JP2010203520A - Apparatus of vaporizing low-temperature liquefied gas and method of vaporizing low-temperature liquefied gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus of vaporizing low-temperature liquefied gas and a method of vaporizing the low-temperature liquefied gas, inexpensive in initial equipment cost as compared with a conventional apparatus of vaporizing the low-temperature liquefied gas and reducing an operating cost. <P>SOLUTION: The apparatus of vaporizing the low-temperature liquefied gas includes: a natural ventilation type air temperature vaporizer 10; a hot-water bath vaporizer 40; and an operation control device performing operation of vaporizing the low-temperature liquefied gas by operating the air temperature vaporizer 10 as the vaporizer for a base load, and supplying the vaporized gas to a destination for supply, wherein outlet gas temperature of the temperature vaporizer 10 is measured, the vaporized gas from the air temperature vaporizer 10 is heated by the hot-water bath vaporizer 40 according to the outlet gas temperature and the vaporized gas is supplied to the destination for supply, or operation of vaporizing the low-temperature liquefied gas by the hot-water bath vaporizer 40 in place of the air temperature vaporizer 10 and supplying the vaporized gas to the destination for supply. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a low-temperature liquefied gas vaporizer for vaporizing and re-gasifying a low-temperature liquefied gas such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG) using the atmosphere (air) as a heat source when used. And a method for vaporizing a low-temperature liquefied gas.

  At small-scale LNG satellite stations, air temperature type vaporizers that use air as the heat source are mostly used as base load (core) vaporizers, and hot water is used as the heat source for vaporization. A hot water bath type vaporizer with good operation responsiveness is installed as a backup for the air temperature type vaporizer.

  The air temperature type vaporizer is a heat exchanger having a finned heat transfer tube made of an aluminum alloy and vaporizes the liquefied natural gas by heat exchange with the atmosphere (outside air). In this air temperature type vaporizer, when vaporized operation of liquefied natural gas is performed, moisture in the atmosphere grows on the surface of the finned heat transfer tube and the vaporization performance (heat transfer performance) decreases gradually. For this reason, it is necessary to temporarily stop the vaporization operation after operating for a certain period of time, and perform ice melting using the heat of the atmosphere or hot water. While this vaporization operation is stopped, the operation is switched to another air temperature type vaporizer installed in parallel with the air temperature type vaporizer as a switching machine (standby machine). The above-mentioned deicing is generally performed by sprinkling with a sprinkling-type ice-melting facility in winter and by natural air in the season (warm season) except for winter.

  In this way, at the small-scale liquefied natural gas satellite base, two air temperature type vaporizers for operation and switching are set as one unit, and the two air temperature type vaporizers and the water spray type icebreaker are installed. A predetermined number of low-temperature liquefied gas vaporizers are provided.

  FIG. 4 is a flowchart schematically showing a configuration of a conventional low-temperature liquefied gas vaporizer.

  As shown in FIG. 4, the conventional low-temperature liquefied gas vaporizer includes two naturally ventilated air temperature vaporizers 70 </ b> A and 70 </ b> B and a watering type ice-melting facility 80. Reference numeral 71 denotes a liquefied natural gas supply line communicating with a liquefied natural gas supply source (not shown). A pipe 72a communicates from the liquefied natural gas supply line 71 to the liquefied natural gas inlet of the first air temperature type vaporizer 70A, and the second air temperature type vaporizer 70B is connected to the liquefied natural gas supply line 71. A pipe 72b communicates with the liquefied natural gas inlet. A natural gas delivery pipe 74 communicates with a gas supply destination (not shown). A line 73a communicates from the natural gas outlet of the first air temperature type vaporizer 70A to the natural gas delivery line 74 and from the natural gas outlet of the second air temperature type vaporizer 70B to the natural gas delivery line 74. The pipe line 73b is in communication with. The natural gas delivery pipe 74 is provided with a natural gas heater 75 for heating the natural gas (NG) from the air temperature type vaporizers 70A and 70B.

  Next, the watering type ice melting facility 80 will be described. 81 is a watering pit, 82 is a watering circulation pump, and 83 is a watering heater. 84a is a first sprinkler header installed close to and above the first air temperature vaporizer 70A, and 84b is a second water spray header installed near and above the second air temperature vaporizer 70B. It is a watering header. Reference numeral 85 is a hot water boiler for producing hot water, and 86 is a hot water circulation pump.

  Further, a pipe line 87a for supplying water to the first watering header 84a communicates from the watering circulation pump 82 through which watering from the watering pit 81 is guided. The sprinkler warmer 83 is provided in the pipe line 87a. Further, a pipe 87b is provided for branching from the pipe 87a to connect the watering circulation pump 82 and the second watering header 84b, and for supplying water to the second watering header 84b. Yes. Reference numeral 88a denotes a pipe for returning the water spray used in the first air temperature type vaporizer 70A to the water spray pit 81, and reference numeral 88b denotes the water spray used in the second air temperature type vaporizer 70B. This is a conduit for returning to

  Also, a pipe 89a for flowing hot water from the hot water circulation pump 86 through which the hot water from the hot water boiler 85 is guided to the sprinkler warmer 83 communicates with the hot water boiler 85 from the sprinkler warmer 83. A pipe line 89b for returning the used hot water is in communication.

  The natural gas heater 75 provided in the natural gas delivery line 74 includes a hot water boiler 85, a hot water circulation pump 86, a natural gas heater 75, and a hot water boiler 85. Is circulated and supplied. The natural gas heater 75 may not be used during the warm season.

  In the low-temperature liquefied gas vaporizer configured as described above, the liquefied natural gas is supplied to the second air temperature type vaporizer 70B during the vaporization operation through the liquefied natural gas supply pipe 71 and the pipe 72b, for example. Natural gas from the warm vaporizer 70B is sent to a gas supply destination outside the system through the pipe 73b and the natural gas delivery pipe 74. On the other hand, the first watering header 84a of the first air temperature type vaporizer 70A during ice melting includes a watering pit 81 → watering circulation pump 82 → watering heater 83 → first watering header 84a → air temperature. Sprinkling water is circulated and supplied through the route of the type vaporizer 70 </ b> A → watering pit 81. Then, sprinkling water is sprayed (sprayed) from the water spray header 84a to the heat exchanger from above the heat exchanger of the air temperature type vaporizer 70A, and the ice layer generated on the finned heat transfer tube surface of the heat exchanger is solved. Ice is done.

  Thus, in the conventional low-temperature liquefied gas vaporizer, when one air temperature type vaporizer 70A is performing ice melting, the other air temperature type vaporizer 70B performs a vaporization operation, and the other air temperature type vaporizer is operated. When 70B is performing ice melting, one of the air temperature type vaporizers 70A performs the vaporization operation, and the continuous operation is performed.

JP 2002-5398 A

  However, in the conventional low-temperature liquefied gas vaporizer described above, the air temperature type vaporizer requires a switching device for de-icing, and it is necessary to provide two units of air temperature type vaporizers with high initial equipment costs as one unit. In addition, since it is necessary to provide a sprinkling type ice-melting equipment for ice-breaking in winter, there is a problem that initial equipment costs are expensive.

  Therefore, the problem of the present invention is that the initial equipment cost (initial cost) is lower than that of a conventional low-temperature liquefied gas vaporizer equipped with two naturally ventilated air temperature type vaporizers as one unit. An object of the present invention is to provide a low-temperature liquefied gas vaporizer and a low-temperature liquefied gas vaporization method capable of reducing operating costs (running costs).

  In order to solve the above problems, the present invention takes the following technical means.

  The invention according to claim 1 is a naturally ventilated air temperature type vaporizer for vaporizing a low-temperature liquefied gas by a heat exchanger having finned heat transfer tubes and supplying the vaporized gas to a gas supply destination, and a hot water bath type vaporizer And operating the air temperature type vaporizer as a base load vaporizer, vaporizing the low temperature liquefied gas from the low temperature liquefied gas supply source in the heat exchanger, supplying the vaporized gas to the gas supply destination, At that time, the outlet gas temperature of the air temperature type vaporizer is measured, and the vaporized gas from the air temperature type vaporizer is heated by the hot water bath type vaporizer according to the outlet gas temperature, and the vaporization is performed. The operation of supplying gas to the gas supply destination, or the low temperature liquefied gas from the low temperature liquefied gas supply source is vaporized by the hot water bath type vaporizer instead of the air temperature type vaporizer, and the vaporized gas is converted into the gas An operation control device for performing an operation to supply to the supply destination; A low-temperature liquefied gas vaporizer apparatus characterized by comprising a.

  According to a second aspect of the present invention, there is provided the low-temperature liquefied gas vaporizer according to the first aspect, wherein a suction fan device having a suction port communicating with a lower space of the heat exchanger of the air temperature type vaporizer, and the air temperature type vaporizer And an air heater that preheats the downward airflow descending along the finned heat transfer tube.

  The invention of claim 3 includes a naturally ventilated air temperature type vaporizer equipped with a heat exchanger having finned heat transfer tubes, and a hot water bath type vaporizer, and the air temperature type vaporizer is vaporized for base load. A low-temperature liquefied gas vaporization method for producing a vaporized gas by vaporizing a low-temperature liquefied gas from a low-temperature liquefied gas supply source, wherein the air temperature type vaporizer uses the low-temperature liquefied gas supply temperature The liquefied gas is vaporized by the heat exchanger, and the vaporized gas is supplied to a gas supply destination. At that time, the outlet gas temperature of the air temperature type vaporizer is measured, and the hot water is determined according to the outlet gas temperature. The vaporized gas from the air temperature type vaporizer is heated by a bath type vaporizer, and the vaporized gas is supplied to the gas supply destination, or the hot water bath type vaporizer is used instead of the air temperature type vaporizer. A low temperature liquefied gas from the low temperature liquefied gas supply source. Vaporizing a vaporizing process of the low-temperature liquefied gas and supplying the vaporized gas into the gas supply destination.

  The low-temperature liquefied gas vaporizer or the low-temperature liquefied gas vaporization method of the present invention is, for example, when the air temperature type vaporizer has a standard size, that is, when the vaporization capacity is 1 ton per hour, Since it is equipped with a hot water vaporizer and one hot water bath type vaporizer as a unit, it has 2 natural ventilation type air temperature type vaporizers that have higher initial equipment costs than the hot water bath type vaporizer. The initial equipment cost is lower than the conventional one with a stand and this unit. In addition, the one natural ventilation type air temperature carburetor is operated as a base load carburetor, and the ice melting in the air temperature carburetor is performed by utilizing the hot water of the hot water bath type carburetor. Since it was made like this, there is no sprinkling and de-icing operation even in winter, and the operation cost can be reduced.

It is a flow figure showing roughly composition of a low-temperature liquefied gas vaporization device by one embodiment of the present invention. It is a figure which shows the flow of the air at the time of the vaporization driving | operation of this air temperature type vaporizer by the suction fan apparatus installed in the natural ventilation type air temperature type vaporizer in FIG. It is a flowchart which shows an example of the procedure of the operation control by an operation control apparatus in the low-temperature liquefied gas vaporizer shown in FIG. It is a flowchart which shows schematically the structure of the conventional low temperature liquefied gas vaporizer.

  Embodiments of the present invention will be described below with reference to the drawings. Here, the case where the air temperature type vaporizer is a standard size, that is, the vaporization capacity is 1 ton per hour will be described as an example. FIG. 1 is a flowchart schematically showing a configuration of a low-temperature liquefied gas vaporizer according to an embodiment of the present invention.

  As shown in FIG. 1, the low-temperature liquefied gas vaporizer according to the present embodiment is a liquefied natural gas vaporizer, and includes a heat exchanger (a group of finned heat transfer tubes) having a large number of finned heat transfer tubes, and a base load. One naturally ventilated air temperature type vaporizer 10 used as a vaporizer, a suction fan device 20 having a suction port leading to a space below the heat exchanger of the air temperature type vaporizer 10, and an air temperature type An air heater 30 for deicing in the air temperature type vaporizer 10 is installed in the vicinity of the vaporizer 10 and above it, and the downward airflow descending along the finned heat transfer tube is heated in advance. And one hot water bath type vaporizer 40 used for heating or vaporization, and the operation and stop of the air temperature type vaporizer 10, the air warmer 30, and the hot water bus type vaporizer 40. An operation control device (not shown) for performing according to a predetermined procedure That.

  The hot water bath type vaporizer 40 has a cylindrical hot water bath tank (shell) closed at both ends, and a stainless steel heat transfer coil is installed in the hot water bath tank to which hot water is circulated and supplied from the outside. In this structure, heat exchange with warm water is performed.

  A liquefied natural gas supply line 51 communicates from a liquefied natural gas supply source (not shown) to the liquefied natural gas inlet of the air temperature type vaporizer 10, and the liquefied natural gas supply line 51 has a valve V 1. Is provided. A natural gas delivery line 52 communicates from a natural gas outlet of the air temperature type vaporizer 10 to a gas supply destination (not shown). The natural gas delivery line 52 is provided with a valve V2 and a thermometer (temperature sensor) T for measuring the outlet gas temperature of the air temperature type vaporizer 10. The temperature measurement value of the thermometer T is transmitted to the operation control device.

  Next, the pipe line related to the hot water bath type vaporizer 40 will be described. The branch line 53 branches from the upstream side of the valve V 1 in the liquefied natural gas supply line 51 and communicates with the liquid or gas inlet of the hot water bath type vaporizer 40. Is provided with a valve V3. The pipe line 54 communicates the gas outlet of the hot water bath type vaporizer 40 and the downstream side of the valve V2 in the natural gas delivery pipe line 52. The pipe 55 branches from the upstream side of the valve V2 in the natural gas delivery pipe 52 and communicates with the liquid or gas inlet of the hot water bath type vaporizer 40. This pipe 55 is provided with a valve V4.

  41 is a hot water boiler, and 42 is a hot water circulation pump. A hot water circulation pump 42 through which hot water from the hot water boiler 41 is led leads to a hot water inlet of the hot water bath type vaporizer 40, and a pipe V <b> 5 is provided in the pipe 56. Further, a conduit 57 for returning the used hot water to the hot water boiler 41 communicates from the hot water outlet of the hot water bath type vaporizer 40.

  The pipe 58 branches from the upstream side of the valve V5 in the pipe 56 through which hot water from the hot water circulation pump 42 flows, and communicates with the hot water inlet of the air warmer 30. The passage 58 is provided with a valve V6. A conduit 59 for returning the used hot water to the hot water boiler 41 communicates from the hot water outlet of the air heater 30.

  Next, the configuration of the suction fan device 20 will be described. FIG. 2 is a view showing the air flow during the vaporizing operation of the air temperature type vaporizer by the suction fan device installed in the natural ventilation type air temperature type vaporizer in FIG.

  The suction fan device 20 has a function (fogging function) for extinguishing white smoke caused by cold air generated in the air temperature type vaporizer 10 and icing in the air temperature type vaporizer 10 in the air heater 30. There is a function of deicing in cooperation with the air temperature, and a function of improving the vaporization performance of the air temperature type vaporizer 10 by eliminating the cool air staying below the air temperature type vaporizer 10.

  As shown in FIG. 2, the air temperature type vaporizer 10 includes a heat exchanger (finned heat transfer tube group) 13 having a large number of finned heat transfer tubes 11. The heat exchanger 13 includes a vertically bent heat transfer pipe that meanders up and down by sequentially connecting a large number of finned heat transfer pipes 11 extending in the vertical direction in series with a U-shaped vent pipe 12. For evaporating the gas by heat exchange with the atmosphere (outside air) to generate natural gas, and for heating the natural gas generated in the vaporization unit 13a by heat exchange with the atmosphere And a heating part (temperature raising part) 13b. The support frame 14 is a rectangular frame and supports the heat exchanger 13 at a predetermined height position on the installation surface G.

  The suction fan device 20 includes a surrounding partition wall 21, a suction chamber 22, a suction fan 23, an electric motor 24, and an exhaust duct 25. When the vaporization operation by the air temperature type vaporizer 10 is started, the suction fan 23 is rotated by the electric motor 24, and air is sucked from the inside of the surrounding partition wall 21 through the suction chamber 22 and exhausted from the exhaust duct 25. Thereby, the white smoke (mist) that has reached the inside of the surrounding partition wall 21 is sucked into the suction chamber 22, and is diluted by being sucked together with the surrounding air, and exhausted from the exhaust duct 25 to the atmosphere. Is diffused and fogged (white smoke is extinguished). Arrows a, b, c, and d indicate the flow of air.

  Next, an example of operation control by the operation control device will be described according to the flowchart shown in FIG.

  First, when an operation start command is input in step 101, the process proceeds to step 102, the valves V1 and V2 are opened, and the vaporization operation of the air temperature type carburetor 10 is started. At the same time, the operation of the suction fan device 20 is started. By the vaporization operation of the air temperature type vaporizer 10, the liquefied natural gas supplied from the liquefied natural gas supply source through the liquefied natural gas supply line 51 is vaporized in the heat exchanger 13, and the natural gas is supplied to the natural gas delivery line 52. It is supplied to the gas supply destination.

  As the time of vaporization operation of the air temperature type vaporizer 10 elapses, icing to the heat exchanger 13 proceeds. In step 103, it is determined whether or not the outlet gas temperature t of the air temperature type vaporizer 10 measured by the thermometer T is equal to or lower than a preset temperature T1 (for example, T1 = −10 ° C.). Is done.

  When the outlet gas temperature t becomes equal to or lower than the set temperature T1 (YES in Step 103), the process proceeds to Step 104, and the heating operation by the hot water bath type vaporizer 40 is started. That is, the valve V4 is opened, and the natural gas from the air temperature type vaporizer 10 is led to the hot water bath type vaporizer 40 through the pipe 55 having the valve V4, and is heated by the hot water bath type vaporizer 40. Thereafter, the gas is supplied to the gas supply destination through the pipeline 54 and the natural gas delivery pipeline 52. The valve V2 is closed after the valve V4 is opened. Hot water is circulated and supplied to the hot water bath type vaporizer 40 through a route of the hot water boiler 41 → the hot water circulation pump 42 → the valve V 5 → the hot water bath type vaporizer 40 → the hot water boiler 41.

  Next, in step 105, the operation of the air warmer 30 is started, and the ice warming in the air temperature type vaporizer 10 during the vaporization operation is started by the air warmer 30. That is, due to the operation of the suction fan device 20, a downward air flow descending along the finned heat transfer tube 11 of the heat exchanger 13 of the air temperature type vaporizer 10 is generated, and the air heater 30 is operated. By de-warming this downward air flow in advance, de-icing in the heat exchanger 13 is started. The hot water is supplied to the air heater 30 in the same manner as the hot water bath type vaporizer 40, and the hot water is supplied from the hot water boiler 41 → the hot water circulation pump 42 → the valve V6 → the air warmer 30 → the hot water boiler 41. Circulated by route.

  Next, in step 106, it is determined whether or not the outlet gas temperature t has exceeded a value obtained by adding the predetermined temperature α to the set temperature T1, for example, (T1 + 5 ° C.). When the defrosting by the air heater 30 in the air temperature type vaporizer 10 during the vaporization operation proceeds and the outlet gas temperature t exceeds (T1 + 5 ° C.) (YES in step 106), in step 107, the hot water bath type vaporization is performed. The heating operation by the vessel 40 is stopped. Thus, the valve V4 is closed after the valve V2 is opened, and the natural gas from the air temperature type vaporizer 10 is supplied to the gas supply destination via the valve V2.

  When the outlet gas temperature t exceeds (T1 + 5 ° C.) (YES in step 106), it is considered that the ice melting in the air temperature type vaporizer 10 during the vaporization operation has been completed, and in step 108, the air heater 30 Is stopped and the valve V6 is closed.

  Next, when the operation of the low-temperature liquefied gas vaporizer is continued (NO in Step 109), the process returns to Step 103. On the other hand, when the vehicle stops (YES in step 109), the process proceeds to step 110, and a predetermined operation end process is performed.

  On the other hand, if the outside air temperature is low such as in winter and the result of step 106 is NO, the process proceeds to step 201 where the outlet gas temperature t of the air temperature type vaporizer 10 measured by the thermometer T is a predetermined set temperature T2 (for example, , T2 = −20 ° C.) or less. In step 201, when the outlet gas temperature t has not decreased to the set temperature T2 (NO in step 201), the process returns to step 106 again.

  If the outlet gas temperature t becomes equal to or lower than the set temperature T2 (YES in step 201) with the elapse of time of the vaporizing operation of the air temperature type vaporizer 10, the hot water bath type vaporizer 40 is obtained in step 202. Is switched to the vaporizing operation, and in step 203, the vaporizing operation of the air temperature type vaporizer 10 is stopped.

  The switching operation in step 202 and step 203 for switching the vaporization operation from the air temperature type vaporizer 10 to the hot water bath type vaporizer 40 is performed as follows, for example. By controlling the opening degree of the valve V1 of the liquefied natural gas supply line 51, the supply amount of the liquefied natural gas supplied to the air temperature type carburetor 10 is gradually reduced from 100% to 0%, and the going valve V4 is closed. In parallel with this, the valve V3 of the branch pipe 53 is opened, the opening degree of the valve V3 is controlled, and the supply amount of the liquefied natural gas supplied to the hot water bath type vaporizer 40 is gradually increased from 0% to 100%. The vaporization operation of the air temperature type vaporizer 10 is stopped, and the vaporization operation of the hot water bath type vaporizer 40 is entered. Note that a check valve V7 is provided so that the liquefied natural gas does not flow back into the pipeline 55 at the time of switching.

  Here, even after the vaporization operation is switched from the air temperature type vaporizer 10 to the hot water bath type vaporizer 40, the operation of the suction fan device 20 and the air warmer 30 is continued (step 204). De-icing is continued in the stopped air temperature type vaporizer 10.

  In step 205, a predetermined time T (for example, T = 2 hours) elapses from the start of the operation of the air warmer 30, and the defrosting in the air temperature type vaporizer 10 in which the vaporization operation is stopped is performed. When completed (YES in step 205), the operation of the air temperature carburetor 10 is started in step 206, the operation of the air warmer 30 is stopped in step 207, and the valve V6 is closed. At 208, the vaporizing operation of the hot water bath vaporizer 40 is stopped.

  Here, the switching operation for switching the vaporization operation from the hot water bath type vaporizer 40 to the air temperature type vaporizer 10 in step 206 and step 208 is performed as follows, for example. First, the valve V2 is opened. Next, by controlling the opening degree of the valve V3 of the branch pipe 53, the supply amount of the liquefied natural gas supplied to the hot water bath type vaporizer 40 is gradually decreased from 100% to 0%, and this is performed in parallel. Then, by controlling the opening degree of the valve V1 of the liquefied natural gas supply line 51, the supply amount of the liquefied natural gas supplied to the air temperature type vaporizer 10 is gradually increased from 0% to 100%, After completion of the switching, the valve V3 of the branch line 53 is closed. When the vaporization operation is switched from the hot water bath type vaporizer 40 to the air temperature type vaporizer 10, the process returns to Step 103.

  As described above, the low-temperature liquefied gas vaporizer or the low-temperature liquefied gas vaporization method of the present invention includes one naturally ventilated air temperature type vaporizer 10 and one hot water bath type vaporizer 40 as one unit. Compared to the conventional one in which two naturally ventilated air temperature type vaporizers 10 are installed, which are expensive compared to the hot water bath type vaporizer 40 and have a high initial facility cost. The initial equipment cost is low. In addition, the one natural ventilation type air temperature carburetor 10 is operated as a base load carburetor, and the deicing in the air temperature carburetor 10 is performed using the hot water of the hot water bath carburetor 40. Therefore, there is no sprinkling and de-icing operation even in winter, and the operation cost can be reduced.

DESCRIPTION OF SYMBOLS 10 ... Natural ventilation type air temperature type vaporizer 11 ... Heat transfer tube with fin 13 ... Heat exchanger 13a ... Vaporization part 13b ... Heating part 14 ... Support frame 20 ... Suction fan apparatus 30 ... Air warmer 40 ... Hot water bath Type vaporizer 41 ... Hot water boiler 42 ... Hot water circulation pump 51 ... Liquefied natural gas supply line 52 ... Natural gas delivery line 53 ... Branch line 54-59 ... Pipe line V1-V7 ... Valve T ... Thermometer

Claims (3)

A naturally ventilated air temperature type vaporizer that vaporizes a low-temperature liquefied gas in a heat exchanger having a finned heat transfer tube and supplies the vaporized gas to a gas supply destination;
With hot water bath vaporizer,
The air temperature type vaporizer is operated as a base load vaporizer, the low temperature liquefied gas from the low temperature liquefied gas supply source is vaporized by the heat exchanger, and the vaporized gas is supplied to the gas supply destination. The outlet gas temperature of the air temperature type vaporizer is measured, and the vaporized gas from the air temperature type vaporizer is heated by the hot water bath type vaporizer according to the outlet gas temperature, and the vaporized gas is Operation to supply to the gas supply destination, or a low temperature liquefied gas from the low temperature liquefied gas supply source is vaporized by the hot water bath type vaporizer instead of the air temperature type vaporizer, and the vaporized gas is supplied to the gas supply destination. A low-temperature liquefied gas vaporizer, comprising:   A suction fan device having a suction port that communicates with the space below the heat exchanger of the air temperature type vaporizer, and installed above and adjacent to the air temperature type vaporizer, descending along the finned heat transfer tube The low-temperature liquefied gas vaporizer according to claim 1, further comprising an air heater that preheats the downward air flow. A natural ventilation type air temperature type vaporizer equipped with a heat exchanger having finned heat transfer tubes and a hot water bath type vaporizer, and using the air temperature type vaporizer as a base load vaporizer, a low-temperature liquefied gas A low-temperature liquefied gas vaporization method for producing a vaporized gas by vaporizing a low-temperature liquefied gas from a supply source,
By the air temperature type vaporizer, the low temperature liquefied gas from the low temperature liquefied gas supply source is vaporized by the heat exchanger, and the vaporized gas is supplied to a gas supply destination. Measuring the outlet gas temperature, and heating the vaporized gas from the air temperature type vaporizer by the hot water bath type vaporizer according to the outlet gas temperature, and supplying the vaporized gas to the gas supply destination; Alternatively, the low temperature liquefied gas from the low temperature liquefied gas supply source is vaporized by the hot water bath type vaporizer instead of the air temperature type vaporizer, and the vaporized gas is supplied to the gas supply destination. A method for vaporizing liquefied gas.

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