JP2015117807A - Hot water type liquefied gas vaporizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water type vaporizer in which change of an outlet gas composition hardly occurs at restart time.SOLUTION: A hot water type liquefied gas vaporizer includes: a shell body 10 installed in a vertically long manner; a tube 11 having a plurality of reversed U-shaped curve parts 11A which are arranged in the shell body 10, and a pair of straight line parts 11B along the shell body 10; a hot water inflow part 12 which is arranged below the shell body 10 and which communicates with one of open ends of the pair of straight line parts 11B; a hot water outflow part 13 which is arranged below the shell body 10 and which communicates with the other open end of the pair of straight line parts 11B; a liquid inflow part 15 which allows a liquid of a liquefied gas to flow into the shell body 10; and a gas outflow part 16 which allows a gas vaporized in the shell body 10 to flow out. A curvature radius of the curved part 11A is set in such a manner that, when hot water flows in the tube 11 at a set flow rate equal to or more than a non-freezing average flow rate at which the hot water does not freeze at the straight line parts 11B, flow rate distribution which is equal to or more than the flow rate distribution of the non-freezing average flow rate at the straight line parts 11B can be acquired at the curved parts 11A.

Description

  The present invention relates to a hot water type liquefied gas vaporizer that vaporizes liquefied gas by heat exchange with hot water.

  As a vaporizer for a liquefied gas such as LNG or liquid nitrogen, one that heats the liquefied gas to the boiling point using heat of hot water is known. Thus, the vaporizer which uses warm water as a heat source arrange | positions the pipe for heat exchange in the warm water with which the inside of the container was filled, and is a warm water bath type which vaporizes this pipe while liquefied gas passes (refer the following patent document 1). And a shell and tube type (see Patent Document 2 below) in which hot water is circulated in the shell and liquefied gas passing through the tube is vaporized using a heat exchanger having a shell and tube structure.

JP 2001-201279 A JP-A-8-188785

  In the hot water bath type vaporizer, it is necessary to increase the heat capacity by enlarging the bath container so that the stored hot water does not freeze. In addition, since the shell and tube type vaporizer described above is difficult to increase the flow rate of the hot water flowing in the shell, the shell is enlarged to increase the heat capacity in order to avoid freezing of the hot water. As with the bus type, the increase in size of the vessel is a problem. Furthermore, there is a problem that the welded portion of the tube is easily damaged by vibration due to the gas-liquid mixed flow caused by vaporization of the liquefied gas in the tube.

  In addition to these problems, the shell-and-tube type vaporizer retains liquefied gas in a liquid state in the tube when it is stopped. It was also a problem that the gas component of this fluctuated.

  This invention makes it an example of a subject to cope with such a problem. That is, it is possible to reduce the size and space of the vessel, suppress the breakage of the tube, and further provide a hot water type vaporizer that is unlikely to change the outlet gas component at the time of restarting, etc. It is an object of the present invention.

In order to achieve such an object, a hot water type liquefied gas vaporizer according to the present invention comprises at least the following configuration.
A vertically disposed shell main body, a plurality of tubes arranged in the shell main body and having an inverted U-shaped curved portion and a pair of straight portions along the shell main body, and a lower portion of the shell main body, A hot water inflow portion in which one open end of a pair of straight portions communicates, a hot water outflow portion in the lower portion of the shell main body that communicates with the other open end of the pair of straight portions, and a liquefied gas in the shell main body A liquid inflow part for injecting the liquid and a gas outflow part for outflowing the gas vaporized in the shell body, and the curvature radius of the curved part is equal to or greater than the non-freezing average flow rate at which the hot water does not freeze in the linear part. The hot water is set such that a flow velocity distribution equal to or higher than the flow velocity distribution of the non-freezing average flow velocity in the straight line portion is obtained in the curved portion when hot water is caused to flow in the tube at a set flow velocity. Liquefaction Scan vaporizer.

  The hot water type liquefied gas vaporizer having such a feature is one in which warm water is allowed to flow in the tube of the shell and tube type vaporizer to vaporize the liquefied gas in the shell body. For this reason, by increasing the flow rate of the hot water flowing in the tube, it becomes possible to efficiently vaporize the liquefied gas while preventing the freezing of the hot water without increasing the size of the vessel. Further, by vaporizing the liquefied gas in the shell main body having a larger capacity than in the tube, there is almost no gas-liquid mixed state, and vibration applied to the tube or shell can be suppressed. Further, since almost no residual liquid is generated in the shell body at the time of stopping, the change in the outlet gas component at the time of restarting hardly occurs.

  In addition, since the radius of curvature of the tube is set so that the hot water flowing in the tube does not freeze, there is no operation failure due to clogging or breakage of the tube due to freezing of the hot water. Since the tube has a structure free from heat shrinkage, it is possible to suppress the occurrence of cracks and the like and obtain a highly durable vaporizer.

It is explanatory drawing (longitudinal sectional view) which showed the whole structure of the hot water type | mold liquefied gas vaporizer which concerns on one Embodiment of this invention. It is AA sectional drawing in FIG. It is explanatory drawing which showed the design method which designs the tube which warm water does not freeze.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are explanatory views (FIG. 1 is a longitudinal sectional view, and FIG. 2 is an AA sectional view) showing an overall configuration of a hot water type liquefied gas vaporizer according to an embodiment of the present invention. The hot water liquefied gas vaporizer 1 includes a shell main body 10, a plurality of tubes 11 disposed in the shell main body 10, a hot water inflow portion 12 and a hot water outflow portion 13 disposed in the lower portion of the shell main body 10, and the shell main body 10. The liquid inflow part 15 into which the liquid of a liquefied gas is made to flow in, and the gas outflow part 16 from which the gas vaporized in the shell main body 10 is made to flow out are provided.

  The shell main body 10 is installed vertically, only the lower end is supported, and the upper end is free. The inside of the shell body 10 is partitioned vertically by a plurality of partition plates 14, but a plurality of holes are formed in the partition plate 14, and the partitioned sections can move a liquid or a gas to each other. ing. The shell body 10 can be formed by vertically stacking ring-shaped divided bodies and connecting them in an airtight manner.

  The tube 11 disposed in the shell main body 10 includes a curved portion 11A in which one tube 11 extends up and down along the shell main body 10 and a curved portion. A plurality of tubes 11 having different curvature radii of 11A are arranged in a plane, and a plurality of tubes 11 having the same curvature radius of the curved portion 11A are arranged in parallel in a direction perpendicular to the illustrated paper surface. The straight portions 11 </ b> B of the plurality of tubes 11 pass through the plurality of partition plates 14 and are supported by the partition plates 14. The tube 11 circulates warm water as a heat medium and releases the heat of the warm water into the shell body 10, but the partition plate 14 supports the tube 11 to dissipate heat transmitted from the tube 11. It is functioning as well.

  The warm water inflow portion 12 has one open end (lower end) of the pair of straight portions 11B in the tube 11 communicating with each other, and the warm water flowing in from the warm water inlet 12A flows into the tube 11 through the warm water inflow portion 12. It is like that. Further, the warm water outflow portion 13 communicates with the other open end (lower end) of the pair of straight portions 11B in the tube 11, and the warm water passing through the tube 11 passes through the warm water outflow portion 13 from the warm water outlet 13A. It comes to leak. The hot water inlet 12A and the hot water outlet 13A may be connected via a circulation channel including a heating source.

  A liquid inflow portion 15 for allowing the liquid of the liquefied gas to flow into the shell main body 10 communicates with the upper section 10 </ b> A in the shell main body 10 partitioned by the partition plate 14. In addition, a gas outflow portion 16 through which the gas vaporized from the liquefied gas flows out communicates with the lower section 10B in the shell main body 10 partitioned by the partition plate 14.

  A liquid pipe 20 to which liquefied gas is supplied is connected to and introduced into the liquid inflow portion 15 so that the liquid of the liquefied gas is dispersed throughout the shell body 10. The liquid pipe 20 is equipped with a pressure adjustment valve 21. In addition, a gas pipe 22 is connected to the gas outflow portion 16, and gas is supplied to the customer through the gas pipe 22. Here, the liquid inflow part 15 is provided in the upper part of the shell main body 10, and the gas outflow part 16 is provided in the lower part of the shell main body 10, and the upper end position of the straight part 11 </ b> B of the tube 11 is set above the liquid inflow part 15. ing. As a result, the bending portion 11A or the vicinity of the bending portion 11A has a structure in which freezing hardly occurs.

  The hot water type liquefied gas vaporizer 1 allows the liquefied gas supplied by the liquid pipe 20 to flow into the shell main body 10 through the liquid inflow portion 15, and the liquefied gas in the shell main body 10 by heat generated from the tube 11 through which the hot water flows. Is to vaporize. The liquefied gas that has flowed into the shell main body 10 via the liquid inflow portion 15 is vaporized by receiving heat from the tube 11 and the partition plate 14 while falling downward, so that the liquid is less likely to accumulate in the shell main body 10. The shell body 10 is filled with the vaporized gas. The vaporized gas flows into the gas pipe 22 connected to the gas outflow portion 16 by the pressure in the shell body 10 and is supplied to the customer through the gas pipe 22.

  In this hot water type liquefied gas vaporizer 1, there is a problem that the hot water in the tube 11 is frozen by the ultra low temperature liquefied gas coming into contact with the tube 11. In order to avoid freezing of the hot water in the tube 11, it is necessary to keep the hot water flowing at a predetermined flow rate or higher during operation. However, even if hot water in the tube 11 is flowed at a somewhat high flow velocity, the curved portion 11A exists in the tube 11, so that the flow velocity distribution in the tube 11 is not necessarily in the same direction from the inner wall surface of the tube 11 toward the center. If the flow velocity in the same direction along the tube 11 is not obtained near the inner wall surface of the tube 11, the hot water is likely to freeze at that point. Therefore, in the hot water type liquefied gas vaporizer 1, the curvature radius of the curved portion 11A is set in relation to the flow rate of the hot water so that the hot water does not freeze in the tube 11.

  FIG. 3 is an explanatory diagram showing a design method for designing the tube 11 in which hot water does not freeze, and is a graph showing the flow velocity distribution in the vicinity of the inner wall of the tube 11 (the horizontal axis is the distance from the inner wall / the vertical axis is the flow velocity). is there. In this design method, the temperature and the processing amount of the liquefied gas, the inner diameter of the tube 11 and the temperature of the hot water flowing through the tube 11 are determined as operating conditions. First, the average flow rate of hot water that does not cause freezing in the straight pipe (straight portion 11B) ( The non-freezing average flow velocity) m1 is experimentally determined. Then, the flow velocity distribution at the non-freezing average flow velocity m1 is obtained by simulation. In FIG. 3, the curve a1 is a flow velocity distribution of the non-freezing average flow velocity m1 in the straight pipe. Here, the liquefied gas is LNG, the processing amount is 0.5 t / h to 1.0 t / h, the inner diameter of the tube 11 is 35 mm, and the hot water temperature is 60 ° C. or higher. The non-freezing average flow velocity of 0.1 m / s (= m1) was experimentally determined, and the flow velocity distribution is shown.

  Next, under the operating conditions described above, on the premise that the average flow velocity of hot water is not less than m1, the curvature radius of the bending portion 11A is changed, and the flow velocity distribution in the bending portion 11A is simulated by a combination of the curvature radius and the flow velocity. In FIG. 3, b1, b2, c1, and c2 are curves of the simulation results. Curve b1 is an example in which the radius of curvature is 67.5 mm and the average flow velocity is 0.3 m / s, and curve b2 is an example in which the radius of curvature is 67.5 mm and the average flow velocity is 0.4 m / s. Curve c1 is an example in which the radius of curvature is 114.5 mm and the average flow velocity is 0.3 m / s, and curve c2 is an example in which the radius of curvature is 114.5 mm and the average flow velocity is 0.4 m / s.

  Based on such a simulation result, the curvature radius of the bending portion 11A and the hot water in the tube 11 are set so that the flow velocity distribution in the bending portion 11A is equal to or greater than the flow velocity distribution a1 in the straight pipe at the non-freezing average flow velocity m1. Set the average flow rate. In the example shown in FIG. 3, when the curvature radius of the curved portion 11A is 67.5 mm, the average flow velocity is set to 0.3 m / s or 0.4 m / s faster than the non-freezing average flow velocity of 0.1 m / s. Even so, the distribution is such that the flow velocity is lower than that of the curve a1 in the vicinity of the inner wall surface of the tube 11 as indicated by the curves b1 and b2, and in such a setting, there is a possibility of freezing. On the other hand, when the curvature radius of the curved portion 11A is 114.5 mm, when the average flow velocity is 0.3 m / s and 0.4 m / s, the flow velocity distribution is all as shown by the curves c1 and c2. In this range, the curve a1 is exceeded, and it can be said that such a setting has no possibility of freezing.

  Further, when the radius of curvature of the curved portion 11A is 100 mm and the average flow velocity is 0.3 m / s, the flow velocity distribution is as shown by the curve d. In this case, although the flow velocity distribution is slightly lower than the curve a1 in the vicinity of the inner wall of the tube 11, a flow velocity distribution substantially equal to or higher than the curve a1 is obtained. In this way, by setting the curvature radius of the curved portion 11A and the average flow velocity of the hot water so that a flow velocity distribution equal to or higher than the flow velocity distribution of the non-freezing average flow velocity m1 in the straight pipe (straight portion 11B) can be obtained, freezing can be achieved. The tube 11 that does not occur can be set.

  According to such a design method, in the tube 11 having the curved portion 11A, an experiment to determine whether or not it actually freezes is performed by performing an experiment for obtaining the non-freezing average flow velocity m1 using a straight tube that is easy to visually check. Since the setting of the radius of curvature and the average flow velocity of the part 11A can be narrowed down using a simulation result by a computer, the verification verification range can be set rationally.

  According to the hot water type liquefied gas vaporizer 1 according to the embodiment of the present invention described above, the hot water type liquefied gas that does not cause the hot water to freeze even if the device is downsized by flowing the hot water in the tube 11 at a relatively high flow rate. The vaporizer 1 can be obtained. Further, by installing the shell main body 10 vertically, it is possible to reduce the installation area, and since the shell main body 10 and the tube 11 are supported at the upper end free, distortion may occur with respect to heat shrinkage. It is possible to suppress the occurrence of cracks and the like. Further, since the liquefied gas is vaporized in the shell body 10, there is little liquid remaining even when stopped, and there is no change in the outlet component even when restarting. Furthermore, since the design of the tube 11 is designed so that the hot water does not freeze, there is no fear of the tube 11 being blocked or damaged by freezing, and stable continuous operation is possible.

  As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to these embodiments, and the design can be changed without departing from the scope of the present invention. Is included in the present invention.

1: Hot water liquefied gas vaporizer,
10: Shell body, 11: Tube, 11A: Curved part, 11B: Straight part,
12: Hot water inflow part, 12A: Hot water inflow port,
13: Hot water outlet, 13A: Hot water outlet,
14: Partition plate, 15: Liquid inflow part, 16: Gas outflow part

Claims (3)

A shell body installed vertically,
A tube having a plurality of inverted U-shaped curved portions disposed in the shell body and a pair of straight portions along the shell body;
A hot water inflow portion disposed at a lower portion of the shell main body and communicating with one open end of the pair of linear portions;
A warm water outflow part arranged at the lower part of the shell main body and communicating with the other open end of the pair of linear parts;
A liquid inflow portion for allowing the liquid of the liquefied gas to flow into the shell body;
A gas outflow part for allowing gas vaporized in the shell body to flow out,
The radius of curvature of the curved portion is equivalent to the flow rate distribution of the non-freezing average flow velocity in the straight portion when the hot water flows in the tube at a set flow rate equal to or higher than the non-freezing average flow velocity at which the hot water does not freeze in the straight portion. A hot water type liquefied gas vaporizer, wherein the above flow velocity distribution is set to be obtained at the curved portion.   2. The hot water liquefied gas vaporizer according to claim 1, wherein when the non-freezing average flow velocity is 0.1 m / s, the set flow velocity is 0.3 m / s and the curvature radius is 100 mm or more.   The hot water liquefied gas vaporizer according to claim 1 or 2, wherein an upper end position of the linear portion is set above the liquid inflow portion.

Images