KR20140050026A

KR20140050026A - Vaporizer for liquefied gas

Info

Publication number: KR20140050026A
Application number: KR1020147002673A
Authority: KR
Inventors: 카츠지 후쿠타니; 카즈오 하루나
Original assignee: 스미토모 세이카 가부시키가이샤
Priority date: 2011-08-22
Filing date: 2011-10-13
Publication date: 2014-04-28
Also published as: WO2013027301A1; JP5039846B1; JP2013044347A; TWI542832B; KR101868198B1; TW201309979A

Abstract

The vaporizer of the present invention vaporizes a liquefied gas by heating it with a heat medium, and the heat medium containers 1 and 2 in which the heat medium is replenishably accommodated, and extend from the bottom of the heat medium containers 1 and 2 to the top and then again It includes a spiral heat transfer tube (3) extending to be folded back. Instead of fixing the upper end of the heat transfer tube 3, only the lower end of the heat transfer tube is supported by the heat medium containers 1 and 2 so that the liquefied gas to be vaporized in the heat transfer tube 3 is continuously flowed to vaporize. .

Description

Vaporizer for liquefied gas {VAPORIZER FOR LIQUEFIED GAS}

The present invention relates to a vaporizer which vaporizes and evaporates liquefied gas such as nitrogen, oxygen, argon or LNG (liquefied natural gas), propane, and supplies it to the consumer in a gas state.

In addition to industrial gases such as liquefied nitrogen, liquefied oxygen, liquefied argon and liquefied carbon dioxide, fuel gases such as LNG (liquefied natural gas) and LPG (liquefied propane gas) are accumulated in the liquid phase in the tank and evaporated in a vaporizer or the like. Evaporating and supplying it in gaseous state is used as an important industrial technique for repeating storage and consumption of liquefied gas in each industrial field. Although various things can be used as a heating source of a vaporizer, it is common to use atmospheric air. In this case, liquefied nitrogen, liquefied oxygen, and liquefied argon are stored at -180 ° C or lower, liquefied carbon dioxide at -25 ° C or lower, LNG at -160 ° C or lower, and LPG at -40 ° C or lower. At evaporation at, the moisture in the atmospheric air is frozen, ice accumulates in the heat transfer tube, and the heat transfer resistance significantly increases. Thus, for example, in an LNG satellite (refering to a medium-scale or small-scale LNG storage facility installed in a plurality of locations away from a large-scale LNG storage facility to be backbone), at least two vaporizers are installed in parallel. The two cars are switched and operated every predetermined time (for example, 4 hours), and while the carburizing operation is performed by one carburetor, the other carburettor frozen is stopped to perform thawing. In addition, vaporizers using a liquid medium such as seawater as a heating source are also known. Conventional vaporizers using seawater and atmospheric air as heating sources are disclosed in, for example, Patent Documents 1 to 3 below.

For example, in the case of the vaporizer which heats and vaporizes LNG which is typical liquefied gas, as can be seen by Unexamined-Japanese-Patent No. 5-203098 (patent document 1), it is a plurality of heat exchanger tubes through which LNG passes, A so-called shell-and-tube heat exchanger, consisting of a seal partitioned by a welded tube plate, was used. This was to incorporate a plurality of heat transfer tubes between the tube plates, to flow seawater to the cell side to warm the LNG to evaporate.

Moreover, Japanese Unexamined Patent Publication No. 5-332499 (Patent Document 2) discloses a vaporizer, called an open rack type, by plurally arranging a plurality of heat transfer tubes having a double pipe structure in the vertical direction, and welding and fixing them to upper and lower manifolds. It was made into a panel-like structure as a whole, and the seawater was sprinkled on the outside, and was heated and evaporated.

In addition, Japanese Laid-Open Patent Publication No. 2005-156141 (Patent Document 3) discloses a vaporizer which is heated by using atmospheric air, and as shown schematically in FIG. The heat transfer tube 23 (fin is not shown) with fins is arrange | positioned in parallel between 21 and 22. The vaporized LNG is introduced from the lower manifold 21, divided into a plurality of finned heat transfer tubes 23, and evaporated by heat exchange with air, and joined in the upper manifold 22 to be recovered. Via the pipe 24, it is supplied to the use place which is not shown in figure. In addition, in FIG. 5, the code | symbol 25 has shown the welding part of the heat exchanger tube 23 and the upper and lower manifolds 21 and 22. In addition, in FIG.

As described above, a vaporizer according to the prior art is commonly used to erect a plurality of pipes, install a partition chamber or a manifold on the top and bottom thereof, and fix the welding. LNG is first supplied from the lower part and then raised in each heat pipe. In the meantime, the vaporized gas was collected in the upper manifold or partition chamber, and warmed and drawn out by the outside air.

In the vaporizer described in Patent Literature 1, since the heating is warmed with seawater, when a sufficient amount of seawater flows, there is no problem that seawater freezes by LNG supplied at a temperature close to -160 ° C, but the heat pipe is welded to the upper and lower tube plates. Since it is fixed, if the degree of warming is changed by the amount of LNG supplied, the heat transfer tube is stretched and thermal stress is applied to the welding point with the tube plate. As a result, if the feeding amount continues to change, this thermal stress is repeated, and at the end, the weld part fixed to the tube plate by thermal fatigue breaks. In addition, since there are a plurality of heat transfer tubes, when the liquid dispersion of LNG in this inside is bad, the temperature difference of each welding part fixed to the tube plate will generate | occur | produce, a distortion will arise in a tube plate, and the said heat fatigue will be accelerated.

The same problem arises also in the vaporizer | carburetor of patent document 2 in which the heat exchanger tube is welded and fixed to the manifold which corresponds to a tube plate.

On the other hand, in the air heating type vaporizer of Patent Document 3 shown in Fig. 5, since the low temperature liquid near -160 ° C is introduced into the heat transfer tube 23 and is heated by atmospheric air from the outside, the moisture in the air is transferred to the heat transfer tube 23. Freezing (the freezing part is denoted by the symbol FZ) on the surface of the heat exchanger significantly lowers the heat transfer efficiency. Moreover, it is difficult to divide LNG evenly into the plurality of heat transfer tubes 23 from the lower manifold 21 toward the upper manifold 22, and in particular, when the flow rate of LNG is reduced to reduce the evaporation load, As shown in FIG. 5, the length of the icing part FZ also differs for every different heat exchanger tube 23, a temperature difference arises between different heat exchanger tubes 23, and the length of expansion and contraction of each heat exchanger tube differs from this difference. For example, in the case of employing aluminum as the material of the heat transfer tube 23, if there is a difference in the temperature difference of 100 ° C, a difference in the amount of expansion and contraction of 2.3 mm occurs per 1 m, and in a heat transfer tube made of stainless steel, There is a difference, and in the iron heat transfer tube, there is a difference in the amount of expansion and contraction of 1.2 mm per meter. For this reason, excessive stress is applied to the welded part 25 fixed to the manifolds 21 and 22, and the intermittent operation of the vaporizer | carburetor frequently caused the problem which the cracked in the welded part 25 produced.

In addition, since the liquefied gas vaporizer is designated as a gas facility under the High Pressure Gas Security Act, the vaporizer must be publicly opened for inspection of the welded portion and the internal configuration once every three years. There has been a demand for a structure that allows visual inspection.

JPH5-203098 A JPH5-332499 A JP 2005-156141 A

In view of the above, the main problem to be solved by the present invention is to provide a carburetor with very few problems such as breakage in the welded portion of the heat transfer tube even when repeated thermal stress is applied.

In addition, a supplementary problem of the present invention is that, due to the decrease in the heat exchange rate due to the freezing of moisture on the surface of the heat transfer tube as in the case of heating with atmospheric air, it is necessary to install two identical vaporizers and alternately operate and thaw. Is to provide a carburetor that is missing.

Further, another complementary object of the present invention is to provide a vaporizer which is subject to the high-pressure gas security law and which has a structure that is easily subject to public inspection of the welded portion and the entire internal structure.

MEANS TO SOLVE THE PROBLEM This invention raises and employ | adopted the following means in order to solve the said subject.

That is, the present invention is a vaporizer which vaporizes a liquefied gas by heating it with a heat medium, and has a heat medium container in which a heat medium is replenishably accommodated, and a spiral shape extending from the bottom of the heat medium container to the top and bending back to the bottom. A vaporizer including a heat pipe, without fixing the upper end of the heat pipe, by supporting only the bottom end of the heat pipe in the heat medium container to continuously vaporize the liquefied gas to be vaporized in the heat pipe.

According to the above structure, a heat exchanger tube is a spiral shape and a heat exchanger tube can absorb the change of length, even if it expands and contracts cooling and heating repeatedly by the fluctuation | variation of the evaporation amount. Therefore, excessive stress can be prevented from being applied to the support portion (joint portion) of the heat transfer tube of the heat transfer tube, thereby eliminating or reducing problems such as breakage of the support portion. In addition, it is also possible to change the heat transfer area by adjusting the extension length by adjusting the winding number and winding density of the heat transfer tube.

In addition, unlike the case of using atmospheric air or seawater, the heat transfer tube is heated at a temperature higher than normal temperature, for example, + 60 ° C, by a heat medium such as hot water. Therefore, freezing does not occur on the surface of the heat pipe. As a result, it is not necessary to wait and thaw the frozen carburetor, and it is not necessary to provide two carburetors, and it becomes possible to continue vaporizing with only one. In addition, compared with the case of heating with air or seawater, for example, using a hot water at + 60 ° C increases the temperature difference between the heating side and the heated side, thereby greatly reducing the heat transfer area and making the vaporizer compact. Can be.

Preferably, the said heat exchanger tube is comprised so that an inner diameter may become large step by step from the upstream to the downstream side. Thereby, even if the volume reaches 70 times or more in the process of liquefied gas, such as LNG, changing from liquid to gas, the flow velocity of a liquid or gas can be optimized according to the evaporation amount in a heat exchanger tube.

Preferably, the said heat exchanger tube is comprised so that an internal diameter may become step by step so that the inner diameter cross-sectional area of the thickest part of the downstream side may become 1.5 to 10 times the inner diameter cross-sectional area of the narrowest part of an upstream side.

Preferably, the heat medium container includes a bottom plate and a main body housing detachably joined to the bottom plate, and the upstream end portion and the downstream end portion of the heat transfer tube are fixed only to the bottom plate. According to this structure, all the components incorporating a heat exchanger tube can be inspected and repaired directly by only removing the main body housing which is a cover from a base plate.

Preferably, the upstream end portion and the downstream side end portion of the heat transfer pipe are supported with respect to the bottom plate via a cap, respectively, and the cap is joined to the upstream end portion or the downstream end portion via a first welding portion. At the same time, it is joined to the base plate via a second welding portion. According to this configuration, the stresses caused by the expansion and contraction of the heat transfer pipe and the cap can be dispersed in the first welding portion and the second welding portion, respectively, and stress concentration can be avoided.

Preferably, the cap has a curved ceiling wall, the heat pipe passes through the cap ceiling wall, and the first welding portion joins the heat pipe and the cap ceiling wall over an obtuse angle. This configuration also makes it possible to more effectively avoid stress concentration in the welded portion.

Preferably, the heat medium container is provided with a heat medium introduction nozzle for supplying a heat medium therein, and the opening of the heat medium introduction nozzle ejects the heat medium along the circumferential direction of the outer circumferential wall of the heat medium container. Thereby, the heat exchange efficiency to the liquefied gas by a heat medium improves.

Preferably, the heat medium container is provided with a heat medium overflow pipe that defines the liquid level of the heat medium in the inside thereof, and the heat medium that overflows beyond the upper end opening of the heat medium overflow tube is heat medium. It is configured to discharge to the outside of the container.

Preferably, gas leakage detecting means for detecting the liquefied gas leaking from the heat transfer tube in the heat medium container is further provided. As a result, the operation can be avoided while the gas is in a leaked state.

The vaporizer of the present invention is particularly suitable for vaporizing liquefied natural gas (LNG), but in addition to vaporization of LNG, liquefied oxygen having a boiling point of -183 ° C, liquefied argon having -186 ° C, liquefied nitrogen at -196 ° C, -42 It is also applicable to the case of vaporizing a liquefied gas stored at low temperature in the liquid phase propane or the like.

Further features, actions and effects of the present invention will become apparent from the embodiments described below based on the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The partial longitudinal cross-sectional view which mainly shows the schematic structure of the vaporizer | carburetor which concerns on embodiment of this invention, and the structure of the heat exchanger coil inside.
Fig. 2 is a partial longitudinal sectional view mainly showing a schematic configuration of members other than heat transfer tubes in the vaporizer.
3 is a cross sectional view showing a schematic configuration of the vaporizer;
4 is an enlarged cross-sectional view showing the structure of a welding location in the vaporizer;
5 is a schematic configuration diagram showing a main portion of a conventional vaporizer.

1-4 shows the structure of the vaporizer for liquefied gas which concerns on embodiment of this invention, The vaporizer is mainly a base plate 1, the shell-shaped main body housing 2, and the heat exchanger tube 3 And a heat medium introduction nozzle 4, a heat medium overflow pipe 5, a heat medium discharge pipe 6, and a gas leak detection tube 7. 1 to 4, the thicknesses of the main body housing 2, the heat transfer tube 3, the heat medium introduction nozzle 4, the heat medium overflow pipe 5, the heat medium discharge pipe 6, and the like are shown for simplicity. Omitted. In addition, although the liquefied gas vaporized below is liquefied natural gas (LNG) and a heating medium is hot water, description may advance, but this invention is not limited to these.

The bottom plate 1 is made of, for example, stainless steel, and includes a plurality of heat pipe insertion holes 1a and 1b (two heat pipe insertion holes in FIG. 1) and a plurality of bolt holes 1c. I have it. The bottom plate 1 may also serve as a footing board for LNG satellites (see definition in paragraph [0002]).

The main body housing 2 is made of, for example, stainless steel, the lower end is opened, and the upper end is closed by a partially spherical or curved ceiling wall 2a. Therefore, the main body housing 2 has a substantially steering shape. An annular flange 2b is integrally formed on the outer periphery of the lower end of the opening of the main body housing 2, and a bolt hole 2c corresponding to the bolt hole 1c of the base plate 1 is formed in the flange 2b. It is. The main body housing 2 and the bottom plate 1 are fixed to each other by bolts (not shown) inserted into the respective bolt holes 1c and 2c. Therefore, by releasing the bolt which is not shown in figure, the main body housing 2 can be easily removed from the base plate 1, and the internal structure can be easily visually inspected. In this embodiment, the heat medium container for accommodating a heat medium, such as hot water, is defined by the base plate 1 and the main body housing 2. Although not shown, a suitable sealing material is inserted between the flange 2b of the main body housing 2 and the bottom plate 1 so that the sealed state is maintained.

As shown in FIG. 1, the heat transfer tube 3 is drawn into the body housing 2 through one of the heat transfer tube insertion holes 1a of the bottom plate 1, and extends upward in a spiral shape. It folds downward and is led to the outside via the heat exchanger tube insertion hole 1b on the other side of the base plate 1. As a result, even if the heat exchanger tube 3 is expanded and contracted by temperature change, it can fully absorb by the part extended in a spiral shape, and a stress is transmitted to the connection part (detail of the structure mentioned later) to the base plate 1 later. It's getting harder.

In the illustrated embodiment, the heat transfer pipe 3 gradually increases in diameter as it extends from the upstream side to the downstream side, and the top portion folded back from the small diameter portion 3a on the upstream side and the small diameter portion 3a. The middle diameter part 3b extended to and the large diameter part 3c extended toward this base plate 1 from this middle diameter part 3b are included. The small diameter portion 3a and the middle diameter portion 3b are connected by a reducer 3d (a known element for connecting tubular bodies having different diameters), and the middle diameter portion 3b and the large diameter portion 3c. ) Are connected by a reducer 3e. Specifically, the small diameter portion 3a is, for example, a stainless steel pipe having an inner diameter of 27.2 mm Φ, and the middle diameter portion 3b is a stainless steel pipe having an inner diameter of 35.5 mm Φ or an inner diameter of 52.7 mm Φ (from 1.7 times in cross-sectional ratio). 3.8 times larger), and the large diameter portion 3c is a stainless steel pipe having an internal diameter of 65.9 mm Φ (enlarged from 1.6 times to 3.4 times larger than the middle diameter portion 3b by the cross-sectional ratio). However, the inner diameter of the heat exchanger tube 3 may be increased in two steps (in this case, the inner diameter may be increased by 5.9 times at a cross-sectional area ratio from the inner diameter of 27.2 mm phi to the inner diameter of 65.9 mm phi at once), and the inner diameter may be increased by dividing into four or more steps.

The small diameter part 3a of the heat exchanger tube 3 is connected to the piping extended from an LNG storage tank, for example in the upstream end part. On the other hand, the large diameter part 3c of the heat exchanger tube 3 is connected to the piping connected to the natural gas utilization site | part (not shown) at the downstream edge part, for example.

As shown in Fig. 2 and Fig. 3, the heat medium introduction nozzle 4 is made of, for example, a stainless steel pipe, is connected to a pipe extending from a heat medium supply source (hot water supply source) not shown, and at the same time, It extends upward through 1). The upper end of the heat medium introduction nozzle 4 is opened in the lower part of the main body housing 2 along the circumferential direction of the outer circumferential wall, and sprays the heat medium so that the heat medium introduced into the main body housing 2 becomes a vortex. have. As the heat medium, a liquid such as hot water, ethanol or ethylene glycol can be used, but in consideration of cost and ease of handling, it is preferable to use hot water.

The heat medium overflow pipe 5 consists of a stainless steel pipe, for example, and extends through the base plate 1 in the sealed state. The upper end opening part 5a of the heat medium overflow pipe 5 is located in the vicinity of the ceiling wall 2 of the main body housing 2, and the heat medium which overflows by supplying the heat medium sequentially from the heat medium introduction nozzle 4 to the outside is provided. Discharge. The heat medium discharged through the heat medium overflow pipe 5 is reheated by a reheating means (not shown) and circulated to the heat medium supply source not shown again.

The heat medium discharge pipe 6 is for discharging the heat medium inside before removing the main body housing 2 from the bottom plate 1 and repairing the inside, and is sealed through the through hole of the bottom plate 1. Communicates with the inside of the main body housing 2. The heat medium discharge pipe 6 is made of, for example, a stainless steel pipe.

The gas leak detection tube 7 is provided in order to function as a check nozzle when liquefied gas such as LNG leaks inside the main body housing 2, and the upper end portion 7a is provided with an overflow tube 5. ) Is located between the upper end opening 5a (which defines the liquid level of the thermal medium) and the ceiling wall 2a of the main body housing 2. The liquefied gas leaked inside the main body housing 2 becomes a gas and is led out by the gas leak detection tube 7 and detected by a sensor (not shown) connected to the gas leak detection tube 7. . When leakage of the liquefied gas is detected, inspection and repair are performed.

Next, the connection structure with respect to the base plate 1 of the heat exchanger tube 3 is demonstrated. The heat transfer tubes 3 are connected to the bottom plate 1 at two positions, that is, at the positions of the heat transfer tube insertion holes 1a and 1b, but the diameters are small and large, but the basic connection structure is the same. As a representative example, the connection structure in the heat pipe insertion hole 1a of the small diameter portion 3a will be described with reference to FIG.

As shown in Fig. 4, the heat pipe insertion through-hole 1a is closed by a cap 8, and the center portion of the hemispherical or curved ceiling wall 8a of the cap 8 is loosened in the heat transfer pipe 3; The neck portion 3a penetrates. Between the small diameter part 3a of the heat exchanger tube 3 and the ceiling wall 8a of the cap 8 is joined by the welding part 9a, and between the sleeve part of the cap 8 and the base plate 1 is the weld part 9b. ) Is joined. As a result, the heat transfer tubes 3 and the caps 8 are fixed to each other at different points, so the expansion and contraction of the heat transfer tubes 3 and the expansion and contraction of the caps 8 are freed separately, so that the two thermal stresses are two welded portions ( 9a) and 9b). Moreover, with respect to the weld part 9a to the heat exchanger tube 3, the stress dispersion effect by the hemispherical or curved ceiling wall 8a in the cap 8 further acts. Therefore, in addition to the elastic absorption effect by having the heat transfer tube 3 in a spiral structure, stress concentration to the weld portions 9a and 9b does not occur. In addition, the cap 8 is preferably made of, for example, stainless steel in the same manner as the heat pipe 3.

In operating the vaporizer of the above structure, hot water of about +60 degreeC is supplied to the main body housing 2 through the heat medium introduction nozzle 4, and the inside of the main body housing 2 is almost filled. The supplied hot water rises inside the main body housing 2 as a vortex, and the excess hot water is discharged to the outside via the heat medium overflow pipe 5, and after being reheated, circulated to a heat medium supply source (not shown). do.

On the other hand, LNG, which is a liquefied gas, once rises inside the heat transfer tube 3 wound in a spiral shape, and is then changed from a liquid to a gas by being heated by hot water as a heat medium while descending. In the process, LNG, which is a liquid, is changed to a gas of -145 ° C from 0.3 MPaG, and its volume increases by about 70 times. However, as mentioned above, since the inner diameter of the heat exchanger tube 3 increases gradually, the resistance to the flow of a fluid does not increase, and the optimum flow velocity of LNG or vaporized gas is ensured. The vaporized natural gas is finally heated to near the normal temperature inside the heat transfer tube 3 and discharged.

For example, if hot water at + 60 ° C. is used to evaporate 600 kg / h of LNG, the surface area of the heat transfer pipe 3 is required to be about 13 m 2, but when it is heated with air or sea water, the heat transfer area is about It is needed more than twice, and the height of equipment increases and the installation area also increases. Therefore, according to the present embodiment, it is possible to realize miniaturization of the vaporizer and reduction of the installation area.

As mentioned above, although embodiment of this invention was described, if the effect by this embodiment is put together, it is as follows.

(1) Since the heat transfer tube 3 is made into a spiral shape, it is possible to absorb the change in expansion and contraction of the heat transfer tube due to the temperature change, hardly apply stress to the weld portion, and hardly break the weld portion. In particular, as in the illustrated embodiment, when one spiral heat transfer tube is used, there is no difference in thermal stress for each heat transfer tube as in the case where a plurality of heat transfer tubes are used, and heat fatigue is less likely to occur. In addition, by adopting the spiral heat transfer tube 3, the heat transfer area can be easily changed by adjusting the total number of heat transfer tubes by adjusting the number of windings and the winding density of the spiral.

(2) Since the joining to the base plate 1 of the heat transfer pipe 3 is divided into two welding parts 9a and 9b via the cap 8, each of the heat transfer pipe 3 and the cap 8 is performed. It can be dispersed without interfering with the thermal stress caused by stretching. In addition, since the stress dispersion effect by the hemispherical or curved ceiling wall 8a in the cap 8 further acts on the welded portion 9a to the heat transfer pipe 3, the stress dispersion effect as a whole is further increased. Increases.

(3) In the process of changing LNG from liquid to gas, even if the volume reaches 70 times or more, the inner diameter of the heat transfer tube 3 is enlarged step by step in accordance with the amount of evaporation in the heat transfer tube 3, so that the flow rate of the liquid or gas is increased. Optimization is possible.

(4) Since heat medium such as hot water is used, the temperature difference between the heating side and the side to be heated becomes large, so that the heat transfer area can be made small and compact. In addition, in order to use a heat medium, since it is not necessary to make a frozen carburetor wait and thaw, it is not necessary to provide two carburetors, and vaporization is possible only by 1 unit.

(5) Since the main body housing 2 covering the heat transfer tube 3 is steered or cap-shaped, and is detachably joined to the bottom plate 1, and the heat transfer tube 3 is welded to the bottom plate 1 only, By only removing the main body housing 2 from the base plate 1, the state of the heat exchanger tube 3 and a welding location can be visually inspected and maintained easily.

The present invention can be modified in various ways without departing from the basic idea. For example, in the illustrated embodiment, the material such as the heat transfer tube 3 is made of stainless steel. However, when weight reduction is desired, the material may be made of aluminum or an aluminum alloy. In addition, although the one heat exchanger tube 3 is used in embodiment shown, you may provide so that a plurality of spiral heat exchanger tubes may not mutually interfere with each other, and each base heat exchanger tube shown in FIG. 4 with respect to the base plate 1 is shown. A joining structure as described above can be employed. In addition to the vaporization of LNG, the vaporizer of the present invention is a liquefied gas in which the boiling point is liquefied oxygen having a boiling point of -183 ° C, liquefied argon of -186 ° C, liquefied nitrogen of -196 ° C, propane of -42 ° C or the like in a liquid phase at low temperature. It can also be applied to vaporize.

1: base plate 2: body housing
2a: body housing ceiling wall 2b: flange of body housing
3: heat pipe 3a: small diameter of heat pipe
3b: Middle diameter of heat exchanger tube 3c: Large diameter of heat transfer tube
4: heating medium introduction nozzle 4a: opening of heating medium introduction nozzle
5: heat medium overflow tube 5a: top opening of the heat medium overflow tube
6: heat medium discharge pipe 7: gas leak detection pipe
7a: Upper part 8: gas leak detection tube
8a: cap ceiling wall 9a, 9b: welded portion

Claims

A vaporizer which vaporizes a liquefied gas by heating it with a heat medium, comprising a heat medium container in which the heat medium is replenishably accommodated, and a spiral heat transfer tube extending from the bottom of the heat medium container to the top and folded back to the bottom, A vaporizer in which only the lower end of the heat transfer tube is supported by the heat medium container without causing the upper end of the heat transfer tube to be fixed so that the liquefied gas to be vaporized in the heat transfer tube is continuously flowed to vaporize.

The vaporizer according to claim 1, wherein the heat transfer pipe has a larger internal diameter in steps from an upstream side to a downstream side of the heat transfer tube.

The vaporizer according to claim 2, wherein the heat transfer tube has an inner diameter that is gradually increased so that the inner diameter cross-sectional area of the thickest portion on the downstream side of the heat transfer tube is in a range of 1.5 to 10 times the inner diameter cross-sectional area of the thinnest portion on the upstream side. .

The vaporizer according to claim 1, wherein the heat medium container includes a bottom plate and a main body housing detachably joined to the bottom plate, and the upstream end portion and the downstream end portion of the heat transfer tube are fixed only to the bottom plate.

The upstream end and the downstream end of the heat transfer tube are respectively supported by the bottom plate via a cap, and the cap is connected to an upstream side end or a downstream end of the heat transfer tube via a first welding portion. The vaporizer | carburetor which is joined together and is joined to the said bottom plate via the 2nd welding part.

The said cap has a curved ceiling wall, the said heat exchanger tube penetrates the said cap ceiling wall, and the said 1st welding part joins the said heat transfer tube and the said cap ceiling wall over an obtuse angle. Carburetor.

The heating medium container is provided with a heating medium introducing nozzle for supplying a heating medium therein, and the opening of the heating medium introducing nozzle sprays the heating medium along the circumferential direction of the outer circumferential wall of the heating medium container. carburetor.

The said heat medium container is provided with the heat medium overflow pipe which defines the liquid level of the heat medium inside, The heat medium which overflows beyond the upper end opening of the heat medium overflow pipe is mentioned above. A vaporizer that is discharged to the outside of the heat medium container.

The vaporizer according to claim 1, further comprising gas leak detection means for detecting liquefied gas leaked from the heat transfer tube in the heat medium container.

The vaporizer of claim 1, wherein the liquefied gas is liquefied natural gas (LNG) and is provided to an LNG satellite.