JP2015078719A - Device and method for supplying low-temperature liquefied gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable prompt precooling of a liquefied gas supply pump for pressure-feeding low-temperature liquefied gas.SOLUTION: A liquefied gas supply device 10 includes a liquefied gas supply pipeline system 30, an atmospheric release pipeline system 40 and a circulation pipeline system 50 as passing pipeline systems of liquefied nitrogen gas. Prior to supply of the liquefied nitrogen gas under operation control of a liquefied gas supply pump 34 included in the liquefied gas supply pipeline system 30, first control and second control are executed in this order. In the first control, after an auxiliary pump 44 included in the atmospheric release pipeline system 40 is stopped, the pipeline system through which the liquefied nitrogen gas passes is switched to the atmospheric release pipeline system 40. In the second control, after the gas pipeline system is switched to the circulation pipeline system 50, the operation of the auxiliary pump 44 is controlled, so as to precool the liquefied gas supply pump 34 by using the liquefied nitrogen gas pressure-fed by the pump.

Description

  The present invention relates to a low temperature liquefied gas supply apparatus and method.

  A liquefied gas supply pump that pumps the low-temperature liquefied gas is used to supply the low-temperature liquefied gas obtained by liquefying the gas from the storage tank to a liquefied gas supply destination such as a high-pressure gas tank. The liquefied gas supply pump is disposed in a liquefied gas supply line system extending from the storage tank to the liquefied gas supply destination, and is pre-cooled at the time of startup for feeding low-temperature liquefied gas. This pump pre-cooling is regarded as important from the viewpoint of suppressing cavitation in the pump, and the low-temperature liquefied gas in the storage tank is converted into a differential pressure between the storage internal pressure in the storage tank and the pressure in the pipe system including the liquefied gas supply pump. It is done by sending it. Various proposals associated with pump pre-cooling have been made (for example, Patent Document 1).

JP 2008-75705 A JP 2008-196687 A

  According to the above-mentioned patent documents, it is possible to promote the discharge of residual gas and vaporized gas remaining in the pump and the pipe line with the precooling of the pump and to reduce the evaporation loss of the low-temperature liquefied gas. However, there is room for improvement in speeding up the precooling of the liquefied gas supply pump itself that is responsible for the gas pressure supply to the liquefied gas supply destination. In addition, during the period when the liquefied gas supply pump is precooled, the low-temperature liquefied gas supplied to the pipeline for precooling is normally released to the atmosphere. For this reason, if the precooling period of the liquefied gas supply pump is long, the amount of gas released into the atmosphere increases. For these reasons, it has been required to speed up the precooling of the liquefied gas supply pump. In addition, there is a demand for a simple device configuration and device control for speeding up the precooling of the liquefied gas supply pump, and further enabling cost reduction.

  In order to achieve at least a part of the problems described above, the present invention can be implemented as the following forms.

  (1) According to one aspect of the present invention, a low-temperature liquefied gas supply device is provided. The low-temperature liquefied gas supply device is a low-temperature liquefied gas supply device that supplies the low-temperature liquefied gas from a low-temperature liquefied gas storage tank to a liquefied gas supply destination, and is capable of pumping the low-temperature liquefied gas. The liquefied gas supply line system for supplying and sending the low-temperature liquefied gas from the storage tank to the liquefied gas supply destination, and the low-temperature liquefied gas can be pressure-fed and have a smaller heat capacity than the liquefied gas supply pump. Circulation through which the low-temperature liquefied gas circulates from the storage tank through the small heat capacity gas pump and the liquefied gas supply pump through the heat capacity gas pump through the atmospheric discharge line system for discharging the low-temperature liquefied gas from the storage tank to the atmosphere The pipeline system and the gas pipeline system used for supplying the low-temperature liquefied gas are cut into any one of the liquefied gas supply pipeline system, the atmospheric discharge pipeline system, and the circulation pipeline system. El together and a control unit for controlling said small heat capacity gas pump and the liquefied gas supply pump in response to the switching tube line system. The control unit controls to stop the small heat capacity gas pump prior to the supply and delivery to the liquefied gas supply destination via the liquefied gas supply pump, and the gas line system is connected to the atmospheric discharge line system. And a second control for switching the gas pipeline system to the circulation pipeline system and controlling the driving of the small heat capacity gas pump in this order.

  The low-temperature liquefied gas supply device having the above-described form is a small heat capacity in which the low-temperature liquefied gas is stopped from the storage tank by the first control by the differential pressure between the storage internal pressure in the storage tank and the internal pressure of the atmospheric discharge pipe system. Pass through the atmospheric discharge line system through a gas pump. Therefore, the small heat capacity gas pump is precooled in a stopped state by the low-temperature liquefied gas passing through the atmospheric discharge pipeline system. Since the heat capacity of the small heat capacity gas pump is smaller than that of the liquefied gas supply pump, the precooling of the small heat capacity gas pump proceeds more quickly than the precooling of the liquefied gas supply pump. During this first control, the low-temperature liquefied gas is released into the atmosphere from the atmospheric discharge end of the atmospheric discharge pipe system, but since the pre-cooling of the small heat capacity gas pump proceeds rapidly, the amount of low-temperature liquefied gas released into the atmosphere is small. It becomes. The low-temperature liquefied gas supply device having the above-described form is configured to drive and control the small heat capacity gas pump by the second control following the first control, and to pump the low-temperature liquefied gas to the circulation line system by the pump. The liquefied gas supply pump is pre-cooled by the low-temperature liquefied gas passing through. The low-temperature liquefied gas pumping with a small heat capacity gas pump is a circulation pipe with a large flow rate compared to the delivery of low-temperature liquefied gas due to the differential pressure between the storage internal pressure in the storage tank and the pipe internal pressure connected to the storage tank. Enables low temperature liquefied gas delivery in the system. As a result, according to the low temperature liquefied gas supply device of the above-described form, it is possible to speed up the precooling of the liquefied gas supply pump of the liquefied gas supply pipeline system. Moreover, during the second control, the low-temperature liquefied gas only circulates in the circulation line system and is not released into the atmosphere, so the amount of low-temperature liquefied gas released into the atmosphere during the first control is small. In combination with the above, according to the low-temperature liquefied gas supply device of the above-described form, the release of the low-temperature liquefied gas into the atmosphere can be reduced. And according to the low temperature liquefied gas supply device of the above-mentioned form, the precooled liquefied gas supply pump is driven and controlled quickly, and the low temperature liquefied gas is supplied from the storage tank to the liquefied gas supply destination in the liquefied gas supply pipeline system. Supply can be performed quickly.

  (2) In the low-temperature liquefied gas supply device according to the above aspect, both the circulation line system and the liquefied gas supply line system are the atmospheric discharge line from the storage tank to the downstream of the small heat capacity gas pump. You may make it contain the pipe line of a system | strain, and the pipe line branched downstream from the said small heat capacity gas pump to the said liquefied gas supply pump. In this way, the pipe line configuration can be simplified by partially sharing the pipe line path.

  (3) According to another aspect of the present invention, a method for supplying a low-temperature liquefied gas is provided. This low-temperature liquefied gas supply method is a liquefied gas supply that supplies the low-temperature liquefied gas from the storage tank of the low-temperature liquefied gas to the liquefied gas supply destination via a liquefied gas supply pump capable of pumping the low-temperature liquefied gas. An atmospheric discharge line system for releasing the low-temperature liquefied gas from the storage tank through a small heat capacity gas pump capable of pumping the low-temperature liquefied gas and having a smaller heat capacity than the liquefied gas supply pump; The low-temperature liquefied gas is supplied from the storage tank to the liquefied gas supply destination by using a circulation line system in which the low-temperature liquefied gas circulates from the storage tank via the small heat capacity gas pump and the liquefied gas supply pump. A method of supplying a low-temperature liquefied gas, wherein the small heat capacity gas pump is stopped and controlled, and a gas line system used for supplying the low-temperature liquefied gas is used as the atmospheric discharge pipe. A first step of switching to a system; a second step of switching the gas pipeline system to the circulation pipeline system; and driving and controlling the small heat capacity gas pump; and the gas pipeline system to the liquefied gas supply pipeline system And a third step of driving and controlling the liquefied gas supply pump.

  Also by the low temperature liquefied gas supply method of the above form, the liquefaction by the rapid cooling of the small heat capacity gas pump in the first step and the low temperature liquefied gas pumping at a large flow rate by the small heat capacity gas pump in the second step. It is possible to speed up the pre-cooling of the gas supply pump. According to the low-temperature liquefied gas supply method of the above aspect, in the third step, the gas line system is switched to the liquefied gas supply line system, and then the liquefied gas supply pump is driven and controlled. The low-temperature liquefied gas is supplied to the liquefied gas supply destination through the liquefied gas supply pipeline system. Further, since the low temperature liquefied gas is not released into the atmosphere in the second step, the amount of the low temperature liquefied gas released into the atmosphere in the first step is small and coupled with the low temperature liquefied gas supply method of the above form. Gas emission to the atmosphere can be reduced.

  The present invention can be realized in various forms, for example, a gas supply station to a vehicle equipped with a gas consuming device such as a high-pressure gas tank and a fuel cell, and a gas flow path connecting them, a factory, A gas supply vehicle that supplies gas to a high-pressure gas tank attached to a fuel cell installed in a store or a residence can also be used.

It is explanatory drawing which shows schematic structure of the liquefied gas supply apparatus 10 as embodiment of this invention. It is a flowchart which shows the processing content of the precooling and gas supply control performed via valve | bulb control and pump control. It is a flowchart which shows the processing content of the precooling and gas supply control of other embodiment performed via valve | bulb control and pump control.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of a liquefied gas supply apparatus 10 as an embodiment of the present invention.

  As illustrated, the liquefied gas supply device 10 includes a storage tank 20, a liquefied gas supply pipeline system 30, an atmospheric discharge pipeline system 40, a circulation pipeline system 50, and a control device 100. The storage tank 20 is also called a cold evaporator (CE), stores nitrogen gas that has been liquefied in a high-pressure environment (hereinafter referred to as liquefied nitrogen gas), a replenishment conduit 22 that reaches from a replenishment filling valve 21, and a pressure sensor. 23. The replenishment filling valve 21 is configured to have a flow rate adjusting function, and guides liquefied nitrogen gas from a supply line (not shown) to the storage tank 20 through a replenishment line 22 under the control of the control device 100 described later. The pressure sensor 23 detects the pressure of the liquefied nitrogen gas in the storage tank 20 and transmits the detection result to the control device 100. The liquefied nitrogen gas is already at a low temperature during the liquefaction and is stored in the storage tank 20 at a low temperature. The control device 100 described later drives and controls the refill valve 21 based on the pressure detected by the pressure sensor 23, and replenishes the storage tank 20 with liquefied nitrogen gas as needed. Note that liquefied hydrogen, liquefied oxygen, or the like may be employed as another liquefied gas species stored in the storage tank 20.

  The atmospheric discharge pipe system 40 includes an upstream pipe 40u extending from the lower end of the storage tank 20, an intermediate area pipe 40m connected to the upstream pipe 40u, and an atmospheric discharge pipe 40d connected to the intermediate pipe 40m. . In addition, the atmospheric discharge pipeline system 40 includes a first pipeline 41 and a second pipeline 42 branched from the intermediate zone pipeline 40m to the storage tank 20, and both the pipelines and the atmospheric pipeline 40d. Are provided with on-off valves V3 to V5. Further, the atmospheric discharge pipe system 40 includes an opening / closing valve V1 in the upstream pipe line 40u. These on-off valves V1 and on-off valves V3 to V5 open and close the pipelines under the control of the control device 100. The on-off valve V4 has a valve configuration having a flow rate adjusting function.

  The first pipeline 41 extends to the vicinity of the ceiling wall of the storage tank 20, and when the on-off valve V3 is opened, the liquefied nitrogen gas or vaporized gas in the pipeline of the atmospheric discharge pipeline system 40 or the auxiliary pump 44 is The liquefied nitrogen gas stored in the storage tank 20 is guided from above the liquid level. The second pipe 42 guides the residual liquefied nitrogen gas in the pipe line or the pump during pre-cooling and gas supply control, which will be described later, to the storage tank 20 from the bottom through the flow rate adjustment by the opening / closing valve V4. In addition, the atmospheric discharge pipe system 40 includes an auxiliary pump 44 at a connection portion between the upstream pipe 40u and the intermediate area pipe 40m, and includes a temperature sensor 45 and a pressure sensor 46 in the intermediate area pipe 40m.

  The auxiliary pump 44 has a centrifugal pump configuration, and pressurizes the liquefied nitrogen gas and pumps it downstream. In this case, the auxiliary pump 44 is smaller and has a smaller capacity than the liquefied gas supply pump 34 described later, so that its heat capacity is smaller than that of the liquefied gas supply pump 34 and the liquefied gas supply pump 34 It is approximately 1/10 to 1/5 of the heat capacity. Further, the auxiliary pump 44 has a function capable of discharging at a relatively large flow rate although its discharge pressure is a low pressure of 0.8 MPa in a steady operation. The temperature sensor 45 detects the temperature of the liquefied nitrogen gas in the pipeline of the intermediate zone pipeline 40m on the downstream side (outside: secondary side) of the auxiliary pump 44, more specifically, the temperature of the liquefied nitrogen gas, The detection result is transmitted to the control device 100. The pressure sensor 46 detects the pressure of the liquefied nitrogen gas in the pipeline of the intermediate zone pipeline 40m on the downstream side (outside: secondary side) of the auxiliary pump 44, more specifically in the pipeline of the intermediate zone pipeline 40m, The detection result is transmitted to the control device 100. Since the atmospheric discharge pipe system 40 has such a pipe structure, the liquefied nitrogen gas can be pumped and the liquefied nitrogen gas is supplied from the storage tank 20 via the auxiliary pump 44 having a smaller heat capacity than the liquefied gas supply pump 34. Release into the atmosphere.

  The liquefied gas supply pipeline system 30 includes a partial pipeline of the above-described atmospheric discharge pipeline system 40, specifically, an upstream pipeline 40u of the atmospheric discharge pipeline system 40 and an intermediate zone pipeline 40m downstream of the auxiliary pump 44. The branch pipe 30v that branches from the pipe and reaches the primary port (in side) of the liquefied gas supply pump 34, and the downstream supply (out side: secondary side) downstream of the liquefied gas supply pump 34 A pipe line 30d. The downstream supply line 30d is fitted with a high-pressure gas tank T as a liquefied gas supply destination at the end thereof, and is provided with an opening / closing valve 36 in the pipe line. The open / close valve 36 opens and closes the pipeline under the control of the control device 100.

  The liquefied gas supply pump 34 has a plunger drive mechanism pump configuration, and the liquefied nitrogen gas supplied from the primary side is boosted to a filling pressure suitable for the high-pressure gas tank T, for example, 70 MPa, and is supplied to the secondary side. Pump to the downstream supply line 30d. Since the liquefied gas supply pipeline system 30 has such a pipeline configuration, the liquefied nitrogen gas is supplied from the storage tank 20 to the high-pressure gas tank T that is the liquefied gas supply destination via the liquefied gas supply pump 34 that pumps the liquefied nitrogen gas. Supply and send out.

  The circulation pipeline 50 includes a partial pipeline of the atmospheric discharge pipeline 40 described above, specifically, an upstream pipeline 40u of the atmospheric discharge pipeline 40 and an intermediate zone pipeline 40m downstream of the auxiliary pump 44, A branch line 30v that branches off from the pipe and forms a part of the liquefied gas supply line system 30 and an intermediate-circulation circulation line that is connected to the branch line 30v on the primary side in the housing of the liquefied gas supply pump 34 50 m and a downstream circulation line 50 d connected to the intermediate region circulation line 50 m. Since the circulation pipeline system 50 has such a pipeline configuration, the liquefied nitrogen gas is circulated and circulated from the storage tank 20 through the auxiliary pump 44 and the liquefied gas supply pump 34 in this order. In addition, the circulation line system 50 includes a storage tank internal pipe 51 and an atmospheric discharge pipe 52 branched from the intermediate zone circulation pipe 50m to the storage tank 20, and both the pipes and the downstream circulation pipe 50d. In addition, open / close valves V6 to V8 are provided, and an open / close valve V2 and a temperature sensor 55 are provided in the intermediate region circulation pipe 50m. These on-off valves V2 and on-off valves V6 to V8 open and close the pipelines under the control of the control device 100. The temperature sensor 55 detects the temperature of the liquefied nitrogen gas in the circulation line system 50, specifically the liquefied nitrogen gas that has passed through the liquefied gas supply pump 34, and enters the intermediate circulation line 50m. It transmits to the control apparatus 100.

  The storage tank pipe 51 extends to the vicinity of the ceiling wall of the storage tank 20, and from above the liquid level of the liquefied nitrogen gas stored in the storage tank 20, in the pipe or pump in the precooling / gas supply control described later. Liquefied nitrogen gas or vaporized gas is circulated to the storage tank 20. Circulation of liquefied nitrogen gas or vaporized gas from the storage tank internal pipe 51 is performed when the on-off valve V6 is opened. The atmospheric discharge pipe 52 releases liquefied nitrogen gas or vaporized gas in the pipe of the circulation pipe system 50 to the atmosphere when the opening / closing valve V8 that is controlled to open in an emergency or the like is opened. It is closed by a valve V8.

  The control device 100 is configured as a computer having a CPU that performs logical operations, a ROM, and a RAM, and opens and closes the open / close valves V1 to V8 described above while receiving inputs from various sensors such as the temperature sensor 45 described above. Control. By such valve control, the control device 100 switches the gas pipeline system through which the liquefied nitrogen gas passes to any one of the liquefied gas supply pipeline system 30, the atmospheric discharge pipeline system 40, and the circulation pipeline system 50. Further, the control device 100 drives and controls the auxiliary pump 44 and the liquefied gas supply pump 34 in accordance with the switching of the pipeline system.

  Next, the precooling / gas supply control of the liquefied gas supply pump 34 executed by the control device 100 will be described. Table 1 shows the state of valve control and pump control with respect to the processing status executed by the control device 100 in the precooling / gas supply control. FIG. 2 is a flowchart showing processing contents of pre-cooling / gas supply control executed through valve control and pump control.

  Since the pre-cooling / gas supply control shown in FIG. 2 is executed through the operation of a supply start switch (not shown), the situation before the operation of the supply start switch, for example, the periodical operation of the control device 100 at night, holidays, etc. In the stop period, the valve pump is in the initial state of Table 1. In this initial state, as shown in the table, the other open / close valves other than the open / close valve V5 and the open / close valve V8 and the open / close valve 36 not shown in the table (see FIG. 1) are in the pipeline closed state. The auxiliary pump 44 shown and the liquefied gas supply pump 34 (see FIG. 1) not shown are both stopped (stop control). Now, when the supply start switch is operated, the control device 100 sets the open / close valve V1 of the atmospheric discharge pipe line system 40 as a supply valve from the storage tank 20 (CE) in order to pre-cool the auxiliary pump 44 of Table 1. The valve opening control (step S100), the valve closing control of the opening / closing valve V2 of the circulation pipeline 50, and the valve opening control of the opening / closing valve V5 of the atmospheric discharge pipeline 40 (step S110) are executed. Such valve control is performed under the stop control of the auxiliary pump 44. By this valve control, the pipeline system through which the liquefied nitrogen gas passes from the storage tank 20 is divided into an upstream pipeline 40u, an intermediate zone pipeline 40m, and an atmospheric discharge pipeline. Switch to 40d atmospheric discharge line system 40. For this reason, the liquefied nitrogen gas passes through the atmospheric discharge pipe system 40 from the storage tank 20 through the auxiliary pump 44 in a stopped state due to the differential pressure between the storage internal pressure of the storage tank 20 and the internal pipe pressure of the atmospheric discharge pipe system 40. To do. In addition, since the opening / closing valve V2 is already in the pipeline closed state in the initial state, the closing signal may not be output to the valve.

  The liquefied nitrogen gas passing through the atmospheric discharge pipeline system 40 cools the pipeline and the stopped auxiliary pump 44 in the pipeline passage process and the passage process of the auxiliary pump 44, and is vaporized according to the degree of cooling. Therefore, the liquefied nitrogen gas passing through the atmospheric discharge pipe system 40 is released into the atmosphere from the atmospheric discharge end of the atmospheric discharge pipe 40d in the state of the gas-liquid mixed fluid at the beginning of the pre-cooling of the auxiliary pump 44. In this case, since the liquefied nitrogen gas does not vaporize as the passage of the liquefied nitrogen gas in the atmospheric discharge pipe system 40 progresses and the cooling proceeds, the liquefied nitrogen gas is released into the atmosphere with the liquid phase increased. The The liquefied nitrogen gas in the state of the gas-liquid mixed fluid is stored during the pre-cooling of the auxiliary pump 44 by closing the open / close valve V2 and the open / close valve V4 in the intermediate zone conduit 40m and the open / close valve V3 and the open / close valve V4 in the intermediate zone conduit 40m. There is no return to 20. Further, during the pre-cooling of the auxiliary pump 44, a gas phase is connected to the pipe of the branch pipe 30v, the liquefied gas supply pump 34, and the pipe of the intermediate region circulation pipe 50m from the pump to the opening / closing valve V2. Of liquefied nitrogen gas remains.

  Following step S110, the control device 100 reads the detected temperature T1 of the temperature sensor 45 downstream of the auxiliary pump 44 in order to determine the completion of the preliminary cooling of the auxiliary pump 44 in Table 1, and this detected temperature T1 is predetermined. It is confirmed that the temperature lower than the contrast temperature (−155 ° C.) has continued for a predetermined time, for example, 20 seconds (step S120). Here, if the detected temperature T1 is equal to or higher than the contrast temperature or the duration of the detected temperature T1 lower than the contrast temperature is not enough for the predetermined time, the processing of steps S100 to S110 is performed, and the detected temperature T1 sets the contrast temperature to the predetermined time. Repeat until it continues to drop. The contrast temperature (−155 ° C.) is defined in advance as a temperature at which the pre-cooling of the pump is completed in consideration of the size of the auxiliary pump 44, the pump configuration, and the heat capacity, and is stored in a predetermined storage area of the control device 100. It is remembered.

  Following step S120, the control device 100 controls the opening and closing of the on-off valve V2 and the on-off valve V6 of the circulation line system 50 and the atmospheric discharge pipe in order to start the auxiliary pump 44 in Table 1 and stabilize its driving. The valve opening control of the opening / closing valve V3 of the system 40, the valve closing control of the opening / closing valve V5 of the atmospheric discharge pipe system 40, and the drive control of the auxiliary pump 44 are executed (S1: Step S130). By driving the valve / pump, the liquefied nitrogen gas is not released into the atmosphere through the atmospheric discharge line 40d, and the line system through which the liquefied nitrogen gas passes is switched from the atmospheric discharge line system 40 to the circulation line system 50. Change. In the opening control of the opening / closing valve V3 and the opening / closing valve V6 in step S130, the state where the detected temperature T1 is lower than the contrast temperature (−155 ° C.) in step S120 is continued for a predetermined time (20 seconds). At the same time.

  The auxiliary pump 44 that has received the drive control in step S130 pumps the liquefied nitrogen gas through the circulation line system 50 and the liquefied gas supply pump 34 included therein, and passes through the storage tank inner line 51 to store the storage tank 20. Circulate from the top of the liquid surface. In this way, the liquefied nitrogen gas circulating through the circulation pipeline 50 is newly passed through the branch pipeline 30v and the passage of each pipeline of the circulation pipeline 50 and the passage of the liquefied gas supply pump 34. The pipeline and the liquefied gas supply pump 34 are cooled and vaporized according to the degree of cooling. Therefore, the liquefied nitrogen gas that passes through the circulation line system 50 is circulated from the upper part of the liquid level to the storage tank 20 through the internal pipe 51 in the state of gas-liquid mixed fluid at the beginning of the precooling of the liquefied gas supply pump 34. Is done. In this case, before the start of precooling of the liquefied gas supply pump 34, as described above, the branch line 30v, the liquefied gas supply pump 34, and the intermediate region circulation pipe from the pump to the open / close valve V2 are provided. The gas phase liquefied nitrogen gas remains in the pipe line of the path 50 m. Therefore, the residual liquefied nitrogen gas is circulated from the upper part of the liquid level to the storage tank 20 via the storage tank inner conduit 51 together with the liquefied nitrogen gas in the state of the gas-liquid mixed fluid fed by the auxiliary pump 44. As the above-described circulation of the liquefied nitrogen gas in the circulation line system 50 progresses and the cooling progresses, the liquefied nitrogen gas does not evaporate. It circulates from the bottom to the storage tank 20 via the path 50d. The liquefied nitrogen gas is circulated from the upper part to the storage tank 20 through the first pipe 41 by opening the opening / closing valve V3 of the atmospheric discharge pipe system 40.

  Following step S130, the control device 100 detects the detected pressure P2 of the pressure sensor 46 on the secondary side of the auxiliary pump 44 and the detection of the pressure sensor 23 of the storage tank 20 in order to confirm an increase in the discharge pressure of the activated auxiliary pump 44. The state in which the differential pressure with respect to the pressure P1 exceeds a predetermined contrast differential pressure (0.13 MPa) has continued for a predetermined time, for example, 60 seconds, or the pressure sensor on the secondary side of the auxiliary pump 44 It is confirmed that the state where the detected pressure P2 of 46 exceeds a predetermined specified pressure (0.59 MPa) is continued for a predetermined time (60 seconds) (S2: step S140). Here, if the differential pressure between the detected pressure P2 and the detected pressure P1 is equal to or lower than the relative differential pressure, or the duration of the differential pressure exceeding the relative differential pressure is not sufficient for a predetermined time, or the detected pressure P2 is the specified pressure. If the duration of the detected pressure P2 exceeding the specified pressure is not enough for a predetermined time, the driving of the auxiliary pump 44 is continued. The differential pressure difference (0.13 MPa) and the specified pressure (0.59 MPa) are discharges necessary for the auxiliary pump 44 in order to precool the pump in consideration of the physique of the liquefied gas supply pump 34, the pump configuration and the heat capacity. The pressure is defined in advance so as to be obtained, and is stored in a predetermined storage area of the control device 100.

  Following step S140, the control device 100 starts the cooling of the liquefied gas supply pump 34 at a stable discharge pressure of the auxiliary pump 44, and the opening / closing valve V3 of the intermediate line 40m and the opening / closing valve of the circulation line 50. The valve closing control of V6 and the valve opening control of the opening / closing valve V4 of the intermediate zone conduit 40m and V7 of the downstream circulation conduit 50d are executed (step S150). At this time, as shown in Table 1, the control device 100 controls the opening degree of both the valves so that the opening degree of the opening / closing valve V7 is about 10 times the opening degree of the opening / closing valve V4. The circulation flow rate of the liquefied nitrogen gas that circulates through the circulation line system 50 is greater than the flow rate that circulates from the atmospheric discharge line system 40 to the storage tank 20 via the open / close valve V4. In addition, the flow rate of the liquefied nitrogen gas that has flowed to the downstream of the intermediate pipe 40m is adjusted by the opening of the on-off valve V4, and collected in the storage tank 20 from the bottom. By such valve control, the gas flow rate passing through the circulation line system 50 and the branch line 30v included in the liquefied nitrogen gas discharged from the auxiliary pump 44 increases. As a result, cooling of the liquefied gas supply pump 34 and the conduits of the circulation conduit system 50 proceeds, and liquid phase conversion of the liquefied nitrogen gas that circulates through the circulation conduit system 50 and the branch conduit 30v included therein also proceeds.

  Following step S150, the control device 100 reads the detected temperature T2 of the temperature sensor 55 downstream of the liquefied gas supply pump 34 in order to confirm the completion of cooling of the liquefied gas supply pump 34 in Table 1, and the detected temperature T2 is Then, it is confirmed that the state where the temperature is lower than the predetermined contrast temperature (−168 ° C.) is continued for a predetermined time, for example, 30 seconds (step S160). Here, if the detected temperature T2 is equal to or higher than the contrast temperature or the duration of the detected temperature T2 lower than the contrast temperature is not enough for a predetermined time, the liquefied gas supply pump 34 using the pressure-feed liquefied nitrogen gas of the auxiliary pump 44 in step S130. This cooling is repeated until the detected temperature T2 continues to decrease the contrast temperature over a predetermined time. The contrast temperature (−168 ° C.) is defined in advance as a temperature at which precooling of the pump is completed in consideration of the physique of the liquefied gas supply pump 34, the pump configuration, and the heat capacity, and is stored in a predetermined storage area of the control device 100. It is remembered.

  Following the completion of the pre-cooling in step S160, the control device 100 starts the supply of the liquefied nitrogen gas to the high-pressure gas tank T by the liquefied gas supply pump 34 in Table 1 and the open / close valve V4 and the circulation of the atmospheric discharge pipe system 40. The valve closing control of the opening / closing valve V2 and the opening / closing valve V7 of the pipe line system 50, the valve opening control of the opening / closing valve 36 (see FIG. 1) of the liquefied gas supply pipe line system 30, and the drive control of the liquefied gas supply pump 34 are performed. Execute (Step S170). By such valve control, the pipeline system through which the liquefied nitrogen gas passes from the storage tank 20 is switched to the liquefied gas supply pipeline system 30 including the aforementioned pipelines of the auxiliary pump 44 and the atmospheric discharge pipeline system 40. Filling the high-pressure gas tank T with liquefied nitrogen gas is started at a pressure of the pumping capacity (70 MPa) of the supply pump 34. The gas supply in step S180 is continued until the filling of the number of high-pressure gas tanks T required to be filled is completed. When the gas supply to the high-pressure gas tank T is completed, the control device 100 ends the precooling / gas supply control shown in FIG. 2 and returns to the initial state shown in Table 1. Note that the opening / closing valve V2 and the opening / closing valve V7 have their valve closing timings adjusted to avoid liquid sealing of the pipe line between the valves.

  In the initial state after the pre-cooling / gas supply control shown in FIG. 2 is finished, liquefied nitrogen gas remains in the pipes and pumps of each pipeline system, so that the liquefied gas supply pump 34 and the auxiliary pump 44 have the remaining liquefaction. It is assumed that it is cooled by nitrogen gas. Therefore, after the completion of the gas supply in step S170, the control device 100 executes temperature / pressure monitoring similar to that in steps S120, S140, and S160 separately from the precooling / gas supply control in FIG. Accordingly, the control at the time of the next operation of the supply start switch is determined. For example, when the temperature / pressure monitoring result described above indicates that the liquefied gas supply pump 34 and the auxiliary pump 44 are still in the cooling state at the next operation of the supply start switch, the control device 100 performs the step Processing corresponding to S170, that is, valve control for switching the liquefied nitrogen gas passage line system to the liquefied gas supply line system 30, drive control of the auxiliary pump 44, and drive control of the liquefied gas supply pump 34 are executed. To do. By doing so, gas supply can be started promptly. On the other hand, if the above-described temperature / pressure monitoring result indicates that the liquefied gas supply pump 34 and the auxiliary pump 44 are not in a cooling state at the next operation of the supply start switch, the control device 100 The pre-cooling / gas supply control 2 is executed to supply the gas.

  When the liquefied gas supply device 10 of the present embodiment having the above-described configuration supplies the liquefied nitrogen gas stored in the storage tank 20 to the high-pressure gas tank T, first, each control shown in FIG. The associated open / close valves among the open / close valves V1 to V8 of the pipeline are controlled to open and close, and the pipeline system through which the liquefied nitrogen gas passes through the storage tank 20 is switched to the atmospheric discharge pipeline system 40 (steps S100 to S110). By such switching of the pipeline system, the liquefied nitrogen gas in the storage tank 20 is discharged from the storage tank 20 via the auxiliary pump 44 in a stopped state due to the differential pressure between the storage internal pressure of the storage tank 20 and the atmospheric discharge pipeline system 40. Pass through 40 and release into the atmosphere. Thereby, the auxiliary pump 44 is pre-cooled while being stopped by the liquefied nitrogen gas passing through the atmospheric discharge pipe system 40. The heat capacity of the auxiliary pump 44 is smaller than the liquefied gas supply pump 34 for high-pressure gas filling due to its pump structure and size, and is only 1/10 to 1/5 of the heat capacity of the liquefied gas supply pump 34. Therefore, if compared with the precooling of the liquefied gas supply pump 34 by liquefied nitrogen gas, the precooling of the auxiliary pump 44 proceeds rapidly. While the auxiliary pump 44 is pre-cooled in this way, the liquefied nitrogen gas is released into the atmosphere from the atmospheric discharge end of the atmospheric discharge line 40d in the atmospheric discharge line system 40. However, since the pre-cooling of the auxiliary pump 44 by liquefied nitrogen gas has a small heat capacity as described above, it proceeds quickly, so the amount of liquefied nitrogen gas released to the atmosphere is small.

  The liquefied gas supply apparatus 10 of the present embodiment is configured so that the liquefied nitrogen gas passes through the pipe system through which the liquefied nitrogen gas passes after the auxiliary pump 44 is precooled, and the related open / close valves in the open / close valves V1 to V8 of the pipes shown in FIG. Is switched to the circulation line system 50, and the precooled auxiliary pump 44 is driven and controlled (step S130). The liquefied nitrogen gas pumped by the auxiliary pump 44 passes through the liquefied gas supply pump 34 included in the circulation line system 50 and circulates to the storage tank 20 by the above-described line system switching. As a result, the liquefied gas supply pump 34 is pre-cooled while being stopped by the liquefied nitrogen gas circulating in the circulation line system 50. The pumping of the liquefied nitrogen gas by the auxiliary pump 44 is performed at a larger flow rate to the circulation line system 50 than the sending of the liquefied nitrogen gas by the differential pressure between the storage internal pressure of the storage tank 20 and the pipe line system connected to the storage tank 20. Enables delivery of liquefied nitrogen gas. As a result, according to the liquefied gas supply apparatus 10 of the present embodiment, the liquefied gas supply pump 34 included in the liquefied gas supply pipeline system 30 can be pre-cooled quickly and reliably. In addition, the liquefied gas supply apparatus 10 of the present embodiment causes the liquefied nitrogen gas to circulate and circulate in the storage tank 20 through the circulation line system 50 during the precooling of the liquefied gas supply pump 34, thereby causing the liquefied nitrogen gas to be released into the atmosphere. Absent. Therefore, according to the liquefied gas supply apparatus 10 of this embodiment, coupled with the small amount of liquefied nitrogen gas released during the pre-cooling of the auxiliary pump 44, the liquefied nitrogen gas released into the atmosphere can be reduced.

  The liquefied gas supply apparatus 10 of the present embodiment circulates liquefied nitrogen gas through the circulation pipe system 50 and precools the liquefied gas supply pump 34, and then the pipe systems through which the liquefied nitrogen gas passes are shown in FIG. The associated open / close valves V1 to V8 are controlled to be switched to the liquefied gas supply line system 30, and the precooled liquefied gas supply pump 34 is driven and controlled (step S170). Since the liquefied gas supply pump 34 is precooled quickly by the liquefied nitrogen gas pumped by the auxiliary pump 44 at a large flow rate, according to the liquefied gas supply device 10 of the present embodiment, the liquefied nitrogen gas is supplied from the storage tank 20 to the high-pressure gas tank. T can be supplied promptly.

  The liquefied gas supply apparatus 10 of the present embodiment is configured such that the liquefied gas supply pipe system 30 and the circulatory pipe system 50 are connected to the liquefied gas supply pump 34 included in both the pipe systems. It was. Therefore, according to the liquefied gas supply device 10 of the present embodiment, the pipeline configuration can be simplified by partially sharing the pipeline route.

  In preliminarily cooling the auxiliary pump 44, the liquefied gas supply device 10 of the present embodiment is provided in the atmospheric discharge pipe system 40 until the detection temperature T1 of the temperature sensor 45 downstream of the auxiliary pump 44 falls below the contrast temperature (−155 ° C.). Cooling with liquefied nitrogen gas is continued (step S120). Therefore, according to the liquefied gas supply apparatus 10 of the present embodiment, the auxiliary pump 44 can be driven for precooling the liquefied gas supply pump 34 after the auxiliary pump 44 is reliably precooled.

  When the liquefied gas supply device 10 of this embodiment precools the liquefied gas supply pump 34, the detected temperature T2 of the temperature sensor 55 downstream of the liquefied gas supply pump 34 is compared with the detected temperature T1 of the temperature sensor 45 as a contrast temperature ( The cooling with the liquefied nitrogen gas in the circulation pipeline 50 is continued until the temperature falls below the contrast temperature (-168 ° C.) lower than −155 ° C. (step S160). In addition, the liquefied gas supply apparatus 10 of the present embodiment controls the opening / closing valve V7 of the circulation line system 50 with an opening larger than the opening / closing valve V4 (step S150), The flow rate of the liquefied nitrogen gas flowing through the area circulation pipe 50m is increased, and the amount of liquefied nitrogen gas circulating through the liquefied gas supply pump 34 is increased. In addition to this, the liquefied gas supply apparatus 10 of the present embodiment is configured such that the differential pressure between the detected pressure P2 of the pressure sensor 46 on the secondary side of the auxiliary pump 44 and the detected pressure P1 of the pressure sensor 23 of the storage tank 20 is a contrast differential pressure ( Until the state exceeding 0.13 MPa) continues for a predetermined time, the circulation amount of liquefied nitrogen gas through the opening control of the opening / closing valve V6 and the closing control of the opening / closing valve V5 is continued. Therefore, according to the liquefied gas supply apparatus 10 of the present embodiment, the liquefied gas supply pump 34 can be driven for gas supply to the high-pressure gas tank T after the liquefied gas supply pump 34 is reliably precooled. In addition, due to the circulatory flow of the liquefied nitrogen gas that has passed through the storage tank pipe line 51 based on the continuation of the valve opening control of the on-off valve V6, the gas phase of the liquefied nitrogen gas circulating in the circulation pipe system 50 is reduced, The ratio increases, which is preferable for promoting the precooling of the liquefied gas supply pump 34.

  The liquefied gas supply apparatus 10 of the present embodiment opens the on-off valve V6 to increase the circulation amount of the liquefied nitrogen gas when the liquefied gas supply pump 34 is precooled, and the liquefied nitrogen gas in the circulation line system 50 is opened. Is recirculated to the storage tank 20 from above the liquid level. Since the liquefied nitrogen gas circulating in this way comes into contact with the gas phase gas region above the liquid level of the liquefied nitrogen gas in the storage tank 20, according to the liquefied gas supply device 10 of the present embodiment, the gas phase gas in the storage tank 20. The gas in the area can be cooled.

  Next, the precooling / gas supply control of the liquefied gas supply pump 34 in another embodiment will be described. Table 2 shows the state of valve control and pump control in another embodiment with respect to the processing status executed by the control device 100 in the precooling / gas supply control. FIG. 3 is a flowchart showing the processing contents of precooling / gas supply control of another embodiment executed through valve control and pump control. In the following description, differences from the above-described embodiment will be described.

  Even in the pre-cooling / gas supply control of this embodiment, as described above, the control is executed through the operation of a supply start switch (not shown), and from the initial state of Table 2, the stop control is performed according to steps S100 to S120 described above. The preliminary implementation of the pre-cooling of the auxiliary pump 44 and the pre-cooling confirmation of the auxiliary pump 44 are performed. In step S130 following step S120, the above-described valve control and drive control of the auxiliary pump 44 are executed, the stop of the liquefied nitrogen gas release to the atmosphere, the switching of the liquefied nitrogen gas pipeline system, and the auxiliary pump 44 The liquefied nitrogen gas is discharged and the liquefied gas supply pump 34 is precooled.

  Following step S130, the control device 100 reads the detected temperature T2 of the temperature sensor 55 downstream of the liquefied gas supply pump 34 in order to confirm the cooling of the liquefied gas supply pump 34 in Table 2, and the detected temperature T2 is Then, it is confirmed that the temperature is lower than the above-described contrast temperature (−168 ° C.) (step S210). Here, if the detected temperature T2 is equal to or higher than the contrast temperature, the cooling of the liquefied gas supply pump 34 by the pressure-feed liquefied nitrogen gas of the auxiliary pump 44 in step S130 is continued until the detected temperature T2 falls below the contrast temperature. In step S210, the process may wait until the state where the detected temperature T2 is lower than the contrast temperature continues for a predetermined time (for example, 5 seconds).

  Following step S210, the control device 100 performs control for closing the open / close valve V3 of the intermediate line 40m and the open / close valve V6 of the circulation line system 50 in order to ensure an increase in the discharge pressure of the auxiliary pump 44 in Table 2. Then, the opening / closing valve V4 of the intermediate zone pipe line 40m and the valve opening control of V7 of the downstream circulation pipe line 50d are executed (step S220). At this time, as shown in Table 2, the control device 100 controls the opening of both the opening and closing valve V7 so that the opening of the opening and closing valve V7 is about 10 times the opening of the opening and closing valve V4. The circulation flow rate of the liquefied nitrogen gas that circulates through the circulation line system 50 is greater than the flow rate that circulates from the atmospheric discharge line system 40 to the storage tank 20 via the open / close valve V4. By such valve control, switching of the pipeline system through which the liquefied nitrogen gas passes is substantially equivalent to switching to the circulation pipeline system 50. In addition, the liquefied nitrogen gas that has flowed to the downstream of the intermediate pipe 40m is recovered in the storage tank 20 by opening the on-off valve V4. The on-off valve V4 may be closed and switched to the circulation line system 50. As a result, cooling of the liquefied gas supply pump 34 and the conduits of the circulation conduit system 50 proceeds, and liquid phase conversion of the liquefied nitrogen gas that circulates through the circulation conduit system 50 and the branch conduit 30v included therein also proceeds. Since the increase in the discharge pressure of the auxiliary pump 44 is slow before the liquid phase of the liquefied nitrogen gas circulating through the circulation line system 50 has progressed, the amount of circulation can be increased by controlling the opening of the opening / closing valve V7. The accompanying increase in the discharge pressure of the auxiliary pump 44 can be ensured by the liquid phase of the liquefied nitrogen gas.

  Following step S220, the control device 100 detects the pressure P2 detected by the pressure sensor 46 on the secondary side of the auxiliary pump 44 and the storage tank so as to ensure the liquid phase state of the liquefied nitrogen gas on the secondary side of the auxiliary pump 44 in Table 2. After confirming that the differential pressure with respect to the detected pressure P1 of the 20 pressure sensors 23 exceeds a predetermined differential pressure (0.13 MPa), the on-off valve V6 is controlled to close (step S230). Here, if the differential pressure is equal to or lower than the contrast differential pressure, the control for closing the on-off valve V6 is waited until the differential pressure exceeds the contrast differential pressure. The contrast differential pressure (0.13 MPa) indicates that almost all of the liquefied nitrogen gas pumped by the auxiliary pump 44 is in a liquid phase state in consideration of the pumping capacity of the liquefied gas supply pump 34 and the stored internal pressure in the storage tank 20. It is preliminarily defined in the viewpoint and is stored in a predetermined storage area of the control device 100. In this case, if the differential pressure between the detected pressure P2 of the pressure sensor 46 and the detected pressure P1 of the pressure sensor 23 exceeds the contrast differential pressure (0.13 MPa), the liquefied nitrogen gas fed by the auxiliary pump 44 is used in step S230. In combination with the confirmation of the pressure increase, the circulation line system 50 is circulated in a substantially liquid phase state.

  Following step S230, the control device 100 determines that the differential pressure between the detected pressure P2 of the pressure sensor 46 and the detected pressure P1 of the pressure sensor 23 is a contrast differential pressure ( It waits until the state exceeding 0.13 MPa continues for a predetermined time (for example, 10 sec) (step S240). Here, when the state where the differential pressure exceeds the contrast differential pressure continues for a predetermined time, the control device 100 assumes that the precooling of the liquefied gas supply pump 34 is completed.

  Following the completion of pre-cooling in step S240, the control device 100 performs various opening / closing operations in the same manner as in step S170 described above in order to start supply of liquefied nitrogen gas to the high-pressure gas tank T by the liquefied gas supply pump 34 in Table 2. Valve control and drive control of the liquefied gas supply pump 34 are executed (step S250). By such valve control, the pipeline system through which the liquefied nitrogen gas passes from the storage tank 20 is switched to the liquefied gas supply pipeline system 30 including the aforementioned pipelines of the auxiliary pump 44 and the atmospheric discharge pipeline system 40. Filling the high-pressure gas tank T with liquefied nitrogen gas is started at a pressure of the pumping capacity (70 MPa) of the supply pump 34. The gas supply in step S180 is continued until the filling of the number of high-pressure gas tanks T required to be filled is completed. When the gas supply to the high-pressure gas tank T is completed, the control device 100 ends the precooling / gas supply control shown in FIG. 2 and returns to the initial state shown in Table 1.

  The effects described above can also be achieved by the pre-cooling / gas supply control of the above-described embodiment.

  The present invention is not limited to the above-described embodiment, and can be realized with various configurations without departing from the spirit of the present invention. For example, the technical features of the embodiments corresponding to the technical features in each embodiment described in the summary section of the invention are intended to solve part or all of the above-described problems, or part of the above-described effects. Or, in order to achieve the whole, it is possible to replace or combine as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

  In the above-described embodiment, when the precooling of the liquefied gas supply pump 34 by the liquefied nitrogen gas pumped by the auxiliary pump 44 is completed, the open / close valve V4 in the second pipeline 42 of the atmospheric discharge pipeline 40 and the circulation pipeline 50 Although the opening / closing valve V2 and the opening / closing valve V7 in the intermediate region circulation pipe 50m are controlled to be closed, the present invention is not limited to this. For example, between the completion of the precooling of the liquefied gas supply pump 34 and the subsequent gas supply, the opening / closing valve V4 in the second pipe 42 and the opening / closing valve V7 in the intermediate-circulation circulation pipe 50m are connected to the opening and opening of both valves. The valve opening control may be performed after reducing the opening degree difference. In this way, if the amount of liquefied nitrogen gas required by the liquefied gas supply pump 34 is temporarily reduced due to pulsation or the like in the pressure supply for gas supply by the liquefied gas supply pump 34, the liquefied gas from the auxiliary pump 44 is temporarily reduced. A part of the liquefied nitrogen gas fed to the supply pump 34 is circulated to the storage tank 20 from the second pipe 42 or the downstream circulation pipe 50d so that the liquefied nitrogen gas is not excessively fed to the liquefied gas supply pump 34. Can be. Therefore, the load applied to the liquefied gas supply pump 34 can be reduced.

  In the above-described embodiment, the liquefied nitrogen gas stored in the storage tank 20 is filled into the high-pressure gas tank T, but liquefied hydrogen gas may be used instead of the liquefied nitrogen gas. In this way, for example, a vehicle equipped with a fuel cell and a hydrogen gas tank that generate power by receiving supply of hydrogen gas and oxidizing gas as fuel gas can be used for filling hydrogen gas into the mounted hydrogen gas tank. it can.

DESCRIPTION OF SYMBOLS 10 ... Liquefied gas supply apparatus 20 ... Storage tank 21 ... Replenishment filling valve 22 ... Replenishment pipeline 23 ... Pressure sensor 30 ... Liquefied gas supply pipeline system 30d ... Downstream supply pipeline 30v ... Branch pipeline 34 ... Liquefied gas supply pump 36 ... Opening / closing valve 40 ... Atmospheric discharge pipeline system 40d ... Atmospheric discharge pipeline 40m ... Intermediate zone pipeline 40u ... Upstream pipeline 41 ... First pipeline 42 ... Second pipeline 44 ... Auxiliary pump 45 ... Temperature sensor 46 ... Pressure sensor DESCRIPTION OF SYMBOLS 50 ... Circulation pipeline system 50d ... Downstream circulation pipeline 50m ... Intermediate area circulation pipeline 51 ... Storage tank pipeline 52 ... Atmospheric discharge pipeline 55 ... Temperature sensor 100 ... Control device T ... High pressure gas tank V1-V8 ... Open / close valve

Claims (3)

A low temperature liquefied gas supply device for supplying the low temperature liquefied gas from a low temperature liquefied gas storage tank to a liquefied gas supply destination,
Via a liquefied gas supply pump capable of pumping the low-temperature liquefied gas, a liquefied gas supply line system for supplying and sending the low-temperature liquefied gas from the storage tank to the liquefied gas supply destination;
An atmospheric discharge line system for releasing the low-temperature liquefied gas from the storage tank through a small heat capacity gas pump capable of pumping the low-temperature liquefied gas and having a smaller heat capacity than the liquefied gas supply pump;
A circulation line system through which the low-temperature liquefied gas circulates from the storage tank via the small heat capacity gas pump and the liquefied gas supply pump;
The gas pipeline system used for supplying the low-temperature liquefied gas is switched to any one of the liquefied gas supply pipeline system, the atmospheric discharge pipeline system, and the circulation pipeline system, and in accordance with the switched pipeline system. A control unit for controlling the liquefied gas supply pump and the small heat capacity gas pump,
The control unit stops and controls the small heat capacity gas pump and switches the gas pipeline system to the atmospheric discharge pipeline system prior to the supply and delivery to the liquefied gas supply destination via the liquefied gas supply pump. The first control and the second control for switching the gas pipeline system to the circulation pipeline system and drivingly controlling the small heat capacity gas pump are sequentially executed in this order.
Low temperature liquefied gas supply device.   Both the circulation pipeline system and the liquefied gas supply pipeline system include a pipeline of the atmospheric discharge pipeline system from the storage tank to the downstream of the small heat capacity gas pump, and the small heat capacity gas pump from the pipeline. The low-temperature liquefied gas supply device according to claim 1, further comprising a pipe branching downstream from the pipe and reaching the liquefied gas supply pump. A liquefied gas supply line system for supplying the low temperature liquefied gas from the storage tank of the low temperature liquefied gas to the liquefied gas supply destination via a liquefied gas supply pump capable of pumping the low temperature liquefied gas, and the low temperature liquefied gas Through the small heat capacity gas pump having a smaller heat capacity than the liquefied gas supply pump, the atmospheric discharge pipe system for discharging the low-temperature liquefied gas from the storage tank to the atmosphere, the small heat capacity gas pump from the storage tank, and the A low-temperature liquefied gas supply method for supplying the low-temperature liquefied gas from the storage tank to the liquefied gas supply destination using a circulation line system in which the low-temperature liquefied gas circulates via a liquefied gas supply pump. ,
A first step of controlling the stop of the small heat capacity gas pump and switching a gas pipe line system used for supplying the low-temperature liquefied gas to the atmospheric discharge pipe line;
A second step of switching the gas pipeline system to the circulation pipeline system and drivingly controlling the small heat capacity gas pump;
Switching the gas line system to the liquefied gas supply line system, and a third step of driving and controlling the liquefied gas supply pump,
Low temperature liquefied gas supply method.

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