 is disposed in the air line 17 on the downstream side of the first heat exchanger 33 in the direction in which air flows. Therefore, the air cooled by the liquefied natural gas in the first heat exchanger 33 is introduced into the second heat exchanger 35. The second heat exchanger 35 is also connected to the liquid hydrogen line 19, and cools the air flowing through the air line 17 with the liquid hydrogen flowing through the liquid hydrogen line 19. The temperature of liquid hydrogen is about -250C, which is lower than the condensation temperature of air under atmospheric pressure. Therefore, in the second heat exchanger 35, the air condenses. That is, in the first embodiment, the air can be liquefied in the air line 17 without being compressed to a high pressure.

  The downstream end of the LNG line 18 and the downstream end of the liquid hydrogen line 19 are connected to the power generation facility 14, respectively. Therefore, the liquefied natural gas used to pre-cool the air before condensing the air is supplied to the power generation facility 14 as fuel. Then, the liquid hydrogen used to liquefy the air is supplied to the power generation facility 14 as fuel.

  The tank 16 is connected to the downstream end of the air line 17 (the end opposite to the open one end). Therefore, the liquid air liquefied in the second heat exchanger 35 flows into the tank 16.

  The tank 16 is connected to a lead-out line 38 for leading out liquid air. The lead-out line 38 is provided with a liquid air pump 41, a carburetor 42, and an air turbine 43. The downstream end of the lead-out line 38 (the end opposite to the connection end of the tank 16) is connected to the power generation facility 14.

  The liquid air pump 41 operates in response to a power generation request, and provides a driving force for sending the liquid air to the vaporizer 42 to the liquid air. The vaporizer 42 heat-exchanges the liquid air with air or water to vaporize the liquid air. Thereby, high-pressure air is obtained. The high-pressure air obtained by the carburetor 42 drives an air turbine 43, thereby generating power. That is, the liquid air pump 41, the vaporizer 42, and the air turbine 43 function as a power generation unit that vaporizes the liquid air stored in the tank 16 and generates power using the vaporized air in response to a power generation request.

  The high-pressure air that drives the air turbine 43 is introduced into the power generation facility 14. In the power generation facility 14, high-pressure air may be mixed with fuel gas and used for combustion, or high-pressure air may be used to drive a turbine connected to a generator.

  Note that the air turbine 43 may be omitted. Further, instead of the lead-out line 38 being connected to the power generation facility 14, the high-pressure air obtained by the vaporizer 42 may be discharged into the atmosphere. Further, the vaporizer 42 may be omitted to discharge the liquid air into the atmosphere.

  Here, the operation of the mixed combustion power generation system 10 will be described. When the blower 31 of the air line 17 operates, the atmosphere (air) is sucked into the air line 17. This air flows through the air line 17. On the other hand, the pump of the LNG line 18 and the pump of the liquid hydrogen line 19 also operate. Thereby, the liquefied natural gas in the LNG tank 21 is sucked into the LNG line 18 and flows through the LNG line 18. Liquid hydrogen in the LH2 rank is sucked into the liquid hydrogen line 19 and flows through the liquid hydrogen line 19.

  In the first heat exchanger 33, the air flowing through the air line 17 and the liquefied natural gas flowing through the LNG line 18 exchange heat, and the air is cooled to, for example, about -155 ° C. That is, since the air is not cooled to the condensing temperature, it flows out of the first heat exchanger 33 as air without being condensed.

  The air cooled by the first heat exchanger 33 flows into the second heat exchanger 35. In the second heat exchanger 35, air exchanges heat with liquid hydrogen flowing through the liquid hydrogen line 19. Since the temperature of the liquid hydrogen is about -250 ° C., in the second heat exchanger 35, the air condenses and becomes liquid air. That is, in the air line 17, a heat exchanger 33 with liquefied natural gas is arranged at a preceding stage, and a heat exchanger 35 with liquid hydrogen at a lower temperature than liquefied natural gas is arranged at a later stage. Therefore, the cold heat of liquefied natural gas and liquid hydrogen can be effectively used. Since the air is condensed only by the cold heat of the liquid hydrogen in the second heat exchanger 35, the first heat exchanger 33 functions as a heat exchanger for pre-cooling the air.

  The liquefied natural gas whose air has been cooled by the first heat exchanger 33 and the liquid hydrogen whose air has been condensed by the second heat exchanger 35 are both supplied to the power generation equipment 14. Liquefied natural gas and liquid hydrogen are combusted in power plant 14 and used to generate high pressure steam. Then, the turbine 14a is driven by the high-pressure steam to generate power.

  The liquid air condensed in the second heat exchanger 35 is stored in the tank 16. The pressure in the tank 16 becomes substantially constant at a pressure slightly higher than the atmospheric pressure. The liquid air stored in the tank 16 is sucked by the liquid air pump 41 and flows through the outlet line 38. This liquid air is heated by the vaporizer 42 and vaporized, and becomes high-pressure air. In the vaporizer 42, the liquid air is vaporized by being heated by water or air.

  The high-pressure air drives the air turbine 43 and is used for power generation. The high-pressure air is also provided to the power generation facility 14 and is also used for power generation in the power generation facility 14.

  In the first embodiment, since only the driving power of the blower 31, the pumps 18a and 19a, and the liquid air pump 41 is required, the charge / discharge efficiency is high and may exceed 200%. Therefore, in the energy balance of charge and discharge, the amount of power generation can exceed the amount of charge. Further, the present invention can be applied to a process in which liquefied natural gas and liquid hydrogen are consumed in large amounts, and the cold heat of liquefied natural gas and liquid hydrogen can be effectively used.

  As described above, in the first embodiment, the air cooled by the liquefied natural gas in the first heat exchanger 33 is further cooled in the second heat exchanger 35 by liquid hydrogen. Thereby, the air becomes liquid air and is stored in the tank 16. That is, energy can be stored as liquid air. In the first embodiment, when liquefying air, liquid hydrogen having a temperature lower than the condensation temperature of air is used. For this reason, it is not necessary to compress the air, or even if the air is compressed, the power required for compressing the air can be reduced as compared with the case where the air is liquefied only with liquefied natural gas. Therefore, it is possible to store more energy in the tank 16 than power required for storage. Therefore, charge and discharge efficiency can be increased.

  In addition, in 1st Embodiment, although the storage apparatus 12 is comprised as a component of the co-firing thermal power generation system 10, it is not restricted to this. For example, the storage device 12 may be configured as a component of a power generation device other than co-firing power generation. That is, while power is generated in the air turbine 43, liquefied natural gas and liquid hydrogen may be used for applications other than power generation.

  In the first embodiment, the configuration is such that the liquid air energy stored in the storage device 12 is extracted as electric energy. However, the configuration is not limited to this. A configuration in which mechanical energy or cold heat is taken out instead of electric energy may be adopted. The same applies to the following embodiments.

(2nd Embodiment)
FIG. 2 shows a second embodiment. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

  In the second embodiment, the storage device 12 includes a control unit 48, and the control unit 48 is connected to a conversion facility 50 that converts renewable energy into electric energy. The conversion facility 50 includes, for example, a solar power generation facility, a solar thermal power generation facility, a wind power generation facility, a hydroelectric power generation facility, a wave power generation facility, or the like. When a surplus occurs in the power obtained from the renewable energy, the conversion equipment 50 outputs a signal indicating the surplus power. This signal is input to the control unit 48. In the control unit 48, the filling amount of the liquid air is determined according to the electric power surplus represented by this signal. Therefore, the signal requests the signal representing the required filling amount of the liquid air or charging in the storage device 12. Function as a charge request signal for

  The liquid hydrogen line 19 is provided with a flow meter 19b for detecting the flow rate of the liquid hydrogen flowing through the liquid hydrogen line 19. The flow meter 19b outputs a signal corresponding to the detected flow rate. The signal output from the flow meter 19b is input to the control unit 48. In addition, the liquid hydrogen flow rate and the liquefied natural gas flow rate are flow rates in accordance with a request issued from the power generation facility 14.

  The tank 16 is provided with a level sensor 16a that outputs a signal corresponding to the amount of stored liquid air. The signal output from the level sensor 16a is input to the control unit 48.

  The control unit 48 monitors a flow rate of the liquid hydrogen and a required filling amount of the liquid air, a flow rate determination unit 53 that determines the rotation speed of the blower 31 based on the monitoring result by the monitoring unit 52, A generation determining unit 54 that determines whether liquid air can be generated based on a signal output from the level sensor 16a. The monitoring unit 52 indicates the first derivation unit 52a that calculates an air flow rate according to the amount of liquid air that can be generated by the power surplus represented by the signal output from the conversion facility 50, and the signal output from the flow meter 19b. A second deriving unit 52b that calculates an air flow rate according to the liquid air amount that can be generated from the liquid hydrogen flow rate.

  The flow rate determining unit 53 compares the air flow rate calculated by the first deriving unit 52a with the air flow rate obtained by the second deriving unit 52b, and derives a smaller amount of air flow as a set flow rate. And a determination unit 53b that determines the rotation speed of the blower 31 based on the set flow rate derived by the generation amount derivation unit 53a. The control unit 48 controls the motor of the blower 31 to rotate the blower 31 at a rotation speed according to the result determined by the flow rate determining unit 53 when the generation determining unit 54 determines that liquid air can be generated. Outputs control signal. The rotation speed of the blower 31 is adjusted by this control signal. That is, the blower 31 functions as a flow rate adjusting unit that adjusts the flow rate of the air flowing toward the tank 16 according to the determination result of the flow rate determining unit 53.

  Here, the operation of the storage device 12 according to the second embodiment will be described with reference to FIG. First, the control unit 48 receives a signal from the level sensor 16a of the tank 16 (Step ST1). The generation determining unit 54 determines whether liquid air can be generated based on the signal (step ST2). If the inside of the tank 16 is filled with liquid air, the determination in step ST2 is NO, and no liquid air is generated (step ST3). On the other hand, when it is determined that the tank 16 can be further filled with the liquid air (YES in step ST2), the control unit 48 acquires the signal output from the conversion equipment 50, and The signal output from the flow meter 19b on the line 19 is obtained (steps ST4 and ST5). Steps ST4 and ST5 may be executed before step ST2.

  Then, control unit 48 determines whether or not the signal output from conversion equipment 50 has been received (step ST6). That is, control unit 48 determines whether or not a signal output when a surplus power has occurred in conversion equipment 50 has been received. If the signal has not been received, the process proceeds to step ST3. When the signal is received, the process proceeds to step ST7, and the control unit 48 calculates the liquefiable air amount. That is, the control unit 48 receives a charge request corresponding to the surplus power of renewable energy, and determines the amount of air liquefaction corresponding to the charge request as the charge amount. Specifically, the first deriving unit 52a calculates an air flow rate according to the amount of liquid air that can be generated by the power surplus represented by the signal output from the conversion facility 50, and the second deriving unit 52b calculates the air flow rate. An air flow rate according to the liquid air amount that can be generated from the liquid hydrogen flow rate detected by 19b is calculated. Then, the generation amount deriving unit 53a compares the air flow rate calculated by the first deriving unit 52a with the air flow rate obtained by the second deriving unit 52b, and as a result of the comparison, determines a smaller air flow rate. Set the flow rate. When the set flow rate is determined by the generation amount deriving section 53a, the determination section 53b determines the rotation speed of the blower 31 according to the set flow rate, and the control section 48 operates the blower 31 at the determined rotation speed. To output a control signal. The blower 31 operates at a rotation speed according to the control signal (step ST8). At this time, the control unit 48 acquires the motor power of the blower 31 operated according to the control signal (step ST9), and adjusts the rotation speed so that the blower 31 is driven by the power obtained by subtracting the power.

  When the rotation speed of the blower 31 is adjusted, air having a flow rate corresponding to the flow rate flows through the air line 17. Then, this air is precooled by liquefied natural gas in the first heat exchanger 33, and then cooled in the second heat exchanger 35 to liquid hydrogen and condensed to become liquid air. This liquid air is stored in the tank 16, and the output value of the level sensor 16a changes according to the newly stored amount.

  The liquid air stored in the tank 16 is sucked by the liquid air pump 41 and flows through the outlet line 38 according to the power generation request, and is heated and vaporized by the vaporizer 42 to become high-pressure air. The high-pressure air drives the air turbine 43 and is used for power generation. The high-pressure air is also provided to the power generation facility 14 and is also used for power generation in the power generation facility 14.

  In the second embodiment, an appropriate air flow rate can be obtained according to the flow rate of liquid hydrogen and the required filling amount of liquid air. That is, the flow rate determination unit 53 determines the flow rate of the air flowing toward the tank 16 so as to be a flow rate corresponding to the required filling amount of the liquid air, or the flow rate of the liquid supplied to the second heat exchanger 35. The flow rate is determined so as to correspond to the flow rate of hydrogen. Then, the rotation speed of the blower 31 is adjusted according to the result so that the flow rate of the air is obtained. Therefore, it can be adjusted to an appropriate air flow rate.

  The description of the other configurations, operations, and effects is omitted, but the description of the first embodiment can be applied to the second embodiment.

(Third embodiment)
FIG. 4 shows a third embodiment of the present invention. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

  In the first embodiment, the liquid air is stored in the tank 16 at a pressure close to the atmospheric pressure, and the blower 31 provided in the air line 17 pressurizes the air to such an extent that the air flows. On the other hand, in the third embodiment, the liquid air is stored in the tank 16 while being compressed at a level considerably higher than the atmospheric pressure. Therefore, in the third embodiment, a compressor 57 is provided in the air line 17 instead of the blower 31.

  The compressor 57 for compressing air is provided on the air line 17 on the upstream side of the first heat exchanger 33 and the second heat exchanger 35. Therefore, air pressurized to a pressure higher than the atmospheric pressure is introduced into the second heat exchanger 35. Therefore, the condensation temperature of air can be raised. For this reason, although power for compressing air is required, the amount of liquefied air can be increased as compared with the first embodiment. That is, in the first embodiment, the liquefied natural gas is used only for pre-cooling the air, and the liquid hydrogen is responsible for the liquefaction of the air. For this reason, the amount of liquefied air depends on the flow rate of liquid hydrogen. In addition, although charging efficiency is high, there are cases where quick charging requests cannot be met. On the other hand, in the third embodiment, the cold heat of the liquefied natural gas is also used for liquefying the air. Therefore, it is possible to meet a request for quick charging.

  The compressor 57 has a plurality of compression stages. That is, the compressor 57 includes a first compression stage 57a configured to compress air, and a second compression stage 57b configured to further compress the air compressed by the first compression stage 57a. ing. However, in the present embodiment, the present invention is not limited to this, and the compressor 57 may have a configuration having a single-stage compression stage, or may have a configuration having three or more compression stages. .

  The first compression stage 57a and the second compression stage 57b may have a configuration in which the rotation speed can be adjusted. In this case, the compressor 57 (the first compression stage 57a and the second compression stage 57b) also functions as a flow rate adjustment unit that adjusts the flow rate of the air flowing toward the tank 16.

  The air line 17 is provided with a cooler 58 for cooling the air compressed by the compressor 57. The cooler 58 has a first cooling unit 58a that cools the air compressed by the first compression stage 57a, and a second cooling unit 58b that cools the air compressed by the second compression stage 57b. Seawater or air can be used as a cold heat source of the cooler 58. Note that the cooler 58 does not need to be provided for all the compression stages 57a and 57b, and a part of the cooling unit may be omitted. Further, the cooler 58 may be omitted.

  A bypass line 60 for bypassing the final compression stage 57b is connected to the air line 17. The bypass line 60 has one end connected between the first cooling section 58a (or the first compression stage 57a) and the second compression stage 57b in the air line 17, and the other end connected to the second cooling section in the air line 17. It is connected between 58 b (or the second compression stage 57 b) and the first heat exchanger 33.

  In the bypass line 60 and the air line 17, a switching mechanism 62 that switches between a state in which the air compressed in the first compression stage 57a flows to the second compression stage 57b and a state in which the air bypasses the second compression stage 57b. Is provided. The switching mechanism 62 includes a first opening / closing valve 62a provided in the bypass line 60 and a second opening / closing valve 62b provided between the connecting portions of the air line 17 and the bypass line 60.

  When the first on-off valve 62a is closed and the second on-off valve 62b is opened, the air flowing toward the first heat exchanger 33 is discharged from the second compression stage 57b or the final compression stage. . On the other hand, when the first on-off valve 62a is opened and the second on-off valve 62b is closed, the air sucked into the air line 17 bypasses the final compression stage. That is, since the operating characteristics and efficiency of each of the stages 57a and 57b of the compressor 57 change depending on the pressure ratio and the flow rate, the switching mechanism 62 is controlled such that the compression power is minimized according to the tank 16 pressure. Note that the switching mechanism 62 is not limited to the configuration configured by the first on-off valve 62a and the second on-off valve 62b. For example, the switching mechanism 62 may be configured by a three-way valve arranged at a connection between the air line 17 and the bypass line 60.

  The tank 16 is provided with a pressure sensor 64 for detecting the pressure in the tank 16 and a pressure regulating valve 65 for adjusting the pressure in the tank 16. The pressure regulating valve 65 is opened and closed according to the pressure detected by the pressure sensor 64.

  In the third embodiment, since the air before being liquefied by the second heat exchanger 35 is compressed by the compressor 57, the temperature at which the air is liquefied can be increased. For this reason, it is possible not only to liquefy the air in the second heat exchanger 35 but also to partially liquefy the air in the first heat exchanger 33. In addition, a pressure regulating valve 65 that is controlled to open and close according to the pressure detected by the pressure sensor 64 is provided in the tank 16. For this reason, the pressure in the tank 16 is adjusted by opening and closing the pressure regulating valve 65, whereby the pressure in the air line 17 is adjusted. That is, the pressure setting of the air is changed according to the amount of the cooling load of the liquefied natural gas and the liquid hydrogen. Thereby, the production amount of liquid air can be adjusted. On the other hand, since each compression stage 57a, 57b of the compressor 57 has a region (pressure ratio and flow rate) where it can be operated efficiently, it becomes motively advantageous in consideration of the characteristics of each compression stage 57a, 57b. Thus, it is necessary to determine whether to bypass the compression stage 57b on the subsequent stage. Therefore, the switching mechanism 62 can appropriately respond to the set pressure by switching whether to bypass the compression stage 57b on the subsequent stage according to the set value of the pressure.

  In the power generation facility 14, when the hydrogen co-firing rate is suppressed to be low, the flow rate of hydrogen flowing through the liquid hydrogen line 19 is to be suppressed to a low level. By doing so, it is possible to suppress the air liquefaction amount from being limited.

  The description of the other configurations, operations, and effects is omitted, but the description of the first embodiment can be applied to the third embodiment.

(Fourth embodiment)
FIG. 5 shows a fourth embodiment of the present invention. Here, the same components as those of the second embodiment and the third embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

  In the fourth embodiment, the LNG line 18 and the liquid hydrogen line 19 are provided with flow meters 18b and 19b, respectively, and the tank 16 is provided with a level sensor 16a and a pressure sensor 64. The flow meter 18b of the LNG line 18 detects the flow rate of LNG flowing through the LNG line 18, and outputs a signal corresponding to the detected flow rate. The flow meter 19b of the liquid hydrogen line 19 detects the flow rate of the liquid hydrogen flowing through the liquid hydrogen line 19, and outputs a signal corresponding to the detected flow rate. The level sensor 16a outputs a signal corresponding to the amount of liquid air stored in the tank 16. The pressure sensor 64 detects the pressure in the tank 16 and outputs a signal corresponding to the detected pressure. The signals output from the flow meters 18b and 19b, the level sensor 16a, and the pressure sensor 64 are input to the control unit 48. The pressure sensor 64 does not need to be disposed in the tank 16, and may be disposed in a portion of the air line 17 between the compressor 57 and the tank 16.

  The control unit 48 includes a monitoring unit 67 that monitors the required filling amount of the liquid air, a pressure determining unit 68 that determines the pressure of the liquid air to be charged into the tank 16 based on the monitoring result by the monitoring unit 67, and a pressure determining unit. It is determined whether or not liquid air can be generated based on a signal output from the pressure adjusting unit 70 that controls the switching mechanism 62 and the pressure regulating valve 65 and the level sensor 16a of the tank 16 in accordance with the set pressure determined by 68. And a generation judging unit 54 for determining whether or not the image data is to be determined. The pressure determining unit 68 determines the pressure of the liquid air based on the signal output when the power surplus occurs in the conversion equipment 50 so that the required filling amount of the liquid air can be satisfied. The pressure adjusting unit 70 determines the number of stages of use of the compressor 57 in accordance with the set pressure determined by the pressure determining unit 68, and adjusts the opening of the pressure regulating valve 65 or controls opening and closing. That is, the pressure adjusting unit 70 switches the control signal for driving the first compression stage 57a and the second compression stage 57b of the compressor 57 and the switching mechanism 62 based on the set pressure determined by the pressure determining unit 68. It outputs a control signal and a control signal for opening and closing the pressure regulating valve 65.

  Here, the operation of the storage device 12 according to the fourth embodiment will be described with reference to FIG. First, the control unit 48 receives a signal from the level sensor 16a of the tank 16 (Step ST11). The generation determining unit 54 determines whether liquid air can be generated based on the signal (step ST12). If the inside of the tank 16 is filled with liquid air, the determination in step ST12 is NO, and no liquid air is generated (step ST13). On the other hand, when it is determined that it is possible to fill the tank 16 with further liquid air (YES in step ST12), the control unit 48 acquires the signal output from the conversion equipment 50 and sets the LNG line. Signals output from the flow meter 18b of the liquid crystal line 18 and the flow meter 19b of the liquid hydrogen line 19 are obtained (steps ST14 and ST15). Steps ST14 and ST15 may be executed before step ST12.

  Then, when the control unit 48 receives a signal output when a surplus power is generated in the conversion equipment 50 (step ST16), the control unit 48 controls the liquid stored in the tank 16 based on the surplus power. The air pressure is calculated (step ST17). That is, when the pressure in the tank 16 is set to the atmospheric pressure, the air cannot be liquefied by the liquefied natural gas, so that the air is liquefied only by the liquid hydrogen. For this reason, when liquid air is obtained based on hydrogen cold heat, the amount of cold heat of liquid hydrogen may be insufficient for the required charging amount. On the other hand, when the pressure in the tank 16 is set to a pressure higher than the atmospheric pressure, the air can be liquefied by the liquefied natural gas. Therefore, as the pressure of the air flowing through the air line 17 increases, the amount of air liquefied by the liquefied natural gas can be increased, and the required charging amount can be satisfied. Therefore, by increasing the set pressure in the tank 16 in accordance with the required charging amount represented by the surplus power, it is possible to obtain an appropriate amount of air liquefaction in accordance with the required charging amount. Therefore, the pressure determination unit 68 of the control unit 48 determines the set pressure of the liquid air in the tank 16 based on the power surplus indicated by the signal output from the conversion equipment 50.

  When the set pressure of the liquid air is determined, the pressure adjusting unit 70 determines the number of stages of use of the compressor 57 and controls the switching mechanism 62 to switch to the determined number of stages of use (step ST18). Specifically, it is determined whether to compress the air in the second compression stage 57b or to bypass the second compression stage 57b according to the determined set pressure of the liquid air. Then, based on the result of this determination, it is determined whether or not the switching of the switching mechanism 62 is necessary.

  Subsequently, the pressure value of the liquid air is obtained from the pressure sensor 64 disposed in the tank 16 (step ST19), and the pressure in the tank 16 is adjusted by the pressure adjusting unit 70 controlling the opening and closing of the pressure regulating valve 65. (Step ST20). In addition, the motor power of the compressor 57 is obtained (step ST21), and the motor rotation speed of the compressor 57 is adjusted (step ST22). Note that the compressor 57 may be configured by the compressor 57 having a constant motor rotation speed, and steps ST21 and ST22 may be omitted.

  In the fourth embodiment, the pressure determining unit 68 determines the pressure of the liquid air filled in the tank 16 based on the monitoring result by the monitoring unit 67. That is, if the pressure of the liquid air filled in the tank 16 is increased, the temperature at which the air is liquefied increases. For this reason, in the first heat exchanger 33, it is possible to liquefy a part of the air with the liquefied natural gas. Therefore, the pressure determining unit 68 determines the pressure of the liquid air to be charged into the tank 16 based on the result of monitoring the required charged amount of liquid air, so that an appropriate liquefied amount can be set. By controlling the switching mechanism 62 and the pressure regulating valve 65, the pressure of the liquid air filled in the tank 16 can be adjusted.

  The description of the other configurations, operations, and effects is omitted, but the description of the first, second, and third embodiments can be applied to the fourth embodiment.

Reference Signs List 10 mixed combustion power generation system 12 liquid air energy storage device 14 mixed combustion power generation equipment 16 tank 31 blower (flow rate adjustment unit)
41 Liquid Air Pump 42 Vaporizer 43 Air Turbine 52 Monitoring Unit 53 Flow Rate Determination Unit 57 Compressor 57a First Compression Stage 57b Second Compression Stage 60 Bypass Line 62 Switching Mechanism 64 Pressure Sensor 65 Pressure Regulator 68 Pressure Determination Unit 70 Pressure Adjustment Unit

Claims (7)

A first heat exchanger for pre-cooling air with liquefied natural gas;
A second heat exchanger for cooling and liquefying the air precooled by the first heat exchanger with liquid hydrogen,
A tank for storing the liquid air liquefied by the second heat exchanger. The liquid air energy storage device according to claim 1,
The liquid air energy storage device further comprising a compressor for compressing the air before being liquefied in the second heat exchanger. The liquid air energy storage device according to claim 1,
A monitoring unit that monitors the flow rate of the liquid hydrogen and the required filling amount of the liquid air,
Based on the monitoring result by the monitoring unit, a flow rate determination unit that determines the flow rate of air flowing toward the tank,
A liquid-air energy storage device, comprising: a flow rate adjusting unit that adjusts a flow rate of air flowing toward the tank according to a determination result of the flow rate determining unit. The liquid air energy storage device according to claim 1,
A compressor having a plurality of compression stages and compressing air before being liquefied in the second heat exchanger;
A bypass line that bypasses a compression stage at a subsequent stage in the compressor,
A pressure sensor for monitoring the internal pressure of the tank,
A pressure regulating valve for adjusting the internal pressure of the tank;
A switching mechanism for switching whether to bypass the subsequent compression stage. The liquid air energy storage device according to claim 4,
A monitoring unit for monitoring a required filling amount of liquid air,
Based on the monitoring result by the monitoring unit, a pressure determination unit that determines the pressure of the liquid air filled in the tank,
A liquid air energy storage device, comprising: a pressure adjusting unit that controls the switching mechanism and the pressure regulating valve according to a determination result of the pressure determining unit. A liquid air energy storage device according to any one of claims 1 to 5,
A power generation unit that vaporizes the liquid air stored in the tank in response to a power generation request and generates power using the vaporized air. A liquid air energy storage device according to any one of claims 1 to 5,
A vaporizer for vaporizing the liquid air stored in the tank,
Co-firing power generation equipment for generating power using air vaporized by the vaporizer, liquefied natural gas that has passed through the first heat exchanger, and liquid hydrogen that has passed through the second heat exchanger, Mixed-fired power generation system.