JP6347966B2 - Underwater combustion type vaporizer - Google Patents

Description

  The technology disclosed herein relates to an underwater combustion type vaporizer, and more particularly to a configuration that enhances the environmental performance of the vaporizer by reducing harmful substances in exhaust gas.

  As one of low temperature liquefied gas vaporizers such as liquefied natural gas, an underwater combustion type vaporizer (Submerged Combustion Vaporizer) is known (see, for example, Patent Document 1). This underwater combustion type vaporizer is provided on a downcomer immersed in a water tank and burns air supplied from a blower and fuel supplied from a fuel supply source in a combustion chamber, and the combustion gas is sparged by a pipe. And a heat exchanger having a heat transfer tube bundle immersed in the water tank. Combustion gas (that is, exhaust gas) ejected as bubbles in the water vaporizes the low-temperature liquefied gas by heating the low-temperature liquefied gas passing through the heat transfer tube bundle while stirring the water in the water tank.

  Also, for example, in FIG. 1 of Patent Document 2, a pilot burner is provided at the upper part of the downcomer, a main burner is provided at the lower part, and air and fuel are distributed and supplied to the pilot burner and the main burner, respectively. Is described.

  Further, in Patent Document 3, as a burner of an underwater combustion type vaporizer, air that has an inner cylinder that divides a combustion chamber and an outer cylinder that is coaxially arranged with the inner cylinder and that is supplied from a blower, A configuration is described in which primary air introduced into the combustion chamber and secondary air introduced between the inner cylinder and the outer cylinder without being introduced into the combustion chamber are described. Further, in this underwater combustion type vaporizer, harmful substances in the exhaust gas are adjusted by adjusting the ratio of primary air and secondary air so as to correspond to the amount of fuel changed according to the load of the vaporizer. Is trying to reduce. Specifically, when the load of the underwater combustion type vaporizer is low and the amount of fuel is small, the primary air amount is small and the secondary air amount is large, whereas the vaporizer is heavily loaded, When the amount of fuel is large, the primary air amount is increased and the secondary air amount is decreased. In this way, by dividing into primary air and secondary air, combustion can be performed at an optimum air-fuel ratio in the entire combustion range, reducing harmful substances in the combustion gas from the burner, while reducing the secondary air to the combustion gas. By joining the two, it becomes possible to ensure a sufficient amount of exhaust gas that is jetted into the water tank and uniformly stirred.

JP 2009-209995 A JP 2006-317047 A JP 2013-2734 A

  By the way, the flame of the burner attached to the downcomer protrudes from the opening of the burner, and at least a part thereof is located in the downcomer. Moreover, in the structure which supplies primary air and secondary air separately with respect to the burner which has an inner cylinder and an outer cylinder as described in patent document 3, especially the load of an underwater combustion type vaporizer When the secondary air amount is low and the secondary air amount is large, a large amount of secondary air flows around the outside of the flame in the downcomer. In this state, the secondary air comes into contact with the flame, the flame is cooled, and the combustion temperature is lowered. Lowering the combustion temperature increases carbon monoxide in the exhaust gas and lowers the environmental performance of the underwater combustion vaporizer.

  The technology disclosed herein has been made in view of the above points, and an object thereof is an underwater combustion type vaporizer that divides air supplied from a blower into primary air and secondary air. Is to improve environmental performance by reducing harmful substances in the exhaust gas.

  The technology disclosed herein relates to an underwater combustion type vaporizer, and the underwater combustion type vaporizer is immersed in a water tank and is configured to vaporize a low-temperature liquefied gas passing through the inside thereof. A burner configured to burn the air supplied from the blower and the fuel supplied from the fuel supply source in the combustion chamber, and the burner is immersed in the water tank, and the burner is attached and from the burner. A downcomer configured to guide combustion gas into the water tank; a plurality of sparge pipes immersed in the water tank and configured to eject exhaust gas containing the combustion gas into the water; and a lower end of the downcomer Each sparge pipe is connected, and the exhaust gas discharged from the downcomer is distributed to each sparge pipe Cormorants and a manifold configured.

The air supplied from the blower is divided into combustion primary air introduced into the combustion chamber of the burner and non-combustion secondary air not introduced into the combustion chamber. the following air, the flame of the burner within the downcomer is Oite at the bottom of the downcomer below the lower end position to reach, are configured to merge with the combustion gases from the burner.
The secondary air merges with the combustion gas from the burner at a lower portion of the downcomer below the lower end position where the flame of the burner reaches in a low load state where the primary air is less than the secondary air. It may be configured.

  Here, the “lower part of the downcomer” can be defined as the lower part (including the boundary) when the downcommer immersed in the water tank extending vertically is divided into two equal parts. is there.

  According to the above configuration, the burner burns the air supplied from the blower (that is, primary air) and the fuel supplied from the fuel supply source. The combustion gas is jetted into the water tank along with the secondary air through the downcomer, the manifold, and a plurality of sparge pipes. The exhaust gas ejected as bubbles in the water (that is, including combustion gas and secondary air) stirs the water in the water tank and heats the low-temperature liquefied gas flowing in the heat exchanger, thereby the low-temperature liquefied gas. Vaporize.

  The air supplied from the blower is divided into primary air and secondary air, and the primary air is introduced into the combustion chamber of the burner and used for combustion. On the other hand, the secondary air is not introduced into the combustion chamber but is jetted into the water tank together with the combustion gas. The ratio of primary air and secondary air is adjusted according to the amount of fuel supplied to the burner. Specifically, when the fuel amount is small, the primary air is small and the secondary air is large, and when the fuel amount is large, the primary air is large and the secondary air is small. In this way, regardless of the load of the underwater combustion type vaporizer, the harmful substances in the exhaust gas are reduced, and the amount of exhaust gas ejected into the water tank is sufficiently secured, so that the heat exchange of the underwater combustion type vaporizer Improves vessel performance.

In the configuration of the secondary air merges at the bottom of the downcomer Oite, the combustion gases from the burner. That is, the secondary air merges with the combustion gas on the downstream side in the flow direction of the combustion gas from the burner to each sparge pipe. The secondary air does not contact the burner flame and it is avoided that the burner flame is cooled by the secondary air. As a result, the flame of the burner is cooled by a large amount of secondary air and the combustion temperature is lowered particularly when the underwater combustion type vaporizer with a small amount of primary air and a large amount of secondary air is operated at low load. This avoids an increase in carbon monoxide in the exhaust gas, and improves the environmental performance of the underwater combustion type vaporizer, particularly in a low-load operation state.

On the other hand, exhaust gas containing a combustion gas and secondary air, after merging with the bottom of the downcomer, because ejected as bubbles in the water through Supajipaipu, can be ejected a sufficient amount of exhaust gas into water become. Thus, the heat exchanger performance of the vaporizer is enhanced, especially during low load operation of the underwater combustion vaporizer where the amount of fuel is small and thereby the amount of combustion gas is small.

The burner has an inner cylinder that defines the combustion chamber and an outer cylinder that is arranged coaxially with the inner cylinder, and is attached to an upper portion of the downcomer, and the primary air is placed in the inner cylinder. After being introduced and introduced between the inner cylinder and the outer cylinder, the secondary air flows into the downcomer from the lower end opening of the burner, and the inner cylinder continues from the lower end of the burner. The lower end of the inner cylinder may be located at a lower portion in the downcomer below the lower end position where the flame of the burner reaches . Here, “the upper part of the downcomer” can be defined as the upper part (not including the boundary) when the downcomer is divided into two equal parts. A burner may be attached to the upper end of the downcomer. Further, the “lower part in the downcomer” can be defined as the lower part (including the boundary) when the inside of the downcomer is divided into two equal parts in the same manner as described above.

  The flame of the burner attached to the upper part of the downcomer protrudes from the lower end of the burner and comes to be located at least in the upper part of the downcomer. Further, the secondary air supplied to the burner having the inner cylinder and the outer cylinder flows into the downcomer through the space between the inner cylinder and the outer cylinder.

  In the above-described configuration, the inner cylinder is disposed so as to extend downward along the downcomer continuously from the lower end of the burner. All or most of the burner flame will be located inside the inner cylinder. As a result, the secondary air immediately after flowing into the downcomer from the lower end opening of the burner is prevented from coming into contact with the flame of the burner by interposing the inner cylinder extending downward. This prevents the burner flame from being cooled by the secondary air.

  The combustion gas discharged from the lower end opening of the inner cylinder merges with the secondary air at the lower end opening position of the inner cylinder. That is, the combustion gas and the secondary air merge at the lower part of the downcomer and are then ejected into the water tank through the sparge pipe.

  Thus, in an underwater combustion type vaporizer provided with a burner having an inner cylinder and an outer cylinder and divided into primary air and secondary air, suppressing a decrease in combustion temperature when the operating load is low; It is compatible with ejecting a sufficient amount of exhaust gas into the water tank.

The underwater combustion vaporizer disclosed herein also includes a heat exchanger that is immersed in a water tank and configured to vaporize a low-temperature liquefied gas passing through the water tank, and an air and fuel supply supplied from a blower. A burner configured to burn fuel supplied from a source in a combustion chamber, and is immersed in the water tank, and the burner is attached and configured to guide combustion gas from the burner into the water tank. Downcomers, a plurality of sparge pipes that are immersed in the water tank and configured to inject exhaust gas containing the combustion gas into the water, and are connected to the lower ends of the downcomers and to which each sparge pipe is connected And a manifold configured to distribute the exhaust gas discharged from the downcomer to each sparge pipe. The air supplied from the blower is divided into combustion primary air introduced into the combustion chamber of the burner and non-combustion secondary air not introduced into the combustion chamber. Air is configured to merge with the combustion gas from the burner in the manifold.

The underwater combustion vaporizer disclosed herein also includes a heat exchanger that is immersed in a water tank and configured to vaporize a low-temperature liquefied gas passing through the water tank, and an air and fuel supply supplied from a blower. A burner configured to burn fuel supplied from a source in a combustion chamber, and is immersed in the water tank, and the burner is attached and configured to guide combustion gas from the burner into the water tank. Downcomers, a plurality of sparge pipes that are immersed in the water tank and configured to inject exhaust gas containing the combustion gas into the water, and are connected to the lower ends of the downcomers and to which each sparge pipe is connected And a manifold configured to distribute the exhaust gas discharged from the downcomer to each sparge pipe. The air supplied from the blower is divided into combustion primary air introduced into the combustion chamber of the burner and non-combustion secondary air not introduced into the combustion chamber, and the downcomer The lower air or the manifold is provided with an inlet for the secondary air, and the secondary air is configured to merge with the combustion gas from the burner at the lower portion of the downcomer or in the manifold. Yes.
By doing so, the secondary air is introduced into the downcomer or the manifold through the inlet provided in the lower part of the downcomer or the manifold. Since the manifold is connected to the lower end of the downcomer, the secondary air introduced to the lower part of the downcomer flows into the manifold without flowing back upward from the downcomer, and from there, each sparger pipe And is ejected into the water tank together with the combustion gas. Therefore, it is avoided that the secondary air touches the flame of the burner. As a result, a decrease in combustion temperature is avoided and carbon monoxide in the exhaust gas is suppressed.

  The plurality of sparge pipes are arranged in a predetermined arrangement direction in the water tank, and the manifold has a base end connected to a lower end portion of the downcomer and extends in the water tank in the arrangement direction. The inlet of the secondary air may be provided at a position on the tip side of the manifold. Here, “the front end side of the manifold” may be defined as the front end side (including the boundary) when the manifold extending in the direction in which the sparge pipes are arranged is equally divided into two in that direction. Preferably, an inlet for secondary air is provided at the tip of the manifold.

  By providing the secondary air introduction port at the position on the front end side of the manifold, the secondary air introduction port is positioned away from the flame of the burner, so that the flame is cooled by the secondary air. This can be avoided reliably.

  The burner may be attached to an upper portion of the downcomer and configured to eject the combustion gas downward.

  In this way, the combustion gas from the burner flows from the upper part to the lower part in the downcomer and is then introduced into each sparge pipe via the manifold connected to the lower end of the downcomer. In this configuration, introducing secondary air into the downcomer lower part or manifold ensures that the secondary air does not touch the flame of the burner located at the top of the downcomer and the amount of secondary air is reduced. Even when there are many, the flame of the burner is prevented from being cooled.

  As described above, according to the above-described underwater combustion type vaporizer, the secondary air out of the air supplied from the blower is configured to merge with the combustion gas from the burner in the lower part of the downcomer or in the manifold. Thus, it is avoided that the flame of the burner is cooled by the secondary air, and carbon monoxide in the exhaust gas is prevented from increasing. At the same time, a sufficient amount of exhaust gas can be ejected into the water as bubbles, and the heat exchanger performance of the underwater combustion type vaporizer can be enhanced.

It is the schematic which shows the whole structure of an underwater combustion type vaporizer. It is sectional drawing which shows the structure of the burner which concerns on Embodiment 1. FIG. It is sectional drawing which shows the structure of the burner which concerns on Embodiment 2. FIG. It is a top view which shows the downcomer and manifold which concern on Embodiment 2. FIG. It is a front view which shows the downcomer and manifold which concern on the modification of Embodiment 2.

(Overall configuration of underwater combustion type vaporizer)
Hereinafter, an embodiment of an underwater combustion type vaporizer will be described based on the drawings. FIG. 1 shows an outline of the entire underwater combustion type vaporizer 1. The underwater combustion vaporizer 1 is a liquefied natural gas (LNG) vaporizer. The underwater combustion type vaporizer 1 includes a heat exchanger 12 that is immersed in, for example, a rectangular water tank 11 and a plurality of heat transfer tubes 12a serving as LNG flow paths are bent and formed in multiple stages. . One end of the heat exchanger 12 communicates with an LNG introduction pipe 12b serving as an LNG inlet, and the other end communicates with an NG exhaust pipe 12c that discharges vaporized natural gas (NG). In FIG. 1, the bundle of heat transfer tubes 12 a is illustrated in a simplified manner, but actually, multiple rows of heat transfer tubes 12 a are arranged at the depth of FIG. 1 and communicate with each other. The number and arrangement of the heat transfer tubes 12a are not particularly limited as long as heat exchange can be performed efficiently.

  The water tank 11 is covered with, for example, a rectangular plate-shaped top plate 11a. The top plate 11 a 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 position.

  A burner 2 is provided at the upper end of the downcomer 13 for burning the fuel gas supplied from a fuel supply source (not shown) through the fuel supply pipe 6 and the air supplied through the blower 14.

  At the bottom of the water tank 11, there is disposed a sparge pipe 15 that communicates with the downcomer 13 and is formed with a large number of small holes 15 a through which the combustion gas of the burner 2 is ejected. Although only one sparge pipe 15 is depicted in FIG. 1, a large number of sparge pipes 15 are actually arranged in the depth direction of FIG. 1 (see also FIGS. 4 and 5), and combustion gas is supplied to the entire heat exchanger 12. The bubble B which contains is made to reach. The number and arrangement of the sparge pipes 15 are not particularly limited, and the small holes 15a may be arranged in order to diffuse the bubbles B evenly and efficiently. The small holes 15a may be provided uniformly or randomly in the sparge pipe 15, and are preferably provided mainly on the upper surface and side surfaces thereof.

  A manifold 17 is interposed between the downcomer 13 and each sparge pipe 15. As illustrated in FIGS. 4 and 5, the manifold 17 is connected to the lower end portion of the downcomer 13 and extends in the direction in which the sparge pipes 15 are arranged. Each sparge pipe 15 communicates with the manifold 17, and the manifold 17 has a function of distributing the combustion gas discharged from the downcomer 13 to each sparge pipe 15.

  The top plate 11a of the water tank 11 is provided with a chimney stack 16 for exhausting combustion exhaust gas, and its upper end communicates with the atmosphere.

  The underwater combustion type vaporizer 1 ejects the combustion gas of the burner 2 as bubbles B into the water tank 11 through the small holes 15a of the sparge pipe 15, thereby passing the heat exchanger 12 while stirring the water in the water tank 11. LNG to be heated. As a result, LNG is vaporized into NG, and this is sent out from the outlet of the NG discharge pipe 12c. The underwater combustion type vaporizer 1 stirs the water in the water tank 11 by jetting the combustion gas as bubbles B into the water tank 11, and the temperature of the combustion exhaust gas discharged from the stack 16 is set as the hot water temperature in the water tank. It is characterized by extremely high thermal efficiency because the combustion product water in the combustion gas can be recondensed by 100% and all of its latent heat can be given to the hot water by making it almost the same.

  The underwater combustion type vaporizer 1 is configured to reduce harmful substances in exhaust gas particularly when the operation load of the underwater combustion type vaporizer 1 is low. Details of the configuration will be described below with reference to the drawings.

(Embodiment 1)
FIG. 2 shows the overall configuration of the burner 2. The burner 2 has a double tube structure including an outer cylinder 21 and an inner cylinder 22. The outer cylinder 21 is closed at its upper end and opened at its lower end. A supply port 23 for supplying air from the blower 14 to the burner 2 is provided on the outer surface of the outer cylinder 21 on the outer side. It is provided so that it may open toward. A partition wall 24 is provided in the outer cylinder 21 so as to divide the inside of the outer cylinder 21 into two parts. The air supply port 23 is also divided into two parts in the vertical direction. Of the two air supply ports 23 divided into two, the upper opening 231 is an opening 231 for primary air that is supplied to a combustion chamber 25 to be described later and into which primary air for combustion with fuel gas flows. On the other hand, the lower opening 232 is an opening 232 for the secondary air that is not supplied into the combustion chamber 25 and is introduced into the sparge pipe 15 together with the combustion gas (see the solid line arrow in the same figure). (See the dashed-dotted arrows).

  The inner cylinder 22 is disposed inside the outer cylinder 21 so as to be coaxial with the outer cylinder 21. An annular space 28 opening downward at the lower end of the burner 2 is defined between the inner cylinder 22 and the outer cylinder 21. The primary air opening 231 communicates with the upper end opening of the inner cylinder 22, whereby the primary air is supplied to the combustion chamber 25 configured in the inner cylinder 22. On the other hand, the secondary air opening 232 communicates with the annular space 28, whereby the secondary air flows into the downcomer 13 from the lower end opening of the burner 2 through the annular space 28.

  Although not shown in FIG. 1, a distribution valve 5 that adjusts the flow rate ratio of primary air and secondary air is connected to the supply port 23 of the burner 2. The distribution valve 5 is interposed between the blower 14 and the burner 2. The distribution valve 5 is a cantilevered butterfly valve having a throttle channel 51 that is throttled in the vertical direction and whose channel cross section is reduced, and a valve body 52 that swings when its proximal end is supported by the stem. It is. The distribution valve 5 is swung from a position where the tip of the valve body 52 is in contact with the upper wall near the minimum cross section of the throttle channel 51 to a position where it is in contact with the lower wall by an actuator (not shown). The flow rate ratio between the primary air and the secondary air supplied to 2 can be changed in the range of 0: 100 to 100: 0. Specifically, during normal operation of the underwater combustion type vaporizer 1, the primary air amount (the amount of air that provides the stoichiometric air-fuel ratio) corresponding to the fuel gas flow rate corresponding to the load of the underwater combustion type vaporizer 1 is obtained. A flow rate ratio between the primary air and the secondary air is set, and the distribution valve 5 is driven so as to have a valve opening degree corresponding to the flow rate ratio. That is, when the load of the underwater combustion type vaporizer 1 is low, the flow rate of the fuel gas is reduced, so that the primary air amount is relatively small, while the secondary air amount is relatively large, and conversely, the underwater combustion type. When the load of the vaporizer 1 is high, the flow rate of the fuel gas is increased, so that the primary air amount is relatively increased while the secondary air amount is relatively decreased.

  Thus, by adjusting the flow rate ratio between the primary air and the secondary air, particularly when the amount of combustion gas supplied to the burner 2 is reduced, the deterioration of the combustion state due to excess air is avoided, while the blower 14 By keeping the total amount of air supplied to the burner 2 constant, the amount of gas ejected from the small hole of the sparge pipe is secured, so that the water tank 11 is sufficiently stirred, and the underwater combustion type vaporizer 1 It is realized that the heat exchanger performance is not deteriorated.

  A main burner 26 is disposed in the combustion chamber 25 that is configured inside the inner cylinder 22. The main burner 26 includes a plurality of fuel gas nozzles 261, and the gas nozzles 261 are equidistant from each other in the circumferential direction so as to surround the lower end portion of the fuel gas supply pipe 262 disposed at the center position of the inner cylinder 22. It is arranged with a gap. The lower end of each gas nozzle 261 is arranged so that a nozzle (not shown) is opened downward, whereas the upper end portion is bent inward in the radial direction, and the bent end is a fuel end. A gas supply pipe 262 is connected. The fuel gas supply pipe 262 passes through the upper end of the closed outer cylinder 21 and extends to the outside. The end of the fuel gas supply pipe 262 is connected to a fuel gas supply source (not shown). Yes.

  In addition to the main burner 26 described above, the burner 2 includes a pilot burner that is driven prior to the main burner 26 when the burner 2 is ignited. Therefore, the illustration and description thereof are omitted.

  The burner 2 is provided with a water injection pipe 18 that suppresses the combustion temperature from becoming too high by injecting water into the combustion chamber 25. The water injection pipe 18 penetrates the upper end of the burner 2 and is disposed along the central axis, and jets water radially from the lower end. The water injection pipe 18 injects water into the combustion chamber 25 during a predetermined operation state in which the combustion temperature is high (for example, when the underwater combustion type vaporizer 1 is in a high load operation state). This suppresses generation of nitrogen oxides (NOx) and reduces harmful substances in the exhaust gas.

  Then, in the burner 2, the inner cylinder 22 projects downward continuously from the lower end of the burner 2, and extends downward along the downcomer 13 in the downcomer 13. The lower end of the inner cylinder 22 is located in the lower part of the downcomer 13 as shown in FIG. Here, the lower part of the downcomer 13 refers to a part below the boundary (see the broken line in FIG. 2) when the downcomer 13 extending in the vertical direction is divided into two equal parts. In the conventional configuration, since the inner cylinder is not extended, the flame of the burner 2 protrudes downward from the lower end opening of the burner 2 and is located in the downcomer 13, and secondary air flows around the outer periphery of the flame. It becomes like this. However, in the above-described configuration in which the inner cylinder 22 is extended, all or most of the flame in the downcomer 13 is located in the extended inner cylinder 22 (particularly during low load operation). Thereby, the secondary air flowing into the downcomer 13 from the lower end opening of the burner 2 flows downward in the annular space between the inner cylinder 22 and the inner peripheral surface of the downcomer 13. That is, the inner cylinder 22 isolates the flame from the secondary air at the upper part in the downcomer 13 so that the flame and the secondary air are not in contact with each other. In this way, the flame of the burner 2 is prevented from being cooled by the secondary air. This cooling prevention of the flame is to surely avoid contact between the flame and the secondary air when the load of the underwater combustion type vaporizer 1 is low, the primary air amount is small and the secondary air amount is large. Is effective. By preventing the cooling of the flame, the generation of carbon monoxide in the combustion gas is suppressed, and harmful substances in the exhaust gas ejected into the water tank 11 and exhausted through the stack 16 are reduced.

  Here, the inner cylinder 22 can be set to an appropriate length within a range in which the lower end thereof is positioned below the downcomer 13. The flame of the burner 2 can change the arrival position in the downcomer 13 according to the amount of fuel supplied and the amount of primary air, but in particular, the amount of primary air is small and the amount of secondary air is large. It is preferable that the inner cylinder 22 extends to the vicinity of the lower end position where the flame of the burner 2 reaches when the load of the underwater combustion type vaporizer 1 is lower than the predetermined load. By doing so, the secondary air and the combustion gas can be merged at a position where the flame of the burner 2 does not reach, as will be described later, without bringing the secondary air into contact with the flame of the burner 2. . The inner cylinder 22 may be as short as possible as long as the above conditions are satisfied.

  The combustion gas is ejected downward from the lower end opening of the inner cylinder 22 as shown by the white arrow in FIG. 2, and is indicated by the one-dot chain line arrow in the same figure at the lower end position of the inner cylinder 22 in the downcomer 13. Merge with secondary air. That is, the combustion gas and the secondary air merge at the lower part of the downcomer 13. As described above, the exhaust gas including the combustion gas and the secondary air flows into the manifold 17 from the lower end portion of the downcomer 13 and is then distributed to each sparge pipe 15. Then, it is ejected into the water tank 11 through the small hole 15a of each sparge pipe 15.

  Thus, by extending the inner cylinder 22 into the downcomer 13, it is possible to prevent the secondary air and the flame from coming into contact with each other, particularly near the lower end of the burner 2, thereby cooling the flame. Environmental performance is improved by suppressing harmful substances (here, carbon monoxide) in the exhaust gas. In other words, avoiding contact between the secondary air and the flame means that the secondary air is passed through the flame tip of the burner 2 and the connection port of the sparge pipe 15 in the manifold 17 (that is, the exhaust gas discharge port in the manifold 17). Between the gas and the combustion gas.

  Further, after the combustion gas and the secondary air are merged, an exhaust gas containing them is jetted into the water tank 11 to ensure a sufficient amount of gas to be jetted into the water tank 11, and an underwater combustion type The heat exchanger performance of the vaporizer 1 can be increased.

(Embodiment 2)
FIG. 3 shows the overall configuration of the burner 20 according to the second embodiment. Unlike the burner 2 shown in FIG. 2, the burner 20 of the second embodiment does not have the outer cylinder 21. Further, the air supply port 23 is not divided, and all the air (that is, primary air) flowing into the burner 20 through the air supply port 23 flows into the cylinder 220 that defines the combustion chamber 25 (see FIG. (See solid arrow). In addition, in the burner 20 shown in FIG. 3, the same code | symbol is attached | subjected about the substantially same structure as the burner 2 shown in FIG. 2, and the description is not repeated.

  Unlike the inner cylinder 22 of the burner 2 of the first embodiment, the cylinder 220 of the burner 20 does not extend to the lower part in the downcomer 13, and the lower end opening is located at the upper end part in the downcomer 13. Yes. Therefore, as conceptually shown in FIG. 3, the flame protruding into the downcomer 13 from the lower end opening of the burner 2 is located in the upper part of the downcommer 13 without being covered by the cylinder 220.

  In the underwater combustion type vaporizer 1 of Embodiment 2, the air supply path which connects the blower 14 and the burner 2 is branched into two, and one branch path (that is, the primary air supply path) is as described above. The other branch passage (that is, the secondary air supply passage) connected to the supply port 23 of the burner 2 is connected to the manifold 17 as shown in FIG. The secondary air inlet is not shown in FIG. 4 but is provided in the vicinity of the connecting end (that is, the base end) of the downcomer 13 in the manifold 17. The secondary air supply communicates with the inlet. The passage 19 is arranged obliquely with respect to the manifold 17 extending in the direction in which the sparge pipes 15 are arranged side by side. As a result, the secondary air that has flowed into the manifold 17 from the secondary air supply passage 19 via the inlet port passes through the manifold 17 on the upstream side (that is, with the downcomer 13 as shown by the one-dot chain line arrow in FIG. 4). From the connection end side) toward the downstream side (that is, the front end side of the manifold 17). Since this is a flow in a direction along the flow of the combustion gas flowing from the downcomer 13 toward the manifold 17, the backflow of the secondary air is prevented. Thus, the secondary air is prevented from coming into contact with the flame of the burner 2 and cooling, and the flame of the burner 2 is stably burned.

  In addition, flow control valves 61 and 62 are provided in each branch path described above, and the amounts of primary air and secondary air are adjusted by adjusting the opening degree of the flow control valves 61 and 62.

  Also in the underwater combustion type vaporizer 1 of Embodiment 2, since secondary air does not touch the flame of the burner 2 in the downcomer 13, the cooling of the flame is prevented. As a result, carbon monoxide in the exhaust gas can be suppressed. On the other hand, since the secondary air can be combined with the combustion gas and supplied into the water tank 11 via each sparge pipe 15, a sufficient amount of exhaust gas is jetted into the water tank 11, Even during the low load operation of the underwater combustion type vaporizer 1, the heat exchanger performance can be maintained high.

  The secondary air introduction port is not limited to the position near the connection end of the manifold 17, but can be provided at a lower portion of the downcomer 13 or at another position of the manifold 17. For example, as conceptually shown in FIG. 5, a secondary air inlet may be provided at the lower end of the downcomer 13 on the side opposite to the connection side of the manifold 17. The lower end portion of the downcomer 13 means a height position corresponding to the connection position of the manifold 17 (that is, substantially the same height position). In this configuration, the secondary air that has flowed into the lower end portion of the downcomer 13 flows into the manifold 17 connected to the lower end portion of the downcommer 13 as it is, so that the secondary air flows back above the downcomer 13. Is prevented. As a result, the flame of the burner 2 is suppressed from coming into contact with the secondary air, and the cooling of the flame is prevented. In addition, although illustration is abbreviate | omitted, the inlet port of the secondary air provided in the lower end part of the downcomer 13 is not limited to providing in the opposite side to the connection side of the manifold 17 so that it may illustrate in FIG. The introduction port of the secondary air can be provided at an appropriate position in the lower end portion of the downcomer 13 in consideration of the arrangement space in the water tank 11. Further, the inlet of the secondary air is not limited to the lower end portion of the downcomer 13 but may be provided above it (however, it is limited to the lower portion of the downcomer 13 so as not to contact the flame of the burner 2). .

  As shown in FIG. 5, the secondary air inlet may be provided at the tip of the manifold 17. The secondary air may be introduced into the manifold 17 in a direction along the axis of the manifold 17 as indicated by an arrow in FIG. In this configuration, the inlet of the secondary air is surely positioned away from the flame of the burner 2, so that the secondary air is reliably prevented from cooling the flame of the burner 2. The secondary air introduction port may be provided at an intermediate position between the distal end portion and the proximal end portion of the manifold 17. Moreover, the introduction direction of the secondary air introduced into the manifold 17 can be set to an appropriate direction regardless of the installation position of the introduction port.

  Further, the number of secondary air inlets provided in the lower part of the downcomer 13 or the manifold 17 is not limited to one, and a plurality of secondary air inlets may be provided.

  In addition, in the second embodiment, the burner 2 may be attached to the lower part of the downcomer 13 in addition to the upper end part of the downcomer 13.

  Furthermore, the technique disclosed here is not limited to an LNG vaporizer, but can be applied to a vaporizer for a low-temperature liquefied gas containing low-temperature LPG.

DESCRIPTION OF SYMBOLS 1 Underwater combustion type vaporizer 11 Water tank 12 Heat exchanger 13 Downcomer 14 Blower 15 Sparge pipe 17 Manifold 2 Burner 20 Burner 21 Outer cylinder 22 Inner cylinder 25 Combustion chamber

Claims (7)

A heat exchanger arranged to be immersed in the aquarium and configured to vaporize the low-temperature liquefied gas passing through the interior thereof;
A burner configured to burn air supplied from a blower and fuel supplied from a fuel supply source in a combustion chamber;
A downcomer that is immersed in the aquarium, the burner is attached and configured to guide combustion gas from the burner into the aquarium;
A plurality of sparge pipes immersed in the water tank and configured to eject exhaust gas containing the combustion gas into the water;
A manifold connected to the lower end of the downcomer and connected to each sparge pipe and configured to distribute the exhaust gas discharged from the downcomer to each sparge pipe,
The air supplied from the blower is divided into primary air for combustion introduced into the combustion chamber of the burner and secondary air for non-combustion not introduced into the combustion chamber,
The secondary air, Oite at the bottom of the downcomer below the lower end position where the flame reaches the burner within the downcomer, the combustion gas and Configured water combustion vaporizer to merge from the burner apparatus. The underwater combustion vaporizer according to claim 1,
The secondary air merges with the combustion gas from the burner at a lower portion of the downcomer below the lower end position where the flame of the burner reaches in a low load state where the primary air is less than the secondary air. An underwater combustion type vaporizer configured. The underwater combustion type vaporizer according to claim 1 or 2 ,
The burner has an inner cylinder that defines the combustion chamber and an outer cylinder that is arranged coaxially with the inner cylinder, and is attached to an upper portion of the downcomer,
The primary air is introduced into the inner cylinder,
The secondary air is introduced between the inner cylinder and the outer cylinder, and then flows into the downcomer from the lower end opening of the burner,
The inner cylinder is continuous from the lower end of the burner and extends downward along the downcomer, and the lower end of the inner cylinder is a lower part in the downcomer below the lower end position where the flame of the burner reaches An underwater combustion vaporizer located in the area. A heat exchanger arranged to be immersed in the aquarium and configured to vaporize the low-temperature liquefied gas passing through the interior thereof;
A burner configured to burn air supplied from a blower and fuel supplied from a fuel supply source in a combustion chamber;
A downcomer that is immersed in the aquarium, the burner is attached and configured to guide combustion gas from the burner into the aquarium;
A plurality of sparge pipes immersed in the water tank and configured to eject exhaust gas containing the combustion gas into the water;
A manifold connected to the lower end of the downcomer and connected to each sparge pipe and configured to distribute the exhaust gas discharged from the downcomer to each sparge pipe,
The air supplied from the blower is divided into primary air for combustion introduced into the combustion chamber of the burner and secondary air for non-combustion not introduced into the combustion chamber,
The submerged combustion type vaporizer configured so that the secondary air merges with the combustion gas from the burner in the manifold. A heat exchanger arranged to be immersed in the aquarium and configured to vaporize the low-temperature liquefied gas passing through the interior thereof;
A burner configured to burn air supplied from a blower and fuel supplied from a fuel supply source in a combustion chamber;
A downcomer that is immersed in the aquarium, the burner is attached and configured to guide combustion gas from the burner into the aquarium;
A plurality of sparge pipes immersed in the water tank and configured to eject exhaust gas containing the combustion gas into the water;
A manifold connected to the lower end of the downcomer and connected to each sparge pipe and configured to distribute the exhaust gas discharged from the downcomer to each sparge pipe,
The air supplied from the blower is divided into primary air for combustion introduced into the combustion chamber of the burner and secondary air for non-combustion not introduced into the combustion chamber,
In the lower part of the downcomer or in the manifold, an inlet for the secondary air is provided ,
The submerged combustion type vaporizer configured such that the secondary air merges with the combustion gas from the burner at a lower part of the downcomer or in the manifold . The underwater combustion vaporizer according to claim 5 ,
The plurality of sparge pipes are arranged in a predetermined alignment direction in the water tank,
The manifold has a proximal end connected to a lower end portion of the downcomer, and is disposed in the water tank so as to extend in the arrangement direction.
The secondary air introduction port is an underwater combustion type vaporizer provided at a position on a tip side of the manifold. The underwater combustion type vaporizer according to claim 5 or 6 ,
The burner is attached to an upper part of the downcomer and is configured to eject the combustion gas downward.

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