TWI695139B - LNG gasification system - Google Patents

Abstract

The liquefied natural gas gasification system includes: a gasifier 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 energy of water flowing out of the gasifier, a circulation flow path, and Circulation pump. The gasifier has an intermediate medium evaporation section and a liquefied natural gas vaporization section. The intermediate medium evaporation section allows the intermediate medium having a freezing point lower than the freezing point of water to exchange heat with the water flowing from the cold energy utilization section, thereby At least a part of the intermediate medium is evaporated, and the liquefied natural gas gasification section is to allow the intermediate medium in the gas phase generated by evaporating the intermediate medium in the liquid phase to exchange heat with the liquefied natural gas, thereby making the liquefied natural gas At least a part of the gasification.

Description

LNG gasification system

The invention relates to a liquefied natural gas gasification system.

A well-known liquefied natural gas gasification system is to gasify liquefied natural gas (LNG) in a gasifier and recover cold energy from the liquefied natural gas, and supply the recovered cold energy to the object of utilization of the cold energy .

For example, Patent Document 1 discloses an LNG combustion combined cycle power generation facility including an LNG gasifier, a gas turbine intake cooler, a gas turbine intake cooling water circulation flow path, a gas turbine intake cooling water circulation pump, And gas turbine power plant. The LNG gasifier contains heat transfer tubes for the flow of LNG. In this LNG gasifier, the LNG flowing in the heat transfer tube and the water in contact with the surface of the heat transfer tube perform heat exchange to vaporize the LNG. In the gas turbine intake cooler, the water (cooling water) flowing out of the LNG vaporizer exchanges heat with the air. In this way, the air is cooled. That is, the gas turbine intake cooler is equivalent to the use of cold energy recovered from liquefied natural gas. The gas turbine suction cooling water circulation flow path connects the LNG gasifier and the gas turbine suction cooler to each other. Water is circulated in the gas turbine suction cooling water circulation flow path. In this way, water flows through the LNG gasifier and the gas turbine intake cooler in sequence. The gas turbine intake cooling water circulation pump is disposed in the gas turbine intake cooling water circulation flow path. The gas turbine power plant includes a gas turbine compressor that compresses the air flowing from the gas turbine intake cooler, and a mixed gas of air and combustion gas of natural gas (NG) discharged from the gas turbine compressor The driven gas turbine and the generator connected to the gas turbine.

In the gasifier of the LNG combustion combined cycle power generation device disclosed in Patent Document 1, icing may occur on the surface of the heat transfer tube for flowing LNG.

On the other hand, Patent Document 2 discloses a liquefied gas gasification system that can suppress the occurrence of icing in a gasifier. Specifically, the system described in Patent Document 2 uses a so-called CFC substitute having a freezing point lower than that of water as a medium for heat exchange with LNG in a heat exchanger. Therefore, the occurrence of icing in the heat exchanger can be suppressed.

In the gasification system of liquefied gas disclosed in Patent Document 2, the flow path for the circulation of the medium (CFC substitute) must be filled with the medium. Therefore, the cost (especially the opening cost) becomes very high. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 06-213001 [Patent Document 2] Japanese Patent No. 6092065

[Problems to be solved by the invention]

An object of the present invention is to provide a liquefied natural gas gasification system that can suppress the occurrence of icing in a gasifier and can suppress an increase in cost. [Technical means to solve the problem]

The liquefied natural gas gasification system according to an aspect of the present invention includes: a gasifier that vaporizes at least a part of the liquefied natural gas by heating the liquefied natural gas with water; and uses the cold energy of the water flowing out of the gasifier A cold energy utilization part, a circulation flow path connecting the gasification vaporizer and the cold energy utilization part so that water circulates between the gasifier and the cold energy utilization part, and a circulation flow path provided in the circulation flow path Circulation pump. The gasifier includes an intermediate medium evaporation unit and a liquefied natural gas vaporization unit. The intermediate medium evaporation unit allows the intermediate medium having a freezing point lower than the freezing point of water to exchange heat with the water flowing out of the cold energy utilization unit To evaporate at least a portion of the intermediate medium in the liquid phase. The liquefied natural gas vaporization section allows the intermediate medium in the gas phase generated by evaporating the intermediate medium in the liquid phase in the intermediate medium evaporation section and the foregoing The liquefied natural gas performs heat exchange, thereby gasifying at least a part of the aforementioned liquefied natural gas.

Hereinafter, embodiments will be described with reference to the attached drawings. The following embodiments are examples of embodying the present invention and are not intended to limit the technical scope of the present invention.

(First embodiment) The LNG gasification system 1 of the first embodiment will be described with reference to FIG. 1. The present liquefied natural gas gasification system 1 uses water to gasify liquefied natural gas (LNG), and supplies the cold energy recovered from the liquefied natural gas at that time to the object of utilization of the cold energy. In the gasification system 1, a so-called intermediate-type gasifier (IFV) is used as the gasifier 10. The LNG gasification system 1 includes a gasifier 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. The circulation channel 30 connects the gasifier 10 and the cold energy utilization unit 20 to each other.

The vaporizer 10 is composed of an intermediate-media vaporizer (IFV). That is, in the gasifier 10, heat is exchanged between water and liquefied natural gas through an intermediate medium M having a freezing point lower than that of water (for example, CFC substitutes such as propane, HFC-32, and R410A). Thereby, at least a part of the liquefied natural gas is gasified. In the gasifier 10, the intermediate medium M is heated by water, and the liquefied natural gas is heated by the intermediate medium M. The gasifier 10 includes an intermediate medium evaporation unit E1, a liquefied natural gas vaporization unit E2, and a housing 11 accommodating the intermediate medium evaporation unit E1, a liquefied natural gas vaporization unit E2, and an intermediate medium M.

In the intermediate medium evaporation part E1, the intermediate liquid M in the liquid phase exchanges heat with the water (warm water) flowing out from the cold energy utilization part 20. By this, at least a part of the intermediate medium M is evaporated. In the present embodiment, the intermediate medium evaporation portion E1 is constituted by a heat transfer tube disposed in the lower part of the casing 11 (the position of the intermediate medium M immersed in the liquid phase in the casing 11). That is, the intermediate medium M which is 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.

In the liquefied natural gas gasification section E2, the liquefied natural gas and the intermediate medium M in the gas phase exchange heat. By this, at least a part of the liquefied natural gas is gasified. In the present embodiment, the liquefied natural gas gasification section E2 is constituted by a U-shaped heat transfer tube. The liquefied natural gas vaporization unit E2 is arranged in an upper part of the casing 11 (a region in the casing 11 above the surface of the intermediate medium M in 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 in the gas phase that is in contact with the surface of the liquefied natural gas vaporization section E2. Specifically, the liquefied natural gas flowing in the liquefied natural gas gasification section E2 is gasified by removing the evaporation latent heat of the gas-phase intermediate medium M. On the other hand, the gas-phase intermediate medium M is Latent heat of evaporation is released to condense.

The housing 11 is connected to an inlet chamber 12 and an outlet chamber 13 which are separated from each other by a partition plate 14. The inlet chamber 12 is connected to one end of the liquefied natural gas gasification section E2 so that the inlet chamber 12 communicates with the liquefied natural gas vaporization section E2. The outlet chamber 13 is connected to the other end of the liquefied natural gas gasification section E2 so that the outlet chamber 13 communicates with the liquefied natural gas vaporization section E2. That is, the liquefied natural gas flowing into the liquefied natural gas gasification section E2 from the inlet chamber 12 is vaporized by at least a part of it by the gaseous intermediate medium M in the process of passing through the liquefied natural gas vaporization section E2, and then exits Chamber 13 flows out.

In addition, a water inlet chamber 15 and a water outlet chamber 16 are connected to the casing 11. The water inlet chamber 15 is provided on one side of the casing 11 so that the water inlet chamber 15 communicates with the intermediate medium evaporation portion E1. The water outlet chamber 16 is provided on the other side of the housing 11 so that the water outlet chamber 16 communicates with the intermediate medium evaporation portion E1. The water (warm water) flowing into the intermediate medium evaporation section E1 from the water inlet chamber 15 is cooled by the liquid intermediate medium M while passing through the intermediate medium evaporation section E1. In other words, water recovers cold energy from the intermediate medium M. The water cooled in the intermediate medium evaporation unit E1 flows out of the circulation channel 30 through the water outlet chamber 16. Although the intermediate medium evaporation portion E1 is composed of a straight tube-shaped heat transfer tube, it may be composed of a U-shaped heat transfer tube. In this case, a partition is provided in the water inlet chamber 15 to allow the water flowing into the intermediate medium evaporation portion E1 to flow back toward the water outlet 16.

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

The circulation pump (cold water pump) 32 is a portion provided on the downstream side of the vaporizer 10 in the circulation flow path 30. The circulation pump 32 sends the water (cold water) flowing out of the gasifier 10 to the cold energy utilization unit 20.

The liquefied natural gas gasification system 1 of the present embodiment includes a cold water tank 34 disposed at a portion between the gasifier 10 and the circulation pump 32 in the circulation flow path 30. The cold water tank 34 temporarily stores water (cold water) flowing out of the gasifier 10.

The LNG gasification system 1 of the present embodiment further includes: a warm water pump 36 disposed downstream of the cold energy utilization unit 20 in the circulation channel 30, and a cold energy utilization unit 20 disposed in the circulation channel 30 and Warm water tank 38 at the part between the warm water pump 36. The warm water pump 36 sends water (warm water) flowing out of the cold energy utilization unit 20 to the vaporizer 10. The warm water tank 38 temporarily stores water (warm water) flowing out of the cold energy utilization unit 20. In the part between the cold energy utilization part 20 and the warm water tank 38 in the circulation flow path 30, the standby heater 39 which heats water by a heat source medium (seawater etc.) may be provided.

The bypass channel 40 is connected to the circulation channel 30 so as to bypass the cooling energy utilization unit 20. The upstream end of the bypass flow path 40 is a portion connected between the vaporizer 10 and the cold water tank 34 in the circulation flow path 30. The downstream end of the bypass flow path 40 is a portion connected between the warm water pump 36 and the vaporizer 10 in the circulation flow path 30. Therefore, the water (cold water) passing through the bypass channel 40 is returned to the gasifier 10 again without being heated by the cold energy utilization unit 20.

The adjustment part 42 is for adjusting the ratio of the flow rate of the water flowing into the cold energy utilization part 20 to the flow rate of the water flowing into the bypass flow path 40 among the flow rates of the water flowing out of the gasifier 10. In this embodiment, the adjustment unit 42 has a bypass pump arranged in the bypass flow path 40. By adjusting the revolutions per minute (frequency) of the bypass pump, the flow rate of the water flowing into the cold energy utilization unit 20 and the flow rate of the water flowing into the bypass flow path 40 among the water flowing out of the gasifier 10 can be adjusted proportion. Instead of a bypass pump, the adjustment part 42 may be constituted by a valve whose opening degree can be adjusted. Alternatively, instead of the aforementioned valve, the adjustment portion 42 may be constituted by a three-way valve arranged at the connecting portion of the upstream end of the circulation flow path 30 and the bypass flow path 40.

The controller 50 includes a memory unit (memory device) and a computing unit (CPU, etc.), and performs predetermined functions by executing computer programs recorded in the memory unit. The function of the controller 50 includes the adjustment unit control unit 51 and the circulation pump control unit 52.

The adjustment unit control unit 51 controls the number of revolutions per minute of the adjustment unit (in this embodiment, the bypass pump) 42. Specifically, the regulator control unit 51 controls the number of revolutions per minute 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 gasifier 10 is detected by the temperature sensor 61 disposed on the downstream side of the gasifier 10 in the circulation flow path 30. 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 revolutions per minute of the circulation pump 32 and the warm water pump 36. Specifically, the circulation pump control unit 52 controls the revolutions per minute of the circulation pump 32 and the warm water pump 36 in response to the load of the cold energy utilization unit 20 indicated by the load signal output by the cold energy utilization unit 20. For example, the circulation pump control unit 52 increases the revolutions per minute of the circulation pump 32 and the warm water pump 36 in accordance with the increase in the load indicated by the load signal. Therefore, if the load on the cold energy utilization unit 20 becomes larger, 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 aforementioned load magnitude, the temperature of the portion downstream of the cold energy utilization unit 20 (for example, detection by the temperature sensor 63 provided in the warm water tank 38 Value) 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) are maintained at a substantially predetermined value (within a predetermined range). For example, if the temperature difference between the temperature on the upstream side of the cold energy utilization unit 20 and the temperature on the downstream side of the cold energy utilization unit 20 becomes larger, the circulation pump control unit 52 will increase the revolutions per minute of the circulation pump 32 and the warm water pump 36. On the other hand, if the aforementioned temperature difference becomes smaller, the revolutions per minute of the circulation pump 32 and the warm water pump 36 are reduced. In this way, the temperature difference between the temperature on the upstream side of the cold energy utilization unit 20 and the temperature on the downstream side is maintained within a predetermined range. Therefore, when the temperature difference is maintained at a substantially predetermined value, it can be determined 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 of the control by the adjustment unit 42 of the adjustment unit control unit 51.

The controller 50 may also be configured to output an alarm when the temperature of the intermediate medium evaporation unit E1 becomes below a preset first temperature (for example, -1°C), and when the temperature of the intermediate medium evaporation unit E1 (the temperature of the tube wall of the heat transfer tube) Temperature) is lower than the first temperature at a predetermined second temperature (for example, -3°C) or lower, the supply of liquefied natural gas to the gasifier 10 is stopped. The temperature of the intermediate medium evaporation part E1 is detected by a temperature sensor 64 provided at the end of the intermediate medium evaporation part E1 on the downstream side.

The warming section E3 is a section disposed between the cold energy utilization section 20 and the vaporizer 10 in the circulation flow path 30, and more specifically, a section disposed between the warm water pump 36 and the vaporizer 10. The heating unit E3 heats the gas flowing out of the vaporizer 10 by the water (warm water) flowing out of the cold energy utilization unit 20. As the heating portion E3, it is preferable to use a so-called shell-and-tube heat exchanger or a so-called plate heat exchanger.

As described above, in the LNG gasification system 1 of the present embodiment, the medium circulating in the circulation flow path 30 is water. Therefore, the increase in cost can be suppressed, and the cold energy recovered in the gasifier 10 can be effectively used in the cold energy utilization unit 20. Furthermore, in the gasifier 10, the 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, thereby suppressing the occurrence of icing in the intermediate medium evaporation part E1.

In addition, since the LNG gasification system 1 includes the bypass flow path 40 and the adjustment unit 42, even when the load of the cold energy utilization unit 20 is relatively low, it is possible to suppress the occurrence of icing in the intermediate medium evaporation unit E1 Water having a sufficient flow rate is supplied to the vaporizer 10, and the water flow rate corresponding to the load of the cold energy utilization unit 20 is circulated. 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 this case, water having a flow rate greater than the flow rate supplied to the cold energy utilization unit 20 flows into the intermediate medium evaporation unit E1 of the gasifier 10 and flows out from the intermediate medium evaporation unit E1. Therefore, the adjustment unit 42 adjusts so that the remaining amount not supplied to the cold energy utilization unit 20 among the water flowing out of the intermediate medium evaporation unit E1 flows into the bypass channel 40. In this way, the water at a flow rate corresponding to the load of the cold energy utilization unit 20 is supplied to the cold energy utilization unit 20, and a sufficient flow rate of water to prevent the temperature of the water flowing out of the intermediate medium evaporation unit E1 from excessively decreasing is to vaporize器10 Provision. Therefore, even when the load of the cold energy utilization unit 20 is small, the occurrence of icing in the intermediate medium evaporation unit E1 can be suppressed.

In addition, since the liquefied natural gas gasification system 1 is provided with the heating section E3, the gas flowing out of the gasifier 10 is effectively heated in the heating section E3.

Furthermore, since the liquefied natural gas gasification system 1 includes the adjustment unit control unit 51, the temperature of the water supplied to the cold energy utilization unit 20 can be automatically maintained at a substantially set temperature.

In addition, because the LNG gasification system 1 includes the circulation pump control unit 52, the revolutions per minute of the circulation pump 32 and the warm water pump 36 can be adjusted in accordance with the load of the cooling energy utilization unit 20, that is, the cooling energy utilization unit 20 and The amount of water supplied by the vaporizer 10.

Furthermore, since the liquefied natural gas gasification system 1 includes the cold water tank 34, the water supply flow rate of the cold energy utilization unit 20 can be effectively adjusted in response to the load fluctuation of the cold energy utilization unit 20. Similarly, because the liquefied natural gas gasification system 1 includes the warm water tank 38, the water supply flow rate of the gasifier 10 can be effectively adjusted in response to the load variation of the gasifier 10.

(Second embodiment) 2, the LNG gasification system 1 of the second embodiment will be described. In the second embodiment, only the parts different from the first embodiment will be described, and the description of the same structure, function, and effect as the first embodiment will be omitted.

In the liquefied natural gas gasification system 1 of the second embodiment, the downstream end of the bypass flow path 40 is a portion connected between the heating portion E3 and the gasifier 10 in the circulation flow path 30. That is, the bypass flow path 40 bypasses the heating portion E3.

In the second embodiment, it is possible to prevent the water (cold water) that has passed through the bypass flow path 40 from flowing into the warming section E3 (the cold energy recovered from the liquefied natural gas in the gasifier 10 is thrown into the warming section E3). Therefore, the E3 gas is effectively heated in the heating section.

(Third Embodiment) 3, the LNG gasification system 1 of the third embodiment will be described. In addition, in the third embodiment, only the parts different from the first embodiment will be described, and the description of the same structure, function, and effect as the first embodiment will be omitted.

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

In the third embodiment, the water (cold water) that has passed through the bypass channel 40 can be prevented from flowing into the warming section E3, so the gas is effectively heated in the warming section E3. Furthermore, only a part of the water flowing out of the cold energy utilization part 20 flows into the heating part E3, compared with the case where the total amount of water flowing out of the cold energy utilization part 20 flows into the heating part E3 as in the first embodiment, the heating part E3 miniaturization becomes possible.

The embodiment disclosed this time is only an example, not a limitation. The scope of the present invention is defined not by the description of the above embodiments but by the scope of patent application, and further includes all modifications within the meaning and scope equivalent to the scope of patent application.

For example, the controller 50 may be omitted, and the revolutions per minute of the circulation pump 32 and the revolutions per minute of the bypass pump are manually controlled by the operator.

In addition, another cooling energy utilization unit may be connected to the circulation channel 30 in parallel with the cooling energy utilization unit 20.

Here, the foregoing embodiment will be briefly described.

(1) The liquefied natural gas gasification system of the foregoing embodiment is provided with: a gasifier that vaporizes at least a part of the liquefied natural gas by heating the liquefied natural gas with water, and uses the cold energy of the water flowing out of the gasifier A cold energy utilization part, a circulation flow path connecting the gasification vaporizer and the cold energy utilization part so that water circulates between the gasifier and the cold energy utilization part, and a circulation flow path provided in the circulation flow path Circulation pump. The gasifier includes an intermediate medium evaporation unit and a liquefied natural gas vaporization unit. The intermediate medium evaporation unit allows the intermediate medium having a freezing point lower than the freezing point of water to exchange heat with the water flowing out of the cold energy utilization unit To evaporate at least a portion of the intermediate medium in the liquid phase. The liquefied natural gas vaporization section allows the intermediate medium in the gas phase generated by evaporating the intermediate medium in the liquid phase in the intermediate medium evaporation section and the foregoing The liquefied natural gas performs heat exchange, thereby gasifying at least a part of the aforementioned liquefied natural gas.

In this LNG gasification system, the medium circulating in the circulation flow path is water. Therefore, the increase in cost can be suppressed, and the cold energy recovered in the gasifier can be effectively used in the cold energy utilization unit. Furthermore, in the gasifier, the heat is transferred from the water to the liquefied natural gas through an intermediate medium (propane, etc.) having a freezing point lower than that of water, so the occurrence of icing in the evaporation portion of the intermediate medium can be suppressed.

(2) The liquefied natural gas gasification system may further include: a bypass flow path connected to the circulation flow path so as to bypass the cold energy utilization portion; and the flow rate of the water flowing into the cold energy utilization portion may be adjusted And an adjustment portion of the flow rate of the water flowing into the bypass flow path.

According to this structure, even when the load of the cold energy utilization part is relatively low, a sufficient flow of water required to suppress the occurrence of icing in the intermediate medium evaporation part can be supplied to the vaporizer and let the cold energy utilization part The load corresponds to the flow of water circulation. For example, when the load of the cold energy utilization unit is relatively low, the flow rate of the water supplied to the cold energy utilization unit decreases. In this case, water having a flow rate larger than the flow rate supplied to the cold energy utilization section is allowed to flow into the intermediate medium evaporation section of the gasifier and flow out from the intermediate medium evaporation section. Therefore, the adjustment part is adjusted so that the remaining amount not supplied to the cold energy utilization part among the water flowing out of the intermediate medium evaporation part flows into the bypass flow path. In this way, water at a flow rate corresponding to the load of the cold energy utilization unit is supplied to the cold energy utilization unit, and water at a sufficient flow rate to prevent the temperature of the water flowing out of the intermediate medium evaporation unit from being excessively reduced is supplied to the vaporizer. Therefore, even if the load in the cold energy utilization part is small, the occurrence of icing in the intermediate medium evaporation part can be suppressed.

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

According to this structure, the temperature of the water supplied to the cold energy utilization unit can be automatically maintained at a substantially set temperature.

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

According to this structure, the ratio of the flow rate of the water flowing into the cold energy utilization part and the flow rate of the water flowing into the bypass flow path can be effectively controlled.

(5) The liquefied natural gas gasification system may further include a warming section, which is a portion disposed between the connection section of the bypass flow path and the gasifier in the circulation flow path, and is used for The gas flowing from the aforementioned gasifier is heated.

According to this configuration, the gas flowing out of the gasifier is effectively heated in the warming section.

(6) In the LNG gasification system, the downstream end of the bypass flow path may be connected to the portion between the heating section and the gasifier in the circulation flow path.

In this aspect, water flowing through the bypass flow path can be prevented from flowing into the warming section (the cold energy recovered from the liquefied natural gas in the gasifier is put into the warming section), so the gas is effectively heated in the warming section .

(7) The liquefied natural gas gasification system may further include: a branch flow path connected to the circulation flow path so as to bypass the heating section. In this case, the downstream end of the bypass flow path may be connected to the portion between the heating section and the vaporizer among the branch flow path or the circulation flow path.

In this aspect as well, the water after passing through the bypass flow path does not flow into the heating section, so the gas is effectively heated in the heating section. Furthermore, because only a part of the water flowing out of the cold energy utilization part flows into the heating part, compared with the case where the entire amount of the water flowing out of the cold energy utilization part flows into the heating part, the miniaturization of the heating part becomes possible .

(8) The liquefied natural gas gasification system may further include a circulation pump control unit that controls the number of revolutions per minute of the circulation pump. In this case, the circulation pump may be disposed between the circulation flow path and the upstream end of the bypass flow path among the circulation flow paths, that is, between the upstream connection portion and the cold energy utilization portion Location. The circulation pump control unit may control the revolutions per minute of the circulation pump in accordance with the load of the cooling energy utilization unit indicated by the load signal output by the cold energy utilization unit.

According to this structure, the revolution per minute of the circulation pump can be adjusted in accordance with the load of the cold energy utilization part, that is, the water supply amount to the cold energy utilization part can be adjusted.

(9) The liquefied natural gas gasification system may further include a cold water tank, which is a portion disposed between the upstream-side connection portion and the circulation pump in the circulation flow path, and is used to store the gasifier from the gasifier. Water flowing out.

According to this aspect, since cold water (water flowing out of the vaporizer) is stored in the cold water tank, the amount of water supplied to the cold energy utilization unit can be effectively adjusted in response to the load fluctuation of the cold energy utilization unit.

As explained above, the occurrence of icing in the gasifier can be suppressed, and a significant increase in cost can be suppressed.

1‧‧‧LNG gasification system 10‧‧‧gasifier 11‧‧‧Housing 12‧‧‧ Entrance room 13‧‧‧Exit room 14‧‧‧Partition 15‧‧‧Water inlet room 16‧‧‧Water outlet room 30‧‧‧Circulation flow path 31‧‧‧Branch flow 32‧‧‧Circulation pump 34‧‧‧cold water tank 36‧‧‧warm water pump 38‧‧‧warm water tank 39‧‧‧Spare heater 40‧‧‧ Bypass flow path 42‧‧‧Adjustment Department 50‧‧‧Controller 51‧‧‧Adjustment Department Control Department 52‧‧‧Circulation Pump Control Department 61~64‧‧‧Temperature sensor E1‧‧‧Intermediary Media Evaporation Department E2‧‧‧LNG Gasification Department E3‧‧‧Heating Department LNG‧‧‧LNG NG‧‧‧Natural gas M‧‧‧Intermediary

FIG. 1 is a schematic diagram showing the structure of the LNG gasification system according to the first embodiment. FIG. 2 is a schematic diagram showing the structure of the LNG gasification system according to the second embodiment. FIG. 3 is a schematic diagram showing the structure of the LNG gasification system according to the third embodiment.

1‧‧‧LNG gasification system

10‧‧‧gasifier

11‧‧‧Housing

12‧‧‧ Entrance room

13‧‧‧Exit Room

14‧‧‧Partition

15‧‧‧Water inlet room

16‧‧‧Water outlet room

20‧‧‧Cool Energy Utilization Department

30‧‧‧Circulation flow path

32‧‧‧Circulation pump

34‧‧‧cold water tank

36‧‧‧warm water pump

38‧‧‧warm water tank

39‧‧‧Spare heater

40‧‧‧ Bypass flow path

42‧‧‧Adjustment Department

50‧‧‧Controller

51‧‧‧Adjustment Department Control Department

52‧‧‧Circulation Pump Control Department

61~64‧‧‧Temperature sensor

E1‧‧‧Intermediary Media Evaporation Department

E2‧‧‧LNG Gasification Department

E3‧‧‧Heating Department

LNG‧‧‧LNG

NG‧‧‧Natural gas

M‧‧‧Intermediary

Claims (9)

A LNG gasification system with: A gasifier for heating at least a portion of the liquefied natural gas by heating the liquefied natural gas with water, The cold energy utilization part that uses the cold energy of the water flowing out of the aforementioned gasifier, A circulation flow path connecting the gasifier and the cold energy utilization part in such a manner that water circulates between the gasifier and the cold energy utilization part, and Circulation pump installed in the aforementioned circulation flow path; The above-mentioned gasifier has an intermediate medium evaporation part and a liquefied natural gas gasification part, The intermediate medium evaporating part allows the intermediate medium having a freezing point lower than that of water to exchange heat with the water flowing out of the cold energy utilization part, thereby evaporating at least a part of the intermediate medium in the liquid phase, The liquefied natural gas gasification section allows at least a portion of the liquefied natural gas to be subjected to heat exchange with the liquefied natural gas in the intermediate medium evaporation section by vaporizing the liquid phase intermediate medium and the liquefied natural gas gasification. The liquefied natural gas gasification system according to claim 1, further comprising: A bypass flow path connected to the circulation flow path in a manner that bypasses the cold energy utilization portion, and An adjusting portion that can adjust the flow rate of the water flowing into the cold energy utilization section and the flow rate of the water flowing into the bypass flow path. The liquefied natural gas gasification system as described in claim 2 further includes: The regulator control section of the regulator section is controlled so that the temperature of the water flowing out of the vaporizer becomes a set temperature. The LNG gasification system according to claim 3, wherein, The adjustment section includes a bypass pump disposed in the bypass flow path, The regulator control unit controls the number of revolutions per minute of the bypass pump so that the temperature of the water flowing out of the vaporizer becomes the set temperature. The liquefied natural gas gasification system according to claim 2, which further includes a heating section, The warming section is a portion disposed between the connecting portion of the bypass flow path and the vaporizer among the circulation flow paths, and is used to heat the gas flowing out of the vaporizer. The liquefied natural gas gasification system according to claim 5, wherein, The downstream end of the bypass flow path is a portion connected between the heating section and the vaporizer in the circulation flow path. The LNG gasification system as described in claim 5, It further includes: a branch flow path connected to the circulation flow path so as to bypass the heating portion, The downstream end of the bypass flow path is a portion connected between the heating section and the vaporizer in the branch flow path or the circulation flow path. The liquefied natural gas gasification system according to any one of claims 2 to 7, It further includes: a circulation pump control unit that controls the number of revolutions per minute of the circulation pump, The circulation pump is a portion disposed between the circulation flow path and the upstream end of the bypass flow path in the circulation flow path, that is, between the upstream connection portion and the cold energy utilization portion, The circulation pump control unit controls the revolutions per minute of the circulation pump in response to the load of the cooling energy utilization unit indicated by the load signal output by the cold energy utilization unit. The liquefied natural gas gasification system according to claim 8, which is further provided with a cold water tank, The cold water tank is a portion disposed between the upstream connection portion and the circulation pump in the circulation flow path, and is used to store water flowing out of the vaporizer.

Images