JP2006029356A - Low temperature liquefied gas vaporizing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low temperature liquefied gas vaporizing device capable of effectively thawing ice attached to an outer surface of a finned heat transfer tube without having water spray equipment or a hot water type vaporizer. <P>SOLUTION: The low temperature liquefied gas vaporizing device 1 has a heat exchanger 2 comprising a vaporization part 21 with the finned heat transfer tube 21c for vaporizing a low temperature liquefied gas through heat exchange with atmospheric air and a heating part 22 with the finned heat transfer tube 22a for heating the vaporization gas vaporized in the vaporization part 21. In this device, an air heater 3 is provided at a position above and near the heat exchanger 2 for heating a downward air flow descending along the finned heat transfer tube 21c of the vaporization part 21. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement of a low-temperature liquefied gas vaporizer that effectively vaporizes a low-temperature liquefied gas such as liquefied natural gas (LNG) using air as a heat source, and more specifically, freezes on a finned heat transfer tube of a heat exchanger. The present invention relates to a low-temperature liquefied gas vaporizer capable of defrosting ice effectively.

  Conventionally, a liquefied natural gas satellite station, which is a low-temperature liquefied gas, is equipped with a natural or forced air-cooled air temperature vaporizer (air temperature heat exchanger) that uses air as a heat source. A vaporizer is installed. Examples of this type of low-temperature liquefied gas vaporizer include the following examples. Hereinafter, a low-temperature liquefied gas vaporizer according to a conventional example will be described with reference to the drawings.

  The low-temperature liquefied gas vaporizer according to Conventional Example 1 is configured as shown in FIG. 5 of its circuit system diagram. In other words, the low-temperature liquefied gas vaporizer according to the conventional example 1 is provided with fins by injecting hot water from the watering header 95 to the finned heat transfer tube 81 of the forced draft type air temperature type vaporizer (heat exchanger) 80. The ice layer formed in the heat transfer tube 81 is defrosted. That is, the watering equipment 90 for injecting hot water to the finned heat transfer pipe 81 is connected to the water supply pipe 92 communicating with the watering header 95 from the watering pit 91 and the water supply pipe 92, and the watering pit A watering pump 93 that sucks and discharges water in the water 91 and a water warmer 94 that heats the water discharged from the watering pump 93 (see, for example, Patent Document 1).

  The low-temperature liquefied gas vaporizer according to Conventional Example 2 is configured as shown in FIG. The low-temperature liquefied gas vaporizer 101 according to Conventional Example 2 has a configuration that does not require watering equipment for injecting hot water as in Conventional Example 3 above. That is, during normal vaporization operation, LNG is supplied from the liquefied natural gas supply line 102 and is evaporated and heated by the first air temperature vaporizer 103 and the hot water vaporizer 104. The NG that has exited the first air temperature type vaporizer 103 is additionally heated by the first vaporizer gas heater 105h as necessary, and the NG that has exited from the hot water vaporizer 104 to the second vaporizer gas delivery line 106 and It is configured to join and be sent to the supply destination side via the first vaporized gas delivery line 105. The first air temperature type vaporizer 103 and the hot water type vaporizer 104 may be provided one by one or plural by the equipment capacity. Further, even during normal vaporization operation, either one of the first air temperature vaporizer 103 and the hot water vaporizer 104 is operated, or both are operated, depending on the amount of vaporization of LNG. A plurality of first air temperature vaporizers 103 and hot water vaporizers 104 may be operated together.

In the case of the low-temperature liquefied gas vaporizer 101, the LNG vaporization operation is switched to the deicing mode, but the first air temperature vaporizer 103 is deiced as follows. That is, the hot water vaporizer 104 installed in parallel is used as a vaporization operation unit, and the LNG supplied from the liquefied natural gas supply pipe 102 is evaporated and heated by the hot water vaporizer 104. The heated NG exiting the hot water vaporizer 104 passes through the vaporized gas circulation line 107, and is supplied to the liquefied natural gas inlet 103a of the first air temperature vaporizer 103 that requires defrosting. In order to heat the tube wall of the finned heat transfer tube of the air temperature type vaporizer 103, the ice adhering to the outer surface of the finned heat transfer tube is defrosted.
Since the temperature of the NG that has exited the first air temperature type vaporizer 103 decreases due to heat exchange with ice, it is heated by the first vaporized gas heater 105h, and passes through the first vaporized gas delivery line 105. Then, it is sent to the supply destination side (see, for example, Patent Document 1).

  The low-temperature liquefied gas vaporizer according to Conventional Example 3 is configured as shown in FIG. That is, in the low-temperature liquefied gas vaporizer 61 according to Conventional Example 3, a plurality of finned heat transfer tubes 62c are arranged vertically and in parallel between an upper header 62a and a lower header 62b that are horizontally arranged. The LNG supplied from the lower header 62b rises up the finned heat transfer tube 62c and reaches the upper header 62a to evaporate by exchanging heat with air. Has been. The NG evaporated by the evaporation unit 62 and discharged from the upper header 62a has the same configuration as the finned heat transfer tube 62c of the evaporation unit 62 from the upper header 62a. The heated heat transfer pipe 63a and a plurality of fin-attached heat transfer pipes 63a are led to a heating section 63 including the upper openings and the U-shaped vent pipe 63b connecting the lower openings to each other. While the lowering and raising of the part 63 are repeated, the temperature is gradually increased by heat exchange with the air, and the NG of a predetermined temperature is sent from the outlet to the supply destination side (see, for example, Patent Document 2). .).

The low-temperature liquefied gas vaporizer according to Conventional Example 4 is configured as shown in FIG. That is, the low-temperature liquefied gas vaporizer 71 according to Conventional Example 4 includes a heat exchanger 72 configured as described later. The heat exchanger 72 is disposed vertically between the horizontally disposed upper header 73a and lower header 73b, and includes a plurality of finned heat transfer tubes 73c that evaporate the low-temperature liquefied gas by heat exchange with the atmosphere. The evaporation unit 73 is provided. Further, the heating unit is connected via upper and lower U-shaped bend pipes 74b, and has a plurality of finned heat transfer tubes 74a for heating the vaporized gas generated by the evaporation of the low-temperature liquefied gas in the evaporation unit 73. 74 is provided. A lower wall of the heat exchanger 72 is provided with a cover wall 75 that covers a lower end portion of the heat exchanger 72 and a lower portion of the lower end portion and prevents mist from flowing out into the atmosphere. An exhaust duct 76a that sucks the mist staying inside the cover wall 75 in the vicinity of the outside of the cover wall 75 and diffuses and exhausts the sucked mist away from the heat exchanger 72, that is, obliquely upward. Is provided (see, for example, Patent Document 2).
JP 2002-005398 A JP 2002-228096 A

  In the low-temperature liquefied gas vaporizer according to the above-described conventional example 1, there is a problem that watering equipment including a watering pit, a watering pump, a watering heater, a water supply pipe, and a watering header is necessary, which is disadvantageous in terms of equipment cost. . In addition, since water scatters when water is sprayed, there is a problem in securing the site that it is necessary to separate the distance between the devices with a predetermined distance (for example, 3 m) from the adjacent machine, and a large space for equipment installation is required. It was. Furthermore, in the case of cold districts, it is necessary to take measures against cold districts to prevent icing of watering equipment consisting of watering pits, watering pumps, watering heaters, water supply pipelines, and watering headers. It was a factor that pushed up equipment costs.

  In addition, the low-temperature liquefied gas vaporizer according to Conventional Example 2 is considered to be excellent because it does not require watering equipment for defrosting, but a hot water vaporizer is additionally provided in the first air temperature vaporizer. There is a need. In addition, piping and switching valves are required for switching between vaporization and de-icing, and there is a problem that equipment costs increase. Further, when switching from vaporization to de-icing, NG heated by the hot water vaporizer is supplied to the liquefied natural gas inlet of the first air temperature vaporizer where the low-temperature LNG remains, so that it remains. Due to the LNG bumping, an abnormal temperature imbalance is generated in the finned heat transfer tube and the metal temperature is changed from a low temperature to a high temperature. It was a factor of.

  Further, the low-temperature liquefied gas vaporizers according to the above-described conventional examples 3 and 4 are systems that utilize the natural convection atmosphere as a heat source for vaporizing the low-temperature liquefied gas, and are applied to the outer surface of the finned heat transfer tube during the vaporization operation. Moisture in the atmosphere becomes ice and is icing. Under severe conditions in winter, the outer surface of the finned heat transfer tube freezes in a short period of time, increasing the amount of icing, requiring a thawing process in a short cycle or making the vaporization operation itself difficult. There is a problem that the operating rate of the low-temperature liquefied gas vaporizer is low and the vaporized efficiency of the liquefied gas is poor.

  Therefore, the object of the present invention is to achieve low-temperature liquefied gas vaporization that makes it possible to effectively defrost ice adhering to the outer surface of the finned heat transfer tube, even though it does not have watering equipment or hot water vaporizers. Is to provide a device.

  The present invention has been made in view of the above circumstances. Therefore, in order to solve the above-mentioned problems, the means employed by the low-temperature liquefied gas vaporizer according to claim 1 of the present invention is the heat exchange with the atmosphere. In the naturally ventilated low-temperature liquefied gas vaporizer comprising a heat exchanger having a heat transfer tube with fins for evaporating the low-temperature liquefied gas and heating the vaporized gas generated by evaporation, The position is provided with an air heater that preheats a downward air flow descending along the finned heat transfer tube.

  The means adopted by the low temperature liquefied gas vaporizer according to claim 2 of the present invention is the low temperature liquefied gas vaporizer according to claim 1, wherein the suction fan device is provided with a suction port leading to a space below the heat exchanger. Is provided.

  The means employed by the low-temperature liquefied gas vaporizer according to claim 3 of the present invention is the low-temperature liquefied gas vaporizer according to claim 2, wherein the heat exchanger side is opened to provide a covering wall that covers the space, The air stagnating in the space is configured to be excluded by the suction fan device.

  The means employed by the low-temperature liquefied gas vaporizer according to claim 4 of the present invention is the low-temperature liquefied gas vaporizer according to claim 3, wherein an enclosure surrounding the air heater and the heat exchanger is provided. It is characterized by.

  The means adopted by the low-temperature liquefied gas vaporizer according to claim 5 of the present invention is the low-temperature liquefied gas vaporizer according to any of claims 1 to 4, wherein the air heater includes a fluid heat transfer tube having a fluid as a heat source. It is characterized by comprising.

  The means employed by the low-temperature liquefied gas vaporizer according to claim 6 of the present invention is the low-temperature liquefied gas vaporizer according to claim 5, characterized in that fins are provided on the outer periphery of the fluid heat transfer tube. Is.

  The means adopted by the low-temperature liquefied gas vaporizer according to claim 7 of the present invention is the low-temperature liquefied gas vaporizer according to any one of claims 1 to 4, wherein the air heater is a current It is an electric heating type air heater to which is supplied.

  In the low-temperature liquefied gas vaporizer according to claim 1 of the present invention, the downward air flow descending along the plurality of finned heat transfer tubes of the heat exchanger is provided with an air heater provided at a position near the upper portion of the heat exchanger. Since the warming is performed in advance by the warmer, the ice adhering to the outer surface of the finned heat transfer tube of the heat exchanger is defrosted by the heated downward air flow.

Therefore, according to the low-temperature liquefied gas vaporizer according to claim 1 of the present invention, the following effects can be obtained.
(1) Since it is not necessary to provide a watering facility as in the conventional example 1, the installation space of the facility can be reduced, the facility cost is advantageous, and icing trouble occurs even in a cold region. There is nothing.
(2) Unlike the conventional example 2, there is no need to add a hot water type vaporizer to the first air temperature type vaporizer, and there is no need for piping and a switching valve for switching between vaporization and ice melting. In addition, when switching from vaporization to de-icing, there is no need to give technical considerations to the bumping of the remaining LNG or the generation of thermal stress due to the metal temperature changing from low to high. There is an excellent effect.
(3) Compared to the conventional examples 3 and 4 that use only the atmospheric heat source of the natural air flow, heating the downward air flow with an air heater increases the continuous operation time performance during the vaporization operation. In addition, it can be vaporized even under severe weather conditions in winter. And in the ice-melting operation process, the ice icing on the finned heat transfer tube can be melted by the heated downward air flow without watering.

  According to the low-temperature liquefied gas vaporizer according to claim 2 of the present invention, the air staying in the lower space is eliminated by the suction of the suction fan device provided so that the suction port communicates with the lower space of the heat exchanger. Therefore, the downward air flow heated by the air heater flows more effectively along the finned heat transfer tube of the heat exchanger, so that the ice melting is performed more than the low temperature liquefied gas vaporizer according to claim 1. Performance is improved. Further, even if mist is generated along the finned heat transfer tube during the vaporizing operation, the mist can be effectively extinguished by sucking the mist together with air with a suction fan device and diffusing and exhausting it into the atmosphere.

  According to the low-temperature liquefied gas vaporizer according to claim 3 of the present invention, since the space below the heat exchanger and its surroundings are partitioned by the covering wall, the air staying in the space by the suction of the suction fan device Is efficiently eliminated. Accordingly, the downward air flow heated by the air heater flows more effectively along the finned heat transfer tube of the heat exchanger, so that the de-icing performance is higher than that of the low-temperature liquefied gas vaporizer according to claim 2. Will improve. Further, even if mist is generated, the mist stays in the space and is sucked, so that the generated mist does not flow out to the surroundings and the defrosting performance is excellent.

  According to the low-temperature liquefied gas vaporizer according to claim 4 of the present invention, the downward air flow heated by the air heater flows inside the enclosure without being dissipated to the outside of the heat exchanger. In addition, even if there is a wind, since the wind is not blocked by the enclosure and the downward air flow is not disturbed, the ice melting performance is improved as compared with the low temperature liquefied gas vaporizer according to the third aspect.

  Hereinafter, a low-temperature liquefied gas vaporizer according to Embodiment 1 of the present invention will be described with reference to FIG. The heat exchanger of the low-temperature liquefied gas vaporizer according to Embodiment 1 of the present invention has the same configuration as the heat exchanger of the low-temperature liquefied gas vaporizer according to Conventional Examples 3 and 4, and the evaporation section of this heat exchanger The heat transfer tubes used for the heating section and the heating section are all provided with fins, but are not shown for simplicity.

  Reference numeral 1 shown in the figure is a low-temperature liquefied gas vaporizer according to Embodiment 1 of the present invention. The low-temperature liquefied gas vaporizer 1 includes a heat exchanger 2 having an evaporation unit 21 and a heating unit 22 that are configured as described later. The evaporator 21 functions to evaporate the supplied low-temperature liquefied gas (hereinafter referred to as LNG) by exchanging heat with the atmosphere. The heating unit 22 functions to heat a vaporized gas (hereinafter referred to as NG) generated by the evaporation of LNG in the evaporation unit 21 to a predetermined temperature.

  More specifically, the evaporation section 21 of the heat exchanger 2 includes an upper header 21a disposed horizontally, and a horizontal lower header 21b disposed directly below the upper header 21a and in parallel with the upper header 21a. And a plurality of finned heat transfer tubes 21c which are disposed between the upper header 21a and the lower header 21b vertically and at a predetermined interval and have fins (not shown) along the longitudinal direction on the outer peripheral portion. It consists of and. That is, while the LNG supplied from the lower header 21b rises up the plurality of finned heat transfer tubes 21c and reaches the upper header 21a, the LNG is convected with the air convection around the plurality of finned heat transfer tubes 21c. It is configured to evaporate when heated by heat exchange.

  The heating unit 22 of the heat exchanger 2 includes a plurality of vertical finned heat transfer tubes 22a having the same configuration as the finned heat transfer tube 21c of the evaporation unit 21, and the plurality of fins. It consists of a U-shaped bend tube 22b connecting the upper openings of the heat transfer tubes 22a and the lower openings. That is, NG flowing from the upper header 21a into the finned heat transfer tube 22a of the heating unit 22 descends the finned heat transfer tube 22a and rises repeatedly, so that the NG is located farthest from the evaporation unit 21. Before reaching the lower end position of the finned heat transfer tube 22a, the heat is exchanged with the downward air flow Adf descending along each finned heat transfer tube 22a to obtain a predetermined temperature of NG. It is configured to be supplied to the supply side. And the fluid heat exchange type air heater 3 provided with the fluid heat exchanger tube to which the fluid used as a heat source is supplied to the position near the upper part of the evaporation part 21 of the heat exchanger 2 through a support bracket (not shown). Are arranged sideways. The fluid heat transfer tube may be provided in a range corresponding to the vertical projected area (installation area) of the evaporation section 21. For example, a plurality of fluid heat transfer tubes may be provided in parallel. Moreover, as a fluid used as a heat source, for example, hot water, steam, hot oil, or the like can be used.

Hereinafter, the operation mode of the low-temperature liquefied gas vaporizer 1 according to the first embodiment will be described. That is, when LNG is supplied from one end side of the lower header 21b constituting the evaporator 21 of the heat exchanger 2, the supplied LNG moves up the plurality of finned heat transfer tubes 21c from the lower header 21b.
Next, before reaching the upper header 21a, it is heated and evaporated by heat exchange with the downward air flow descending along the finned heat transfer tube 21c, and becomes low-temperature NG. The low-temperature NG flows into the finned heat transfer tube 22a of the heating unit 22 and repeatedly rises and lowers the finned heat transfer tube 22a. Then, the lower airflow Adf descending along each finned heat transfer tube 22a until reaching the lower end of the finned heat transfer tube 22a disposed at the position farthest from the evaporator 21. The temperature is raised by heat exchange and is supplied to a supply destination (not shown) as NG having a predetermined temperature.

  By continuing the LNG vaporization operation of the low-temperature liquefied gas vaporizer 1, ice freezes on the outer surface of the finned heat transfer tube 21 c of the evaporator 21 of the heat exchanger 2. However, in the low-temperature liquefied gas vaporizer 1 according to the first embodiment of the present invention, the downward air flow Adf descending along the finned heat transfer tube 21c is an air heater provided near the upper position of the heat exchanger 2. 3, and the ice adhering to the outer surface of the finned heat transfer tube 21 c of the evaporator 21 is defrosted by the heated downward air flow Adf. Therefore, according to the low-temperature liquefied gas vaporizer 1 according to Embodiment 1 of the present invention, the following effects can be obtained.

(1) Since it is not necessary to provide a watering facility as in the conventional example 1, the installation space of the facility can be reduced, the facility cost is advantageous, and icing trouble occurs even in a cold region. There is nothing.
(2) Unlike the conventional example 2, there is no need to add a hot water type vaporizer to the first air temperature type vaporizer, and there is no need for piping and a switching valve for switching between vaporization and ice melting. In addition, when switching from vaporization to de-icing, there is no need to give technical considerations to the bumping of the remaining LNG or the generation of thermal stress due to the metal temperature changing from low to high. There is an excellent effect.
(3) Compared to conventional examples 1 and 2 that use only the atmospheric heat source of the natural air flow, heating the downward air flow with an air heater improves the continuous operation time performance during the vaporization operation. In addition, it can be vaporized even under severe weather conditions in winter. And in the ice-melting operation process, the ice icing on the finned heat transfer tube can be melted by the heated downward air flow without watering.

  A low-temperature liquefied gas vaporizer according to Embodiment 2 of the present invention will be described with reference to FIG. The low-temperature liquefied gas vaporizer according to the second embodiment of the present invention is different from the low-temperature liquefied gas vaporizer according to the first embodiment in that a suction fan device is added, and the other configuration is exactly the same. Therefore, the same reference numerals are given to the same components as those in the first embodiment, and different points will be mainly described.

  That is, in the low-temperature liquefied gas vaporizer 1 according to Embodiment 2 of the present invention, the suction fan device 4 having the suction fan 4a is provided at the lower part of the heat exchanger 2, and the suction port 4b leading to the space is provided and sucked. An exhaust duct 4c that exhausts the air obliquely upward is provided.

  Therefore, according to the low-temperature liquefied gas vaporizer 1 according to Embodiment 2 of the present invention, the air staying in the space below the heat exchanger 2 is sucked by the suction fan device 4 provided at the lower part of the heat exchanger 2. Exclude. As a result, the downward air flow Adf heated by the air heater 3 flows more effectively along the finned heat transfer tube 21c of the heat exchanger 2, so that the low temperature liquefied gas vaporizer according to the first embodiment is used. De-icing performance is improved. Further, even if a mist is generated along the finned heat transfer tube 21c during the vaporizing operation, the mist can be effectively extinguished by being sucked by the suction fan device 4 and diffused and exhausted into the atmosphere. There is also white smoke prevention effect. In addition, in FIG. 2 which shows the low temperature liquefied gas vaporization apparatus which concerns on form 2 of this invention, although the suction port 4b formed in circular shape is illustrated, rectangular shape, slit shape, porous shape, etc. Various shapes can be adopted.

  A low-temperature liquefied gas vaporizer according to Embodiment 3 of the present invention will be described with reference to FIG. The low-temperature liquefied gas vaporizer according to the third embodiment of the present invention is different from the low-temperature liquefied gas vaporizer according to the second embodiment in that a cover wall is provided, and the other configuration is exactly the same. Therefore, the same reference numerals are given to the same components as those in the second embodiment, and different points will be mainly described.

  In the low-temperature liquefied gas vaporizer 1 according to Embodiment 3 of the present invention, a cover wall 5 is provided to open the heat exchanger 2 side and cover the space below the heat exchanger 2. The air staying in the enclosed space is configured to be removed by the suction fan device 4. The covering wall 5 is formed from the lower end of the heat exchanger 2, more specifically from the fins of the finned heat transfer tubes 21c of the evaporation unit 21 and the fins of the finned heat transfer tubes 22a of the heating unit 22. It is arranged in a state surrounding its lower part. That is, the covering wall 3 is cooled by heat exchange with the LNG rising in the finned heat transfer tube 21c and the NG flowing in the finned heat transfer tube 22a and flows downward to the lower side of the heat exchanger 2 Adf. The mist consisting of fine water droplets contained in the stagnation is retained so as not to flow out into the atmosphere. Further, the covering wall 3 is configured to be installed and removed in order to avoid a decrease in heat exchange efficiency of the heat exchanger 2. And this covering wall 5 is manufactured from lightweight materials, such as an aluminum material and a plastic material, in order to make installation and removal easy. Note that an openable / closable window portion may be provided on the cover wall 5 so that the cover wall 5 is stationary.

  Therefore, according to the low-temperature liquefied gas vaporizer 1 according to the third aspect of the present invention, the space below the heat exchanger 2 and the periphery thereof are partitioned by the covering wall 5, so that the suction of the suction fan device 4 is performed. Thus, the air staying in the space is efficiently removed. Accordingly, since the downward air flow Adf heated by the air heater 2 flows more effectively along the finned heat transfer tube 21c of the heat exchanger 2, the low-temperature liquefied gas vaporizer according to the second embodiment is used. De-icing performance is improved. In addition, even if mist is generated, it stays in the space and is sucked in, so that the generated mist does not flow out to the surroundings and the defogging performance is excellent.

  A low-temperature liquefied gas vaporizer according to Embodiment 4 of the present invention will be described with reference to FIG. Note that the low-temperature liquefied gas vaporizer according to Embodiment 4 of the present invention is different from the low-temperature liquefied gas vaporizer according to Embodiment 3 above in that an enclosure is provided at the top of the cover wall, and other than that Since it is the same structure, the same code | symbol is attached | subjected to the same thing as the said form 3, and the difference is mainly demonstrated.

  The low-temperature liquefied gas vaporizer 1 according to the fourth embodiment of the present invention has a configuration in which an enclosure 6 surrounding the air heater 3 and the heat exchanger 2 is provided. In this case, the base end side of the air heater 3 is fixed to the inner wall near the upper end of the enclosure 6 by mechanical fastening means such as bolts.

  Therefore, according to the low-temperature liquefied gas vaporizer 1 according to Embodiment 4 of the present invention, the downward air flow Adf heated by the air heater is not dissipated outside the heat exchanger 2, and In addition to flowing inside, even if there is a wind, the wind is blocked by the enclosure 6 and the downward air flow Adf flows along the finned heat transfer tube 21c without being disturbed. De-icing performance is improved compared to the liquefied gas vaporizer. The enclosure 6 is made of the same lightweight material as the cover wall 5 and can be detachable. Further, if it is surrounded by a plurality of roll curtains or a bellows-like tube, the heat exchanger portion can be easily surrounded or exposed as necessary. In these cases, the air heater 3 may be supported by providing a support or the like separately.

In the low-temperature liquefied gas vaporizer 1 according to the above embodiment, the example in which the air heater having the fluid electric heating tube in which the fin is not provided in the outer peripheral portion is provided has been described, but the fin is provided in the outer peripheral portion. An air heater having a fluid electric heating tube can be provided. Thereby, since the contact area with the atmosphere increases, the effect that the downward air flow can be heated more efficiently than the air heater 3 of the low-temperature liquefied gas vaporizer 1 according to the first to fourth aspects is obtained. be able to.
Moreover, although the example of the air warmer using fluids, such as warm water, a vapor | steam, and hot oil, was demonstrated as a heat source, the electric heating type air warmer supplied with an electric current can also be used. Accordingly, the present invention is not limited to the configuration of the low-temperature liquefied gas vaporizer 1 according to Embodiments 1 to 4, and design changes and the like can be freely made without departing from the technical idea of the present invention.

It is typical structure explanatory drawing of the low temperature liquefied gas vaporization apparatus which concerns on form 1 of this invention. It is typical structure explanatory drawing of the low temperature liquefied gas vaporization apparatus which concerns on form 2 of this invention. It is typical structure explanatory drawing of the low temperature liquefied gas vaporization apparatus which concerns on form 3 of this invention. It is typical structure explanatory drawing of the low temperature liquefied gas vaporization apparatus which concerns on form 4 of this invention. FIG. 6 is a circuit system diagram of a low-temperature liquefied gas vaporizer according to Conventional Example 1. It is a systematic diagram of a low-temperature liquefied gas vaporizer according to Conventional Example 2. It is schematic structure explanatory drawing of the low temperature liquefied gas vaporization apparatus which concerns on the prior art example 3. It is typical structure explanatory drawing of the low temperature liquefied gas vaporization apparatus which concerns on the prior art example 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Low temperature liquefied gas vaporizer, 2 ... Heat exchanger, 21 ... Evaporating part, 21a ... Upper header, 21b ... Lower header, 21c ... Heat transfer pipe with fin, 22 ... Heating part, 22a ... Heat transfer pipe with fin, 22b DESCRIPTION OF SYMBOLS ... Bend pipe | tube, 3 ... Air warmer, 4 ... Suction fan apparatus, 4a ... Suction fan, 4b ... Suction port, 4c ... Exhaust duct, 5 ... Cover wall, 6 ... Enclosure, Adf ... Downward airflow.

Claims (7)

  In the naturally ventilated low-temperature liquefied gas vaporizer comprising a heat exchanger having a finned heat transfer tube for evaporating the low-temperature liquefied gas by heat exchange with the atmosphere and heating the vaporized gas generated by the evaporation, A low-temperature liquefied gas vaporizer characterized in that an air heater for preheating a downward air flow descending along the finned heat transfer tube is provided at a position near the upper portion of the exchanger.   The low-temperature liquefied gas vaporizer according to claim 1, further comprising a suction fan device having a suction port that communicates with a space below the heat exchanger.   The low-temperature liquefied gas according to claim 2, wherein a cover wall is provided to open the heat exchanger side and cover the space, and the air staying in the space is excluded by the suction fan device. Vaporizer.   4. The low-temperature liquefied gas vaporizer according to claim 3, further comprising an enclosure that surrounds the air heater and the heat exchanger.   The low-temperature liquefied gas vaporizer according to any one of claims 1 to 4, wherein the air heater includes a fluid heat transfer tube using a fluid as a heat source.   The low-temperature liquefied gas vaporizer according to claim 5, wherein fins are provided on an outer peripheral portion of the fluid heat transfer tube. The low-temperature liquefied gas vaporizer according to any one of claims 1 to 4, wherein the air heater is an electrothermal air heater to which an electric current is supplied.

Images