JP2705721B2 - Liquefied gas evaporator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporator capable of efficiently covering a wide range from a large flow rate to a small flow rate. In particular, it is particularly suitable for an evaporator having a usage range from a large flow rate to a small flow rate used in a liquefied natural gas carrier, or a dual purpose evaporator having a large flow rate and a small flow rate can be used for different purposes. Liquefied gas evaporator.

[0002]

2. Description of the Related Art A liquefied natural gas carrier will be described by way of example. In this liquefied natural gas carrier, several evaporators having various purposes are mounted and used.

As shown in the system diagram of FIG. 9, an evaporator 51 having a wide use range from a large flow rate to a small flow rate is referred to as an LNG vapor riser.
G evaporator ”). The liquefied gas carrier 52 is equipped with several LNG tanks 53,
In the tank 53, the loaded liquid 54 (-160 ° C
And a cargo pump 55 for unloading cryogenic liquefied natural gas (excess temperature), which can be supplied from the pump 55 to an onshore facility via an unloading line 56. At the time of unloading, a part of the liquid is sent from the spray pump 57 to the LNG evaporator 51 via the liquefied gas supply line 58 so that the inside of the tank 53 does not become a negative pressure, where it is gasified and the gas is returned to the original state. The tank 53 is returned. In this case, the liquid flowing to the evaporator 51 has a large flow rate (for example, about 20 t / h) for the purpose of preventing a negative pressure in the tank 53 during cargo handling.

On the other hand, if the cargo pump 55 fails for some reason, it becomes impossible to discharge the cargo. Therefore, the LNG evaporator 51 is used as a countermeasure. That is, for example, it is assumed that the cargo pump 55 of the first tank has failed. In this case, after the unloading of the second tank is completed, a part of the liquid is sent from the spray pump 57 to the evaporator 51 in the same manner as described above, where it is gasified and the gas is discharged into the upper boil-off gas of the first tank. It is pushed into the space 53a to apply pressure inside the tank. Under the pressure, the liquid material 54 is transferred from the unloading line 56 to the second tank through a filling (filling) line 59 provided to the second tank. Thereafter, the cargo is discharged to land using the cargo pump 55 installed in the normally operating second tank. In this application, the LNG evaporator 51 is used for a small flow rate (for example, about 5 t / h).

As described above, the LNG evaporator 51 has a flow rate of 5 to 5.
It is used for a wide range of uses such as 20 t / h.

Next, FIG. 10 is a system diagram including an evaporator 61 (hereinafter referred to as a "forced evaporator") called a hosing vaporizer. This is because a part of the liquid is sucked up by a spray pump 57 and sent to a forced evaporator 61 where the liquid is gasified. The gas is pressurized by a compressor 62 and then heated by a heater 63 to a predetermined temperature. The fuel is fed to a boiler (not shown) and used as fuel for the boiler. The forced evaporator 61 used for this purpose is L
The NG evaporator 51 has a smaller flow rate than when the small flow rate is used. For example, it is about 500 kg to 4 t / h.

The above-mentioned LNG evaporator 51 and forced evaporator 6
1. All other equipment (compressor, heater, etc.)
As shown in the figure, the upper deck 52A is disposed in a machine room 64 provided by utilizing a space between the tanks 53 of the upper deck 52A.

The above-mentioned LNG evaporator 51 and forced evaporator 61
Although there is a difference in capacity due to the difference in flow rate,
Each of them has a structure as shown in FIG. FIG.
Is the system diagram. The outer shape of the evaporator (LNG evaporator 51 or forced evaporator 61) has a cylindrical shape, and is divided into right and left by a perforated plate 3 provided at a biased position. On the right is a heat exchange chamber 4, which is a steam pipe S for sending steam from above.
Is provided, and a drain pipe D is provided below. The space on the left is further partitioned by a horizontal plate 5 up and down, and a liquid distribution chamber 6 is formed in a lower stage, and a gas collecting chamber 7 is formed in an upper stage. A heating tube 8 is connected to each of the plurality of small holes 3a of the perforated plate 3 facing the liquid distribution chamber 6, and the heating tube 8 is piped in a U-shape in the heat exchange chamber 4 to form a small hole of the upper perforated plate 3. 3b. The liquid distribution chamber 6 is connected to a liquefied gas supply line 9 for introducing the liquid conveyed from the LNG tank. A gas temperature adjusting line 10 branched to the supply line 9 and led to the gas collecting chamber 7.
Is provided. The liquefied gas supply line 9 and the gas temperature control line 10 are provided with a flow control valve 13 and a temperature control valve 14, respectively.
Is provided.

A part of the low-temperature charged liquid entering the liquid distribution chamber 6 is gasified, and most of the charged liquid is distributed through the small holes 3a of the perforated plate 3 into the heating tubes 8 group, and Flows in the direction of the arrow, and is gasified by being heated by the steam sent from the steam pipe S during that time, and flows out into the gas collecting chamber 7 from the small holes 3 b of the upper porous plate 3. Since the gas collected in the gas collecting chamber 7 has a high temperature, a low-temperature liquid is sprayed in a mist form from the spray nozzle 11 provided at the tip of the gas temperature control line 10 so that the gas temperature reaches a predetermined temperature. I try to lower it. The gas temperature is controlled by detecting the temperature of the gas flowing in the gas outlet line 12 by the outlet gas temperature controller 15 and changing the opening of the temperature control valve 14 to inject the gas from the spray nozzle 11. The flow rate of the liquid is adjusted to control the gas temperature to a predetermined temperature. The gas having a predetermined temperature is supplied from the gas outlet line 12 to the above-described predetermined location.

[0010]

[Problems to be Solved by the Invention] Problems in LNG Evaporator Used from Large Flow Rate to Small Flow Rate Although the above-mentioned conventional LNG evaporator is used for a time from a large flow rate to a small flow rate, satisfactory performance is not necessarily obtained. I couldn't. That is, since the LNG evaporator is designed and manufactured on the basis of a large flow rate, the liquid distribution chamber has a disproportionately large volume at a small flow rate. Therefore, when used as a small flow rate, the liquid flowing into the liquid distribution chamber is not evenly distributed to many small holes, resulting in uneven flow distribution, so that sufficient performance is exhibited even if there are many heating tubes. Not done.

In addition, a small flow rate of the charged liquid is transferred to the large liquid distribution chamber 6.
When the gas is introduced into the liquid distribution chamber, the rate of gasification at the time of entering the liquid distribution chamber becomes extremely large, and this gas prevents the liquid from entering the heating tube 18, and at the same time, the introduced gas is heated to a high temperature. An abnormally high outlet gas temperature reduces the efficiency of heat exchange.

Further, since the flow control valve 13, the temperature control valve 14 and the spray nozzle 11 are provided for a large flow rate, the flow control valve 13 and the temperature control valve 14 have poor controllability in a small flow rate range. The spray function of the spray nozzle 11 also could not be exhibited in the small flow rate range, the gas outlet temperature fluctuated, and the spray nozzle 11 did not stabilize.

Problems when LNG evaporator and forced evaporator are used together Since LNG evaporator and forced evaporator have different purposes and cannot be used at the same time, the viewpoint of equipment reduction and the above-mentioned machine room 6
Because the space of FIG. 4 (FIG. 11) is also narrow, there is a demand that both should be configured as one evaporator, that is, both should be used as an evaporator.

However, when a dual-purpose evaporator is simply used, the use ranges of the LNG evaporator and the forced evaporator are greatly different (the former is a large flow rate, and the latter is a small flow rate). A similar problem will occur if it is present in the evaporator.

As described above, conventionally, there has been no evaporator suitable for a large flow rate and a small flow rate at the same time, so that the above-mentioned problems cannot be solved and the demands cannot be met. .

The present invention has been made in view of the above-mentioned problems, and has as its object to provide a liquefied gas evaporator capable of coping with a large flow rate to a small flow rate without lowering the evaporation efficiency.

[0017]

Means for Solving the Problems To achieve the above object, means according to claim 1 has a liquid distribution chamber and a gas collecting chamber,
In a liquefied gas evaporator of the type in which the liquid distribution chamber and the gas collecting chamber are connected by a number of heating tubes, a gas vent line is connected to the liquid distribution chamber, and the gas vent line is connected to the gas collecting chamber. Alternatively, the liquefied gas evaporator is connected to a gas outlet line communicating with the gas collecting chamber and provided with a float check valve in the gas vent line.

According to a second aspect of the present invention, there is provided an evaporator for a liquefied gas having a liquid distribution chamber and a gas collecting chamber, wherein the liquid distribution chamber and the gas collecting chamber are connected by a plurality of heating tubes. An upper guide plate having a gas vent tube as a heating tube group opening at the upper part of the liquid distribution chamber and having an end at a high position of the liquid distribution chamber below the opening of the heating tube group for degassing, A liquefied gas evaporator in which a lower guide plate having an end at a lower position is disposed in a liquid distribution chamber.

According to a third aspect of the present invention, a gas vent line is connected to the liquid distribution chamber of the second aspect, and the gas vent line is connected to the gas collecting chamber or a gas outlet line communicating with the gas collecting chamber. A liquefied gas evaporator, wherein a float check valve is provided in the gas vent line.

According to a fourth aspect of the present invention, there is provided an evaporator for a liquefied gas of a type having a liquid distribution chamber and a gas collecting chamber, wherein the liquid distribution chamber and the gas collecting chamber are communicated with a plurality of heating tubes. In the above, a partition plate is provided in the liquid distribution chamber to form a small volume liquid distribution chamber corresponding to a small flow rate, and the flow rate is adjusted to the small volume liquid distribution chamber and the other large volume liquid distribution chamber, respectively. A liquefied gas supply line is connected via a valve, a gas vent line is connected to a large volume liquid distribution chamber, and this gas vent line is connected to the gas collecting chamber or a gas outlet line communicating with the gas collecting chamber. A liquefied gas evaporator, wherein a float check valve is provided in the gas vent line.

According to a fifth aspect of the present invention, in any one of the above structures, the gas temperature adjusting line is branched from a liquefied gas supply line and connected to a gas collecting chamber or a gas outlet line of an evaporator. A liquefied gas evaporator characterized in that a line having a large flow rate spray nozzle and a line having a small flow rate spray nozzle are provided at the end of the line via a temperature control valve.

[0022]

According to the first aspect of the present invention, a gas that is gasified when a large or small flow of liquefied gas (liquid) is supplied to the liquid distribution chamber (the gasification rate is large when the flow is small). It is led to a gas outlet line by a venting line. Therefore, the possibility that the gasified material enters the heating tube together with the liquid is reduced, and at the same time, the liquid is uniformly distributed to a large number of heating tubes because the liquid distribution is not hindered by the gas. Even if a part of the liquid flows from the liquid distribution chamber into the gas vent line, the flow of the liquid to the gas vent line is prevented by the action of the float check valve. Since the degassing of the liquid distribution chamber is performed quickly, the above-mentioned obstacle due to gasification in the liquid distribution chamber is eliminated, so that the effect of improving the evaporation efficiency is exhibited regardless of the large flow rate and the small flow rate. In the means according to claim 2, gas is likely to be generated in the liquid distribution chamber at the beginning when the liquefied gas is supplied to the liquid distribution chamber (similarly when the liquefied gas is supplied at a small flow rate). Quickly removed from the heating tube group. Thus, in the case of a small flow rate, the liquid separated from the gas is uniformly distributed to the heating tube at a low position while being guided by the lower guide plate, and is heated to a high position while being guided by the upper guide plate at a large flow rate. Evenly distributed in tubes.

In particular, in the means according to claim 3, claim 2
In addition to the effect of the configuration of the first aspect, it has the same operation as that of the means according to claim 1, and since the gas in the liquid distribution chamber is quickly released, the evaporation efficiency is reduced due to the presence of gas in the liquid distribution chamber. Etc. are prevented.

In particular, in the means according to claim 4, claim 1
In addition to the operation of the above configuration, the partitioning plate provided in the liquid distribution chamber separates the liquid distribution chamber for large flow rate (large volume) and the liquid distribution chamber for small flow rate (small volume). Even if a flow of liquefied gas (liquid) enters the liquid distribution chamber, the amount of gasification is reduced, so that the liquid is evenly distributed in the corresponding heating tube.

In particular, in the means according to the fifth aspect, since a flow rate and temperature control valve and a spray nozzle corresponding to a large flow rate or a small flow rate are respectively provided, the controllability of the flow rate and temperature control valve is good, and The spray function of the nozzle is also properly exhibited.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

First, an embodiment in which a partition is not provided in the liquid distribution chamber, which can efficiently cope with a wide flow rate range from a large flow rate to a small flow rate, will be described with reference to FIGS. Note that the detailed structure of the evaporator is the same as that of FIG. 12 described above, unless otherwise specified, and the description thereof is omitted here.

As shown in the system diagram of FIG. 1, the evaporator 1 has a cylindrical side wall 2 and is partitioned on the left and right by a perforated plate 3, and a heat exchange chamber 4 is formed in the right section. . And the left section is further partitioned by a horizontal plate 5,
A liquid distribution chamber 6 is formed in a lower stage, and a gas collecting chamber 7 is formed in an upper stage. A large number of small holes (see FIG. 12) provided in the perforated plate 3 are provided between the small holes 3a at the lower stage and the small holes 3b at the upper stage. Tube 8
As a result, the liquid distribution chamber 6 and the gas collecting chamber 7 communicate with each other through the heating tubes 8. In the figure, S is a steam pipe communicating with the heat exchange chamber, and D is a drain pipe.

The liquid distribution chamber 6 is connected to a liquefied gas supply line 9 for introducing a liquefied gas (loading liquid) fed from the LNG tank into the liquid distribution chamber 6, and branches from the supply line 9. As a result, the gas temperature adjustment line 10 is led to the gas collecting chamber 7. A spray nozzle 11 is provided at the tip of the gas temperature adjustment line 10. The gas temperature adjustment line 10 may be connected to a gas outlet line 12 extending from the gas collecting chamber 7 instead of leading to the gas collecting chamber 7. The spray nozzles may be provided separately for the large flow rate 11a and the small flow rate 11b.

Before the liquefied gas supply line 9 is connected to the liquid distribution chamber 6, a flow rate control valve 13 is provided, and a gas temperature control line 10 is provided with a temperature control valve 14. Temperature control valve 1 on gas temperature control line 10
4 detects the temperature of the gas passing through the gas outlet line 12 and adjusts the injection amount from the spray nozzle 11 by the outlet gas temperature controller 15 to adjust the gas temperature. Therefore, a control air line 16 is provided between the controller 15 and the temperature control valve 14, and a temperature detector 17 is provided in the gas outlet line 12, and the temperature detector 17 is provided between the temperature detector 17 and the controller 15. A capillary tube 18 for transmitting temperature is provided. In order to ensure controllability in a small flow rate region, the flow control valve 13 may have a large flow rate valve and a small flow rate valve.

The evaporator 1 is of a wide use type which is used for both a large flow rate and a small flow rate, but its structure is designed and manufactured for a large flow rate. Therefore, when used at a small flow rate, the same problem as in the related art occurs.
Therefore, in the present embodiment, a gas vent line 19 is provided between the liquid distribution chamber 6 and the gas outlet line 12 so that such a problem does not occur. That is, as shown in FIG. 1, a gas vent line 19 communicating with the liquid distribution chamber 6 is provided, and the gas vent line 19 is connected to the gas outlet line 12 via a float check valve 20 in the middle. Note that the gas vent line 19 may be connected to the upper portion of the liquid distribution chamber 6 where the gas stays. In addition, the float check valve 20 is connected to the partition plate 5.
Or just above the level of the gas collection chamber. The steam pipe S for feeding steam is provided with a control valve for adjusting the amount of steam supplied to the evaporator 1 and the temperature according to the amount of gasification from a large flow rate to a small flow rate.

FIG. 2 is a structural sectional view of the float check valve 20. That is, the ball-shaped float 20b is provided in the ball-shaped valve body 20a, and the gas entering from the inlet 20c flows through the gap between the float 20b and the inner surface of the valve body 20a to the outlet 20d side as it is. Go. Normally, gasified gas flows out to the degassing line 19, but there is a possibility that a part of the liquid introduced into the liquid distribution chamber 6 may enter the degassing line 19 together with the gas. is there. In this case, a certain amount of liquid flows into the float check valve 20, and the float 20b floats up to the position of the imaginary line as shown in FIG. 2 and contacts and closes the projection 20e protruding from the inner surface of the valve body 20a. To the outlet 20d side. When the liquid in the liquid distribution chamber 6 flows toward the heating tube 8, the amount of liquid in the float check valve 20 naturally drops, so that the float 20b descends again and only the gas flows out from the outlet 20d. Become. For example, a hollow stainless steel ball is used for the float 20b.

The function of the float check valve 20 produces the following operation.

That is, when a small amount of liquid is introduced into the liquid distribution chamber 6 through the supply line 9, it is conceivable that a considerable amount of gas is converted into gas here. As described above, this adversely affects the evaporator efficiency. Therefore, the gas that has been gasified by the gas vent line 19 is supplied to the gas outlet line 1.
2, the gas in the liquid distribution chamber 6 is evacuated so as not to enter the heating tube 8. As a result, the amount of gas present in the liquid distribution chamber 6 together with the liquid is greatly reduced, so that the liquid is easily distributed uniformly to the heating tubes 8.

FIG. 3 shows another embodiment for obtaining the same function. As described above, a large number of U-shaped heating tube groups are provided in the heat exchange chamber. One opening of these heating tube groups faces the liquid distribution chamber 6. Among these heating tube groups, the heating tube group 8A located above the liquid distribution chamber 6 degass the liquid distribution chamber 6 (particularly, when the liquefied gas is supplied into the liquid distribution chamber, In the case of the flow rate, since a large amount of gas is contained, the gas is used as a degassing pipe for quickly removing the gas. Then, an upper guide plate 22A having an L-shaped cross section and having an end at a high position A of the liquid distribution chamber 6 below the liquid distribution chamber 6 is horizontally moved from the perforated plate 3 separating the liquid distribution chamber and the heat exchange chamber to the liquid distribution chamber 6 side. It is provided to protrude.
Similarly, a lower guide plate 22B having an L-shaped cross section and having an end at a position B lower than A is provided. Accordingly, the heating tube 8 group includes a gas release heating tube 8A group opened above the upper guide plate 22A, a heating tube 8B group opened between the upper guide plate 22A and the lower guide plate 22B, and the lower guide plate 22.
Heating tubes 8C that open below B are grouped into three groups. With such a configuration, when a small flow of liquefied gas enters the liquid distribution chamber 6 from the supply line 9, the gas separates and rises, enters the upper heating tube 8A, is quickly degassed, and the liquid is guided to the lower guide. Plate 22B
And smoothly enters the heating tube 8C. When the flow rate is large, the upper guide plate 22A uniformly enters the heating tubes 8B at a higher position. The introduction port of the liquefied gas supply line 9 to the liquid distribution chamber 6 is arranged at a position away from the end of the guide plate, and
It is preferable to prevent the gas from being guided to the heating tube 8 along 2A and 22B.

In the embodiment shown in FIG. 3, if the above-described gas venting line with a float check valve is further provided, the gas venting action is enhanced. Since the gas existing in the upper part of the liquid distribution chamber 6 is removed, mixing of gas into the heating tube is drastically reduced, and the heat exchange efficiency in the heating tube can be further improved.

Next, an embodiment in which a partition plate is provided in the liquid distribution chamber in order to efficiently handle a large flow rate to a small flow rate will be described with reference to FIGS.

FIG. 4 is a system diagram when the liquid distribution chamber is partitioned. That is, a partition plate 21 is provided to divide the liquid distribution chamber 6 into two sections, and the liquid distribution chamber 6 is divided into a large volume liquid distribution chamber 6A and a small volume liquid distribution chamber 6B. The smaller volume is specially provided as a liquid distribution chamber 6B corresponding to a small flow rate.
For a large flow rate, only the large volume liquid distribution chamber 6A may be used, but usually the entire liquid distribution chamber 6 is used. That is,
Although the partition plate 21 is provided and divided into two, it is preferable to use both the liquid distribution chamber 6A and the liquid distribution chamber 6B for a large flow rate. Therefore, the liquefied gas supply lines 9A, 9B are individually provided to the liquid distribution chambers 6A, 6B, respectively, and the flow control valves 13A,
3B is connected in the middle. Further, a gas temperature adjusting line 10 is provided branching from the liquefied gas supply line 9, and large and small flow lines 10 A, 10 B are provided on the way.
And each is connected to a gas outlet line 12. The branch lines 10A and 10B have temperature control valves 14A,
14B are provided respectively, and each temperature control valve 14A, 1
Control air lines 16A and 16B are connected to 4B, and are connected to the gas temperature controller 15 via the switching cock 22. The gas temperature controller 15 is connected to a temperature detection line 18 for detecting the gas temperature of the gas outlet line 12. When switching from the large flow rate to the small flow rate, the flow control valve 13A on the liquefied gas supply line is closed, and the flow rate is controlled by the flow control valve 13B. By operating the switching cock 22, the temperature control valve 14 is switched between a large flow rate (A) and a small flow rate (B). In the case of a large flow rate, both of the flow control valves 13A and 13B are opened to use the entire liquid distribution chamber 6, and the temperature control valve 14A is operated.
Flow control valves 13A, 13 corresponding to a large flow rate or a small flow rate
Since B and the temperature control valves 14A and 14B are properly used, good controllability is maintained even when the evaporator is used from a large flow rate to a small flow rate. The above configuration may be applied to the embodiments shown in FIGS.

FIGS. 5 to 8 show some arrangements of the partition plate 21 provided in the liquid distribution chamber 6. FIG. 5 shows an example in which the partition plate 21 is provided so as to be biased downward so that the upper part of the liquid distribution chamber 6 has a large volume. In this case, the partition plate 21 extends horizontally to the end wall 2A of the liquid distribution chamber 6 as shown in FIG. 6 (a), or (b) hangs down to the lower side wall 2 halfway as shown in FIG. It may be an L-shaped partition plate. (A) or (b) may be selected so that the volume of the liquid distribution chamber 6B divided by the partition plate 21 is suitable for the actual small flow rate. In the case of using a large flow rate, the entire liquid distribution chamber 6 is normally used as described above, even if the liquid distribution chamber 6 is divided by the partition plate 21. The liquid distribution chamber 6A
1 and 6B are connected to a gas vent line having a float check valve as in FIG.
It is even better that various obstacles caused by the presence of A and 6B are eliminated.

FIG. 7 shows the right (or left) corner of the liquid distribution chamber 6.
This is an example in which a partition plate 21 is provided vertically at a position deviated to the right side, and a liquid distribution chamber 6B for small flow is provided on the right side.

FIG. 8 shows an example in which a semicircular arc-shaped partition plate 21 is provided concentrically with the cylindrical side wall 2 of the liquid distribution chamber 6. In this case, the partition plate 21 is provided at a position deviated to the side wall 2 side, and is set so that the liquid distribution chamber 6B has an appropriate volume. The partition plate 21 may extend to the end wall of the liquid distribution chamber as shown in FIG. 6 (a), or may be provided hanging down the way as shown in FIG. 6 (b). What is necessary is just to select suitably considering the ratio of the large flow rate and the small flow rate.

[0042]

According to the first to fifth aspects of the present invention, it is possible to provide an evaporator capable of coping with a large flow rate to a small flow rate without lowering the evaporation efficiency. As a result, in the case of an LNG evaporator having a wide range of use, even when the LNG evaporator is used at a small flow rate, the liquid introduced into the liquid distribution chamber is easily distributed to a large number of small holes. Efficiency) can be improved.

In particular, when a gas vent line connected to the liquid distribution chamber is provided, various obstacles caused by the presence of gas in the liquid distribution chamber can be eliminated, and the evaporation efficiency can be greatly improved. it can.

In particular, the controllability of the flow rate or temperature regulating valve and the spray nozzle does not become a problem, and the gas outlet temperature is settled at a predetermined temperature because the spray function of the spray nozzle is properly exhibited. be able to.

2) According to the first to fifth aspects, the large and small flow rate L
A dual-purpose evaporator that can be efficiently used as an NG evaporator or a forced evaporator with a small flow rate can be obtained. As a result, in a liquefied gas carrier, the number of evaporators can be reduced, and the cost of equipment and the related piping work are eliminated. At the same time, there is an advantage that the arrangement of equipment and the piping work in a limited machine room are facilitated.

[Brief description of the drawings]

FIG. 1 is a system diagram of an embodiment of the invention according to the present application (in a case where a liquid distribution chamber is not partitioned), in which a gas vent line having a float check valve is provided in the liquid distribution chamber.

FIG. 2 is a structural sectional view of a float check valve.

FIG. 3 shows another embodiment of the invention according to the present application (in a case where the liquid distribution chamber is not partitioned), which is an essential part of the evaporator when the open ends of the heating tube group are arranged at two levels in the liquid distribution chamber. It is a fragmentary sectional view.

FIG. 4 is a system diagram of an embodiment of the invention according to this application, in which a liquid distribution chamber is partitioned to form a liquid distribution chamber for a small flow rate.

FIG. 5 is a front view of a main part of the liquid distribution chamber.

FIG. 6 is a side sectional view of a main part of the liquid distribution chamber, (a) shows a case where a partition plate is extended to an end wall of the liquid distribution chamber, and (b) shows a case where the partition plate is hung down to a side wall to form an L-shape. It is.

FIG. 7 is a front view of a main part of the liquid distribution chamber when a partition plate is vertically arranged at a corner of the liquid distribution chamber.

FIG. 8 is a front view of a main part of a liquid distribution chamber when a partition plate is provided concentrically with a side wall.

FIG. 9 L that can be used in a wide range from a large flow rate to a small flow rate
It is a system diagram regarding NG evaporator.

FIG. 10 is a system diagram relating to a forced evaporator used as a small flow rate.

FIG. 11 is a perspective view of a front portion of a liquefied gas carrier including a machine room.

FIG. 12 is a partially cutaway perspective view showing the entire conventional LNG evaporator or forced evaporator.

FIG. 13 is a system diagram relating to a conventional liquefied gas evaporator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Evaporator 2 ... Side wall 3 ... Perforated plate 4 ... Heat exchange chamber 6 ... Liquid distribution chamber 6A ... (Large volume) liquid distribution chamber 6B ... (Small volume) liquid distribution chamber 7 ... Liquefied gas supply line 9A Liquefied gas supply line (to large volume liquid distribution chamber) 9B Liquefied gas supply line (to small volume liquid distribution chamber) 10 Gas temperature control lines 11a, 11b Spray nozzle 12 Gas Outlet line 13, 13A, 13B: Flow control valve 14, 14A, 14B: Temperature control valve 15: Temperature controller 19: Gas release line 20: Float check valve 21: Partition plate 22A: Upper guide plate 22B: Lower guide plate

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akira Ikeuchi 1 Kawasaki-cho, Sakaide-shi, Kagawa Kawasaki Heavy Industries, Ltd. Inside the Sakaide factory (56) References International Publication 94/17325 (WO, A)

Claims (5)

(57) [Claims] 1. A liquefied gas evaporator of the type having a liquid distribution chamber and a gas collecting chamber, wherein the liquid distribution chamber and the gas collecting chamber are connected by a number of heating tubes. And a gas check line connected to the gas collecting chamber or a gas outlet line communicating with the gas collecting chamber, and a float check valve provided in the gas collecting line. Gas evaporator. 2. A liquefied gas evaporator of the type having a liquid distribution chamber and a gas collecting chamber, wherein the liquid distribution chamber and the gas collecting chamber are connected by a number of heating tubes. A heating tube group opened to the upper part is a degassing tube, an upper guide plate having an end at a high position of the liquid distribution chamber below the opening of the degassing heating tube group, and an end at a lower position than the upper guide plate. A liquefied gas evaporator, wherein a lower guide plate having the same is disposed in a liquid distribution chamber. 3. A gas vent line is connected to the liquid distribution chamber according to claim 2, and the gas vent line is connected to the gas collecting chamber or a gas outlet line communicating with the gas collecting chamber.
3. The liquefied gas evaporator according to claim 2, wherein a float check valve is provided in the gas vent line. 4. A liquefied gas evaporator of the type having a liquid distribution chamber and a gas collecting chamber, wherein the liquid distribution chamber and the gas collecting chamber are connected by a number of heating tubes. A liquid distribution chamber having a small volume corresponding to a small flow rate is specially formed by providing a partition plate, and the liquefied gas is supplied to the small volume liquid distribution chamber and the other large volume liquid distribution chamber via flow rate control valves, respectively. A supply line is connected, a gas vent line is connected to a large-volume liquid distribution chamber, and this gas vent line is connected to the gas collecting chamber or a gas outlet line communicating with the gas collecting chamber, and to the gas vent line. An evaporator for liquefied gas, comprising a float check valve. 5. A gas temperature adjusting line branched from a liquefied gas supply line and connected to a gas collecting chamber or a gas outlet line of an evaporator, a line provided with a large flow rate spray nozzle at the tip of the gas temperature adjusting line. The liquefied gas evaporator according to any one of claims 1 to 4, wherein a line having a spray nozzle and a small flow rate spray nozzle is provided via a temperature control valve.