JP2008157144A - Liquefied gas vaporization system and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquefied gas vaporization system and its control method, preventing supply of two-phase fluid to a state converting device and stably recovering a predetermined flow rate of gas at a predetermined temperature, in a liquefied gas vaporization system having a stirling engine. <P>SOLUTION: Gas stored in a liquid-phase state in a liquefied gas tank 200 is supplied to the stirling engine 400 through a liquefied gas flow rate adjusting device 300, and the stirling engine receives heat quantity of liquefied gas, thereby power is produced in the stirling engine 400. Liquefied gas in a single liquid-phase state is converted by a liquefied gas carburetor 800, and discharged as a gas-phase liquefied gas. Further, in the intake of the liquefied gas carburetor 800, pressure and temperature of liquefied gas are detected by a pressure measuring device 710 and a temperature measuring device 720, and a flow rate of liquefied gas is adjusted based on the pressure and temperature of the liquefied gas by the liquefied gas flow rate adjusting device 300. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquefied gas vaporization system capable of completely vaporizing liquefied gas and supplying a predetermined amount of gas at a predetermined temperature, and a control method thereof.

  Conventionally, as an example of a liquefied gas vaporization system, there is an LNG (Liquefied Natural Gas) vaporization facility composed of a liquefied gas tank, a liquefied gas supply device, a vaporizer, and the like. The purpose of this LNG vaporization facility is to completely vaporize the liquefied gas and supply a predetermined amount of gas at a predetermined temperature.

  Patent Document 1 discloses a Stirling engine that can use LNG as a coolant for a cooler. In the Stirling engine described in Patent Document 1, a cooler having a cooling liquid intake port and an outlet formed by using a heat insulating material that cools gas entering and exiting the head of the displacer cylinder, and one end portion being compressed in the head The other end communicates with the expansion space across the displacer piston of the displacer cylinder, the regenerative heat exchanger provided on the outer periphery of the displacer cylinder, and the opposite side of the cooler on the outer periphery of the displacer cylinder A heater provided in the cylinder, a power cylinder having a power piston provided in communication with the expansion space of the displacer cylinder, and a rotating device such as a crankshaft connected to both pistons with a phase difference. It consists of.

  As a result, the Stirling engine describes the effect that LNG can be used as a coolant for the cooler.

Japanese Patent Laid-Open No. 11-022550

  Here, a Stirling engine that can use liquefied gas as a cooling liquid for a cooler is a Stirling engine that can recover power by exchanging heat with a liquefied gas as a cooling source and a heat source. .

  However, when a Stirling engine that can use LNG described in Patent Document 1 as a cooling liquid for a cooler is incorporated in a vaporization system, a part of the liquefied gas is vaporized in the Stirling engine cooler, and the liquid phase state and There is a possibility that two-phase fluids with a phase state are generated, and these two-phase fluids are supplied to the vaporizer in the subsequent stage.

  When a two-phase fluid is supplied to the subsequent vaporizer, add a special gas-liquid dispersion structure in the vaporizer to the vaporizer and make a significant structural change, or uneven distribution in each vaporizer pipe Alternatively, liquid phase drift occurs in the vaporizer piping, and sufficient vaporization does not occur in the vaporizer, and a predetermined temperature and a predetermined amount of gas cannot be obtained at the discharge port. In addition, when a two-phase fluid is supplied to a subsequent vaporizer, pipe vibration is generated in each vaporizer pipe in the vaporizer. As a result, it is desired that the supply of the two-phase fluid to the vaporizer can be prevented and the vaporization can be completely completed at the end of the system and a predetermined amount of gas can be recovered at a predetermined temperature, as in a general vaporization system.

  As another problem, when a Stirling engine is used as a part of the vaporization system, there may be no power usage destination depending on the location conditions of the LNG vaporization facility. In that case, there is also a problem that the recovered power cannot be effectively used.

  Furthermore, in the LNG vaporization equipment, a heat source is required for cold energy use or heat storage use. However, depending on the location conditions of the LNG vaporization equipment, there is a possibility that the heat source cannot be secured, which is a problem. Also, depending on where the system is placed, there may be cases where there is no heat source used for the Stirling engine heat source, or where heat cannot be obtained continuously. In this case, it becomes a problem that power recovery with high efficiency cannot be performed by sufficiently utilizing the cold energy of the liquefied gas.

  An object of the present invention is a liquefied gas vaporization system having a Stirling engine, which prevents the supply of a two-phase fluid to a state change device and stably recovers a predetermined flow rate of gas at a predetermined temperature and its control. Is to provide a method.

  Another object of the present invention is to prevent the supply of a two-phase fluid to the state change device, stably collect a gas at a predetermined flow rate at a predetermined temperature, and easily secure a heat source for use in a Stirling engine. And the liquefied gas vaporization system which can utilize effectively the motive power collect | recovered from the Stirling engine, and its control method are provided.

Means for Solving the Problems and Effects of the Invention

(1)
A liquefied gas vaporization system according to the present invention is a liquefied gas vaporization system having a Stirling engine, and the liquefied gas vaporization system includes a liquefied gas tank capable of storing a predetermined gas in a liquid phase state, and a liquefied gas supplied from the liquefied gas tank. A liquefied gas flow rate adjusting device that adjusts the gas flow rate, a Stirling engine that is provided downstream of the liquefied gas flow rate adjusting device and generates power using the heat amount of the liquefied gas at the adjusted flow rate, and a heat amount to the Stirling engine Including a state change device capable of discharging the delivered liquefied gas as a vaporized gas, and a detection device for detecting the pressure and temperature of the liquefied gas at the intake port of the state change device. The flow rate of the liquefied gas can be adjusted based on the pressure and temperature of the liquefied gas at the mouth.

  In the liquefied gas vaporization system according to the present invention, the gas stored in the liquid phase state in the liquefied gas tank is supplied from the liquefied gas tank to the Stirling engine via the liquefied gas flow rate adjusting device for adjusting the flow rate of the liquefied gas. The amount of heat is transferred and power is generated in the Stirling engine. In addition, the liquefied gas in the single-phase flow state of either the single-phase liquid state of the liquefied gas or the single-phase gas phase state of the liquefied gas is changed in state by the state change device, and is converted into a gas-phase liquefied gas. Discharged. Further, the pressure and temperature of the liquefied gas are detected by the detection device at the intake port of the state change device.

  In this case, since the gas flow rate adjustment device can adjust the flow rate of the liquefied gas based on the pressure and temperature of the liquefied gas at the intake port of the state change device, the liquefied gas is in a single-phase liquid phase state of the liquefied gas or The liquefied gas flow rate adjusting device can be controlled so as to be in a single-phase flow state of any one of the liquefied gas phases. In addition, the Stirling engine can easily extract power by using the amount of heat of the liquefied gas. Furthermore, it is possible to prevent uneven distribution or liquid phase drift in the state change device, prevent supply of two-phase fluid to the state change device, and stably collect a gas at a predetermined flow rate at a predetermined temperature. Can do.

(2)
The state change device may be a liquefied gas vaporizer that vaporizes the liquefied gas.

  In this case, since the state change device includes a liquefied gas vaporizer, the liquefied gas having a single-phase liquid phase state can be stably vaporized in the liquefied gas vaporizer. In addition, a predetermined amount of gas sufficiently vaporized by using the liquefied gas flow rate adjusting device can be supplied at the outlet of the liquefied gas vaporizer.

(3)
The state change device may be a liquefied gas heater.

  In this case, since the state change device includes the liquefied gas temperature rising device, the temperature of the liquefied gas having a single-phase gas phase state can be stably raised in the liquefied gas temperature increasing device. Further, by using the liquefied gas flow rate adjusting device, the sensible heat and latent heat of evaporation of the liquefied gas can be completely used in the Stirling engine, and the power can be increased. A boil-off gas (BOG) heater may be used instead of the liquefied gas heater.

(4)
The liquefied gas flow rate adjusting device may adjust the flow rate of the liquefied gas so that the pressure and temperature of the intake port of the state change device become a temperature and pressure in a range in which the liquefied gas maintains a single-phase liquid phase state.

  In this case, since the flow rate of the liquefied gas is adjusted so that the liquefied gas maintains a single-phase liquid phase state, the supply of the two-phase fluid consisting of the liquid phase state and the gas phase state to the state change device is prevented, A gas having a predetermined flow rate can be stably recovered.

(5)
The liquefied gas flow rate adjusting device may adjust the flow rate of the liquefied gas so that the pressure and temperature of the intake port of the state change device become a temperature and pressure in a range in which the liquefied gas maintains a single-phase gas phase state.

  In this case, since the flow rate of the liquefied gas is adjusted so that the liquefied gas maintains a single-phase gas phase state, the supply of the two-phase fluid consisting of the liquid phase state and the gas phase state to the state change device is prevented, A gas having a predetermined flow rate can be stably recovered.

(6)
A liquefied gas distribution device further comprising: a liquefied gas distribution device provided between the liquefied gas flow rate adjusting device and the Stirling system; and a flow rate measuring device provided at an intake port of the state change device to measure the flow rate of the liquefied gas. Distributes the liquefied gas supplied from the liquefied gas flow control device to the piping that supplies the Stirling engine and the bypass piping that supplies the flow measuring device, and the liquefied gas piping discharged from the Stirling engine is upstream of the flow measuring device. May be connected to the bypass pipe.

  In this case, since the flow rate of the liquefied gas can be adjusted based on a flow rate measuring device provided near the intake port of the state change device, the flow rate of the gas phase gas discharged from the state change device can be stably taken out. be able to. In addition, since the liquefied gas used in the Stirling engine can be maintained in an optimum state by the liquefied gas distribution device, a heat source used in the Stirling engine can be easily secured.

(7)
A liquefied gas vaporizer for vaporizing the liquefied gas may be further provided in a bypass pipe provided between the liquefied gas distribution device and the flow rate measuring device, and the state change device may include a temperature raising device for vaporizing the liquefied gas. .

  In this case, due to the action of the liquefied gas vaporizer, the gas phase liquefied gas consisting of a single phase is reliably supplied to the intake port of the temperature raising device. As a result, the supply of the two-phase fluid consisting of the liquid phase state and the gas phase state can be prevented, and the gas at a predetermined flow rate can be stably recovered at a predetermined temperature.

(8)
A rotation power recovery device that recovers power generated from the Stirling engine, and a power interlocking mechanism that transmits the power recovered by the rotation power recovery device as power of the liquefied gas flow rate adjustment device may be further provided.

  In this case, the power generated from the Stirling engine is recovered by the rotational power recovery device, and the power recovered by the power interlocking mechanism can be used as the power of the liquefied gas flow rate adjustment device. As a result, the liquefied gas can be vaporized, and the energy consumption of the entire system in the liquefied gas vaporization system can be reduced for effective use.

(9)
As a heat source of the Stirling engine, a stationary heat storage device or a mobile heat storage device may be used, and heat supplied from the stationary heat storage device or the mobile heat storage device may be used for the Stirling engine.

  In this case, it is possible to effectively use the exhaust heat that has been dissipated around the conventional liquefied gas vaporization system, to reduce the amount of energy in the liquefied gas vaporization system, and to efficiently use the cold energy of the liquefied gas. It becomes possible.

(10)
The control method of the liquefied gas vaporization system according to the present invention supplies the liquefied gas stored in the liquefied gas tank to the state change device, takes out a predetermined gas, and uses the amount of heat from the liquefied gas through a Stirling engine. A control method for a liquefied gas vaporization system having a Stirling engine for extracting power, the control method for the liquefied gas vaporization system includes a detection process for detecting the pressure and temperature of the liquefied gas at the intake port of the state change device, and a state And a liquefied gas flow rate adjustment process for adjusting the flow rate of the liquefied gas based on the pressure and temperature of the liquefied gas at the intake port of the changing device.

  In the control method of the liquefied gas vaporization system according to the present invention, the flow rate of the liquefied gas is adjusted based on the pressure and temperature of the liquefied gas at the intake port of the state change device.

  In this case, the liquefied gas flow rate adjustment process can be controlled so that the liquefied gas becomes a single-phase flow in the state change device. Moreover, power can be easily taken out by the Stirling engine. As a result, non-uniform distribution or liquid phase drift in the state change device can be prevented, the supply of the two-phase fluid to the state change device is prevented, and a gas having a predetermined flow rate is stably recovered at a predetermined temperature. be able to.

(First embodiment)
Hereinafter, first to sixth embodiments according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram showing an example of a liquefied gas vaporization system 100 using a Stirling engine according to the first embodiment of the present invention.

  As shown in FIG. 1, in a liquefied gas vaporization system 100 using a Stirling engine, a liquefied gas tank 200, a liquefied gas flow rate adjusting device 300, a Stirling engine 400, a power recovery device 500, a heat exchanger 600, a pressure measuring device 710, A temperature measuring device 720, a control unit 750, and a liquefied gas vaporizer 800 are included.

  Stirling engine 400 includes a cooler 410, a first cylinder 420, a power piston 430, a crank 440, a flywheel 445, a second cylinder 450, a displacer piston 460, a heater 470, a pump 480 and an on-off valve 490.

  The liquefied gas tank 200 supplies liquefied gas to the liquefied gas flow rate adjusting device 300, and the liquefied gas flow rate adjusting device 300 supplies liquefied gas to the Stirling engine 400. The Stirling engine 400 uses the amount of heat of the liquefied gas in the cooler 410 and supplies the liquefied gas after use to the liquefied gas vaporizer 800. Here, a pressure measuring device 710 and a temperature measuring device 720 are provided in the piping from the outlet of the Stirling engine 400 to the intake port of the liquefied gas vaporizer 800. The pressure measuring device 710 and the temperature measuring device 720 measure the temperature and pressure of the liquefied gas in the vicinity of the intake port of the liquefied gas vaporizer 800 and provide the measured temperature to the control unit 750. The control unit 750 gives an instruction to the liquefied gas flow rate adjusting device 300 according to the signals TS and PS from the pressure measuring device 710 and the temperature measuring device 720. The liquefied gas flow rate adjusting device 300 adjusts the flow rate of the liquefied gas flowing through the piping based on the instruction given from the control unit 750.

  The Stirling engine 400 uses the latent heat of the liquefied gas given to the cooler 410 to cool the gas in the first cylinder 420. Further, the air in the second cylinder 450 is heated by the heater 470. The heating medium in the heater 470 is circulated by the pump 480 and the on-off valve 490, supplied with heat by the heat exchanger 600 provided in the middle of the circulation, and returned to the heater 470. As a result, the power piston 430 and the displacer piston 460 reciprocate while maintaining the phase difference, and the crank 440 rotates. Further, the rotation of the crank 440 is stabilized by the flywheel 445 provided on the crank 440, and power is given to the power recovery device 500.

  Next, a control system of the liquefied gas vaporization system 100 using the Stirling engine 400 in the present embodiment will be described.

  FIG. 2 is a flowchart showing an example of the operation of the control unit 750 in the control system of the liquefied gas vaporization system 100 using the Stirling engine.

  First, the CPU of the control unit 750 acquires the measured values of the vaporizer intake port pressure P0 and the vaporizer intake port temperature T0 based on the signals TS and RS received from the pressure measurement device 710 and the temperature measurement device 720 (step S1). ).

  Next, the CPU determines whether or not the vaporizer intake port pressure P0 measured in step S1 is smaller than the lower limit pressure threshold P1 (step S2). When determining that the vaporizer intake port pressure P0 is smaller than the lower limit pressure threshold value P1, the CPU determines whether or not the vaporizer intake port temperature T0 is larger than the upper limit temperature threshold value T1 (step S3). When determining that the vaporizer inlet temperature T0 is larger than the upper limit temperature threshold T1, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to increase the flow rate of the liquefied gas (step S4). Specifically, in the process of step S4, an upper limit temperature threshold value T1, which is a boiling point, is estimated from the operating pressure and compared with the vaporizer intake port temperature T0.

  On the other hand, when determining that the vaporizer intake port temperature T0 is not larger than the upper limit temperature threshold T1, the CPU determines whether the vaporizer intake port temperature T0 is smaller than the lower limit temperature threshold T2 (step S5). When determining that the vaporizer intake port temperature T0 is not lower than the lower limit temperature threshold T2, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to maintain the flow rate of the liquefied gas (step S6).

  When determining that the vaporizer intake port temperature T0 is lower than the lower limit temperature threshold T2, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to reduce the flow rate of the liquefied gas (step S7).

  On the other hand, when it is determined in step S2 that the vaporizer intake port pressure P0 is not smaller than the lower limit pressure threshold P1, it is determined whether the vaporizer intake port temperature T0 is larger than the upper limit temperature threshold T1 (step S8). . When determining that the vaporizer intake port temperature T0 is higher than the upper limit temperature threshold value T1, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to increase the flow rate of the liquefied gas as in the process of step S4.

  When determining that the vaporizer intake port temperature T0 is not larger than the upper limit temperature threshold T1, the CPU determines whether or not the vaporizer intake port temperature T0 is smaller than the lower limit temperature threshold T2 (step S9). When determining that the vaporizer intake port temperature T0 is lower than the lower limit temperature threshold T2, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to reduce the flow rate of the liquefied gas as in the process of step S7.

  On the other hand, if it is determined that the vaporizer intake port temperature T0 is not smaller than the lower limit temperature threshold T2, it is determined whether the vaporizer intake port pressure P0 is larger than the upper limit pressure threshold P2 (step S10). When it is determined that the vaporizer intake port pressure P0 is larger than the upper limit pressure threshold value P2, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to reduce the flow rate of the liquefied gas as in the process of step S7.

  When determining that the vaporizer intake port pressure P0 is not larger than the upper limit pressure threshold value P2, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to maintain the liquefied gas flow rate as in the process of step S6. After performing the processes in step S4, step S6, and step S7, the CPU returns to the process in step S1 again, acquires the measurement value, and repeats the processes from step S1 to step S10.

  Hereinafter, description will be made using a specific example. For example, consider the case where the liquefied gas accumulated in the liquefied gas tank 200 is made of liquid nitrogen, and the liquid nitrogen is stored in the liquefied gas tank 200 at a temperature of 80K and a pressure of 1.0 MPa.

  Assuming that the liquid nitrogen passes through the cooler 410 of the Stirling engine 400 and that the pressure at the intake port of the liquefied gas vaporizer 800 decreases to 0.78 MPa due to pipe pressure loss, the saturation of 0.78 MPa of liquid nitrogen Since the temperature is 100K, sensible heat with a temperature difference of 20K from 80K to 100K can be used in the cooler 410 of the Stirling engine 400.

  In this case, if the pressure of the liquid nitrogen at the intake port of the liquefied gas vaporizer 800 is 0.78 MPa or more and the temperature can be maintained in the range of 100 K or less, the liquefied nitrogen is converted into a single-phase liquid phase. 800 can be supplied.

  Therefore, as shown in FIG. 2, control is performed so that the measured values of the vaporizer intake port pressure P0 and the vaporizer intake port temperature T0 measured by the pressure measuring device 710 and the temperature measuring device 720 satisfy predetermined conditions. . That is, when the vaporizer inlet pressure P0 measured by the pressure measuring device 710 decreases, it is confirmed that the vaporizer intake port pressure P0 is lower than the set lower limit pressure threshold value P1, and the liquefied gas flow rate adjusting device 300 is controlled to increase the liquefied gas flow rate. When the liquefied gas flow rate is increased, it is confirmed that the pressure of the pressure measuring device 710 exceeds the upper limit pressure threshold P2, and the liquefied gas flow rate of the liquefied gas flow rate adjusting device 300 is decreased.

  Furthermore, when the vaporizer intake port temperature T0 measured by the temperature measuring device 720 increases, it is confirmed that the temperature exceeds the set upper limit temperature threshold T1, and control is performed to increase the liquefied gas flow rate of the liquefied gas flow rate adjusting device 300. When the liquefied gas flow rate is increased, it is confirmed that the vaporizer inlet temperature T0 measured by the temperature measuring device 720 is lower than the lower limit temperature threshold T2, and the liquefied gas flow rate of the liquefied gas flow rate adjusting device 300 is decreased. Take control.

  Further, in the present embodiment, the liquefied gas flow rate MLg [Kg / sec], the liquefied gas specific heat CpLg [KJ / KgK], and the usable temperature difference ΔT [with respect to the cooling capacity Qc [KW] of the cooler 410 of the Stirling engine 400. K] (saturation temperature T1 [K] −storage temperature To [K]) needs to satisfy the following equation.

  Qc <MLg × CpLg × ΔT (1)

  By satisfying the condition of the formula (1), it is possible to prevent excessive heat supply in the cooler 410 and to prevent the two-phase state of the liquefied gas in the cooler 410.

  As described above, in the control system of the liquefied gas vaporization system 100 using the Stirling engine 400, the liquefaction is performed based on the measured values by the pressure measuring device 710 and the temperature measuring device 720 disposed at the intake port of the liquefied gas vaporizer 800. By controlling the flow rate of the liquefied gas with the gas flow rate adjusting device 300, the liquefied gas at the intake port of the liquefied gas vaporizer 800 can be maintained in a single-phase liquid phase state.

(Second Embodiment)
Next, FIG. 3 is a schematic diagram showing an example of a liquefied gas vaporization system 100a using a Stirling engine according to the second embodiment of the present invention.

  The liquefied gas vaporization system 100a using the Stirling engine 400 shown in FIG. 3 is different from the liquefied gas vaporization system 100 using the Stirling engine 400 shown in FIG. 1 in the following points.

  The liquefied gas vaporization system 100a using the Stirling engine 400 shown in FIG. 3 includes a liquefied gas distribution device 310, a flow rate measuring device 730, and a bypass pipe BP in addition to the configuration of the liquefied gas vaporization system 100 using the Stirling engine 400. One end side of the bypass pipe BP is connected to the liquefied gas distribution device 310, and the other end side of the bypass pipe BP is connected to the intake port of the liquefied gas vaporizer 800. Further, the liquefied gas used by the Stirling engine 400 is returned in the middle of the bypass pipe BP. The flow rate measuring device 730 is disposed near the intake port of the liquefied gas vaporizer 800 in the bypass pipe P.

  The liquefied gas tank 200 supplies liquefied gas to the liquefied gas flow rate adjusting device 300, and the liquefied gas flow rate adjusting device 300 supplies liquefied gas to the liquefied gas distribution device 310. The liquefied gas distribution device 310 distributes the liquefied gas to the bypass pipe BP and the Stirling engine 400. The Stirling engine 400 uses the amount of heat of the liquefied gas in the cooler 410 and supplies the used liquefied gas in the middle of the bypass pipe BP. Here, a pressure measurement device 710 and a temperature measurement device 720 are provided in the piping from the outlet of the Stirling engine 400 to the supply to the bypass piping BP. The pressure measuring device 710 and the temperature measuring device 720 measure the temperature and pressure of the liquefied gas flowing in the pipe, and give signals TS and PS to the control unit 750. The control unit 750 gives an instruction to the liquefied gas distribution device 310 according to the signals TS and PS from the pressure measurement device 710 and the temperature measurement device 720. The liquefied gas distribution device 310 adjusts the distribution ratio of the liquefied gas to be circulated through the bypass pipe BP and the Stirling engine 400 based on the instruction given from the control unit 750. Further, the flow rate measuring device 730 measures the flow rate of the liquefied gas in the bypass pipe BP and gives it to the control unit 750. The control unit 750 gives an instruction to the liquefied gas flow rate adjusting device 300 according to the signal FS from the flow rate measuring device 730. The liquefied gas flow rate adjusting device 300 adjusts the liquefied gas flow rate in accordance with an instruction from the control unit 750.

  The Stirling engine 400 uses the latent heat of the liquefied gas given to the cooler 410 to cool the gas in the first cylinder 420. Further, the air in the second cylinder 450 is heated by the heater 470. The heating medium in the heater 470 is circulated by the pump 480 and the on-off valve 490, supplied with heat by the heat exchanger 600 provided in the middle of the circulation, and returned to the heater 470. As a result, the power piston 430 and the displacer piston 460 reciprocate while maintaining the phase difference, and the crank 440 rotates. Further, the rotation of the crank 440 is stabilized by the flywheel 445 provided on the crank 440, and power is given to the power recovery device 500.

  In this case, a stable gasified liquefied gas is provided by providing a flow rate measuring device 730 and a bypass pipe BP disposed at the intake port of the liquefied gas vaporizer 800 and controlling the flow rate of the liquefied gas by the liquefied gas flow rate adjusting device 300. Can be obtained from the liquefied gas vaporizer 800. That is, even when liquefied gas is not required in the cooler 410 of the Stirling engine 400, a desired amount of vaporized liquefied gas can be obtained by supplying the liquefied gas into the bypass pipe BP.

  In addition, the liquefied gas distribution device 310 controls the flow rate of the liquefied gas based on the measured values by the pressure measuring device 710 and the temperature measuring device 720 disposed downstream of the Stirling engine 400, thereby The liquefied gas at the intake port can be maintained in a single-phase liquid phase state.

(Third embodiment)
Next, FIG. 4 is a schematic diagram showing an example of a liquefied gas vaporization system 100b using a Stirling engine according to the third embodiment of the present invention.

  The liquefied gas vaporization system 100b using the Stirling engine 400 shown in FIG. 4 is different from the liquefied gas vaporization system 100 using the Stirling engine 400 shown in FIG. A liquefied gas temperature riser 900 is provided in place of the gas vaporizer 800. That is, in the liquefied gas vaporization system 100 using the Stirling engine 400 shown in FIG. 1, the purpose is to supply a liquefied gas having a single-phase liquid phase state to the liquefied gas vaporizer 800. Is different in that it aims to supply a liquefied gas consisting of a single-phase gas phase to the liquefied gas temperature riser 900.

  The liquefied gas tank 200 supplies liquefied gas to the liquefied gas flow rate adjusting device 300, and the liquefied gas flow rate adjusting device 300 supplies liquefied gas to the Stirling engine 400. The Stirling engine 400 uses the amount of heat of the liquefied gas in the cooler 410 and supplies the liquefied gas after use to the liquefied gas temperature riser 900. Here, a pressure measuring device 710 and a temperature measuring device 720 are provided in the piping from the outlet of the Stirling engine 400 to the intake port of the liquefied gas temperature riser 900. The pressure measuring device 710 and the temperature measuring device 720 measure the temperature and pressure of the liquefied gas flowing in the pipe, and give signals TS and PS to the control unit 750. The control unit 750 gives an instruction to the liquefied gas flow rate adjusting device 300 according to the signals TS and PS from the pressure measuring device 710 and the temperature measuring device 720. The liquefied gas flow rate adjusting device 300 adjusts the flow rate of the liquefied gas flowing through the piping based on the instruction given from the control unit 750.

  The Stirling engine 400 uses the latent heat of the liquefied gas given to the cooler 410 to cool the gas in the first cylinder 420. Further, the air in the second cylinder 450 is heated by the heater 470. The heating medium in the heater 470 is circulated by the pump 480 and the on-off valve 490, supplied with heat by the heat exchanger 600 provided in the middle of the circulation, and returned to the heater 470. As a result, the power piston 430 and the displacer piston 460 reciprocate while maintaining the phase difference, and the crank 440 rotates. Further, the rotation of the crank 440 is stabilized by the flywheel 445 provided on the crank 440, and power is given to the power recovery device 500.

  Next, a control system of the liquefied gas vaporization system 100b using the Stirling engine 400 will be described.

  FIG. 5 is a flowchart showing an example of the operation of the control unit 750 in the control system of the liquefied gas vaporization system 100b using the Stirling engine 400.

  First, the CPU of the control unit 750 acquires signals TS and PS from the pressure measuring device 710 and the temperature measuring device 720, and acquires measured values of the vaporizer intake port temperature T0 and the vaporizer intake port pressure P0 (step). S11).

  Next, the CPU determines whether or not the vaporizer intake port pressure P0 measured in step S11 is larger than the upper limit pressure threshold value P1 (step S12). When determining that the vaporizer intake port pressure P0 is larger than the upper limit pressure threshold value P1, the CPU determines whether or not the vaporizer intake port temperature T0 is smaller than the lower limit temperature threshold value T1 (step S13). When determining that the vaporizer intake port temperature T0 is lower than the lower limit temperature threshold T1, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to increase the flow rate of the liquefied gas (step S14). Specifically, in the process of step S14, the lower limit temperature threshold value T1, which is the boiling point, is estimated from the operating pressure and compared with the vaporizer intake port temperature T0.

  On the other hand, when determining that the vaporizer intake port temperature T0 is not smaller than the lower limit temperature threshold T1, the CPU determines whether or not the vaporizer intake port temperature T0 is larger than the lower limit temperature threshold T2 (step S15). When determining that the vaporizer intake port temperature T0 is not larger than the lower limit temperature threshold T2, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to maintain the flow rate of the liquefied gas (step S16).

  If it is determined that the vaporizer intake port temperature T0 is higher than the lower limit temperature threshold T2, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to reduce the flow rate of the liquefied gas (step S17).

  On the other hand, if it is determined in step S12 that the vaporizer intake port pressure P0 is not larger than the upper limit pressure threshold value P1, it is determined whether the vaporizer intake port temperature T0 is smaller than the lower limit temperature threshold value T1 (step S18). . When determining that the vaporizer intake port temperature T0 is lower than the lower limit temperature threshold value T1, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to increase the flow rate of the liquefied gas as in the process of step S14.

  When determining that the vaporizer intake port temperature T0 is not smaller than the lower limit temperature threshold T1, the CPU determines whether or not the vaporizer intake port temperature T0 is larger than the lower limit temperature threshold T2 (step S19). When determining that the vaporizer intake port temperature T0 is larger than the lower limit temperature threshold T2, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to decrease the flow rate of the liquefied gas as in the process of step S17.

  On the other hand, when it is determined that the vaporizer intake port temperature T0 is not larger than the lower limit temperature threshold T2, it is determined whether the vaporizer intake port pressure P0 is smaller than the lower limit pressure threshold P2 (step S20). When it is determined that the vaporizer intake port pressure P0 is smaller than the lower limit pressure threshold P2, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to reduce the flow rate of the liquefied gas as in the process of step S17.

  When determining that the vaporizer intake port pressure P0 is not smaller than the lower limit pressure threshold value P2, the CPU gives a signal to the liquefied gas flow rate adjusting device 300 so as to maintain the liquefied gas flow rate as in the process of step S16. After performing the processes in step S14, step S16, and step S17, the CPU returns to the process in step S11 again, acquires the measurement value, and repeats the processes from step S11 to step S20.

  Hereinafter, description will be made using a specific example. For example, consider the case where the liquefied gas accumulated in the liquefied gas tank 200 is made of liquid nitrogen, and the liquid nitrogen is stored in the liquefied gas tank 200 at a temperature of 80K and a pressure of 1.0 MPa.

  Assuming that liquid nitrogen passes through the cooler 410 of the Stirling engine 400 and that the pressure at the intake port of the liquefied gas temperature riser 900 decreases to 0.78 MPa due to pipe pressure loss, 0.78 MPa of liquid nitrogen Since the saturation temperature is 100K, sensible heat and latent heat of vaporization with a temperature difference of 20K from 80K to 100K can be used.

  In this case, if the pressure of liquid nitrogen at the intake port of the liquefied gas temperature riser 900 is 0.78 MPa or less and the temperature can be maintained in the range of 100 K or more, the liquefied gas is increased as a single-phase gas phase. It becomes possible to supply to the warmer 900.

  Therefore, as shown in FIG. 5, control is performed so that the measured values of the vaporizer intake port pressure P0 and the vaporizer intake port temperature T0 measured by the pressure measuring device 710 and the temperature measuring device 720 satisfy the conditions. That is, when the vaporizer intake port pressure P0 measured by the pressure measuring device 710 decreases, it is confirmed that the vaporizer intake port pressure P0 is lower than the set lower limit pressure threshold value P1, and the liquefied gas flow rate adjusting device 300 is controlled to decrease the liquefied gas flow rate. When the liquefied gas flow rate is decreased, it is confirmed that the pressure of the pressure measuring device 710 exceeds the upper limit pressure threshold value P2, and control is performed to increase the liquefied gas flow rate of the liquefied gas flow rate adjusting device 300.

  Further, when the vaporizer intake port temperature T0 measured by the temperature measuring device 720 increases, it is confirmed that the temperature exceeds the set upper limit temperature threshold value T1, and control for decreasing the liquefied gas flow rate of the liquefied gas flow rate adjusting device 300 is performed. When the liquefied gas flow rate is decreased, it is confirmed that the vaporizer inlet temperature T0 measured by the temperature measuring device 720 is lower than the lower limit temperature threshold T2, and the liquefied gas flow rate of the liquefied gas flow rate adjusting device 300 is increased. Take control.

  Further, in the present embodiment, the cooling capacity Qc [Kw] of the cooler 410 of the Stirling engine 400 is set such that the liquefied gas flow rate MLg [Kg / sec], the liquefied gas specific heat CpLg [Kj / KgK], and the usable temperature difference ΔT ( The conditions of saturation temperature T1 [K] −storage temperature To [K]) and liquefied gas vaporization latent heat HLg [KJ · Kg] must satisfy the following equation.

  Qc> MLg × (CpLg × ΔT + HLg) (2)

  By satisfying the condition of the expression (2), it is possible to prevent excessive heat supply in the cooler 410 and to prevent the generation of the two-phase state of the liquefied gas in the cooler 410.

  Thus, in the control system of the liquefied gas vaporization system 100c using the Stirling engine 400, the liquefaction by the liquefied gas flow rate adjusting device 300 is based on the measured values by the pressure measuring device 710, the temperature measuring device 720, and the flow rate measuring device 730. By controlling the flow rate of the gas and the distribution ratio of the liquefied gas by the liquefied gas distributor 310, the liquefied gas at the intake port of the liquefied gas heating device 900 can be maintained in a single-phase gas phase state.

  As a result, in the liquefied gas temperature riser 900, compared to the case of using a conventional vaporizer, the heat transfer area of a device used for increasing the temperature of the supplied liquefied gas to room temperature is reduced. It becomes possible to reduce. That is, the liquefied gas heating device 900 can be made compact, and the liquefied gas vaporization system 100c using the Stirling engine 400 can be miniaturized.

  For example, in terms of conversion based on the above example of liquid nitrogen, in the case of liquid nitrogen under atmospheric pressure (boiling point 77.53 K), the latent heat of vaporization is 213 Kj / Kg, and the specific heat at 80 K is 1.112 Kj / KgK. Since the specific heat of 273 K is 1.041 Kj / KgK, the amount of heat Qh [KJ] required to raise 1 Kg of liquid nitrogen to 273 K is expressed by the following equation.

  Qh = 1 × (213KJ / Kg + (1.041KJ / KgK × 273K−1.112KJ / KgK × 77533K)) = 410.98KJ (3)

  From this equation (3), the latent heat of vaporization is 213 KJ / Kg, so if the temperature rise is 197.98 KJ (410.98 KJ-213 KJ), the capacity of the liquefied gas heater 900 is reduced to half or less. Can do.

(Fourth embodiment)
Next, FIG. 6 is a schematic diagram showing an example of a liquefied gas vaporization system 100c using the Stirling engine 400 in the fourth embodiment according to the present invention.

  The liquefied gas vaporization system 100c using the Stirling engine 400 shown in FIG. 6 differs from the liquefied gas vaporization system 100a using the Stirling engine 400 shown in FIG. 3 in the following points.

  A liquefied gas vaporization system 100c using the Stirling engine 400 shown in FIG. 6 includes a liquefied gas temperature raising device 900 instead of the liquefied gas vaporizer 800 of the liquefied gas vaporization system 100 using the Stirling engine 400 of FIG. A liquefied gas vaporizer 810 is included. The liquefied gas vaporizer 810 is disposed in a bypass pipe BP downstream of the liquefied gas distribution device 310 and upstream of the flow rate measuring device 730.

  In this case, since the liquefied gas vaporizer 810 is additionally provided in the bypass pipe BP, a predetermined amount of liquefied gas is supplied to the Stirling engine 400 even when the flow rate of the vaporized gas desired to be acquired from the liquefied gas temperature riser 900 increases. By supplying the remaining liquefied gas to the bypass pipe BP and the liquefied gas vaporizer 810, the liquefied gas composed of a single-phase gas phase can be stably supplied to the liquefied gas temperature riser.

  As a result, the generation of the two-phase state of the liquefied gas can be prevented, and the liquefied gas flow rate adjusting device 300 can be used based on the measured value by the flow rate measuring device 730 disposed at the intake port of the liquefied gas temperature riser 900. By controlling the flow rate of the liquefied gas, the liquefied gas at the intake port of the liquefied gas temperature riser 900 can be maintained in a single-phase gas phase state. In addition, the liquefied gas distribution device 310 controls the liquefied gas flow rate ratio based on the measurement values obtained by the pressure measuring device 710 and the temperature measuring device 720 disposed downstream of the Stirling engine 400, thereby increasing the liquefied gas temperature riser. The liquefied gas at the 900 inlet can be maintained in a single-phase gas phase.

(Fifth embodiment)
Next, FIG. 7 is a schematic diagram showing an example of a liquefied gas vaporization system 100d using the Stirling engine 400 in the fifth embodiment according to the present invention.

  The liquefied gas vaporization system 100d using the Stirling engine 400 shown in FIG. 7 differs from the liquefied gas vaporization system 100 using the Stirling engine 400 shown in FIG. Instead of the device 500, a rotational power recovery device 650 and a power interlocking mechanism 660 are provided.

  As shown in FIG. 7, in the liquefied gas vaporization system 100 d using the Stirling engine 400, the power recovered from the Stirling engine 400 is recovered by the rotational power recovery device 650, and is linked to the power disposed in the rotational power recovery device 650. The liquefied gas supply device 300 is supplied via the mechanism 660. As a result, the liquefied gas supply device 300 that has been operated by other power is operated by the power supplied to the liquefied gas supply device 300.

  As described above, in the liquefied gas vaporization system 100d, the liquefied gas is vaporized, and the power recovered by the rotary power recovery device 650 and the power interlocking mechanism 660 is supplied to the liquefied gas vaporization system 100d itself. Since it can be used as power, the energy consumption of the entire system in the liquefied gas vaporization system 100d can be reduced, and effective use can be achieved.

(Sixth embodiment)
Next, FIG. 8 is a schematic diagram showing an example of a liquefied gas vaporization system 100e using a Stirling engine according to the sixth embodiment of the present invention.

  The liquefied gas vaporization system 100e using the Stirling engine shown in FIG. 8 is different from the liquefied gas vaporization system 100 using the Stirling engine shown in FIG. This is a point provided with a pump 680 and a mobile heat storage device 690.

  As shown in FIG. 8, in the Stirling engine 400, in the heat exchanger 600 of the Stirling engine 400, a separate circulation pipe is formed, a heat medium pump 680 is inserted in the circulation pipe, and a mobile heat storage device is connected to the circulation pipe. 690 is disposed. Thereby, the heat radiated in the heat exchanger 600 is transferred to the mobile heat storage device 690 by the medium circulated in the circulation pipe by the heat medium pump 680. For example, the medium can use water, other liquids, or the like.

  If heat cannot be obtained continuously, a stationary heat storage device is provided instead of the mobile heat storage device 690, heat is stored in the stationary heat storage device, and is supplied to the heater 470 of the Stirling engine 400 when necessary. May be.

  By the above method, the exhaust heat radiated around the liquefied gas vaporization system 100e can be effectively used, the amount of energy in the liquefied gas vaporization system 100e can be reduced, and the chilled gas energy of the liquefied gas can be increased. It can be used efficiently.

  The format of the Stirling engine 400 is not limited to the Stirling engine in the first to sixth embodiments, but may be α type, β type, γ type, dual acting type of any other Stirling engine. There may be.

  In the first to sixth embodiments, the Stirling engine 400 corresponds to the Stirling engine, the liquefied gas vaporization systems 100 to 100e correspond to the liquefied gas vaporization system, and the liquefied gas tank 200 corresponds to the liquefied gas tank. The liquefied gas flow rate adjusting device 300 corresponds to the liquefied gas flow rate adjusting device, the liquefied gas vaporizer 800 and the liquefied gas temperature riser 900 correspond to the state change device, and the pressure measuring device 710 and the temperature measuring device 720 are detection devices. The liquefied gas vaporizers 800 and 810 correspond to the liquefied gas vaporizer, the liquefied gas temperature riser 900 corresponds to the liquefied gas temperature riser, the liquefied gas distribution device 310 corresponds to the liquefied gas distribution device, The flow rate measuring device 730 corresponds to the flow rate measuring device, the bypass pipe BP corresponds to the bypass pipe, and the rotational power recovery device 650 rotates. Corresponds to the force collecting device, a power interlock mechanism 660 corresponds to the power interlock mechanism, the refrigerant pump 680 and mobile thermal storage device 690 corresponds to the stationary heat storage device or mobile heat storage equipment.

  Although the present invention has been described in the first to sixth preferred embodiments described above, the present invention is not limited thereto. It will be understood that various other embodiments may be made without departing from the spirit and scope of the invention. Furthermore, in this embodiment, although the effect | action and effect by the structure of this invention are described, these effect | actions and effects are examples and do not limit this invention.

Schematic diagram showing an example of a liquefied gas vaporization system using a Stirling engine The flowchart figure which shows an example of operation | movement of the control part in the control system of the liquefied gas vaporization system using a Stirling engine Schematic diagram showing an example of a liquefied gas vaporization system using a Stirling engine Schematic diagram showing an example of a liquefied gas vaporization system using a Stirling engine The flowchart figure which shows an example of operation | movement of the control part in the control system of the liquefied gas vaporization system using a Stirling engine Schematic diagram showing an example of a liquefied gas vaporization system using a Stirling engine Schematic diagram showing an example of a liquefied gas vaporization system using a Stirling engine Schematic diagram showing an example of a liquefied gas vaporization system using a Stirling engine

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Liquefied gas vaporization system 200 Liquefied gas tank 300 Liquefied gas flow volume adjustment apparatus 310 Liquefied gas distribution apparatus 400 Stirling engine 650 Rotation power recovery apparatus 660 Power interlock mechanism 680 Heat transfer medium pump 690 Mobile heat storage device 710 Pressure measurement apparatus 720 Temperature measurement apparatus 730 Flow volume Measuring device 800,810 Liquefied gas vaporizer 900 Liquefied gas heater BP Bypass piping

Claims (10)

A liquefied gas vaporization system having a Stirling engine,
The liquefied gas vaporization system includes:
A liquefied gas tank capable of storing a predetermined gas in a liquid phase; and
A liquefied gas flow rate adjusting device for adjusting the flow rate of the liquefied gas supplied from the liquefied gas tank;
A Stirling engine that is provided downstream of the liquefied gas flow rate adjusting device and generates power using the calorific value of the liquefied gas at the adjusted flow rate;
A state change device capable of discharging the liquefied gas delivered to the Stirling engine as vaporized gas;
A detection device for detecting the pressure and temperature of the liquefied gas at the intake port of the state change device,
The gas flow rate adjusting device is a liquefied gas vaporization system capable of adjusting the flow rate of the liquefied gas based on the pressure and temperature of the liquefied gas at the intake port of the state change device.   The liquefied gas vaporization system according to claim 1, wherein the state change device is a liquefied gas vaporizer that vaporizes the liquefied gas.   The liquefied gas vaporization system according to claim 1, wherein the state change device is a liquefied gas heater.   The liquefied gas flow rate adjusting device adjusts the flow rate of the liquefied gas so that the pressure and temperature of the intake port of the state change device become a temperature and pressure in a range in which the liquefied gas maintains a single-phase liquid phase state. The liquefied gas vaporization system according to claim 1 or 2 characterized by things.   The liquefied gas flow rate adjusting device adjusts the flow rate of the liquefied gas so that the pressure and temperature of the intake port of the state change device become a temperature and pressure in a range in which the liquefied gas maintains a single-phase gas phase state. The liquefied gas vaporization system according to claim 1 or 3 characterized by things. A liquefied gas distribution device provided between the liquefied gas flow control device and the Stirling system;
A flow rate measuring device provided near the intake port of the state change device and measuring the flow rate of the liquefied gas; and
The liquefied gas distribution device distributes the liquefied gas supplied from the liquefied gas flow rate adjusting device to a piping for supplying the Stirling engine and a bypass piping for supplying to the flow measuring device, and the liquefied gas discharged from the Stirling engine The liquefied gas vaporization system according to any one of claims 1 to 5, wherein a gas pipe is connected to a bypass pipe upstream of the flow rate measuring device. A liquefied gas vaporizer that vaporizes the liquefied gas is further provided in the bypass pipe provided between the liquefied gas distribution device and the flow rate measuring device;
The liquefied gas vaporization system according to claim 6, wherein the state change device includes a heating device that vaporizes the liquefied gas.   A rotating power recovery device that recovers the power generated from the Stirling engine; and a power interlocking mechanism that transmits the power recovered by the rotational power recovery device as power of the liquefied gas flow rate adjustment device. The liquefied gas vaporization system according to any one of claims 1 to 7, wherein the liquefied gas vaporization system is characterized.   The stationary heat storage device or the mobile heat storage device is used as the heat source of the Stirling engine, and the heat supplied from the stationary heat storage device or the mobile heat storage device is used for the Stirling engine. The liquefied gas vaporization system of any one of Claims 8. Liquefied gas vaporization having a Stirling engine that supplies the liquefied gas stored in the liquefied gas tank to the state change device, takes out the predetermined gas, and takes out power using the amount of heat from the liquefied gas through the Stirling engine A system control method comprising:
The control method of the liquefied gas vaporization system is:
A detection process for detecting the pressure and temperature of the liquefied gas at the intake port of the state change device;
And a liquefied gas flow rate adjusting process for adjusting a flow rate of the liquefied gas based on the pressure and temperature of the liquefied gas at the intake port of the state change device.