JP7011516B2 - Liquefied natural gas vaporization system - Google Patents

Description

The present invention relates to a liquefied natural gas vaporization system.

Conventionally, there is known a liquefied natural gas vaporization system that supplies cold heat recovered from liquefied natural gas in a vaporizer for vaporizing liquefied natural gas (LNG) to a destination of the cold heat.

For example, Patent Document 1 includes an LNG vaporizer, a gas turbine intake cooler, a gas turbine intake cooling water circulation system path, a gas turbine intake cooling water circulation pump, and a gas turbine power generation device. The equipment is disclosed. The LNG vaporizer includes a heat transfer tube for flowing LNG. In this LNG vaporizer, LNG is vaporized by exchanging heat between LNG flowing in the heat transfer tube and water in contact with the surface of the heat transfer tube. The gas turbine intake cooler cools the air by exchanging heat between the water (cooling water) flowing out of the LNG vaporizer and the air. That is, this gas turbine intercooler corresponds to the utilization destination of the cold heat recovered from the liquefied natural gas. The gas turbine intake cooling water circulation system path connects the LNG vaporizer and the gas turbine intake cooling system. The water flows through the LNG vaporizer and the gas turbine intake cooler in this order by circulating in the gas turbine intake cooling water circulation system path. The gas turbine intake cooling water circulation pump is provided in the gas turbine intake cooling water circulation system path. The gas turbine power generator is driven by a gas turbine compressor that compresses the air flowing out of the gas turbine intake cooler, and a mixed gas of the air discharged from the gas turbine compressor and the combustion gas of natural gas (NG). It has a gas turbine and a generator connected to the gas turbine.

In the vaporizer of the LNG-fired combined cycle power generation facility described in Patent Document 1, icing may occur on the surface of the heat transfer tube through which LNG flows.

On the other hand, as a system capable of suppressing the occurrence of icing in such a vaporizer, the liquefied gas vaporization system disclosed in Patent Document 2 is known. Specifically, in the system described in Patent Document 2, a so-called alternative freon having a freezing point lower than the freezing point of water is used as a medium for heat exchange with LNG in the heat exchanger. Therefore, the occurrence of icing in the heat exchanger is suppressed.

Japanese Unexamined Patent Publication No. 06-21001 Japanese Patent No. 6092065

In the liquefied gas vaporization system described in Patent Document 2, since the flow path through which the medium (alternative chlorofluorocarbon) circulates needs to be filled with the medium, the cost (particularly the initial cost) becomes very high.

An object of the present invention is to provide a liquefied natural gas vaporization system capable of suppressing the occurrence of icing in a vaporizer and suppressing a significant increase in cost.

As a means for solving the above-mentioned problems, the present invention is a liquefied natural gas vaporization system, in which at least a part of the liquefied natural gas is vaporized by heating the liquefied natural gas with the heat of water via an intermediate medium. A circulation that connects the vaporizer and the cold heat utilization unit so that the vessel, the cold heat utilization unit that utilizes the cold heat of the water flowing out of the vaporizer, and the water flows through the vaporizer and the cold heat utilization unit in this order. The gas generated from the liquefied natural gas by being heated via the flow path, the circulation pump provided in the circulation flow path, and the intermediate medium in the vaporizer, and the gas flowing out from the vaporizer. The vaporizer comprises the intermediate medium having a freezing point lower than the freezing point of the water and the cold heat utilizing section. An intermediate medium evaporating section that evaporates at least a part of the intermediate medium by exchanging heat with the water flowing out of the intermediate medium, and a vapor phase generated by evaporating the liquid phase intermediate medium in the intermediate medium evaporating section. Provided is a liquefied natural gas vaporization system including a liquefied natural gas vaporizing unit that vaporizes at least a part of the liquefied natural gas by exchanging heat between the intermediate medium and the liquefied natural gas.

In this liquefied natural gas vaporization system, the medium that circulates in the circulation flow path is water, so the cold heat recovered in the vaporizer can be effectively used in the cold heat utilization section while suppressing the increase in cost, and water in the vaporizer. Since heat exchange between water and liquefied natural gas is performed via an intermediate medium (propane or the like) having a freezing point lower than that of the intermediate medium, the occurrence of ice formation in the evaporation part of the intermediate medium is suppressed. Moreover, the gas flowing out of the vaporizer is effectively heated in the heating section.

Further, in the liquefied natural gas vaporization system, a bypass flow path connected to the circulation flow path so as to bypass the cold heat utilization section, a flow rate of the water flowing into the cold heat utilization section, and an inflow to the bypass flow path. It is preferable to further include an adjusting unit capable of adjusting the flow rate of the water.

In this way, even when the load on the cold heat utilization section is relatively low, the vaporizer is cooled while supplying water at a flow rate sufficient to suppress the occurrence of icing in the intermediate medium evaporation section. It is possible to supply water at a flow rate corresponding to the load of the cold / heat utilization unit to the utilization unit. For example, when the load of the cold heat utilization unit is relatively low, the flow rate of water supplied to the cold heat utilization unit is also small. In that case, a larger amount of water than the flow rate supplied to the cold heat utilization unit flows into the intermediate medium evaporation section of the vaporizer and flows out from the intermediate medium evaporation section, and among the water flowing out from the intermediate medium evaporation section, the cold heat utilization section By adjusting the adjusting unit so that the excess amount of water supplied to the bypass flow path flows into the bypass flow path, water having a flow rate corresponding to the load is supplied to the cold heat utilization unit, and an intermediate medium is supplied to the vaporizer. Since a sufficient flow of water is supplied to prevent an excessive decrease in the temperature of the water flowing out from the evaporating part, the occurrence of ice formation in the intermediate medium evaporating part is suppressed.

Further, in the liquefied natural gas vaporization system, it is preferable to further include an adjustment unit control unit that controls the adjustment unit so that the temperature of the water flowing out of the vaporizer becomes a set temperature.

By doing so, the temperature of the water supplied to the cold heat utilization unit is automatically maintained at the set temperature.

Further, the adjusting unit has a bypass pump provided in the bypass flow path, and the adjusting unit control unit uses the bypass pump so that the temperature of the water flowing out of the vaporizer becomes the set temperature. It is preferable to control the number of revolutions.

By doing so, the ratio of the flow rate of the water flowing into the cold heat utilization unit and the flow rate of the water flowing into the bypass is effectively controlled.

In the liquefied natural gas vaporization system, the downstream end of the bypass flow path may be connected to a portion of the circulation flow path between the heating portion and the vaporizer.

In this embodiment, the inflow of water that has passed through the bypass flow path into the heating section (injection of the cold heat recovered from the liquefied natural gas into the heating section in the vaporizer) is avoided, so that the gas is released in the heating section. It is heated effectively.

Alternatively, in the liquefied natural gas vaporization system, a branch flow path connected to the circulation flow path so as to bypass the heating portion is further provided, and the downstream end of the bypass flow path is the branch flow path. Alternatively, it may be connected to a portion of the circulation flow path between the heating portion and the vaporizer.

Also in this embodiment, since the water that has passed through the bypass flow path does not flow into the heating portion, the gas is effectively heated in the heating portion. Furthermore, since only a part of the water flowing out from the cold heat utilization part flows into the heating part, the size of the heating part can be reduced as compared with the case where the entire amount of water flowing out from the cold heat utilization part flows into the heating part. It will be possible.

Further, in the liquefied natural gas vaporization system, a circulation pump control unit for controlling the rotation speed of the circulation pump is further provided, and the circulation pump is located on the upstream side of the circulation flow path and the bypass flow path in the circulation flow path. The circulation pump control unit is a signal output by the cold heat utilization unit and is provided in a portion between the upstream connection portion, which is a connection portion with the end portion of the pump, and the cold heat utilization unit. It is preferable to control the rotation speed of the circulation pump according to the load signal indicating the load of the unit.

By doing so, the rotation speed of the circulation pump, that is, the amount of water supplied to the cold heat utilization unit is adjusted according to the load of the cold heat utilization unit.

Further, in the liquefied natural gas vaporization system, a cold water tank provided in a portion of the circulation flow path between the upstream connection portion and the circulation pump and storing the water flowing out of the vaporizer is provided. It is preferable to further prepare.

In this aspect, since cold water (water flowing out from the vaporizer) is stored in the cold water tank, it is possible to effectively adjust the amount of water supplied to the cold heat utilization unit according to the fluctuation of the load of the cold heat utilization unit. ..
The circulation flow path may be provided with a backup warmer that heats the water that flows out of the cold heat utilization unit and before flowing into the vaporizer.

As described above, according to the present invention, it is possible to provide a liquefied natural gas vaporization system capable of suppressing the occurrence of icing in the vaporizer and suppressing a significant increase in cost.

It is a figure which shows the outline of the structure of the liquefied natural gas vaporization system of 1st Embodiment of this invention. It is a figure which shows the outline of the structure of the liquefied natural gas vaporization system of the 2nd Embodiment of this invention. It is a figure which shows the outline of the structure of the liquefied natural gas vaporization system of the 3rd Embodiment of this invention.

A preferred embodiment of the present invention will be described below with reference to the drawings.

(First Embodiment)
The liquefied natural gas vaporization system 1 of the first embodiment of the present invention will be described with reference to FIG. This liquefied natural gas vaporization system 1 is a system that vaporizes liquefied natural gas (LNG) with water and supplies the cold heat recovered from the liquefied natural gas at that time to the user of the cold heat. As No. 10, a so-called intermediate medium type vaporizer (IFV) is adopted. Specifically, the liquefied natural gas vaporization system 1 includes a vaporizer 10, a cold / heat utilization unit 20, a circulation flow path 30, a circulation pump 32, a bypass flow path 40, an adjustment unit 42, and a controller 50. It is equipped with a hot part E3. The circulation flow path 30 connects the vaporizer 10 and the cold heat utilization unit 20 in this order.

The vaporizer 10 is liquefied by exchanging heat between water and liquefied natural gas via an intermediate medium (for example, propane or an alternative fron such as HFC-32, R410A) M having a freezing point lower than the freezing point of water. An intermediate medium vaporizer (IFV) that vaporizes at least a portion of the gas. That is, in the vaporizer 10, the intermediate medium M is heated by water, and the liquefied natural gas is heated by the intermediate medium M. Specifically, the vaporizer 10 has an intermediate medium evaporation unit E1, a liquefied natural gas vaporization unit E2, an intermediate medium evaporation unit E1, a liquefied natural gas vaporization unit E2, and a shell 11 capable of accommodating the intermediate medium M. ..

The intermediate medium evaporation unit E1 evaporates at least a part of the intermediate medium M by exchanging heat between the liquid phase intermediate medium M and the water (hot water) flowing out from the cold heat utilization unit 20. In the present embodiment, the intermediate medium evaporation unit E1 is configured by a heat transfer tube. The intermediate medium evaporation section E1 is arranged in the lower part of the shell 11 (the position in the shell 11 where the liquid phase is immersed in the intermediate medium M). That is, the intermediate medium M in contact with the surface of the intermediate medium evaporation section E1 is heated by the water flowing in the intermediate medium evaporation section E1.

The liquefied natural gas vaporization unit E2 vaporizes at least a part of the liquefied natural gas by exchanging heat between the liquefied natural gas and the intermediate medium M of the gas phase. In the present embodiment, the liquefied natural gas vaporization unit E2 is composed of a U-shaped heat transfer tube. The liquefied natural gas vaporization unit E2 is arranged in the upper part of the shell 11 (the region in the shell 11 above the surface of the intermediate medium M of the liquid phase). That is, the liquefied natural gas flowing in the liquefied natural gas vaporization section E2 is heated by the intermediate medium M of the gas phase in contact with the surface of the liquefied natural gas vaporization section E2. Specifically, the liquefied natural gas flowing in the liquefied natural gas vaporization unit E2 is vaporized by taking away the latent heat of evaporation of the intermediate medium M of the gas phase, while the intermediate medium M of the gas phase releases the latent heat of evaporation. Condensate.

An entrance chamber 12 and an exit chamber 13 partitioned from each other by a partition plate 14 are connected to the shell 11. The inlet chamber 12 is connected to one end of the liquefied natural gas vaporizing section E2 so that the inside of the inlet chamber 12 and the inside of the liquefied natural gas vaporizing section E2 communicate with each other. The outlet chamber 13 is connected to the other end of the liquefied natural gas vaporizing section E2 so that the inside of the outlet chamber 13 and the inside of the liquefied natural gas vaporizing section E2 communicate with each other. That is, at least a part of the liquefied natural gas that has flowed into the liquefied natural gas vaporization section E2 from the inlet chamber 12 is heated by the intermediate medium M of the gas phase in the process of passing through the liquefied natural gas vaporization section E2. It vaporizes and flows into the exit chamber 13.

Further, the water inlet chamber 15 and the water outlet chamber 16 are connected to the shell 11. The water inlet chamber 15 is connected to one side of the shell 11 so that the inside of the water inlet chamber 15 and the inside of the intermediate medium evaporation unit E1 communicate with each other. The water outlet chamber 16 is connected to the other side of the shell 11 so that the inside of the water outlet chamber 16 and the inside of the intermediate medium evaporation unit E1 communicate with each other. That is, the water (warm water) that has flowed into the intermediate medium evaporation section E1 from the water inlet chamber 15 recovers cold heat from the liquid phase intermediate medium M in the process of passing through the intermediate medium evaporation section E1 and closes the water outlet chamber 16. It flows out to the circulation flow path 30 via the route. A partition plate may be provided in the water inlet chamber 15, and the water flowing into the intermediate medium evaporation section E1 may be turned back.

The cold heat utilization unit 20 utilizes the cold heat of the water flowing out from the vaporizer 10. Examples of the cold heat utilization unit 20 include a heat exchanger used for cooling the air supplied to the gas turbine combined cycle power generation device, a heat exchanger used for cooling various facilities, and the like.

The circulation pump (cold water pump) 32 is provided in a portion of the circulation flow path 30 on the downstream side of the vaporizer 10. The circulation pump 32 sends the water (cold water) flowing out of the vaporizer 10 to the cold heat utilization unit 20. The liquefied natural gas vaporization system 1 of the present embodiment includes a cold water tank 34 provided at a portion of the circulation flow path 30 between the vaporizer 10 and the circulation pump 32. The cold water tank 34 stores the water (cold water) that has flowed out of the vaporizer 10.

Further, the liquefied natural gas vaporization system 1 of the present embodiment has a hot water pump 36 provided in a portion of the circulation flow path 30 on the downstream side of the cold heat utilization unit 20, and a cold heat utilization unit 20 and hot water in the circulation flow path 30. A hot water tank 38 provided at a portion between the pump 36 and the pump 36 is further provided. The hot water pump 36 sends the water (hot water) flowing out from the cold / heat utilization unit 20 to the vaporizer 10. The hot water tank 38 stores the water (hot water) that has flowed out from the cold heat utilization unit 20. Further, a backup warmer 39 that heats water by a heat source (seawater or the like) may be provided at a portion of the circulation flow path 30 between the cold heat utilization unit 20 and the hot water tank 38.

The bypass flow path 40 is connected to the circulation flow path 30 so as to bypass the cold heat utilization unit 20. The upstream end of the bypass flow path 40 is connected to a portion of the circulation flow path 30 between the vaporizer 10 and the cold water tank 34. The downstream end of the bypass flow path 40 is connected to a portion of the circulation flow path 30 between the hot water pump 36 and the vaporizer 10. Therefore, the water (cold water) passing through the bypass flow path 40 is returned to the vaporizer 10 again without receiving heat in the cold heat utilization unit 20.

The adjusting unit 42 adjusts the ratio of the flow rate of the water flowing out of the vaporizer 10 to the flow rate of the water flowing into the cold heat utilization unit 20 and the flow rate of the water flowing into the bypass flow path 40. In the present embodiment, a bypass pump is provided in the bypass flow path 40 as the adjusting unit 42. By adjusting the rotation speed (frequency) of the bypass pump, the ratio of the flow rate of the water flowing out of the vaporizer 10 to the flow rate of the water flowing into the cold heat utilization unit 20 and the flow rate of the water flowing into the bypass flow path 40 is adjusted. .. Instead of the bypass pump, an on-off valve whose opening degree can be adjusted may be provided in the bypass flow path 40 as the adjusting unit 42. Alternatively, instead of the on-off valve, a three-way valve may be provided as an adjusting portion 42 at the connection portion between the circulation flow path 30 and the upstream end portion of the bypass flow path 40.

The controller 50 has an adjusting unit control unit 51 and a circulation pump control unit 52.

The adjusting unit control unit 51 controls the rotation speed of the adjusting unit (bypass pump in this embodiment) 42. Specifically, the adjusting unit control unit 51 controls the rotation speed of the bypass pump so that the temperature of the water flowing out of the vaporizer 10 becomes a set temperature (for example, 4 ° C.). The temperature of the water flowing out of the vaporizer 10 is detected by a temperature sensor 61 provided in a portion of the circulation flow path 30 on the downstream side of the vaporizer 10.

The circulation pump control unit 52 controls the rotation speeds of the circulation pump 32 and the hot water pump 36. Specifically, the circulation pump control unit 52 controls the rotation speeds of the circulation pump 32 and the hot water pump 36 according to the signal output by the cold / heat utilization unit 20 and indicating the load of the cold / heat utilization unit 20. For example, the circulation pump control unit 52 increases the rotation speed of the circulation pump 32 and the hot water pump 36 as the load signal increases. Here, when the amount of water supplied to the cold / heat utilization unit 20 corresponds to the magnitude of the load signal, the temperature of the portion downstream of the cold / heat utilization unit 20 (for example, the temperature sensor 63 provided in the hot water tank 38). The temperature difference between the temperature of the portion upstream of the cold / heat utilization unit 20 (for example, the detected value of the temperature sensor 62 provided in the cold water tank 34) is maintained at a substantially specified value. Therefore, when the temperature difference is generally maintained at a specified value, it can be determined that the amount of water supplied to the cold heat utilization unit 20 corresponds to the magnitude of the load signal. The circulation pump 32 and the hot water pump 36 are controlled by the circulation pump control unit 52 independently of the control of the adjustment unit 42 by the adjustment unit control unit 51.

Further, the controller 50 outputs an alarm when the temperature of the intermediate medium evaporation unit E1 becomes equal to or lower than the first predetermined temperature (for example, -1 ° C.), and outputs the temperature of the intermediate medium evaporation unit E1 (the temperature of the tube wall of the heat transfer tube). ) Is lower than the first predetermined temperature to the second predetermined temperature (for example, -3 ° C.) or less, the supply of the liquefied natural gas to the vaporizer 10 may be stopped. The temperature of the intermediate medium evaporation unit E1 is detected by a temperature sensor 64 provided at the downstream end of the intermediate medium evaporation unit E1.

The heating portion E3 is provided in a portion of the circulation flow path 30 between the cold heat utilization portion 20 and the vaporizer 10, and more specifically, in a portion between the hot water pump 36 and the vaporizer 10. The heating unit E3 heats the gas flowing out from the vaporizer 10 with the water (hot water) flowing out from the cold heat utilization unit 20. As the heating unit E3, a so-called shell-and-tube heat exchanger or a so-called plate heat exchanger is preferably used.

As described above, in the liquefied natural gas vaporization system 1 of the present embodiment, since the medium circulating in the circulation flow path 30 is water, the cold heat recovered in the vaporizer 10 is used as the cold heat utilization unit while suppressing the increase in cost. In the vaporizer 10, heat exchange between water and liquefied natural gas is performed via the intermediate medium M having a freezing point lower than the freezing point of water, so that the vaporizer 10 can be effectively used in 20 and is therefore in the intermediate medium evaporation section E1. Occurrence of icing is suppressed.

Further, since this liquefied natural gas vaporization system 1 includes a bypass flow path 40 and an adjusting unit 42, even when the load of the cold heat utilization unit 20 is relatively low, the intermediate medium evaporation unit is supplied to the vaporizer 10. It is possible to supply water at a flow rate corresponding to the load of the cold / heat utilization unit 20 to the cold / heat utilization unit 20 while supplying water at a flow flow sufficient to suppress the occurrence of ice formation in E1. For example, when the load of the cold heat utilization unit 20 is relatively low, the flow rate of water supplied to the cold heat utilization unit 20 is also small. In that case, a larger amount of water than the flow rate supplied to the cold heat utilization unit 20 flows into the intermediate medium evaporating section E1 of the vaporizer 10 and flows out from the intermediate medium evaporating section E1 and flows out from the intermediate medium evaporating section E1. Of these, the adjusting unit 42 is adjusted so that the surplus of the flow rate supplied to the cold heat utilization unit 20 flows into the bypass flow path 40, so that the water flow rate corresponding to the load of the cold heat utilization unit 20 is the cold heat utilization unit. In addition to being supplied to 20, the vaporizer 10 is supplied with water at a sufficient flow rate to prevent an excessive decrease in the temperature of the water flowing out from the intermediate medium evaporating unit E1. Is suppressed.

Further, since the liquefied natural gas vaporization system 1 includes the heating unit E3, the gas flowing out from the vaporizer 10 is effectively heated in the heating unit E3.

Further, since the liquefied natural gas vaporization system 1 includes the adjustment unit control unit 51, the temperature of the water supplied to the cold heat utilization unit 20 is automatically maintained at a set temperature.

Further, since the liquefied natural gas vaporization system 1 includes a circulation pump control unit 52, the rotation speeds of the circulation pump 32 and the hot water pump 36 according to the load of the cold heat utilization unit 20, that is, the cold heat utilization unit 20 and the vaporizer. The amount of water supplied to 10 is adjusted.

Further, since the liquefied natural gas vaporization system 1 includes a cold water tank 34, it is possible to effectively adjust the amount of water supplied to the cold heat utilization unit 20 according to the fluctuation of the load of the cold heat utilization unit 20. Similarly, since the liquefied natural gas vaporization system 1 includes a hot water tank 38, it is possible to effectively adjust the amount of water supplied to the vaporizer 10 according to the load fluctuation of the vaporizer 10.

(Second Embodiment)
Next, the liquefied natural gas vaporization system 1 of the second embodiment of the present invention will be described with reference to FIG. In the second embodiment, only the parts different from the first embodiment will be described, and the description of the same structure, operation and effect as in the first embodiment will be omitted.

In the liquefied natural gas vaporization system 1 of the present embodiment, the downstream end of the bypass flow path 40 is connected to a portion of the circulation flow path 30 between the heating portion E3 and the vaporizer 10.

In this embodiment, the inflow of water (cold water) that has passed through the bypass flow path 40 into the heating portion E3 (injection of the cold heat recovered from the liquefied natural gas in the vaporizer 10 into the heating portion E3) is avoided. , The gas is effectively heated in the heating unit E3.

(Third Embodiment)
Next, the liquefied natural gas vaporization system 1 of the third embodiment of the present invention will be described with reference to FIG. In the third embodiment, only the parts different from those in the first embodiment will be described, and the description of the same structure, operation and effect as in the first embodiment will be omitted.

The liquefied natural gas vaporization system 1 of the present embodiment further includes a branch flow path 31 connected to the circulation flow path 30 so as to bypass the heating portion E3, and the downstream end portion of the bypass flow path 40 is provided. , Is connected to a portion of the branch flow path 31 or the circulation flow path 30 between the heating portion E3 and the vaporizer 10.

Also in this embodiment, since the inflow of water (cold water) that has passed through the bypass flow path 40 into the heating unit E3 is avoided, the gas is effectively heated in the heating unit E3. Further, since only a part of the water flowing out from the cold heat utilization unit 20 flows into the heating unit E3, the entire amount of the water flowing out from the cold heat utilization unit 20 flows into the heating unit E3 as in the first embodiment. Compared with the above, the heating unit E3 can be downsized.

It should be noted that the embodiments disclosed this time are exemplary in all respects and are not considered to be restrictive. The scope of the present invention is shown by the scope of claims rather than the description of the embodiment described above, and further includes all modifications within the meaning and scope equivalent to the scope of claims.

For example, the controller 50 may be omitted, and the rotation speed of the circulation pump 32 or the rotation speed of the bypass pump may be manually controlled by the operator.

Further, another cold heat utilization unit may be connected to the circulation flow path 30 so as to be in parallel with the cold heat utilization unit 20.

1 Liquefied natural gas vaporization system 10 Vaporizer 20 Cold heat utilization unit 30 Circulation flow path 31 Branch flow path 32 Circulation pump (cold water pump)
34 Cold water tank 36 Hot water pump 38 Hot water tank 40 Bypass flow path 42 Adjustment part (bypass pump)
50 Controller 51 Adjustment unit Control unit 52 Circulation pump control unit E1 Intermediate medium evaporation unit E2 Liquefied natural gas vaporization unit E3 Heating unit M Intermediate medium

Claims (9)

A liquefied natural gas vaporization system
A vaporizer that vaporizes at least a portion of the liquefied natural gas by heating the liquefied natural gas with the heat of water through an intermediate medium .
A cold heat utilization unit that utilizes the cold heat of the water flowing out of the vaporizer, and
A circulation flow path connecting the vaporizer and the cold heat utilization unit so that the water flows through the vaporizer and the cold heat utilization unit in this order.
The circulation pump provided in the circulation flow path and
The gas generated from the liquefied natural gas by being heated via the intermediate medium in the vaporizer and flowing out of the vaporizer is passed through the cold heat utilization unit in the circulation flow path. Equipped with a heating part to heat ,
The vaporizer is
An intermediate medium evaporation section that evaporates at least a part of the intermediate medium by heat exchange between the intermediate medium having a freezing point lower than the freezing point of the water and the water flowing out from the cold heat utilization section.
Vaporization of liquefied natural gas that vaporizes at least a part of the liquefied natural gas by exchanging heat between the intermediate medium of the gas phase generated by the evaporation of the intermediate medium of the liquid phase and the liquefied natural gas in the intermediate medium evaporation section. A liquefied natural gas vaporization system with a part. In the liquefied natural gas vaporization system according to claim 1.
A bypass flow path connected to the circulation flow path so as to bypass the cold heat utilization section, and a bypass flow path.
A liquefied natural gas vaporization system further comprising an adjusting unit capable of adjusting the flow rate of the water flowing into the cold heat utilization unit and the flow rate of the water flowing into the bypass flow path. In the liquefied natural gas vaporization system according to claim 2.
A liquefied natural gas vaporization system further comprising an adjustment unit control unit that controls the adjustment unit so that the temperature of the water flowing out of the vaporizer reaches a set temperature. In the liquefied natural gas vaporization system according to claim 3 .
The adjusting unit has a bypass pump provided in the bypass flow path.
The adjusting unit control unit is a liquefied natural gas vaporization system that controls the rotation speed of the bypass pump so that the temperature of the water flowing out of the vaporizer becomes the set temperature. In the liquefied natural gas vaporization system according to claim 2 .
A liquefied natural gas vaporization system in which the downstream end of the bypass flow path is connected to a portion of the circulation flow path between the heating portion and the vaporizer. In the liquefied natural gas vaporization system according to claim 2 .
A branch flow path connected to the circulation flow path so as to bypass the heating portion is further provided.
A liquefied natural gas vaporization system in which the downstream end of the bypass flow path is connected to a portion of the branch flow path or the circulation flow path between the heating portion and the vaporizer. In the liquefied natural gas vaporization system according to any one of claims 2 to 6 .
Further, a circulation pump control unit for controlling the rotation speed of the circulation pump is provided.
The circulation pump is provided at a portion of the circulation flow path between the upstream connection portion, which is a connection portion between the circulation flow path and the upstream end portion of the bypass flow path, and the cold heat utilization portion. Ori,
The circulation pump control unit is a liquefied natural gas vaporization system that controls the rotation speed of the circulation pump according to a load signal output by the cold heat utilization unit and indicating a load of the cold heat utilization unit. In the liquefied natural gas vaporization system according to claim 7 .
A liquefied natural gas vaporization system provided at a portion of the circulation flow path between the upstream connection portion and the circulation pump, further comprising a cold water tank for storing the water flowing out of the vaporizer. In the liquefied natural gas vaporization system according to claim 1,
A liquefied natural gas vaporization system provided with a backup warmer that heats the water that flows out of the cold heat utilization section and before flowing into the vaporizer in the circulation flow path.

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