WO2019187894A1

WO2019187894A1 - Liquefied natural gas vaporization system

Info

Publication number: WO2019187894A1
Application number: PCT/JP2019/007243
Authority: WO
Inventors: 正英岩崎; 浅田　和彦; 江頭　慎二; 朝寛鈴木
Original assignee: 株式会社神戸製鋼所
Priority date: 2018-03-30
Filing date: 2019-02-26
Publication date: 2019-10-03
Also published as: PH12020551569A1; TWI695139B; JP7011516B2; TW201942514A; JP2019178699A

Abstract

A liquefied natural gas vaporization system having: a vaporizer for heating liquefied natural gas with water and thereby vaporizing at least a portion of the liquefied natural gas; a cold heat utilization unit for utilizing cold heat of water flowing from the vaporizer; a circulation flow path; and a circulation pump. The vaporizer has: an intermediate medium evaporation unit for evaporating at least a portion of an intermediate medium by carrying out a heat exchange between the intermediate medium, which has a freezing point lower than the freezing point of water, and the water flowing from the cold heat utilization unit; and a liquefied natural gas vaporization unit for vaporizing at least a portion of the liquefied natural gas by carrying out a heat exchange between the liquefied natural gas and the gas-phase intermediate medium generated by the evaporation of liquid-phase intermediate medium in the intermediate medium evaporation unit.

Description

Liquefied natural gas vaporization system

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

Conventionally, a liquefied natural gas vaporization system that recovers cold heat from liquefied natural gas by vaporizing liquefied natural gas (LNG) in a vaporizer and supplies the collected cold heat to a destination of the cold heat is known.

For example, Patent Document 1 discloses an LNG-fired combined cycle power generation including an LNG vaporizer, a gas turbine intake air cooler, a gas turbine intake cooling water circulation system, a gas turbine intake cooling water circulation pump, and a gas turbine power generation device. Equipment is disclosed. The LNG vaporizer includes a heat transfer tube for flowing LNG. In this LNG vaporizer, LNG is vaporized by heat exchange between the LNG flowing in the heat transfer tube and the water contacting the surface of the heat transfer tube. In the gas turbine intake air cooler, water (cooling water) flowing out of the LNG vaporizer and air exchange heat. Thereby, air is cooled. In other words, the gas turbine intake air cooler corresponds to the use destination of the cold energy recovered from the liquefied natural gas. The gas turbine intake cooling water circulation system path connects the LNG vaporizer and the gas turbine intake cooler to each other. Water circulates in the gas turbine intake cooling water circulation system. Thereby, water flows through the LNG vaporizer and the gas turbine intake air cooler in this order. The gas turbine intake cooling water circulation pump is disposed in the gas turbine intake cooling water circulation system. The gas turbine power generator is driven by a gas turbine compressor that compresses air flowing out from the gas turbine intake air cooler, and a mixed gas of air discharged from the gas turbine compressor and combustion gas of natural gas (NG). A gas turbine; and a generator connected to the gas turbine.

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

On the other hand, Patent Document 2 discloses a liquefied gas vaporization system capable of suppressing the occurrence of icing in the vaporizer. Specifically, in the system described in Patent Document 2, a so-called alternative chlorofluorocarbon 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. For this reason, generation | occurrence | production of the icing in a heat exchanger is suppressed.

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

Japanese Patent Laid-Open No. 06-21001 Japanese Patent No. 6092065

An object of the present invention is to provide a liquefied natural gas vaporization system that can suppress the occurrence of icing in a vaporizer and can suppress an increase in cost.

A liquefied natural gas vaporization system according to an aspect of the present invention uses a vaporizer that vaporizes at least a part of the liquefied natural gas by heating the liquefied natural gas with water, and cold heat of water flowing out of the vaporizer. A cooling heat utilization part, a circulation flow path connecting the vaporizer and the cold heat utilization part so that water circulates between the vaporizer and the cold heat utilization part, and a circulation pump provided in the circulation flow path And comprising. The vaporizer is an intermediate medium that evaporates at least a part of the intermediate medium in a liquid phase by exchanging heat between the intermediate medium having a freezing point lower than the freezing point of water and the water flowing out from the cold heat utilization unit. At least a part of the liquefied natural gas is vaporized by heat-exchanging the vaporized intermediate medium and the liquefied natural gas with the vapor phase intermediate medium generated by evaporation of the liquid intermediate medium in the intermediate medium evaporating section. A liquefied natural gas vaporizing section.

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

Embodiment

Hereinafter, embodiments will be described with reference to the accompanying drawings. In addition, the following embodiment is an example which actualized this invention, Comprising: The thing of the character which limits the technical scope of this invention is not.

(First embodiment)
The liquefied natural gas vaporization system 1 of 1st Embodiment is demonstrated referring FIG. The liquefied natural gas vaporization system 1 is a system that vaporizes liquefied natural gas (LNG) with water and supplies the cold energy recovered from the liquefied natural gas at that time to the use destination of the cold heat. In the vaporization system 1, a so-called intermediate medium vaporizer (IFV) is employed as the vaporizer 10. The liquefied natural gas vaporization system 1 includes a vaporizer 10, a cold energy utilization unit 20, a circulation channel 30, a circulation pump 32, a bypass channel 40, an adjustment unit 42, a controller 50, and a heating unit E3. It is equipped with. The circulation channel 30 connects the vaporizer 10 and the cold energy utilization unit 20 to each other.

The vaporizer 10 is configured by an intermediate medium vaporizer (IFV). That is, in the vaporizer 10, the water and the liquefied natural gas exchange heat through an intermediate medium (for example, propane, alternative CFCs such as HFC-32 and R410A) M having a freezing point lower than the freezing point of water. Thereby, at least a part of the liquefied natural gas is vaporized. In the vaporizer 10, the intermediate medium M is heated by water, and the liquefied natural gas is heated by the intermediate medium M. The vaporizer 10 includes an intermediate medium evaporation unit E1, a liquefied natural gas vaporization unit E2, and a shell 11 that houses the intermediate medium evaporation unit E1, the liquefied natural gas vaporization unit E2, and the intermediate medium M.

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

In the liquefied natural gas vaporization section E2, the liquefied natural gas and the gas phase intermediate medium M exchange heat. Thereby, at least a part of the liquefied natural gas is vaporized. In this embodiment, the liquefied natural gas vaporization part E2 is comprised with the heat exchanger tube formed in the U-shape. The liquefied natural gas vaporization section E2 is disposed in an upper portion of the shell 11 (a region above the surface of the liquid phase intermediate medium M in the shell 11). That is, the liquefied natural gas flowing in the liquefied natural gas vaporization section E2 is heated by the gas phase intermediate medium M 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 section E2 is vaporized by taking away the latent heat of vaporization of the vapor phase intermediate medium M, while the vapor phase intermediate medium M is released by releasing the latent heat of vaporization. Condensate.

The shell 11 is connected to an inlet chamber 12 and an outlet chamber 13 which are partitioned by a partition plate 14. The inlet chamber 12 is connected to one end of the liquefied natural gas vaporizer E2 so that the inlet chamber 12 and the liquefied natural gas vaporizer E2 communicate with each other. The outlet chamber 13 is connected to the other end of the liquefied natural gas vaporization unit E2 so that the inside of the outlet chamber 13 and the liquefied natural gas vaporization unit E2 communicate with each other. That is, at least a part of the liquefied natural gas flowing into the liquefied natural gas vaporization section E2 from the inlet chamber 12 is heated by the gas phase intermediate medium M while passing through the liquefied natural gas vaporization section E2. Vaporizes and flows into the outlet chamber 13.

Further, a water inlet chamber 15 and a water outlet chamber 16 are connected to the shell 11. The water inlet chamber 15 is connected to a portion on one side of the shell 11 so that the water inlet chamber 15 and the intermediate medium evaporation portion E1 communicate with each other. The water outlet chamber 16 is connected to a portion on 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 part E1 communicate with each other. The water (warm water) that has flowed into the intermediate medium evaporator E1 from the water inlet chamber 15 is cooled to the liquid-phase intermediate medium M in the process of passing through the intermediate medium evaporator E1. That is, water recovers cold energy from the intermediate medium M. The water cooled in the intermediate medium evaporation part E1 flows out to the circulation flow path 30 via the water outlet chamber 16. In addition, although the intermediate medium evaporation part E1 is comprised by the straight tubular heat exchanger tube, you may be comprised by the U-shaped heat exchanger tube. In this case, a partition plate is provided in the water inlet chamber 15, and the water that has flowed into the intermediate medium evaporation section E <b> 1 flows so as to be turned toward the water outlet 16.

The cold energy utilization unit 20 utilizes the cold heat of the water that has flowed out of the vaporizer 10. Examples of the cold heat utilization unit 20 include a heat exchanger used for cooling 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 channel 30 on the downstream side of the vaporizer 10. The circulation pump 32 sends the water (cold water) flowing out from the vaporizer 10 to the cold energy utilization unit 20.

The liquefied natural gas vaporization system 1 of the present embodiment includes a cold water tank 34 disposed in a portion of the circulation channel 30 between the vaporizer 10 and the circulation pump 32. The cold water tank 34 temporarily stores water (cold water) flowing out from the vaporizer 10.

The liquefied natural gas vaporization system 1 of the present embodiment includes a hot water pump 36 disposed in a portion of the circulation flow path 30 on the downstream side of the cold heat utilization section 20, and a cold heat utilization section 20 and a hot water pump 36 in the circulation flow path 30. And a hot water tank 38 disposed at a position between the two. The hot water pump 36 sends water (hot water) that has flowed out of the cold energy utilization unit 20 to the vaporizer 10. The hot water tank 38 temporarily stores water (hot water) that has flowed out of the cold energy utilization unit 20. A backup heater 39 that heats water by a heat source medium (seawater or the like) may be provided in a portion of the circulation flow path 30 between the cold heat utilization unit 20 and the hot water tank 38.

The bypass channel 40 is connected to the circulation channel 30 so as to bypass the cold energy 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 channel 40 is connected to a portion of the circulation channel 30 between the hot water pump 36 and the vaporizer 10. For this reason, the water (cold water) passing through the bypass channel 40 is returned to the vaporizer 10 again without receiving heat in the cold heat utilization unit 20.

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

The controller 50 has a configuration including a storage unit (memory device) and a calculation unit (CPU or the like), and exhibits a predetermined function by executing a computer program recorded in the storage unit. Functions of the controller 50 include an adjustment unit control unit 51 and a circulation pump control unit 52.

The adjustment unit control unit 51 controls the rotation speed of the adjustment unit (bypass pump in the present embodiment) 42. Specifically, the adjustment 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.). Note that the temperature of the water flowing out of the vaporizer 10 is detected by a temperature sensor 61 disposed in a portion of the circulation flow path 30 on the downstream side of the vaporizer 10. The adjustment unit control unit 51 controls the adjustment unit 42 according to the detection value of the temperature sensor 61.

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 in accordance with the load of the cold energy utilization unit 20 indicated by the load signal output from the cold energy utilization unit 20. For example, the circulation pump control unit 52 increases the rotation speeds of the circulation pump 32 and the hot water pump 36 as the load indicated by the load signal increases. Therefore, when the load on the cold energy utilization unit 20 increases, the flow rate of water supplied to the cold energy utilization unit 20 increases. When the supply flow rate of water to the cold energy utilization unit 20 is adjusted according to the magnitude of the load, the temperature of the downstream portion of the cold energy utilization unit 20 (for example, the detection value of the temperature sensor 63 provided in the hot water tank 38) ) And the temperature of the portion upstream of the cold energy utilization unit 20 (for example, the detection value of the temperature sensor 62 provided in the cold water tank 34) is maintained at a generally specified value (within a predetermined range). For example, when the temperature difference between the temperature on the upstream side and the temperature on the downstream side of the cold energy utilization unit 20 increases, the circulation pump control unit 52 increases the rotation speed of the circulation pump 32 and the hot water pump 36 while the temperature is increased. When the difference becomes smaller, the rotational speeds of the circulation pump 32 and the hot water pump 36 are lowered. Thereby, the temperature difference between the temperature on the upstream side and the temperature on the downstream side of the cold energy utilization unit 20 is maintained within a predetermined range. For this reason, when the temperature difference is substantially maintained at a specified value, it is possible to determine that the amount of water supplied to the cold energy utilization unit 20 corresponds to the magnitude of the load. The control of the circulation pump 32 and the hot water pump 36 by the circulation pump control unit 52 is performed independently from the control of the adjustment unit 42 by the adjustment unit control unit 51.

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

The heating unit E3 is disposed in a portion of the circulation channel 30 between the cold heat utilization unit 20 and the vaporizer 10, more specifically, 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 water (hot water) flowing out from the cold heat utilization unit 20. Note that a so-called shell-and-tube heat exchanger or a so-called plate heat exchanger is preferably used as the heating unit E3.

As described above, in the liquefied natural gas vaporization system 1 of the present embodiment, the medium circulating in the circulation channel 30 is water. For this reason, the cold energy recovered in the vaporizer 10 can be effectively used in the cold energy utilization unit 20 while suppressing an increase in cost. In addition, in the vaporizer 10, heat is transferred from the water to the liquefied natural gas through the intermediate medium M having a freezing point lower than the freezing point of water, so that the occurrence of icing in the intermediate medium evaporation unit E1 is suppressed.

In addition, since the liquefied natural gas vaporization system 1 includes the bypass flow path 40 and the adjustment unit 42, icing occurs in the intermediate medium evaporation unit E1 even when the load of the cold heat utilization unit 20 is relatively low. It is possible to circulate water at a flow rate corresponding to the load of the cold energy utilization unit 20 while supplying the vaporizer 10 with a flow rate sufficient to suppress the above. For example, when the load of the cold energy utilization unit 20 is relatively low, the flow rate of water supplied to the cold energy utilization unit 20 decreases. In that case, water having a flow rate higher than that supplied to the cold energy utilization unit 20 flows into the intermediate medium evaporation unit E1 of the vaporizer 10 and flows out from the intermediate medium evaporation unit E1. For this reason, the adjustment part 42 is adjusted so that the surplus part which is not supplied to the cold energy utilization part 20 flows out into the bypass flow path 40 among the water which flowed out from the intermediate | middle medium evaporation part E1. Thereby, the water of the flow volume according to the load of the cold energy utilization part 20 is supplied to the cold energy utilization part 20, and it is enough to prevent the vaporizer 10 from excessively decreasing the temperature of the water flowing out from the intermediate medium evaporation part E1. Water with a proper flow rate is supplied. Therefore, even when the load on the cold energy utilization unit 20 is small, it is possible to suppress the occurrence of icing in the intermediate medium evaporation unit E1.

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.

Furthermore, 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.

Moreover, since the liquefied natural gas vaporization system 1 is provided with the circulation pump control part 52, the rotation speed of the circulation pump 32 and the hot water pump 36 according to the load of the cold energy utilization part 20, ie, the cold energy utilization part 20 and the vaporizer. The amount of water supply to 10 is adjusted.

Furthermore, since the liquefied natural gas vaporization system 1 includes the cold water tank 34, it is possible to effectively adjust the feed water flow rate to the cold energy utilization unit 20 according to the fluctuation of the load of the cold energy utilization unit 20. Similarly, since the liquefied natural gas vaporization system 1 includes the hot water tank 38, it is possible to effectively adjust the feed water flow rate to the vaporizer 10 according to the load fluctuation of the vaporizer 10.

(Second Embodiment)
A liquefied natural gas vaporization system 1 according to a second embodiment will be described with reference to FIG. In the second embodiment, only 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 according to the second embodiment, the downstream end of the bypass flow path 40 is connected to a portion of the circulation flow path 30 between the heating unit E3 and the vaporizer 10. That is, the bypass flow path 40 bypasses the heating part E3.

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

(Third embodiment)
A liquefied natural gas vaporization system 1 according to a third embodiment will be described with reference to FIG. In the third embodiment, only 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.

The liquefied natural gas vaporization system 1 according to the third embodiment further includes a branch flow path 31 connected to the circulation flow path 30 so as to bypass the heating unit E3. The upstream end of the branch flow path 31 is connected to a portion of the circulation flow path 30 between the hot water pump 36 and the heater E3. The downstream end of the branch flow path 31 is connected to a portion of the circulation flow path 30 between the heater E3 and the vaporizer 10. The downstream end of the bypass channel 40 is connected to a portion of the circulation channel 30 between the heating unit E3 and the vaporizer 10. Note that the downstream end of the bypass channel 40 may be connected to the branch channel 31.

In the third embodiment, since the inflow of water (cold water) that has passed through the bypass channel 40 into the heating unit E3 is avoided, the gas is effectively heated in the heating unit E3. Furthermore, since only a part of the water flowing out from the cold energy utilization unit 20 flows into the heating unit E3, the total amount of water flowing out from the cold heat utilization unit 20 flows into the heating unit E3 as in the first embodiment. Compared to the above, the heating unit E3 can be downsized.

In addition, it should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

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

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

Here, the embodiment will be outlined.

(1) The liquefied natural gas vaporization system according to the embodiment uses a vaporizer that evaporates at least a part of the liquefied natural gas by heating the liquefied natural gas with water, and a cold heat of water flowing out of the vaporizer. A cooling heat utilization unit, a circulation channel connecting the vaporizer and the cold utilization unit so that water circulates between the vaporizer and the cold utilization unit, and a circulation pump provided in the circulation channel And comprising. The vaporizer is an intermediate medium that evaporates at least a part of the intermediate medium in a liquid phase by exchanging heat between the intermediate medium having a freezing point lower than the freezing point of water and the water flowing out from the cold heat utilization unit. At least a part of the liquefied natural gas is vaporized by heat-exchanging the vaporized intermediate medium and the liquefied natural gas with the vapor phase intermediate medium generated by evaporation of the liquid intermediate medium in the intermediate medium evaporating section. A liquefied natural gas vaporizing section.

In this liquefied natural gas vaporization system, the medium circulating in the circulation channel is water. For this reason, the cold collected in the vaporizer can be effectively utilized in the cold utilization unit while suppressing an increase in cost. In addition, in the vaporizer, heat is transferred from water to liquefied natural gas via an intermediate medium (such as propane) having a freezing point lower than that of water, so that the occurrence of icing in the intermediate medium evaporation unit is suppressed. .

(2) The liquefied natural gas vaporization system includes a bypass channel connected to the circulation channel so as to bypass the cold energy utilization unit, a flow rate of the water flowing into the cold energy utilization unit, and the bypass channel. An adjustment unit capable of adjusting the flow rate of the water flowing in.

In this way, even when the load of the cold energy utilization unit is relatively low, the cold energy utilization unit supplies water to the vaporizer with a flow rate sufficient to suppress the occurrence of icing in the intermediate medium evaporation unit. It becomes possible to circulate water at a flow rate corresponding to the load. For example, when the load of the cold energy utilization unit is relatively low, the flow rate of water supplied to the cold energy utilization unit is reduced. In that case, water having a flow rate higher than the flow rate supplied to the cold energy utilization unit flows into the intermediate medium evaporation unit of the vaporizer and flows out from the intermediate medium evaporation unit. For this reason, an adjustment part is adjusted so that the surplus part which is not supplied to a cold-heat utilization part among the water which flowed out from the intermediate-medium evaporation part flows in into a bypass flow path. As a result, water having a flow rate according to the load of the cold energy utilization unit is supplied to the cold energy utilization unit, and the water flow rate sufficient to prevent an excessive decrease in the temperature of the water flowing out from the intermediate medium evaporation unit to the vaporizer. Is supplied. Therefore, even when the load on the cold energy utilization unit is small, it is possible to suppress the occurrence of icing in the intermediate medium evaporation unit.

(3) The liquefied natural gas vaporization system may further include an adjustment unit control unit that controls the adjustment unit such that the temperature of water flowing out of the vaporizer becomes a set temperature.

In this way, the temperature of the water supplied to the cold energy utilization part is automatically maintained at a set temperature.

(4) The adjustment unit may include a bypass pump disposed in the bypass flow path. In this case, the adjustment unit control unit may control the rotation speed of the bypass pump so that the temperature of water flowing out of the vaporizer becomes the set temperature.

In this way, the ratio of the flow rate of water flowing into the cold energy utilization part and the flow rate of water flowing into the bypass is effectively controlled.

(5) The liquefied natural gas vaporization system is disposed in a portion of the circulation flow path between the connection portion of the bypass flow path and the vaporizer, and heats the gas flowing out of the vaporizer. You may further provide a warm part.

In this way, the gas flowing out of the vaporizer is effectively heated in the heating section.

(6) 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 unit and the vaporizer.

In this aspect, since the inflow of water that has passed through the bypass channel to the warming part (injection of cold heat recovered from liquefied natural gas in the vaporizer into the warming part) is avoided, the gas in the warming part Heated effectively.

(7) The liquefied natural gas vaporization system may further include a branch channel connected to the circulation channel so as to bypass the heating unit. In this case, the downstream end of the bypass channel may be connected to a portion of the branch channel or the circulation channel between the heating unit and the vaporizer.

Also in this aspect, since the water that has passed through the bypass channel does not flow into the heating section, the gas is effectively heated in the heating section. Furthermore, since only a part of the water that has flowed out of the cold energy utilization unit flows into the heating unit, the heating unit can be downsized compared to the case where the entire amount of water that has flowed out of the cold heat utilization unit flows into the heating unit. It becomes possible.

(8) The liquefied natural gas vaporization system may further include a circulation pump control unit that controls the number of revolutions of the circulation pump. In this case, the circulation pump is disposed at a portion between the upstream side connection portion that is a connection portion between the circulation passage and the upstream end portion of the bypass passage among the circulation passages and the cold heat utilization portion. It may be arranged. The circulation pump control unit may control the number of rotations of the circulation pump in accordance with a load of the cold energy utilization unit indicated by a load signal output from the cold energy utilization unit.

If it does in this way, the rotation speed of a circulation pump, ie, the amount of water supply to a cold energy utilization part, is adjusted according to the load of a cold energy utilization part.

(9) The liquefied natural gas vaporization system is disposed in a portion of the circulation channel between the upstream connection portion and the circulation pump, and includes a cold water tank that stores water flowing out of the vaporizer. Further, it may be provided.

In this aspect, since cold water (water that has flowed out of the vaporizer) is stored in the cold water tank, it is possible to effectively adjust the amount of water supplied to the cold energy utilization unit in accordance with fluctuations in the load of the cold energy utilization unit. .

As described above, it is possible to suppress the occurrence of icing in the vaporizer and to suppress a significant increase in cost.

Claims

A vaporizer that vaporizes at least a portion of the liquefied natural gas by heating the liquefied natural gas with water;
A cold energy utilization unit that utilizes the cold heat of water flowing out of the vaporizer;
A circulation flow path connecting the vaporizer and the cold energy utilization unit so that water circulates between the vaporizer and the cold energy utilization unit;
A circulation pump provided in the circulation flow path,
The vaporizer is
An intermediate medium having a freezing point lower than the freezing point of water, and water that has flowed out of the cold energy utilization unit,
An intermediate medium evaporating section that evaporates at least a part of the intermediate medium in the liquid phase by heat exchange
A liquefied natural gas that vaporizes at least a portion of the liquefied natural gas by heat-exchanging the liquefied natural gas with a gas phase intermediate medium generated by evaporating the liquid phase intermediate medium in the intermediate medium evaporation section. A liquefied natural gas vaporization system having a vaporization section.
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 energy utilization section;
A liquefied natural gas vaporization system, further comprising: an adjustment unit capable of adjusting a flow rate of the water flowing into the cold heat utilization unit and a flow rate of the water flowing into the bypass passage.
The liquefied natural gas vaporization system according to claim 2,
The liquefied natural gas vaporization system further comprising an adjustment unit control unit that controls the adjustment unit such that the temperature of water flowing out of the vaporizer becomes a set temperature.
The liquefied natural gas vaporization system according to claim 3,
The adjustment unit has a bypass pump disposed in the bypass flow path,
The said adjustment part control part is a liquefied natural gas vaporization system which controls the rotation speed of the said bypass pump so that the temperature of the water which flowed out from the said vaporizer may become the said setting temperature.
The liquefied natural gas vaporization system according to claim 2,
A liquefied natural gas vaporization system, further comprising a heating unit that is disposed in a portion of the circulation channel between a connection portion of the bypass channel and the vaporizer and that heats the gas flowing out of the vaporizer. .
The liquefied natural gas vaporization system according to claim 5,
The liquefied natural gas vaporization system, wherein the downstream end of the bypass channel is connected to a portion of the circulation channel between the heating unit and the vaporizer.
The liquefied natural gas vaporization system according to claim 5,
Further comprising a branch channel connected to the circulation channel so as to bypass the heating unit;
The liquefied natural gas vaporization system, wherein 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 unit and the vaporizer.
The liquefied natural gas vaporization system according to any one of claims 2 to 7,
A circulation pump control unit for controlling the number of rotations of the circulation pump;
The circulation pump is disposed at a portion between the upstream side connection portion that is a connection portion between the circulation flow channel and the upstream end portion of the bypass flow channel in the circulation flow channel, and the cold energy utilization unit. And
The circulatory pump control unit is a liquefied natural gas vaporization system that controls the number of revolutions of the circulation pump according to a load of the cold heat utilization unit indicated by a load signal output from the cold heat utilization unit.
The liquefied natural gas vaporization system according to claim 8,
A liquefied natural gas vaporization system, further comprising a cold water tank that is disposed in a portion of the circulation channel between the upstream connection portion and the circulation pump and stores water flowing out of the vaporizer.