JP2002039692A - Heat exchanger and heat exchange system for liquefied natural gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent LNG and air from combusting upon leakage in case of emergency in a heat exchanger for the LNG and air, eliminate the need of an LNG evaporator, and improve safety and economy. SOLUTION: There are provided a flow passage of LNG, a flow passage for air, a flow passage for an inactive fluid surrounding the former passages, and an injection nozzle capable of injection of sea water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger capable of safely and efficiently exchanging a fluid, such as a combustible substance or a poison, which is not desired to leak from a flow path.

[0002]

2. Description of the Related Art As a prior art, a heat exchanger for safely exchanging heat between flammable liquefied natural gas (hereinafter, referred to as LNG) and compressed air having flammability has been disclosed in JP-A-2000-2000. There is one described in Japanese Patent No. In this prior art, in order to avoid an unexpected event due to leakage, it is proposed to provide a buffer passage between a heated passage through which air flows and a heated passage through which LNG flows. Should a leak occur in the heating-side flow path or the heated-side flow path, the leaked fluid is discharged to an adjacent buffer flow path,
Mixing with the fluid on the other side for heat exchange is prevented.

[0003]

In the above-mentioned known example, measures to prevent mixing of air and LNG have been taken, and improvement in safety has been achieved. However, water and carbon dioxide in the air are cooled, No countermeasures were taken when ice or dry ice was generated and adhered to the heat transfer surface. When ice or dry ice adheres to the heat transfer surface, the heat transfer resistance increases, the flow path becomes narrower, the pressure loss increases, and the heat transfer performance deteriorates.

[0004] It is an object of the present invention to provide a heat exchanger for recovering cold from LNG, which has improved heat transfer performance.

[0005]

In order to achieve the above object, a heat exchanger according to the present invention is a heat exchanger for liquefied natural gas, comprising: a first flow passage through which liquefied natural gas flows; It is characterized by having a second flow path through which a heating fluid that superheats liquefied natural gas flows, and a third flow path divided from the first and second flow paths.

[0006]

(Embodiment 1) FIG. 3 and FIG.
1 shows an embodiment of a gas turbine power generation system utilizing an LNG cold energy, which includes a heat exchanger according to the present invention. The main components of the present invention are a compressor 51 for compressing air to high pressure, a combustor for burning compressed air and fuel such as LNG, a gas turbine 7 driven by expansion of high-temperature and high-pressure combustion gas, A generator 8 arranged on the same axis as the gas turbine 7,
A regenerative heat exchanger 9 for recovering heat of the exhaust gas from the gas turbine 7.

[0007] The main components of the embodiment are as follows.
A heat exchanger 70 for exchanging heat between LNG supplied from the LNG storage tank 43 via the pipe 40 and intake air of the compressor 51. In the heat exchanger 70, the cold heat recovery system is stopped, (A) the cold heat recovery mode for recovering the cold energy of the LNG, and (B) the ice melting mode for freezing the ice or dry ice generated in the air pipe. In this case, there are three types of operation modes of (C) vaporization mode in which LNG is vaporized alone. In this embodiment, the heat exchanger 70a in FIG. 3 operates as the cold heat recovery mode, and the heat exchanger 70b in FIG. Works as ice mode,
5 illustrates a case where the heat exchanger 70c of FIG. 4 operates in the vaporization mode. As means for switching the operation mode, switching valves 78a, 78b, 78c and check valves 79a, 79
b, 79c. In addition, a water source 45 using marine water, a water supply pipe 1 for supplying water from the water source 45 to the heat exchanger
5, drainage pipe 16 for discharging water supplied by water supply pipe 15, water condensed in the air pipe of the heat exchanger, and water generated in the deicing mode are discharged by condensed water pipe 47 and temporarily stored. The condensed water tank 46 is a characteristic component.

FIG. 1 is a schematic view of a heat exchanger according to an embodiment of the present invention. In the present embodiment, the heat exchanger 70 includes a heating-side fluid heat transfer tube group 23 forming the air passage 18 and a heated-side fluid heat transfer tube group 24 forming the natural gas passage 19. Are parallel to each other,
They are connected to each other by plate fins 22 made of aluminum alloy. The heating-side fluid heat transfer tube group 23 and the heated-side fluid heat transfer tube group 24 are copper tubes, and grooves are formed on the inner surfaces of the tubes to promote heat transfer. As shown in FIG. 1, one end of each of these heat transfer tubes is gently bent at an angle of 90 ° with respect to the central axis, and the heating-side fluid heat transfer tube group 23 and the heated-side fluid heat transfer tube Group 24
After being inserted into the plate fins 22 in directions facing each other, the pipes are expanded by a mandrel or hydraulic pressure, and are mechanically joined to the plate fins 22. The thickness of the plate fins 22 is 0.3 mm, and the pitch is 3 mm.
Headers 25 and 26 are connected to the tube ends of the heat transfer tubes, and integrate the flow of each heat transfer tube group. Further, an injection nozzle 60 is disposed above the heating-side fluid heat transfer tube group 23 and the heated-side fluid heat transfer tube group 24, and water from a water source 45 supplied from the water supply pipe 15 is supplied to the heat transfer tube group and the plate fin 22. Is set to be sprayed on the whole. The heat exchanger 70 is housed in the body 30 (not shown), and the space inside the body becomes the inert gas flow path 20 made of nitrogen gas. Further, the water melted in the deicing mode is transferred to the heating-side fluid heat transfer tube group 2.
The condensed water pipe 47 is connected to the header 25
Attached to the bottom of the In addition, in order to promote the discharge of moisture from the heating-side fluid heat transfer tube group 23, the condensed water pipe 4
The entire heat transfer tube group is arranged so as to be inclined such that 7 is at a lower position.

FIG. 2 shows the configuration of a safety system and a deicing / vaporizing system relating to the heat exchanger. The configuration shown in FIG. 2 is for a single unit of the heat exchanger,
When a plurality of units are used, a switching valve 78 and a check valve 79 are separately required as shown in FIGS. As a safety system, nitrogen gas supplied from a nitrogen gas supply device 76 is supplied via a gas pressure control valve 75,
Inert gas flow path 20 inside body 30 of heat exchanger 70
To one end. At the other end of the inert gas flow path, a pressure gauge 81 and a gas detector 82 are installed. If a failure occurs in the natural gas (hereinafter, referred to as NG) flow path, the NG becomes inert gas. In the case of leakage into the flow path, the shut-off valves 85a to 85d are automatically closed by a command from the control circuit 83. At the same time, shutoff valves 85f and 85e
Is automatically operated so that water can be injected from the injection nozzle 60 to the heat transfer tube, and the water can be drained as necessary. Also,
A rupture disk 86 that opens automatically when the pressure rises above a certain limit is installed in the flow path of the inert gas, and the other end of the rupture disk 86 is connected to a flare stack 88 by a pipe 87.

The operation of this embodiment will be described with reference to FIGS. 1, 2 and 3. The state of the switching valve 78 shown in FIG.
The heat exchanger 70a operates in the cold heat recovery mode, and the heat exchanger 70b operates in the thawing mode. The air at a temperature of about 30 ° C. sucked by the operating air blower 80 flows into the air passage 18 of the heat exchanger 70a by the operation of the switching valve 78a. On the other hand, LNG at a temperature of about −160 ° C. stored in the LNG storage tank 43 is pressurized by a pump, and is operated by the switching valve 78 b through the pipe 40.
It is supplied to the natural gas channel 19 of the heat exchanger 70a. Further, the seawater of the water source 45 is transferred by a pump, and is operated from the water supply pipe 15 by the operation of the switching valve 78c.
Is supplied to the injection nozzle 60.

In the heat exchanger 70a, from the heating-side fluid heat transfer tube group 23 through which air flows to the heated-side fluid heat transfer tube group 24 through which NG flows, from the inner wall surface of the air to the heating-side fluid heat transfer tube group 23 to the heat transfer tube group. Material-Outer wall surface of the heat transfer tube-Plate fin 2
Heat is transmitted by convective heat transfer, heat conduction, and contact heat transfer in a route of the material No. 2, the tube outer wall surface of the heated-side fluid heat transfer tube group 24, the heat transfer tube material, the tube inner wall surface, and NG. Heat exchanged. By the action of this heat exchange, the air becomes -1
The NG is cooled to about 30 ° C. and heated to −10 ° C. The intake air cooled to −130 ° C.
Is compressed to about 15 atm. At this time, since the air that has been cooled and has a high density is compressed, the air can be compressed with less than half the power as compared with the case where the normal temperature air is compressed to about 15 atm. Although the temperature of the compressed air rises to about 70 ° C., it is further heated to about 500 ° C. by the regenerative heat exchanger 9 and burned in the combustor 5 together with the fuel 50 such as LNG. In the gas turbine 7, the generator 8 is driven by the expansion force of the high-temperature and high-pressure combustion gas to generate electric power. The exhaust gas of the gas turbine 7 is
The heat is recovered by the regenerative heat exchanger 9 and discharged from the stack 55 to the atmosphere. In this way, by utilizing the cold energy possessed by LNG, usually, the gas turbine output of 50 to
The power of the air compressor that consumes 60% can be greatly reduced,
As a result, the power generation output can be greatly increased. However, if this operation mode is continued, since the air is cooled to a low temperature, the temperature becomes lower than the melting point of moisture or carbon dioxide contained in the air, and there is a problem that ice or dry ice sticks to the inner wall surface of the heat transfer tube. . As a method of avoiding this, there are a method of switching and using a plurality of heat exchangers, and a method of installing a filter that adsorbs moisture and carbon dioxide upstream of the heat exchanger. In this embodiment, by switching the flow path,
A method of removing generated ice and dry ice was adopted.

The heat exchanger 70b operates to remove ice and dry ice generated during the operation described in the heat exchanger 70a. No fluid is supplied to the heating-side fluid heat transfer tube group 23 and the heated heat-side fluid heat transfer tube group 24 from the outside, and the water from the water source 45 is supplied to the injection nozzle 60. The water supplied to the injection nozzle 60 is injected into the entirety of the heat transfer tube groups 23 and 24 and the plate fins 22 and flows down along the fins. At this time, ice and dry ice generated on the inner wall surface of the heat-side fluid heat transfer tube group 23 are finally heated to near the water temperature of the water source 45 by heat conduction between the fins and the heat transfer tubes,
Thaw. The melted water flows down toward the header 25 in the tube of the heating-side fluid heat transfer tube group 23 installed at an angle,
The condensed water is collected from a condensed water pipe 47 into a condensed water tank 46.
The melted dry ice is dissolved in water and condensed water tank 4
6 and stay in the pipe, but are discharged outside before the next operation starts. The time during which the thawing mode is continued is determined by the time required for the thawing, and depends on the water temperature of the water source 45 and the flow rate. The use of hot water that utilizes the waste heat of a gas turbine instead of seawater reduces the time required for de-icing. Further, if antifreeze is used as the water source 45 instead of seawater or water, it is possible to prevent the liquid used at the time of defrosting from freezing on the surface of the plate fin 22,
The flow rate supplied from the water source 45 can be reduced.

Next, the operation when the heat exchanger 70c is switched to the vaporization mode will be described with reference to FIG. Switching valve 78 for supplying LNG from LNG storage tank 43
b, both systems are open, and the switching valve 78c of the line for supplying seawater from the water source 45 is also open. Further, the switching valve 78a of the line for supplying air from the air blower 80 is closed in both systems. The seawater supplied to the injection nozzle 60 is supplied to the heat transfer tube group 2
3, 24 and the entire plate fin 22 is sprayed,
Flow down along the fins. Heated fluid transfer tube group 24
NG is flowing through the fins, and heat is exchanged with seawater by heat conduction between the fins and the heat transfer tubes. Since seawater crosses the heat transfer tube almost at right angles, the temperature drop is small, but in order to prevent freezing, it is cooled down to 0 ° C or less to prevent freezing. Set. The LNG is vaporized and heated, and eventually rises in temperature to near the water temperature of the water source 45. The seawater used for heating the LNG flows down the body 30 of the heat exchanger 70c along the slope, passes through the check valve 79c, and is discharged to the sea from the drainage pipe 16. When seawater is used as the water source 45, the necessary flow rate is determined from the viewpoint of preventing freezing, and the transfer power of the pump may reduce the overall efficiency. If the water or antifreeze is heated using the waste heat of the gas turbine instead of seawater, the required flow rate is reduced, and the transfer power of the pump can be reduced. In this case, it is desirable that the drainage pipe 16 be connected to the water source 45 and reheated to reuse water and antifreeze. If a water-repellent coating such as Teflon (registered trademark) is applied to the surface of the plate fin 22, the fin surface is less likely to be wet, and seawater and the like can be prevented from freezing on the surface of the plate fin 22. The supply flow rate can be reduced. At this time, since the portion close to the outlet of the NG has a relatively high temperature and is originally hard to freeze, it is desirable to limit the water-repellent treatment to the fins at the inlet of the LNG. The reason is that the water-repellent treatment increases the production cost of the heat exchanger and lowers the heat transfer coefficient.

As described above, the heat exchanger and the heat exchange system according to the present embodiment have a mode in which the LNG vapor can be operated independently, in addition to a mode utilizing the cold heat possessed by LNG. Conventionally, it is necessary to separately install an LNG vaporizer capable of vaporizing LNG equivalent to the amount used in the system using LNG cold heat in preparation for the case where the system using LNG cold heat is stopped or stopped.
In this case, the total facility construction cost will be increased. On the other hand, according to the present embodiment, it is not necessary to construct a carburetor that is separately required in preparation for the stoppage of a system utilizing cold heat, such as a cold-heat-utilizing gas turbine power generation system, thereby improving the economics of the entire plant. be able to.

Next, referring to FIG. 2, in this embodiment,
The operation in the event that a leak occurs in the heat exchanger 70 will be described. The flammable LNG flows in the cold heat recovery mode and the vaporization mode, and each mode will be described.

In the cold recovery mode, as described above, air at normal temperature and about atmospheric pressure flows through the air flow path 18.
Pressurized LNG is supplied to the natural gas channel 19 and is heated by heat exchange to become NG. Further, nitrogen gas is supplied to the inert gas passage 20 from a nitrogen gas supply device 76. With the operation of the heat exchanger 70, the supplied nitrogen gas is also cooled and its volume is reduced, so that the nitrogen gas pressure in the inert gas flow path 20 is reduced to about atmospheric pressure by automatic control of the gas pressure control valve 75. Control so that Also,
When the operation is stopped and the temperature of the entire heat exchanger 70 rises, the pressure of the inert gas flow path 20 rises. Therefore, the nitrogen gas discharge valve 77 is operated to control the pressure to about the atmospheric pressure. I do. It is assumed that any part of the natural gas flow path 19 through which NG flows is damaged. The NG is discharged into the inert gas passage 20 which is a space in the body 30 of the heat exchanger 70. A pressure gauge 81 is provided at one end of the inert gas flow path 20.
And a gas detector 82 are installed, and when the pressure changes,
By detecting the change in the gas concentration, the shutoff valves 85a to 85d are closed according to a command from the control circuit 83. further,
The shutoff valve 85f is opened, and the seawater of the water source 45 is supplied from the injection nozzle 60 to the heat transfer tube groups 23, 24 and the plate fins 22.
Inject the whole. This prevents the NG from being heated to a high temperature required for ignition or combustion at each location in the heat exchanger. By closing the shutoff valve 85e, the body 30
The inside can be filled with water and further suppresses the combustion reaction. If the flow rate of the leakage is large and the pressure in the cylinder 30 rises above a set limit, the rupture disk 86 automatically ruptures and opens, and the NG does not mix with the combustion assisting air. The gas is guided to the flare stack 88 via the pipe 87 while being mixed with the inert gas filled in the gas, and is safely discharged outside the system while burning the unburned gas.
This event ends as soon as all the NG present inside the shut-off valves 85a and 85b of the heat exchanger 70 is released.

In the case of the vaporization mode, there is no flow in the air flow path 18, and pressurized LNG is supplied to the natural gas flow path 19.
5 are injected into the entirety of the heat transfer tube groups 23 and 24 and the plate fins 22. The inert gas passage 20 is filled with nitrogen gas, as in the case of the cold heat recovery mode. It is assumed that any part of the natural gas flow path 19 through which NG flows is damaged. The NG is discharged into the inert gas passage 20 which is a space in the body 30 of the heat exchanger 70. As in the case of the cold heat recovery mode, the change in pressure and the change in gas concentration are detected by the pressure gauge 81 and the gas detector 82, and the shutoff valves 85a to 85b are closed by a command from the control circuit 83. In the vaporization mode, since the shut-off valve 85f is open from the beginning, the injection nozzle 60f
From above, the seawater of the water source 45 is injected into the entirety of the heat transfer tube groups 23 and 24 and the plate fins 22. This prevents the NG from being at a high temperature required for ignition or combustion at each location in the heat exchanger. By closing the shut-off valve 85e, the inside of the trunk 30 can be filled with water,
Further, the combustion reaction can be suppressed. If the leakage flow rate is large and the pressure in the barrel 30 rises above a set limit, the rupture disk 86 automatically ruptures and opens, and the leakage operation is quickly performed by the same operation as in the cold heat recovery mode. finish. (Embodiment 2) Next, a heat exchange system according to another embodiment of the present invention will be described with reference to FIGS. 5, 6, and 7. FIG. This embodiment is substantially the same as the heat exchange system of the above embodiment, including the fact that it can be applied to an LNG cold-heat-utilizing gas turbine power generation system, so only different parts will be described. In the present embodiment, a cylindrical triple tube type is assumed as the heat exchanger 70. Natural gas flow path 19 through which LNG flows
Is the innermost flow path, the air flow path 18 through which air flows is disposed at the outermost circumference, and the inert gas flow path 20 is located in the middle of these. Fins 22 are provided in the air flow path 18 and the natural gas flow path 19 to promote heat transfer between the fluid and the heat transfer tube wall. The air flow path 18 and the natural gas flow path 1 are formed in the inert gas flow path 20 by heat conduction of the fin material.
For the purpose of enabling the heat transfer of No. 9, metal fins 22 having good heat conductivity are provided. The heat exchanger of this embodiment differs from the heat exchanger of the embodiment described with reference to FIG. 1 in that there is no injection nozzle 60 for injecting water and that the heat transfer tubes are arranged almost vertically. is there.

FIG. 7 shows a configuration of a safety system and an ice melting / vaporizing system relating to the heat exchanger. The configuration shown in FIG. 7 is a configuration for a single unit of the heat exchanger. When a plurality of units are used, the configuration shown in FIG.
As shown in FIG. 4, a switching valve 78 and a check valve 79 are separately required. FIG. 7 is different from the embodiment described with reference to FIG. 2 in that, instead of having the injection nozzle 60, the water source 4 is supplied to the inert gas flow path 20 by operating the shut-off valve 85f.
5 is to supply seawater directly.

The operation of this embodiment will be described with reference to FIGS.

In the cold heat recovery mode, air is supplied to the heat exchanger 70 in the air flow path 18 and N is supplied to the natural gas flow path 19.
G is supplied to the inert gas flow path 20. From the outer air flow path 18 through which air flows to the inner natural gas flow path 19 through which NG flows, the air-fins of the air flow path-the pipe material outside the inert gas flow path 20 -the inert gas flow path 20 Heat is transmitted by convection heat transfer, heat conduction, and contact heat transfer through the route of the fin material, the inner tube material, the inner fin of the inner tube, and NG, and the NG is exchanged with air.

In the thawing mode, an operation for removing ice or dry ice generated in the air flow path 18 is performed. No fluid is supplied to the air flow path 18 and the natural gas flow path 19 from the outside, and the water of the water source 45 is supplied to the inert gas flow path 20 by opening the shutoff valve 85f. Inert gas flow path 20
Is supplied through the flow path, the fins of the inert gas flow path 20 ~ the tube material outside the inert gas flow path 20 ~
Convection heat transfer, heat conduction, contact heat transfer, and the like are generated in a path from the fin to the air in the air flow path 18, and ice and dry ice generated on the fins and the pipe wall surface of the air flow path 18 are heated and melted. The melted water flows downward in the pipe of the air flow path 18 installed substantially vertically, and is discharged.

In the vaporization mode, no fluid is supplied to the outside air passage 18 from outside, and the inside natural gas passage 19 is not supplied.
And LNG, and the seawater of the water source 45 is supplied to the inert gas flow path 20 sandwiched between them. Seawater to inert gas channel 2
0 fin material-inner tube material-inner tube inner fin-N
In the path G, heat is transmitted by convective heat transfer, heat conduction, and contact heat transfer, and heat exchange occurs between seawater and LNG. In order to prevent seawater from freezing, the flow rate of seawater is set by calculating the heat balance so as not to be cooled to a temperature of 0 ° C. or less. L
The NG is vaporized and heated, and eventually rises in temperature to near the water temperature of the water source 45. The seawater used for heating the LNG is drained from the drainage pipe 16 into the sea. If the water source 45 is not seawater but is heated from water and antifreeze using the waste heat of a gas turbine, the required flow rate can be reduced and the pumping power can be reduced. Same as the example.

Next, referring to FIG. 7, in this embodiment,
The operation in the event that a leak occurs in the heat exchanger 70 will be described. The flammable LNG flows in the cold heat recovery mode and the vaporization mode, and each mode will be described.

In the cold heat recovery mode, as described above, air at normal temperature and about atmospheric pressure flows through the air flow path 18.
Pressurized LNG is supplied to the natural gas channel 19 and is heated by heat exchange to become NG. Further, nitrogen gas is supplied to the inert gas passage 20 from a nitrogen gas supply device 76. The method of controlling the pressure of the nitrogen gas is the same as that in the above embodiment. It is assumed that any part of the natural gas flow path 19 through which NG flows is damaged. N
G is discharged into an inert gas passage 20 existing outside the natural gas passage 19. At one end of the inert gas flow path 20, a pressure gauge 81 and a gas detector 82 are installed.
By detecting changes in pressure and changes in gas concentration,
The shutoff valves 85a to 85d are closed by a command from the control circuit 83. The shutoff valves 85e and 85f are closed from the beginning. When the pressure in the inert gas passage 20 rises above a set limit due to leakage, the rupture disk 86 automatically ruptures and opens, and the NG does not mix with the combustion assisting air. The flare stack 8 is mixed with the inert gas filled in the passage 20 via the pipe 87 while being mixed.
8, and thereafter, the operation is the same as in the above embodiment.

In the vaporization mode, there is no flow in the air flow path 18, pressurized LNG is supplied to the natural gas flow path 19, and the seawater of the water source 45 is supplied to the inert gas flow path 20. Supplied. Natural gas flow path 19 in which NG flows
It is assumed that any of the parts is damaged. The NG is discharged into the inert gas passage 20 adjacent to the outside of the natural gas passage 19. Although a large amount of seawater flows in the inert gas flow path 20, the pressure of the line can be detected by the pressure gauge 81, and from the change in the pressure, the shutoff valves 85a to 85b are instructed by the control circuit 83. Closes. In the vaporization mode, since the shut-off valve 85f is open from the beginning, a large amount of seawater flows in the inert gas flow path 20, and the temperature becomes high enough to ignite or burn NG in the heat exchanger. Is prevented. After the operation of the rupture disk 86 when the pressure in the inert gas flow path 20 exceeds the set limit, the operation is the same as that of the above-described embodiment.

According to the above two embodiments, the heat exchanger according to the present invention, the heat exchange system, and the LNG having the heat exchanger
Although the embodiment of the cold-heat-utilizing gas turbine power generation system has been described as an example, the present invention also includes, for example, L
The present invention can be applied to all systems utilizing the cold heat of LNG, such as an NG cold heat utilizing liquid air production system.

[0027]

According to the present invention, in a heat exchanger for recovering cold heat from LNG, it is possible to provide a heat exchanger with improved heat transfer performance.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a heat exchanger according to the present embodiment.

FIG. 2 is a schematic diagram of a gas turbine power generation system utilizing LNG cold energy according to the embodiment.

FIG. 3 is a schematic diagram of a safety system and an ice melting / vaporizing system according to the embodiment.

FIG. 4 is a schematic diagram of a safety system and an ice melting / vaporizing system according to the present embodiment.

FIG. 5 is a schematic sectional view of the heat exchanger according to the embodiment.

FIG. 6 is a schematic diagram of a heat exchanger according to the present embodiment.

FIG. 7 is a schematic diagram of a safety system and an ice melting / vaporizing system according to the present embodiment.

[Explanation of symbols]

5: Combustor, 7: Gas turbine, 8: Generator, 9: Regeneration heat exchanger, 15: Water supply pipe, 16: Drain pipe, 18: Air flow path, 19: Natural gas flow path, 20: Inert gas Channel,
Reference numeral 22: fin, 23: heating-side fluid heat transfer tube group, 24: heated-side fluid heat transfer tube group, 25, 26: header, 30: trunk, 4
0 ... pipe, 43 ... LNG storage tank, 45 ... water source, 46
... condensed water tank, 47 ... condensed water piping, 51 ... air compressor, 55 ... stack, 60 ... injection nozzle, 70 ... heat exchanger, 75 ... gas pressure control valve, 76 ... nitrogen gas supply device,
77: nitrogen gas discharge valve, 78: switching valve, 79: check valve,
80: air blower, 81: pressure gauge, 82: gas detector,
83: control circuit, 85: shut-off valve, 86: rupture disk, 87: piping, 88: flare stack.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koichi Chino 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in Hitachi, Ltd. Electric Power and Electrical Development Laboratory 3L044 AA00 BA00 CA02 DB03 EA04 FA04 HA05 JA03 JA06 KA02 KA04 3L103 AA35 AA44 BB30 CC03 CC18 CC22 CC40 DD09 DD10 DD22 DD33 DD38 DD42 DD61 DD63

Claims (9)

[Claims] 1. A heat exchanger for liquefied natural gas, comprising: a first flow path for circulating liquefied natural gas; a second flow path for circulating a heating fluid for heating the liquefied natural gas; 1
And a third flow passage partitioned from the second flow passage. 2. A heat exchanger for liquefied natural gas, comprising: a first flow path for circulating liquefied natural gas; a second flow path for circulating a heated fluid for superheating the liquefied natural gas; 1
And a third flow path partitioned from the second flow path, and provided with an injection nozzle capable of injecting a nonflammable liquid into an internal space of the third flow path. Liquefied natural gas heat exchanger. 3. The liquefied natural gas heat exchanger according to claim 1, wherein the first passage through which the liquefied natural gas flows is provided.
A heat exchanger for liquefied natural gas, characterized in that the second flow paths for flowing the heating fluid are each formed by a heat transfer tube, and the heat transfer tubes are connected to each other by a heat conductive member. 4. The liquefied natural gas heat exchanger according to claim 3, wherein a part or all of the surface of the heat conductive member is coated with a water-repellent substance. Liquefied natural gas heat exchanger. 5. A first flow path for circulating liquefied natural gas,
A second flow of a heating fluid that superheats the liquefied natural gas;
A non-combustible gas and a non-combustible liquid are supplied to the third flow path which is divided from the first and second flow paths. A heat exchange system for liquefied natural gas, comprising a possible pipe. 6. A liquefied natural gas heat exchanger, comprising: a first flow path for flowing liquefied natural gas; a second flow path for flowing a heated fluid for superheating the liquefied natural gas; 1
And a third flow path partitioned from the second flow path; an injection nozzle capable of injecting a nonflammable liquid into an internal space of the third flow path; Is provided with a pipe capable of supplying a nonflammable gas, and a pipe capable of supplying a nonflammable liquid to the injection nozzle. 7. The liquefied natural gas heat exchange system according to claim 5, wherein the non-flammable liquid is seawater, water, or an antifreeze. Heat exchange system. 8. A first flow path for circulating liquefied natural gas,
A second flow of a heating fluid that superheats the liquefied natural gas;
, A third flow path partitioned from the first and second flow paths, and a non-flammable gas or a non-flammable liquid is switchably supplied to an internal space of the third flow path. A liquefied natural gas heat exchange system comprising a supply device. 9. An air cooler for cooling air by using cold heat of liquefied natural gas, a compressor for compressing the cooled air, and a combustor for burning the compressed air and LNG fuel. A gas turbine driven by expansion of the combustion gas, and a power generator driven by a power generated by the gas turbine, wherein the air cooler is configured to circulate liquefied natural gas. A gas flow path, a second flow path through which a heating fluid that superheats the liquefied natural gas flows, and a third flow path partitioned from the first and second flow paths. Turbine power generation system.