JP5409272B2 - Liquefied gas vaporization system - Google Patents

Description

  The present invention relates to a liquefied gas vaporization system that vaporizes liquefied gas, and more particularly to a liquefied gas vaporization system that can supply gas and electric power using a Stirling engine.

  The conventional liquefied gas vaporization system simply warms the liquefied gas with seawater or the like and vaporizes it, and the latent heat of the liquefied gas is released without being effectively used. In particular, LNG (Liquid Natural Gas), which is a typical liquefied gas, has a low latent temperature of minus 162 ° C. and a large latent heat, but is released during vaporization to become city gas.

  Therefore, in order to effectively utilize the latent heat of the liquefied gas (hereinafter referred to as LNG representatively), a technique for driving the Stirling engine and recovering the latent heat energy at the time of LNG vaporization has been proposed in Patent Documents 1 and 2 below. ing. In these, the LNG is passed through a cooler that covers the heat recovery part (head part) of the Stirling engine to forcibly cool the heat recovery part, and the Stirling engine is driven by a relative temperature difference from the crankcase part. In the device described in Patent Document 2 in which Patent Document 1 is a prior art, a liquid phase state and a gas phase state two-phase fluid generated in a cooler are prevented from inducing drift and vibration in a subsequent vaporizer. Therefore, the pressure and temperature are detected immediately before the vaporizer and the LNG supply amount is controlled as needed. However, such a control device is complicated and expensive, and the amount of passage through the cooler becomes a problem in the vaporization efficiency of the entire liquefied gas vaporization system.

Japanese Patent Laid-Open No. 11-022550 JP 2008-157144 A

  Therefore, the present invention provides a liquefied gas vaporization system that can supply a power and supply a gas while appropriately vaporizing a liquefied gas by using a Stirling engine without requiring a complicated control device. Is an issue.

In order to solve the above problems, a liquefied gas vaporization system of the present invention includes a liquefied gas tank capable of storing liquefied gas in a liquid phase, and a first flow rate for adjusting a flow rate of the liquefied gas supplied from the liquefied gas tank. An adjustment device, a vaporization tank disposed downstream of the first flow rate adjustment device and capable of storing a gas in a gas phase in which the liquefied gas is vaporized and a liquid liquefied gas in a liquid phase; An exhaust pipe for discharging the gas in the gas phase state, a second flow rate adjusting device for adjusting the flow rate of the gas in the gas phase state discharged through the exhaust pipe, and the vaporization tank, A plurality of Stirling engines in which respective heat recovery units are arranged so as to be immersed in the retained liquefied gas in the vaporization tank, and a liquid level detection that is disposed in the vaporization tank and detects the liquid level of the retained liquefied gas Means based on the detection result of the liquid level detection means. , In which it was decided to adjust the flow rate of the first of said liquefied gas by the flow controller flow rate, and gas in the gaseous state by the second flow control device.

  In the above liquefied gas vaporization system, each of the plurality of Stirling engines includes a housing that slidably supports a piston member in the cylinder and fixes a proximal end portion of the cylinder, and the vaporization is performed on the distal end portion of the cylinder. It is good to set it as the structure which arrange | positions in a tank and supports the said housing in the said vaporization tank.

  In the above liquefied gas vaporization system, each of the plurality of Stirling engines has a mounting hole that fits the cylinder, a mounting member that is mounted on the vaporizing tank, and a support cylinder that is fitted so as to surround the cylinder. And a first support member that supports the support cylinder to the mounting member, and a second support member that supports the housing to the mounting member, the second support member and the first support It is good to set it as the structure supported by the said vaporization tank by a member. An annular groove may be formed on the outer peripheral surface of the cylinder, and a ring member fitted into the annular groove may be provided, and the ring member may be sandwiched between the housing and the support cylinder.

Since this invention is comprised as mentioned above, there exists an effect as described below. That is, in the above liquefied gas vaporization system, the heat recovery parts of a plurality of Stirling engines are arranged so as to be immersed in the retained liquefied gas in the vaporization tank, so that each Stirling engine requires a cooler and its piping. Without this, heat recovery by a plurality of Stirling engines becomes possible. In particular, since the heat recovery part of each Stirling engine is always immersed in a stable liquefied gas that is a single phase, a two-phase fluid is generated as in a small-capacity cooler, resulting in a decrease in power generation efficiency. In addition, there is no adverse effect on the downstream piping, and there is no need to perform complicated control for preventing the two-phase fluidization. Furthermore, the liquid level detection means of the staying liquefied gas is provided in the vaporization tank, and the ratio of the staying liquefied gas amount and the vaporized gas quantity in the vaporization tank can be grasped, so that the first flow rate is based on this. If the adjusting device and the second flow rate adjusting device are adjusted, the efficiency of the entire system can be optimized both when vaporization is promoted and when vaporization is stopped.

  Further, in the liquefied gas vaporization system of the present invention, when the liquid phase state is maintained by suppressing the vaporization of the retained liquefied gas, the retained liquefied gas is cooled via the heat recovery unit by forcibly driving the Stirling engine. Can do. In such a cooling operation, without adding a special device, electric power is supplied to a generator installed in the Stirling engine to function as an electric motor, and the Stirling engine is forced to drive to function as a refrigerator. Can be made. Thus, since the Stirling engine can function as a refrigerator to cool the liquefied liquefied gas, the liquefied gas vaporization system can be prevented from being vaporized even when the liquefied gas vaporization system is stopped, thereby preventing unnecessary gas release. Can do. Thus, a highly efficient liquefied gas vaporization system can be provided by arranging a plurality of Stirling engines in parallel without requiring a complicated control device. The number of Stirling engines to be cooled and driven may be arbitrarily determined according to conditions.

  If the Stirling engine is configured as described above, it is appropriately supported by the vaporization tank via the first and second support members, so that the stress is not concentrated on the heat recovery portion of the cylinder, and the displacer Smooth operation of the piston can be ensured. In addition, since the housing can be removed from the vaporization tank while the cylinder is fixed to the mounting member, maintenance for the Stirling engine can be easily performed.

  And since a deformation stress does not act on the sealing member of the support part to the vaporization tank of a Stirling engine, appropriate sealing performance is maintained. Thus, reliable airtightness can be ensured between the Stirling engine and the vaporization tank. Furthermore, the heat recovery part is attached to the vaporization tank so that it is located at the bottom, and the Stirling engine can be supported in an inverted position, so even if wear powder, oxide scale, etc. occur near the displacer piston, Reaching the piston portion can be prevented.

It is a block diagram of the liquefied gas vaporization system which concerns on one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the specific structure of the Stirling engine with which it uses for one Embodiment of this invention. It is a cross-sectional view which shows the specific structure of the Stirling engine provided to one Embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows a part of basic composition of the Stirling engine provided to one Embodiment of this invention. It is a circuit diagram which shows an example of a mounting state and a control circuit when applying a Stirling engine to a generator and comprising a Stirling engine generator. It is a flowchart which shows the operation | movement by the control circuit of FIG.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall view of a liquefied gas vaporization system according to an embodiment of the present invention, where the left-right direction corresponds to the horizontal direction in the three-dimensional space, and the up-down direction corresponds to the vertical direction. The liquefied gas tank LT capable of storing the liquefied gas in the liquid phase state is connected to the vaporization tank VT capable of storing the gas phase gas in which the liquefied gas is vaporized and the liquid gas state retained liquefied gas through the introduction pipe IN. ing.

  The liquefied gas tank LT of the present embodiment is a well-known LNG tank and has a function of storing liquefied gas (hereinafter referred to as LNG) in a liquid phase for a long period of time. The vaporization tank VT is a sealed container having robustness and heat insulation properties. In the present embodiment, the vaporization tank VT has a rectangular cross section and extends in the depth direction of the paper as shown in FIG. The liquefied gas tank LT and the vaporizing tank VT are connected in communication via an introduction pipe IN, and the LNG in the liquefied gas tank LT is introduced into the vaporizing tank VT in a single liquid phase state. A discharge pipe EX is connected to the vaporization tank VT, and gas in a vapor phase in the vaporization tank VT is discharged through the discharge pipe EX.

  Further, an adjustment valve VA1 constituting the first flow rate adjusting device of the present invention is disposed in the introduction pipe IN, and the flow rate of the liquefied gas supplied from the liquefied gas tank LT is adjusted by the adjusting valve VA1. . In addition, the discharge pipe EX is provided with an adjustment valve VA2 constituting the second flow rate adjusting device of the present invention, and this adjustment valve VA2 adjusts the flow rate of the gas in the vapor phase in the vaporization tank VT. Is done.

  A plurality of Stirling engines (typically represented by SE) are arranged in the vaporization tank VT, and the respective heat recovery units HC are arranged so as to be immersed in the retained liquefied gas (LNG) in the vaporization tank VT. . The heat recovery operation and the refrigeration operation of each Stirling engine SE are controlled at any time by the Stirling engine controller CE. During the heat recovery operation (during power generation), the generated electric power is not shown via the Stirling engine controller CE. Alternatively, power is distributed to the power storage facility, and power is supplied from an overhead line or power storage facility (not shown) via the Stirling engine controller CE during the refrigeration operation (when driven as a prime mover). Thus, the operation of each Stirling engine SE is controlled by the Stirling engine controller CE according to the control of the entire liquefied gas vaporization system by the system controller CS. The structure of the Stirling engine SE will be described later with reference to FIGS.

  Residual liquefied gas (LNG at minus 162 ° C) in the vaporization tank VT is actively vaporized by a slight rise in liquid temperature due to the residence, fills the space in the vaporization tank VT, and is discharged as a single gas phase retained gas. It is discharged via the tube EX. The vaporization is also promoted by the operation of each Stirling engine SE. Further, in order to promote vaporization, the vaporization tank VT may be forcibly heated by a circulation medium. Further, in preparation for the case where the two-phase fluid is discharged through the discharge pipe EX during a transient operation or the like, a conventional vaporizer VP (indicated by a two-dot chain line in FIG. 1) is installed in the discharge pipe EX in order to completely vaporize Although it may be arranged in the middle, it is not necessary in this embodiment.

  A well-known liquid level sensor FS is installed on the inner wall surface of the vaporization tank VT as the liquid level detecting means of the present invention, and it is constantly monitored whether or not the liquid level of the staying liquefied gas (LNG) is at an optimum level. The optimum level is a position where the heat recovery unit HC can be surely immersed in the staying liquefied gas (LNG) and a space of a predetermined volume can be secured in the vaporization tank VT, and is stored in the system controller CS in advance. In order to maintain this optimum level, the opening degree of the regulating valves VA1 and VA2 and the operation of each Stirling engine SE are controlled by the system controller CS, and the vaporization operation and the refrigeration operation are performed. As described above, according to the present embodiment, as in Patent Document 2 described above, stable vaporization is achieved by liquid level monitoring by the liquid level sensor FS without providing a cooler pipe or a complicated sensor and control system for each Stirling engine. Operation and freezing operation can be performed.

  The operation of the liquefied gas vaporization system of the present embodiment configured as described above, that is, control by the system controller CS will be described. During the vaporization operation, first, the regulating valve VA2 is fully opened, and then the regulating valve VA1 is driven to a predetermined opening. Is done. Next, when it is confirmed by the liquid level sensor FS that a predetermined volume of retained liquefied gas (LNG) has accumulated in the vaporization tank VT, the heat recovery operation of each Stirling engine SE is started. The retained liquefied gas (LNG) is sequentially vaporized and discharged through the discharge pipe EX. If the supply of the retained liquefied gas (LNG) cannot keep up with the vaporization rate, the opening of the adjustment valve VA1 is appropriately increased. If the supply amount of the staying liquefied gas (LNG) into the vaporization tank VT is increased and the reverse is true, the opening of the adjustment valve VA1 may be appropriately reduced. If the vaporization amount suddenly increases due to an external factor, the safety valve VS disposed in the discharge pipe EX shown in FIG. 1 is opened, and the gas is temporarily discharged through the discharge pipe EZ. That's fine.

  When stopping the vaporization operation, the regulating valve VA2 and the regulating valve VA1 are sequentially closed, and each Stirling engine SE is stopped to prevent unintentional vaporization when the vaporization operation is stopped. Therefore, it is only necessary to supply electric power to forcibly drive each Stirling engine SE to cool the liquefied liquefied gas (LNG) in the vaporization tank VT. Also in this case, each Stirling engine SE (functioning as a refrigerator) is controlled by the system controller CS so that the liquid level of the staying liquefied gas (LNG) monitored by the liquid level sensor FS is maintained within an allowable level. The drive is properly controlled.

  Next, a specific structure of the Stirling engine SE according to the present embodiment will be described with reference to FIGS. The Stirling engine SE according to the present embodiment is a mechanical link type (kinematic type) Stirling engine. A cylinder 10 of the Stirling engine is fixed to a housing 1 of the Stirling engine SE, and a motor generator 2 that functions as an electric motor and a generator is provided. It is fixed. If this motor generator 2 functions as an electric motor, the Stirling engine SE can function as a refrigerator as described above. A displacer piston 20 is accommodated in the cylinder 10 to form a high temperature space HS and a low temperature space LS, and the displacer piston 20 moves in the axial direction of the cylinder 10 while the working fluid in both spaces periodically moves through the regenerator 30. The power piston 40 disposed coaxially with the displacer piston 20 is configured to reciprocate in the axial direction of the cylinder 10. 2 shows a state in which the high temperature space HS has a maximum capacity and the low temperature space LS has a minimum capacity, and FIG. 3 shows a state in which the high temperature space HS has a minimum capacity and the low temperature space LS has a maximum capacity.

  The cylinder 10 is formed by welding a cylinder head 11 and a cylindrical cylinder body 12, and covers the inner wall surface of the cylinder 10 and the outer wall surface of the displacer piston 20 over the entire length of the reciprocating movement locus of the displacer piston 20 in the cylinder 10. The displacer piston 20 is supported so as to be axially movable with respect to the power piston 40 so as to maintain a constant annular gap therebetween. A regenerator 30 is disposed in the annular gap and is supported by the cylinder 10 so as to maintain an annular flow path having a constant gap with respect to the working fluid during the reciprocating movement of the displacer piston 20 in the cylinder 10. ing. The working fluid is a gas, and helium gas is used in this embodiment, but air may be used.

  The regenerator 30 of the present embodiment is composed of a laminated cylinder having a plurality of metal mesh layers. For example, after a single metal mesh is wound a plurality of times, the winding end is spot-welded to form a laminated cylinder. It is formed. Or it replaces with this and it is good also as using the other member which can make the ensuring of heat storage amount and reduction of ventilation resistance compatible. The regenerator 30 may be attached to the displacer piston 20.

  As shown in FIGS. 2 and 3, the piston members of the displacer piston 20 and the power piston 40 slidably supported in the cylinder 10 are connected to a crank mechanism 70 described later in the housing 1. The base end portion is fixed to the housing 1, and the tip end portion (cylinder head 11) of the cylinder 10 is disposed in the vaporization tank VT. In the vaporization tank VT of the present embodiment, a mounting member 4 that is a disc-shaped lid is fixed around a mounting hole 6 h of the top plate 6 by a bolt B 6 via a ring member 5. Further, the mounting member 4 is formed with a mounting hole 4r into which the cylinder 10 is fitted. As described above, the Stirling engine SE is disposed in the vaporization tank VT so that the cylinder head 11 of the heat recovery unit HC is at the lowest position, and is supported by the mounting member 4 in an inverted posture. Even if the part HC is surely immersed in the staying liquefied gas (LNG) and wear powder or oxide scale is generated in the vicinity of the displacer piston 20, it does not reach the power piston 40.

  An annular groove 4g is formed on the inner peripheral surface of the attachment hole 4r of the attachment member 4, and an annular seal member S is fitted in the annular groove 4g. Further, a support cylinder 13 fitted so as to surround the cylinder 10 is provided, and the support cylinder 13 is supported by the mounting member 4 by a stay 3b which is a first support member. The housing 1 is supported by the mounting member 4 by a stay 3a as a second support member. These stays 3a and 3b have a body portion with a U-shaped cross section having high rigidity and bent portions formed at both ends thereof, and are fixed by bolts B1 to B3 to be rigidly connected.

  The support cylinder 13 is provided with a heating medium inflow portion and a heating medium outflow portion (not shown), and is heated in the heating medium flow channel CH in the annular space defined by the annular recess 12 r and the support cylinder 13. A medium (for example, hot water) is introduced from the heating medium inflow part and discharged from the heating medium outflow part, and these constitute a heater, and a high temperature space HS is formed in the cylinder body 12. On the other hand, the cylinder head 11 is provided with a plurality of fins 11f, and the cylinder head 11 is cooled by LNG in the vaporization tank VT through these fins 11f, and a low temperature space LS is formed in the cylinder head 11. It is configured as follows. Thus, the regenerator 30 is held in the cylinder 10 so as to be positioned between the high temperature space HS and the low temperature space LS, and the working fluid in both spaces periodically moves via the regenerator 30. However, the displacer piston 20 can reciprocate in the axial direction of the cylinder 10.

  4, an annular recess 10r is formed on the inner wall surface of the cylinder 10, and the regenerator 30 is fitted into the annular recess 10r. The reciprocating movement locus of the displacer piston 20 in the cylinder 10 is shown. The displacer piston 20 slides relative to the power piston 40 so that a constant gap (clearance d) is maintained in the circumferential direction between the inner wall surface of the regenerator 30 and the outer wall surface of the displacer piston 20 over the entire length. The displacer piston 20 is supported in such a manner that the annular flow path CP with a constant gap (d) is maintained with respect to the working fluid during the reciprocating movement of the displacer piston 20 in the cylinder 10.

  As described above, the displacer piston 20 is supported by the power piston 40 so as to be movable in the axial direction. That is, a rod 50 is fixed to the displacer piston 20, and this rod 50 extends out of the cylinder 10 through the power piston 40 and is supported by the power piston 40 so as to be movable in the axial direction. If surface hardening treatment such as DLC coating (diamond-like carbon) is performed on the support portion of the rod 50 and / or the power piston 40, the displacer piston 40 can be held in a stable state, and the inside of the cylinder 10 During the reciprocating movement of the displacer piston 40, the annular flow path CP having a constant gap with respect to the working fluid can be more reliably maintained. Furthermore, it is preferable to subject the sliding portion between the power piston 40 and the cylinder 10 to a surface hardening treatment by DLC coating or the like.

  Further, one end of a rod 60 is swingably supported by the power piston 40, and a link 72 swingably supported at the tip of the rod 50 with respect to a plate 71 rotatably supported at the other end. The crank mechanism 70 is constituted by these components and is connected to the motor generator 2 via the flywheel 80. The motor generator 2 is constituted by, for example, a well-known permanent magnet synchronous motor and functions as an electric motor and a generator, and a description of the structure thereof is omitted.

  FIG. 5 shows an example of a mounting state of the Stirling engine generator provided with the Stirling engine SE and the motor generator 2 shown in FIG. 2 and an example of a control circuit for using this for power generation control. The heat recovery section HC is a vaporization tank VT. The heat recovery part HC is always cooled because it is mounted so as to extend in and is immersed in the staying liquefied gas (LNG) in the vaporization tank VT. The motor generator 2 is connected to a DC power source 202 by a main circuit 201 via a relay RC1 that intermittently connects the motor generator 2, and three circuits are connected in parallel to the main circuit 201.

  First, the first circuit is a rotation speed substitute circuit, in which a relatively small resistor 203 and a relatively large resistor 204 are connected in series, and the voltage Vs across the relatively large resistor 204 varies in the range of 0 to 10V. Is set as follows. Since this voltage Vs is proportional to the engine speed, it is used as a value representing the rotational speed. Next, the second circuit is a dummy resistor circuit, and includes a dummy resistor 205 having a capacity capable of absorbing the power generation capacity, and a relay RC2 that intermittently connects the circuit leading to the dummy resistor 205. The third circuit is a battery charging circuit, and a charge controller 206 is interposed between the relay RC3 and the battery 207 for intermittently connecting the third circuit. The voltage of 0 to 30V on the power generation side is regulated to about 14V by the charge controller 206, and supplied to the 12V battery 207 for charging. In addition, power is supplied to the cooling fan 208 attached to the outside via the charge controller 206.

  In FIG. 5, as an example of power use of the battery 207, the DC-AC converter 209 converts the voltage from DC 12 V to AC 100 V and uses the external device 210 such as lighting. It is desirable to reduce the power consumption by the dummy resistor 205 by making the power generated by the external device 210 on the power use side and the Stirling engine generator substantially equal. When the battery 207 is in the vicinity of full charge or the like, the load on the generator side becomes light, the engine speed enters an overspeed state, and the voltage Vs becomes equal to or higher than the reference voltage Vh, the charging circuit for the battery 207 Is cut off, the power generation side is connected to the dummy resistor 205, the engine rotation is returned to normal, and the dummy resistor 205 absorbs part of the generated power. On the other hand, when the power of the battery 207 is consumed and charging is started from a state close to empty discharge, initially, the charging current is large, so the load increases and the engine speed tends to decrease. As a result, when the voltage Vs becomes equal to or lower than the reference voltage Vl, the circuit of the dummy resistor 205 on the generator side is cut off, recovery of the engine speed is promoted, and the voltage on the generator side is Is controlled to be 14V to 30V, and the battery 207 is charged. Thus, the battery 207 can be appropriately charged by the Stirling engine generator in a stable state due to the intermittent circuit of the dummy resistor 205.

  FIG. 6 is a flowchart for explaining the operation of the control circuit of FIG. 5. When activated in step S1, the relays RC1 and RC3 are turned off (disconnected state) and the relay RC2 is turned on (conducted state). When the heat recovery unit HC is cooled and it is determined in step S2 that the cooling source temperature (temperature in the vaporization tank VT) Tg is lower than a reference value Tk (for example, minus 150 ° C.), the process proceeds to step S3 and the relay RC1 is performed. Is turned on, the motor generator 2 functions as an electric motor, and the Stirling engine is started. About 2 seconds later, when it is determined in step S4 that the aforementioned rotation speed substitute voltage Vs has exceeded the reference voltage Vl, and the independence as a Stirling engine generator is confirmed, the process proceeds to step S5 and the relay RC3 is turned on. The electric power generated by the motor generator 2 is charged in the battery 207.

  Since the working fluid of the Stirling engine generator is always constant, even if the temperature on the cooling side (the temperature in the vaporization tank VT) fluctuates, the output voltage only fluctuates in the range of 0 to 30V. When fluctuation occurs on the (power generation) load side according to the state of charge of 207, the engine rotation fluctuates greatly because it is input to the Stirling engine SE at a substantially constant value. For example, when the battery 207 is nearly fully charged and the load on the generator side (motor generator 2 side) becomes low, the voltage Vs becomes relatively high. As a result, if it is determined in step S6 that the voltage Vs has become equal to or higher than the reference voltage Vh, the process proceeds to step S7 before the engine overspeeds, and the relay RC3 is turned off (at this time, the relay RC2 is in step S1). On position), the generated electric power is consumed by the dummy resistor 205. Accordingly, when it is determined in step S6 that the voltage Vs has become less than the reference voltage Vh, the relay RC3 is turned back on in step S8, and the process proceeds to step S9. If it is determined in step S6 that the voltage Vs is lower than the reference voltage Vh, the relay RC3 is maintained in the on state and the process proceeds to step S9.

  On the other hand, when the battery 207 is in a fully discharged state, the load on the generator side increases, so the voltage Vs decreases. As a result, if it is determined in step S9 that the voltage Vs has become equal to or lower than the reference voltage Vl, the process proceeds to step S10, the relay RC2 is turned off, and the circuit of the dummy resistor 205 is cut off. As a result, the engine speed is recovered, and when it is determined in step S9 that voltage Vs has exceeded reference voltage Vl, relay RC2 is turned back on in step S11, and all outputs of motor generator 2 are connected to battery 207. Will be used for charging. Thus, an end determination is made in step S12. If not completed, the process returns to step S6, and the processes in steps S6 to S11 are repeated until it is determined to end.

  As described above, when the battery 207 is in the vicinity of full charge, the load on the generator side becomes light, the engine speed enters an overspeed state, and the voltage Vs becomes equal to or higher than the reference voltage Vh. The charging circuit for the battery 207 is shut off, the power generation side is connected to the dummy resistor 205, the engine rotation is returned to normal, and a part of the power generation is absorbed by the dummy resistor 205. On the other hand, when the power of the battery 207 is consumed and charging is started from a state close to empty discharge, initially, the charging current is large, so the load increases and the engine speed tends to decrease. As a result, when the voltage Vs becomes equal to or lower than the reference voltage Vl, the circuit of the dummy resistor 205 on the generator side is cut off, recovery of the engine speed is promoted, and the voltage on the generator side is Is controlled to be 14V to 30V, and the battery 207 is appropriately charged.

  Note that the type, configuration, shape, and the like of each Stirling engine SE and vaporization tank VT are not limited to the above embodiment, and the liquefied gas is not limited to LNG.

SE Stirling engine HC heat recovery section LT liquefied gas tank VT vaporization tank IN inlet pipe EX discharge pipe VA1, VA2 regulating valve FS liquid level sensor CS system controller CE Stirling engine controller 1 housing 2 motor generator 10 cylinder 11 cylinder head 12 cylinder body 15 ring Member 20 Displacer piston 30 Regenerator 40 Power piston 70 Crank mechanism 80 Flywheel HS High temperature space LS Low temperature space

Claims (4)

A liquefied gas tank capable of storing liquefied gas in a liquid phase, a first flow rate adjusting device for adjusting the flow rate of the liquefied gas supplied from the liquefied gas tank, and a downstream side of the first flow rate adjusting device A vaporization tank capable of storing a gas in a gas phase in which the liquefied gas is vaporized and a staying liquefied gas in a liquid phase, a discharge pipe for discharging the gas in a gas phase in the vaporization tank, and the discharge pipe. A second flow rate adjusting device that adjusts the flow rate of the gas in the gas phase discharged through the heat recovery unit, and each heat recovery unit disposed in the vaporization tank and immersed in the retained liquefied gas in the vaporization tank A plurality of Stirling engines, and a liquid level detection means for detecting the liquid level of the staying liquefied gas disposed in the vaporization tank, based on the detection result of the liquid level detection means, The flow rate of the liquefied gas by the first flow rate adjusting device, and the front Liquefied gas vaporization system, characterized by adjusting the flow rate of said vapor-phase gas by the second flow control device.   Each of the plurality of Stirling engines includes a housing that slidably supports a piston member in the cylinder and fixes a base end portion of the cylinder, and a tip end portion of the cylinder is disposed in the vaporization tank, The liquefied gas vaporization system according to claim 1, wherein the housing is supported by a tank. Each of the plurality of Stirling engines includes an attachment member that has an attachment hole for fitting the cylinder, is attached to the vaporization tank, a support cylinder that is fitted so as to surround the cylinder, and the support cylinder is A first support member that is supported by the mounting member, and a second support member that supports the housing by the mounting member, and is supported by the vaporization tank by the second support member and the first support member. The liquefied gas vaporization system according to claim 2 characterized by things. An annular groove formed on the outer peripheral surface of the cylinder, comprises a ring member which fits into the annular groove, claim 3, wherein the sandwiching said ring member between the support cylinder and the housing Liquefied gas vaporization system.

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