KR102457000B1 - Vaporizer for low-temperature liquefied gas - Google Patents

Abstract

The present invention is to suppress thermal stress and thermal fatigue of a heat transfer tube in a low-temperature liquefied gas vaporizer.
The low-temperature liquefied gas vaporizer (underwater combustion type vaporizer 1) has a plurality of sparging pipes 15 having a plurality of bubble ejection holes 151 formed on the surface, and at the same time, the high-temperature gas is bubbled. The bubble jetting mechanism 100 configured to blow out into the water through the jetting hole, and disposed on the upper side of the bubble jetting mechanism in the water tank, and blown out from the sparge pipe A heat exchanger configured to vaporize the low-temperature liquefied gas flowing through the heat transfer tube 31 by stirring and heating the water by the air bubbles. The bubble ejection mechanism is configured to reach the heat transfer tube of the heat exchanger while bypassing the air bubbles ejected from the sparge pipe.

Description

Low-temperature liquefied gas vaporizer {VAPORIZER FOR LOW-TEMPERATURE LIQUEFIED GAS}

The technology disclosed herein relates to an apparatus for vaporizing low-temperature liquefied gas.

Patent Document 1 describes a submerged combustion vaporizer as one of the vaporizers for low-temperature liquefied gas. The underwater combustion type vaporizer is one of the vaporizers for low-temperature liquefied gas such as liquefied natural gas, and is immersed in a water tank and blows the combustion gas from the burner into a bubble blowing hole formed on the surface. ) and a heat exchanger having a plurality of sparge pipes ejected into the water through the sparge pipe, and a heat transfer tube disposed above the sparge pipe in the water tank. The combustion gas ejected as bubbles into the water heats the low-temperature liquefied gas flowing through the heat transfer tube while stirring the water in the water tank. Thereby, the low-temperature liquefied gas is vaporized.

In addition, similarly to the underwater combustion type vaporizer, a vaporizer for vaporizing the low-temperature liquefied gas flowing in the heat transfer tube immersed in the water tank by ejecting the hot gas as bubbles from the sparge pipe arranged in the water tank, a steam ejector An intermediate heat medium type vaporizer, such as an anticorrosive vaporizer, is also known.

Japanese Patent Laid-Open No. 2013-2734

As described above, each sparge pipe disposed in the water tank has a bubble blowing hole formed on the surface thereof, and the bubble blowing hole is generally formed on an upper surface of the sparge pipe. The bubbles ejected into the water through the bubble blowing hole rise as they are and reach the heat transfer tube of the heat exchanger. The temperature of the gas ejected into the water tank is close to 1000°C, while the temperature of the low-temperature liquefied gas flowing in the heat transfer tube is about -160°C. The bubbles ejected into the water and the water heated by it rise as they are with the force ejected from the sparge pipe, so that the bubbles and the water around them strongly collide with the heat transfer tube, and heat transfer in the heat transfer tube becomes strong. In addition, the bubbles ejected from the sparge pipe directly reach the heat transfer tube before the temperature is lowered to heat the outside of the heat transfer tube. Therefore, the temperature difference between the inside and outside of the heat pipe increases, and the thermal stress acting on the heat pipe increases.

Since the submerged combustion type vaporizer and the intermediate heat medium type vaporizer are also used for emergencies to cover a sudden increase in demand, starting and stopping may be repeated. Therefore, an increase in the temperature difference between the inside and outside of the heat pipe causes thermal fatigue of the heat pipe.

The technology disclosed herein has been made in view of such a point, and is intended to suppress thermal stress and thermal fatigue of the heat transfer tube in a low-temperature liquefied gas vaporizer.

The technology disclosed herein relates to a vaporizer for a low-temperature liquefied gas, the vaporizer having a plurality of sparging pipes immersed in a water tank and having a plurality of bubble ejection holes formed on the surface, and simultaneously evaporating the high-temperature gas into the bubbles A bubble jetting mechanism configured to blow out into water through a jetting hole, and disposed above the bubble jetting device in the water tank, the inside of the heat transfer tube is heated by stirring and heating of water by the bubbles jetted from the sparge pipe. and a heat exchanger configured to vaporize the flowing low-temperature liquefied gas.

And, the plurality of sparge pipes are arranged extending in a predetermined direction from the base end, which is the inlet end of the high-temperature gas, respectively, and at the same time, the front end is closed, and the bubble ejection mechanism is the spar and to reach the heat transfer tube of the heat exchanger while diverting the bubbles ejected from the bubble blowing hole of at least a part of the branch pipe.

According to this structure, in the water tank, the bubble blowing mechanism which has a sparge pipe is arrange|positioned at the lower side, and the heat exchanger which has a heat transfer tube is arrange|positioned at the upper side. Bubbles of the high-temperature gas ejected from the sparge pipe rise and stir the water in the water tank, and at the same time heat the low-temperature liquefied gas flowing through the heat transfer tube together with the water heated by the bubbles. In this way, the low-temperature liquefied gas is vaporized.

In the above configuration, the bubbles ejected from the bubble blowing holes of at least a part of the sparge pipe bypass and reach the heat transfer tube of the heat exchanger. "Bubble bypasses" means that the bubbles ejected into the water from the bubble blowing hole of the sparge pipe rise as they are and reach the heat transfer tube of the heat exchanger immediately, rather than reaching the heat transfer tube of the heat exchanger after returning far away. it means. By bypassing, the bubble does not rise as it is with the ejected force, but rises mainly by buoyancy after the force is weakened to reach the heat pipe. In this way, since it is avoided that air bubbles and the water around it strongly collide with the heat transfer tube, heat transfer in the heat transfer tube becomes weak by that much.

In addition, by bypassing the bubble, after being ejected from the sparge pipe in water, it rises as it is, and moves a longer distance than the distance to reach the heat transfer tube of the heat exchanger directly to reach the heat transfer tube. Alternatively, it takes a longer time to reach the heat pipe than directly to the heat pipe. Since heat exchange is made between a bubble and the water in a water tank while bypassing, the temperature of a bubble falls. When the bubble reaches the heat pipe, the temperature of the bubble is lower than when the bubble reaches the heat pipe without bypassing it.

In this way, the temperature difference between the inside and outside of the heat transfer tube becomes small, and the thermal stress acting on the heat transfer tube is suppressed. In addition, thermal fatigue of the heat transfer tube is also suppressed.

At least a part of the bubble blowing hole formed on the surface of the sparge pipe may be a bypass bubble blowing hole formed so that the axis of the hole is downward than the horizontal line.

The bubbles ejected from the bypass bubble blast hole with the hole axis downward move downward in the water tank, and after almost disappearing the ejected force, they are converted to rise and reach the heat transfer tube. Since the bubble and the surrounding water do not strongly collide with the heat transfer tube, excessive heat transfer in the heat transfer tube is suppressed.

In addition, as the bubble moves downward, the bubble is detoured, and the temperature of the bubble when it reaches the heat transfer tube is lowered. In particular, when a bubble vent is formed near the lower end of the sparge pipe, the hole axis is almost directly downward, so it moves downward in the water tank and switches to rising, then ascends while avoiding the sparge pipe to reach the heat pipe. . In this case, since the bypass distance of the bubble becomes longer, or the time until reaching the heat transfer tube becomes longer, the temperature of the bubble when it reaches the heat transfer tube is further lowered.

By setting the hole axis of the bubble vent hole downward from the horizontal line, thermal stress suppression and thermal fatigue suppression of the heat transfer tube are effectively made respectively.

The bypass bubble ejection hole may be formed in a proximal end of the sparge pipe.

The proximal end of the sparge pipe tends to relatively increase the amount of air bubble ejection compared to the front end, but by making the air bubble ejection hole formed at the base end of the sparge pipe the bypass bubble ejection hole, as described above, the sparge pipe Air bubbles and the surrounding water do not collide strongly with the heat transfer tube located above the base end of the heat transfer tube, thereby suppressing thermal stress and thermal fatigue of the heat transfer tube.

Here, the proximal end portion of the sparge pipe may be at least a part of the proximal end portion when the portion in which the bubble ejection hole is formed in the sparge pipe extending in the predetermined direction is divided into two equal parts in the predetermined direction, and further, the sparge pipe The tip portion may be at least a part of the tip side portion when the portion where the bubble ejection hole is formed is divided into two equal parts.

The bypass bubble blowing hole may be formed from the base end to the front end of the sparge pipe.

In this way, from the base end to the front end of the sparge pipe, air bubbles and the surrounding water do not strongly collide with the heat transfer tube located above the sparge pipe, thereby suppressing the thermal stress and thermal fatigue of the heat transfer tube.

In addition, when a high-temperature gas is supplied into the sparge pipe, the high-temperature gas accumulates in the upper part of the sparge pipe. When the bubble ejection hole is formed in the upper surface of the sparge pipe, the high-temperature gas accumulated in the upper part from the proximal end in the sparge pipe is ejected in turn. As a result, it becomes difficult to evenly spread the hot gas to the tip of the sparge pipe. That is, the proximal end portion of the sparge pipe has a large amount of bubbles ejected and the tip portion has a small amount of bubbles ejected, so that the amount of bubbles ejected tends to be uneven in the longitudinal direction of the sparge pipe.

On the other hand, the bypass bubble vent with the hole axis below the horizontal line is formed in the lower part of the sparge pipe (generally circular in cross-section). Therefore, in the configuration in which the bypass bubble blowing hole is formed from the proximal end to the front end of the sparge pipe, even if the high-temperature gas accumulates in the upper part of the sparge pipe, the high-temperature gas is discharged from the bypass bubble blowing hole formed in the lower side of the sparge pipe. After the gas accumulates in the entire upper part from the tip to the base end of the sparge pipe without being ejected, the hot gas is ejected through the downward bypass bubble blast hole all at once from the tip to the base end of the sparge pipe. That is, the configuration in which the bypass bubble blowing hole is formed from the proximal end to the front end of the sparge pipe makes it possible to equalize the bubble blowing amount in the longitudinal direction of the sparge pipe.

As a result of the equalization of the amount of bubble ejection in the longitudinal direction of the sparge pipe in this way, it is also possible to suppress the thermal stress and thermal fatigue of the heat transfer tube located above the base end of the sparge pipe.

The angle of the hole axis of the bypass bubble ejection hole formed at the proximal end of the sparge pipe with respect to the vertical direction may be greater than the angle of the hole axis of the bubble ejection hole formed at the tip of the sparge pipe.

Here, the bubble blower formed at the tip of the sparge pipe may be a bypass bubble blowing hole whose hole axis is downward than the horizontal line, and the hole axis may be a horizontal bubble blowing hole along a horizontal line or upwards than a horizontal line.

According to the above configuration, since the hole axis of the bypass bubble blowing hole formed at the proximal end of the sparge pipe has a large angle with respect to the upper side in the vertical direction, the bubbles ejected from the bypass bubble blowing hole move greatly downward and then rise and rise to the heat pipe. to reach Since the bypass distance of a bubble becomes further longer by this, while the temperature of the bubble when it reaches a heat exchanger tube becomes still lower, it is avoided that a bubble and the surrounding water collide strongly with a heat exchanger tube.

A cold water region may be formed below the sparge pipe. By doing in this way, the bubbles ejected downward in the water tank through the bypass bubble ejection hole whose hole axis is lower than the horizontal line are promoted for heat exchange in the cold water region formed at the lower side of the sparge pipe. As a result, it becomes possible to further lower the temperature of the bubble when it reaches|attains a heat exchanger tube.

The bubble ejection mechanism has a baffle plate disposed between the sparge pipe and the heat transfer tube, and at least some of the air bubbles ejected from the sparge pipe bypass the baffle plate and reach the heat transfer tube. also be

According to this configuration, at least a portion of the bubbles ejected from the sparge pipe bypass the baffle plate and reach the heat transfer tube. Since the force ejected at the time of making a detour weakens, it is avoided that a bubble and the water around it collide strongly with a heat exchanger tube.

Moreover, since the bubble exchanges heat with water in the water tank while bypassing the baffle plate, it becomes possible to lower the temperature of the bubble when it reaches the heat transfer tube.

As a result, similarly to the above, it becomes possible to suppress the thermal stress by reducing the temperature difference between the inside and outside of the heat transfer tube, and at the same time, it becomes possible to suppress thermal fatigue.

Here, the bubble vent formed in the sparge pipe may be a bypass bubble vent whose hole axis is downward from the horizontal line, and the hole axis may be a horizontal bubble vent or an upward bubble vent from the horizontal line.

The baffle plate may be disposed at the proximal end of the sparge pipe.

In this way, at the base end of the sparge pipe, air bubbles can be bypassed by the baffle plate to reach the heat transfer tube, so that the air bubbles and the surrounding water do not strongly collide with the heat transfer tube located above the base end of the sparge pipe. of thermal stress suppression and thermal fatigue suppression.

The baffle plate may be disposed from a proximal end to a distal end of the sparge pipe.

In this way, from the base end to the front end of the sparge pipe, air bubbles and the surrounding water do not strongly collide with the heat transfer tube located above the sparge pipe, thereby suppressing the thermal stress and thermal fatigue of the heat transfer tube.

The baffle plate may be disposed on the side of the heat transfer tube between the sparge pipe and the heat transfer tube.

By doing in this way, it becomes possible to prevent further reliably that a bubble and the water around it collide strongly with respect to a heat exchanger tube.

A through hole may be formed in the baffle plate. In this way, some of the bubbles pass through the through hole of the baffle plate, but at this time, the rising speed is reduced, so that the bubbles and the surrounding water are prevented from strongly colliding with the heat transfer tube. In addition, if the size of the bubble after passing through the through hole of the baffle plate is made small, the rising speed is reduced and heat exchange between the bubble and water is promoted while the bubble reaches the heat pipe. A decrease in the temperature of the bubbles at the time is achieved.

In the case of forming the through hole in the baffle plate, it is preferable to form the through hole in the baffle plate to such an extent that at least some of the air bubbles bypass the baffle plate and reach the heat transfer tube.

As described above, according to the vaporizer of the low-temperature liquefied gas, the bubbles and the surrounding water strongly collide with the heat transfer tube by allowing the air bubbles ejected from the sparge pipe to reach the heat transfer tube while bypassing the heat transfer tube. At the same time, heat exchange between the bubbles and the water in the water tank is promoted, and it becomes possible to lower the temperature of the bubbles when they reach the heat transfer tube. As a result, the temperature difference between the inside and outside of the heat transfer tube is small, so that the thermal stress is suppressed and the thermal fatigue of the heat transfer tube is suppressed.

1 is a conceptual diagram showing the overall configuration of an underwater combustion type vaporizer.
2 is a front view showing a heat exchanger and a bubble ejection mechanism disposed in a water tank.
3 is a plan view of the heat exchanger and bubble ejection mechanism shown in FIG. 2 .
4 is a side view of the heat exchanger and bubble ejection mechanism shown in FIG. 2 .
5 is a bottom view showing the sparge pipe of the bubble ejection mechanism shown in FIG.
Fig. 6 is a cross-sectional explanatory view of the bubble ejection mechanism shown in Fig. 2;
7 is a bottom view showing a sparge pipe according to a modified example.
8 is a plan view showing a heat exchanger and a bubble ejection mechanism according to another embodiment.
Fig. 9 is a side view of the heat exchanger and the bubble ejection mechanism shown in Fig. 8;
Fig. 10 is a cross-sectional explanatory view of the bubble ejection mechanism shown in Fig. 8;
11 is a side view of a heat exchanger and a bubble ejection mechanism according to a modification.

Hereinafter, an embodiment of an apparatus for vaporizing low-temperature liquefied gas will be described with reference to the drawings. 1 shows the outline of the entire underwater combustion type vaporizer 1 . 2 to 4 show the configuration of the heat exchanger 32 and the bubble ejection mechanism 100 immersed in the water tank 11, respectively. The underwater combustion type vaporizer 1 is one of the vaporizers for low-temperature liquefied gas, and vaporizes liquefied natural gas (LNG) here.

The submerged combustion type vaporizer 1 is immersed in, for example, a rectangular parallelepiped water tank 11, and at the same time, a number of heat transfer tubes 31 serving as flow passages for LNG are bent in multiple stages, and heat exchange constituted. A group 32 is provided. One end of each heat transfer pipe 31 communicates with an LNG inlet pipe 12b serving as an inlet of LNG, and the other end is connected to an NG discharge pipe 12c for discharging vaporized natural gas (NG). it works In FIG. 1, the heat pipe 31 is simplified, but in reality, as shown in FIGS. 2 to 4, a plurality of heat pipes 31 are arranged in a Y direction, and each heat pipe 31 is an LNG inlet pipe 12b. ) connected to the header tank 33 and the header tank 34 connected to the NG discharge pipe 12c, respectively. The number and arrangement of the heat transfer tubes 31 are appropriately determined according to the performance of the submerged combustion type vaporizer 1 .

The water tank 11 is covered by, for example, a rectangular plate-shaped top plate 11a. The top plate 11a can be walked by an operator, and is arranged so that a cylindrical downcomer 13 is immersed in the water tank 11 at a predetermined portion thereof.

At the upper end of the downcomer 13, there is a burner 2 that burns fuel gas supplied from a fuel supply source other than that shown through the fuel supply pipe 6 and air supplied through a blower 14. is installed

At the bottom of the water tank 11, a number of bubble ejection holes (here, not shown in FIG. 1, etc.) are formed in successive communication with the downcomer 13 and at the same time, the combustion gas of the burner 2 is ejected. A sparge pipe 15 is arranged. Although only one sparge pipe 15 is also drawn in FIG. 1, in reality, as shown in FIGS. 2 to 4, each of the sparge pipes 15 extends in the Y direction and is arranged in a plurality in the X direction, and the heat exchanger 32 as a whole The bubble (B) containing the combustion gas is supplied. The number and arrangement of the sparge pipes 15 are not particularly limited. The bubble blowing mechanism 100 which blows combustion gas into the water tank 11 as bubble B by the some sparge pipe 15 is comprised.

A manifold 17 is disposed between the downcomer 13 and each sparge pipe 15 . As shown in Fig. 4, the manifold 17 is connected to the lower end of the downcomer 13 and is arranged extending in the X direction as shown in Fig. 3 . Here, in FIGS. 1 and 4 , the arrangement of the manifold 17 and the direction of the sparge pipe 15 are reversed. The proximal end of each sparge pipe 15 communicates with the manifold 17 in succession, and the manifold 17 functions to distribute the combustion gas from the burner 2 to each sparge pipe 15 . have Here, the tip of each sparge pipe 15 is closed.

The top plate 11a of the water tank 11 is provided with a stack 16 having a cylindrical shape for exhausting the combustion gas ejected in the water tank 11, and the upper end thereof is opened to the atmosphere.

The underwater combustion type vaporizer (1) agitates the water in the water tank (11) by blowing the combustion gas of the burner (2) into the water tank (11) as bubbles (B) through the bubble blowing holes of the sparge pipe (15) While heating the LNG flowing in the heat transfer tube 31 . Accordingly, it is configured to vaporize LNG to NG, and to send it out from the outlet of the NG discharge pipe 12c. The underwater combustion type vaporizer 1 ejects combustion gas as bubbles B into the water tank 11 to stir the water in the water tank 11, and sets the temperature of the exhaust gas discharged from the stack 16 into the water tank ( 11) By lowering the temperature of the hot water in the interior, it is possible to recondensate 100% of the combustion product water in the combustion gas and to give all of this latent heat to the hot water, so the thermal efficiency is very high.

Next, the configuration of the bubble ejection mechanism 100 having the sparge pipe 15 will be described in detail with reference to the drawings. In such an underwater combustion type vaporizer 1, the temperature of the combustion gas ejected into the water tank 11 is close to 1000°C, whereas the temperature of the LNG flowing in the heat transfer tube 31 is about -160°C. Accordingly, the temperature difference between the inside and outside of the heat transfer tube 31 increases, and the thermal stress acting on the heat transfer tube 31 increases. In addition, since the underwater combustion type vaporizer 1 is also used for an emergency for covering a sudden increase in demand, the starting and stopping may be repeated. As the temperature difference between the inside and outside of the heat pipe 31 is large, thermal fatigue of the heat pipe 31 is caused.

Therefore, in this submerged combustion type vaporizer 1, the bubble ejection mechanism 100 is comprised so that the thermal stress and thermal fatigue of the heat transfer tube 31 of the heat exchanger 32 may be suppressed. 5 is a bottom view of the sparge pipe 15 . As described above, the sparge pipe 15 has a plurality of bubble ejection holes 151 formed on its surface. The bubble blowing hole 151 extends over a wide range in the longitudinal direction from the closed front end side (left side in Fig. 5) of the sparge pipe 15 to the base end side (right side in Fig. 5) connected to the manifold 17 is formed In the example of the drawing, the bubble blowing hole 151 is formed so that the row of holes extending in the longitudinal direction of the sparge pipe 15 forms 5 rows in the circumferential direction, and at the same time, the row of holes of the adjacent bubble blowing hole 151 is It is arranged so that it may become a rhombic grid shape. Here, the arrangement of the bubble ejection holes 151 is not limited to a rhombic lattice shape. The bubble ejection holes 151 may be arranged, for example, in a rectangular grid shape. Moreover, it is also possible to employ|adopt other structures suitably. The diameters of the bubble ejection holes 151 are all the same.

FIG. 6 shows a cross section VI-VI of FIG. 5 . The sparge pipe 15 has a circular cross-section, and the bubble ejection hole 151 is formed in the lower surface of the sparge pipe 15 in the water tank 11 . Each bubble ejection hole 151 is formed through the sparge pipe 15 so that the hole axis passes through the center of the circle. As described above, the bubble ejection holes 151 (three rows are drawn in the cross section shown in FIG. 6 ) formed in five rows in the circumferential direction are each on both sides of the circumferential direction with the lower end of the sparge pipe 15 as the center. is formed within a predetermined angle range. In the drawing example, the angle θ formed by the hole axis of the bubble ejection hole 151 is set to 60°. The angle with respect to the vertical direction upward of the hole axis of each bubble blowing hole 151 is included in the range of 180 ° ± 30 °. Accordingly, all of the hole axes of the bubble blowing holes 151 formed in the sparge pipe 15 are set to be downward from the horizontal line indicated by the broken line in FIG. ) is ejected into the water below the horizon. These bubble blowing holes 151 correspond to the bypass bubble blowing holes, and the bypass bubble blowing holes are formed in the sparge pipe 15 from the proximal end to the front end of the sparge pipe 15 .

As shown by the arrow in Fig. 6, the bubble (B) ejected in the water downward from the bubble ejection hole 151 formed on the lower surface of the sparge pipe 15 once moves downward and the ejected force is weakened. , mainly converted to ascending by buoyancy. And, although the bubble B is shown virtually in FIG. 6 , it reaches the heat transfer tube 31 disposed above the sparge pipe 15 . In particular, the bubble (B) ejected from the bubble jetting hole 151 formed near the lower end of the sparge pipe 15 moves almost immediately down and then switches to the rising, but this bubble B is the sparge pipe 15 ) while bypassing it and ascending to reach the heat transfer tube (31). In this way, by making the hole axis of the bubble ejection hole 151 downward, the bubble B does not rise as it is with the ejected force, but instead diverts to reach the heat transfer tube 31, and the air bubble and the surrounding water are transferred to the heat transfer tube. A strong collision with (31) is avoided. Moreover, the distance which the bubble B moves in the inside of the water tank 11 becomes long as much as it detoured. Alternatively, the time until reaching the heat transfer tube 31 becomes longer. In the meantime, since heat exchange is made between the bubble B and the water in the water tank 11, the temperature of the bubble B at the time of reaching|attaining the heat transfer tube 31 becomes low.

Moreover, as shown in FIG.2 and FIG.4, in the water tank 11, a comparatively wide space|interval is formed between the sparge pipe 15 and the bottom of the water tank 11, and this sparge pipe 15 and the water tank (11) Between the floor and the water temperature is a relatively low cold water region (110). As a result of promoting heat exchange in the cold water region 110 of the bubble B ejected downward, the temperature thereof is further lowered. In this way, the temperature when the bubble B detours and reaches the heat transfer tube 31 is lower than the temperature when the bubble B does not detour and reaches the heat transfer tube 31 .

As described above, the difference between the temperature of the combustion gas ejected from the sparge pipe 15 and the temperature of the LNG flowing in the heat transfer tube 31 is large, and the bubbles B ejected from the sparge pipe 15 are sparge When the force ejected from the pipe 15 rises as it is and collides with the heat pipe 31 together with the surrounding water at a high temperature, the heat transfer in the heat pipe 31 becomes stronger and the temperature difference inside and outside the heat pipe 31 increases. On the other hand, since the bubble ejection mechanism 100 described above is configured such that the bubble B bypasses and reaches the heat pipe 31, the bubble and surrounding water are prevented from strongly colliding with the heat pipe, and at the same time, the heat pipe 31 It becomes possible to make low the temperature of the bubble B at the time of reaching|attaining. As a result, the temperature difference between the inside and outside of the heat transfer tube 31 becomes small, and the thermal stress acting on the heat transfer tube 31 is suppressed. Moreover, in the submerged combustion type vaporizer 1 in which starting and stopping are repeated, it becomes possible to suppress the thermal fatigue of the heat transfer tube 31 by making small the temperature difference inside and outside the heat transfer tube 31. As shown in FIG.

When the combustion gas is supplied into the sparge pipe 15, the combustion gas accumulates in the upper part of the sparge pipe 15, as shown in FIG. In this bubble ejection mechanism 100, the bubble ejection hole 151 is formed in the lower surface of the sparge pipe 15, but is not formed in the upper surface portion. Therefore, over the entire area in the longitudinal direction of the sparge pipe 15, after the combustion gas accumulates in the upper part, the combustion gas is blown out as bubbles (B) all at once from the bubble ejection holes 151 of the entire area in the longitudinal direction. do. This equalizes the amount of bubble ejection in the longitudinal direction of the sparge pipe 15 . That is, in an underwater combustion type vaporizer of a conventional configuration in which the bubble vents were formed on the upper surface of the sparge pipe, the combustion gas accumulated in the upper part of the sparge pipe is sequentially ejected from the bubble vents formed on the proximal side of the sparge pipe, It becomes difficult to evenly spread the combustion gas to the tip side of the sparge pipe. As a result, the proximal end portion of the sparge pipe had a relatively large amount of bubble ejection, and the tip portion had a relatively small amount of air bubble ejection. Accordingly, the heat transfer tube positioned above the base end of the sparge pipe is particularly susceptible to the influence of the aforementioned thermal stress and thermal fatigue.

On the other hand, since the bubble blowing mechanism 100 of the above configuration can achieve equalization of the bubble blowing amount in the longitudinal direction of the sparge pipe 15, the heat transfer tube 31 located above the base end of the sparge pipe 15. It becomes possible to suppress the thermal stress and thermal fatigue of

In addition, the bubble ejection hole 151 formed on the surface of the sparge pipe 15 may have a hole axis downward than a horizontal line. Therefore, in the case of forming the bubble blowing hole 151 on the surface of the sparge pipe 15 so that the hole axis passes through the center of the circle in the sparge pipe 15 having a circular cross-section, the lower half of the sparge pipe 15 What is necessary is to form a bubble ejection hole 151 in the (下半) portion. However, in order to make the bypass distance of the bubble (B) as long as possible, the bubble blowing hole 151 is preferably formed near the lower end of the sparge pipe 15 . For example, in each of both sides of the circumferential direction with the lower end of the sparge pipe 15 as the center, the angle (θ) formed by the hole axis of the bubble blowing hole 151 is within an angle range within 90°. 151) may be formed.

In addition, the diameter of the bubble ejection hole 151 is not made to be all the same, but may be changed according to the position of the longitudinal direction of the sparge pipe 15. As shown in FIG. For example, the diameter of the bubble blowing hole 151 formed at the proximal end of the sparge pipe 15 is relatively small, and the diameter of the bubble blowing hole 151 formed at the tip of the sparge pipe 15 is relatively large. You can do it. This suppresses the bubble ejection amount from becoming uneven in the longitudinal direction of the sparge pipe 15 .

Further, as a modification, the angle of the hole axis of the bubble blowing hole 151 may be changed in accordance with the position in the longitudinal direction of the sparge pipe 15 in the vertical direction. For example, FIG. 7 is a bottom view of the sparge pipe 15 which concerns on a modified example. As shown in the same figure, at the base end when the portion where the bubble blowing hole 151 is formed in the sparge pipe 15 is divided into three equal parts into the proximal end, the middle and the tip, the bubble blowing hole 151 is formed in the sparge pipe ( 15), while forming a bubble blowing hole 151 on the side of the sparge pipe 15 at the front end, and forming a bubble blowing hole 151 at the middle of the lower surface of the sparge pipe 15 and You may form between it and a side surface. Each bubble ejection hole 151 is formed so that the hole axis passes through the center of the circle. In this configuration, the angle (that is, about 180°) with respect to the vertical direction upward of the hole axis of the bubble blowing hole 151 formed at the base end of the sparge pipe 15 is the bubble blowing hole formed at the tip of the sparge pipe 15 ( 151), which is larger than the angle of the hole axis (that is, about 90°).

By doing in this way, at least bypass bubble blowing holes are formed in the proximal end and the middle portion of the sparge pipe 15, and the thermal stress is suppressed in the heat transfer tube 31 located above the proximal end and the middle portion of the sparge pipe 15. and suppression of thermal fatigue, respectively. This configuration is also suppressed from becoming uneven in the amount of blowing air in the longitudinal direction of the sparge pipe 15 .

And, unlike the configuration example of FIG. 7 , a bubble ejection hole 151 may be formed on the upper surface of the sparge pipe 15 at the tip of the sparge pipe 15 . In this case, in the middle portion of the sparge pipe 15 , the bubble ejection hole 151 may be formed on the side surface of the sparge pipe 15 .

In addition, in the configuration example of FIG. 7, the angle of the hole axis of the bubble blowing hole 151 is changed in stages from the tip side of the sparge pipe 15 toward the base end side, but unlike this, the tip side of the sparge pipe 15 As a result of continuously changing the angle of the hole axis of the bubble ejection hole 151 toward the base end side, the hole axis of the bubble ejection hole 151 formed in the base end may be downward rather than a horizontal line.

In addition, in the example of FIG. 7, the portion in which the bubble blowing hole 151 of the sparge pipe 15 is formed is divided into three equal parts, the front end, the middle part, and the base end, and the angle of the hole axis of the bubble blowing hole 151 is different in each part. One, for example, after dividing the portion in which the bubble blowing hole 151 of the sparge pipe 15 is formed into two, the front end and the base end, at the base end, the hole axis of the bubble blowing hole 151 is downward than the horizontal direction in the vertical direction may be made relatively large, and the angle of the hole axis may be relatively small at the tip. At this time, as for the bubble ejection hole 151 formed in the front-end|tip part, the axis|shaft of the hole may be downward from a horizontal line, it may follow a horizontal line, or may become upward rather than a horizontal line. The bypass bubble blowing hole with the hole axis downward than the horizontal line may be formed only at the proximal end of the sparge pipe (15). Here, the division|segmentation number regarding the change of the height position of the bubble blowing hole 151 is not limited to 2 or 3, You may set it as 4 or more suitably.

And, the bubble ejection hole 151 formed on the surface of the sparge pipe 15 is not limited to being formed so that the hole axis passes through the center of the circle.

8 to 10 show another configuration of the bubble ejection mechanism. The bubble ejection mechanism 101 has a sparge pipe 15 and a baffle plate 152 . The baffle plate 152 is disposed between the sparge pipe 15 and the heat transfer tube 31 to correspond to each sparge pipe 15 .

In this bubble blowing mechanism 101, the bubble blowing hole 151 is formed in the upper surface part of the sparge pipe 15, as shown in FIG. The bubble ejection hole 151 is formed within a predetermined angle range on both sides of the circumferential direction with the upper end of the sparge pipe 15 as the center. Therefore, contrary to the above configuration, the axis of the hole of the bubble ejection hole 151 is upward from the horizontal line. In addition, the bubble blowing hole 151 formed in the upper surface part of the sparge pipe 15 is configured similarly to the arrangement of the bubble blowing hole 151 shown in FIG. It is formed in a predetermined arrangement over a wide range in the longitudinal direction from the left side of Fig. 5) to the base end side connected to the manifold 17 (the right side of Fig. 5).

As shown in FIG. 8, the baffle plate 152 has a substantially circular arc shape in which its cross-sectional shape becomes convex upward, and is arranged to extend along the longitudinal direction of the sparge pipe 15, as shown in FIG. do. Thereby, the baffle plate 152 expands in the circumferential direction so as to cover the entire bubble ejection hole 151 formed in the sparge pipe 15 and extends in the longitudinal direction at the same time.

As shown in Fig. 10, in the bubble blowing mechanism 101 of this configuration, since the bubble blowing hole 151 is formed in the upper surface portion of the sparge pipe 15, the bubbles ejected upward from the bubble blowing hole 151 ( B) rises underwater but is blocked by the baffle plate 152 . Therefore, the bubble B cannot reach the heat transfer tube 31 with the force ejected from the sparge pipe 15, and bypasses the baffle plate 152 to the heat transfer tube 31 as shown by the arrow in FIG. will be reached As with the above configuration, by bypassing, the bubbles rise mainly due to buoyancy, so that strong collision of the bubbles and the water around them against the heat transfer tube 31 is avoided, and the moving distance of the bubbles B increases as much as the detour. . Alternatively, the time until reaching the heat transfer tube 31 becomes longer. Thereby, it becomes possible to make low the temperature of the bubble B at the time of reaching|attaining the heat transfer tube 31 . Therefore, it becomes possible to suppress the thermal stress and thermal fatigue of the heat transfer tube 31 by reducing the temperature difference between the inside and outside of the heat transfer tube 31 also in the bubble ejection mechanism 101 of this structure.

In addition, in the baffle plate 152 having an arc-shaped cross-section that is convex upward, bubbles (that is, combustion gas) accumulate on the lower surface of the baffle plate 152, and then the bubbles (B) overflowing from the side end of the baffle plate 152 rise and the heat transfer tube 31 ) is reached. Here, since the bubble ejection hole 151 is formed in the upper surface portion of the sparge pipe 15, as described above, the base end of the sparge pipe 15 has a relatively large amount of bubble ejection, and the tip has a relatively large amount of air bubble ejection. less However, by configuring the gas to accumulate on the lower surface of the baffle plate 152 disposed between the sparge pipe 15 and the heat transfer tube 31 , the amount of air bubbles B ejected from the sparge pipe 15 is ejected. Even if silver is uneven in the longitudinal direction, it becomes possible that the supply amount of the air bubbles B supplied from the baffle plate 152 to the heat transfer tube 31 becomes substantially equal in the longitudinal direction. Therefore, also in this bubble ejection mechanism 101, it becomes possible to suppress the thermal stress and thermal fatigue of the heat transfer tube 31 located above the base end of the sparge pipe 15. As shown in FIG.

Here, although the structural example shown in FIG. 8 etc. exemplifies the baffle plate 152 having an arc-shaped cross-section, the shape of the baffle plate is not limited thereto. Although not illustrated, for example, a baffle plate having an inverted V-shape in cross section may be employed. Moreover, it is also possible to employ|adopt a flat baffle plate, as long as only the function of bypassing the bubble B is acquired.

In addition, in the structural example shown in FIG. 8 etc., although the bubble blowing hole 151 is formed in the upper surface part of the sparge pipe 15, in the bubble blowing mechanism 101 which has the baffle plate 152, the structure shown in FIG. As in the example, the bubble ejection hole 151 may be formed on the lower surface of the sparge pipe 15 . That is, the baffle plate 152 may be combined with the formation of the bubble ejection hole 151 in the lower surface of the sparge pipe 15 .

In addition, the diameter of the bubble ejection hole 151 is not made to be all the same, but may be changed according to the position of the longitudinal direction of the sparge pipe 15. As shown in FIG. For example, the diameter of the bubble blowing hole 151 formed at the proximal end of the sparge pipe 15 is relatively small, and the diameter of the bubble blowing hole 151 formed at the tip of the sparge pipe 15 is relatively large. You can do it. This suppresses the bubble ejection amount from becoming uneven in the longitudinal direction of the sparge pipe 15 .

In addition, you may change the angle with respect to the vertical direction upper direction of the hole axis|shaft of the bubble blowing hole 151 according to the position of the longitudinal direction of the sparge pipe 15. As shown in FIG. For example, as shown in FIG. 7 , the bubble blowing hole 151 formed at the base end of the sparge pipe 15 makes the angle of the hole axis relatively large, and the bubbles formed at the tip of the sparge pipe 15 . The blower hole 151 may make the said angle of the hole axis|shaft relatively small. This suppresses the amount of blowing air bubbles from becoming uneven in the longitudinal direction of the sparge pipe 15 .

As a modification, as shown in FIG. 11 , the baffle plate 153 may be disposed only above the base end of the sparge pipe 15 . By doing in this way, the rising air bubbles at the proximal end of the sparge pipe 15 are blocked by the baffle plate 153 . The proximal end of the sparge pipe 15 tends to relatively increase the amount of air bubble ejected, but the baffle plate 153 suppresses the thermal stress and thermal fatigue of the heat transfer tube 31 located above the proximal end of the sparge pipe 15. thing becomes possible

And the example of FIG. 11 is a configuration in which the baffle plate 153 is disposed at the base end when the portion in which the bubble blowing hole 151 is formed of the sparge pipe 15 is divided into three at the front end, the middle portion and the base end as an example. Although shown, the range in which the baffle plate 153 is disposed with respect to the longitudinal direction of the sparge pipe 15 can be set to an appropriate range.

In addition, in the structural example shown in FIG. 11, the bubble blowing hole 151 formed in the sparge pipe 15 extends from the base end of the sparge pipe 15 to the whole front end, and the lower surface part, similarly to the structural example shown in FIG. Alternatively, as in the configuration example shown in FIG. 7 , the angle of the hole axis of the bubble ejection hole 151 with respect to the vertically upward direction may be changed according to the position in the longitudinal direction of the sparge pipe 15 .

In the configuration example shown in FIG. 8 and the like, the baffle plates 152 and 153 are disposed between the sparge pipe 15 and the heat transfer tube 31 on the side closer to the sparge pipe 15, but the baffle plate 152, 153) may be disposed on the side closer to the heat transfer tube 31 . For example, the baffle plates 152 and 153 may be disposed directly below the heat transfer tube 31 . The baffle plates 152 and 153 disposed directly below the heat transfer tube 31 may be disposed along the heat transfer tube 31 . This configuration is advantageous in reliably preventing the air bubbles and the water around them from strongly colliding with the heat transfer tube 31 .

In addition, one or a plurality of through holes may be formed in the baffle plates 152 and 153 . In this way, some of the bubbles clogged by the baffle plates 152 and 153 pass through the through holes of the baffle plates 152 and 153, but at this time, the rising speed is reduced, so that the bubbles and the surrounding water are transferred to the heat transfer tube ( 31) is prevented from hitting hard. In addition, if the diameter of the through-hole is relatively small so that the size of the bubble after passing through the through-hole of the baffle plates 152 and 153 is reduced, the rising speed is reduced and the bubble reaches the heat transfer tube (31). Heat exchange between bubbles and water is promoted. As a result, it becomes possible to aim at the temperature fall of the bubble at the time of reaching|attaining a heat exchanger tube. Here, it is preferable that at least some of the bubbles form a through hole to bypass the baffle plates 152 and 153 .

In addition, although not shown, the baffle plate may be configured and/or arranged differently between the baffle plate disposed on the proximal side of the sparge pipe 15 and the baffle plate disposed on the tip side of the sparge pipe 15 . do. For example, the size of the baffle plate disposed on the proximal end side of the sparge pipe 15 and the baffle plate disposed on the front end side may be different from each other. In addition, the height position of the baffle plate arranged on the proximal end side of the sparge pipe 15 and the height position of the baffle plate arranged on the distal end side may be different from each other. Further, when a curved baffle plate is used, the curvature of the curvature of the baffle plate disposed on the proximal end side of the sparge pipe 15 and the baffle plate disposed on the front end side may be different from each other. In addition, when the through-holes are formed in the baffle plate, the number and size of the through-holes of the baffle plate disposed on the proximal side of the sparge pipe 15 and the through-holes of the baffle plate disposed on the tip side of the sparge pipe 15 may be different from each other.

In addition, the technology disclosed herein can also be applied to an intermediate heat medium type vaporizer including a steam ejector type vaporizer having a sparge pipe disposed in a water tank.

1: Underwater combustion type vaporizer (evaporator) 11: Water tank
15: sparge pipe 100, 101: bubble ejection mechanism
110: cold water area 151: bubble blowing hole
152, 153: baffle plate 31: heat pipe
32: heat exchanger

Claims (15)

It has a plurality of sparge pipes that are immersed in a water tank and have a plurality of bubble blowing holes formed on the surface, and at the same time, hot gas is discharged into the bubble blowing holes. A bubble ejection mechanism configured to eject into water through
A heat exchanger disposed on the upper side of the bubble ejection mechanism in the water tank and configured to vaporize the low-temperature liquefied gas flowing through the heat transfer tube by stirring and heating water by the bubbles ejected from the sparge pipe do,
The plurality of sparge pipes are arranged extending in a predetermined direction from the base end, which is the inlet end of the high-temperature gas, respectively, and the front end is blocked,
The bubble blowing mechanism is configured to reach the heat transfer tube of the heat exchanger while bypassing the bubbles ejected from the bubble blowing hole of at least a part of the sparge pipe,
At least a part of the bubble blowing hole formed on the surface of the sparge pipe is a bypass bubble blowing hole formed so that the axis of the hole is downward from the horizontal line. According to claim 1,
The vaporizing device of the low-temperature liquefied gas is formed at the base end of the sparge pipe in the bypass bubble ejection hole. According to claim 1,
The bypass bubble blowing hole is a vaporizer of low-temperature liquefied gas that is formed from the base end to the front end of the sparge pipe. 3. The method of claim 2,
The hole axis of the bypass bubble ejection hole formed at the base end of the sparge pipe has an angle with respect to the upper side in the vertical direction greater than the angle of the hole axis of the bubble ejection hole formed at the tip of the sparge pipe. vaporizer. 4. The method of claim 3,
The hole axis of the bypass bubble blowing hole formed at the base end of the sparge pipe has an angle with respect to the upper side in the vertical direction greater than the angle of the hole axis of the bubble jet hole formed at the tip of the sparge pipe. According to claim 1,
A low-temperature liquefied gas vaporizer in which a cold water region is formed on the lower side of the sparge pipe. According to claim 1,
The bypass bubble blower is formed on each of both sides of the circumferential direction with the lower end of the sparge pipe as the center, and the bypass bubble blower has an angle formed by the axis of the hole in the cross section of the sparge pipe at 90° A vaporization device for low-temperature liquefied gas provided in an angle range within the range. A bubble blowing mechanism immersed in a water tank and having a plurality of sparge pipes having a plurality of bubble jetting holes formed on the surface, and configured to jet high temperature gas into the water through the bubble blowing holes;
A heat exchanger disposed above the bubble ejection mechanism in the water tank and configured to vaporize the low-temperature liquefied gas flowing through the heat transfer tube by stirring and heating water by the bubbles ejected from the sparge pipe;
Each of the plurality of sparge pipes is arranged extending in a predetermined direction from the base end, which is the inlet end of the high-temperature gas, and at the same time the front end is closed,
The bubble blowing mechanism is configured to reach the heat transfer tube of the heat exchanger while bypassing the bubbles ejected from the bubble blowing hole of at least a part of the sparge pipe,
The bubble ejection mechanism has a baffle plate disposed between the sparge pipe and the heat transfer tube, and at least some of the air bubbles ejected from the sparge pipe bypass the baffle plate and reach the heat transfer tube. A vaporizer for low-temperature liquefied gas. 9. The method of claim 8,
The baffle plate is a low-temperature liquefied gas vaporizer disposed at the proximal end of the sparge pipe. 9. The method of claim 8,
The baffle plate is a low-temperature liquefied gas vaporizer disposed from the proximal end to the front end of the sparge pipe. 11. The method according to any one of claims 8 to 10,
The baffle plate is a low-temperature liquefied gas vaporizer disposed on the side of the heat transfer tube between the sparge pipe and the heat transfer tube. 11. The method according to any one of claims 8 to 10,
A device for vaporizing low-temperature liquefied gas in which a through hole is formed in the baffle plate. 12. The method of claim 11,
A device for vaporizing low-temperature liquefied gas in which a through hole is formed in the baffle plate. delete delete

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