JP2554900Y2 - Underwater combustion type vaporizer - Google Patents

Description

[Detailed description of the invention]

[0001]

This invention relates to liquefied natural gas and / or
In addition, the present invention relates to an improvement of an underwater combustion type vaporizer for liquefied petroleum gas, and relates to an underwater combustion type vaporizer configured to vaporize a residual liquid in the vaporizer at the time of operation stop and minimize a change in heat quantity at the time of restart of operation.

[0002]

2. Description of the Related Art An open rack type vaporizer often used as a liquefied natural gas vaporizer is, for example, a fin tube having a pair of fins projecting in a diameter direction arranged in the fin direction to form a single panel. A heat exchange panel is formed by providing a header tank at the upper and lower ends thereof, a plurality of the panels are arranged in parallel, and seawater of the heat medium flows down to the heat exchange panel surface from a sprinkler disposed above the heat exchange panel. Structure.

[0003] Usually, an open rack type vaporizer is provided with a submerged vaporizer (submerged vaporizer) for meeting the demand for city gas or the like but insufficient or for emergency use. As shown in FIG. 2, the underwater combustion type vaporizer blows out combustion gas generated in the burner 11 and the combustion chamber 14 from the sparge pipe 15 into the water tank 1,
This is a vaporizer configured to heat liquefied natural gas flowing through a heat exchanger 5 disposed in the water tank 1 with water 2 as an intermediate heat medium.

Although the heat exchanger 5 is simplified in the figure,
It is composed of a header tank and a tube bundle tube 5a,
The tube 5a is a straight tube having a plurality of U-turns. The mixed solution flows in from the lower header 5c, is heated while moving up the tube 5a, and is sent out as a vaporized gas from the upper header 5b. In order to keep the calorific value of the vaporized gas constant, liquefied natural gas (LNG) and liquefied petroleum gas (LP)
And G) in a liquid state to vaporize this.

[0005] As shown in FIG.
Normally, it is a semi-underground structure in which about half of the water tank 1 is buried underground, and a pipe 7 for supplying liquefied natural gas to the vaporizer is arranged at a height near the ground, and a mixer with the liquefied petroleum gas is used. 8 and the shutoff valves 9 and 10 for liquefied natural gas and liquefied petroleum gas for shutting down operation are also arranged at the same level, and are connected to the header pipe 6 of the vaporizer which rises near the water tank 1 and then enters the water tank 1. Consists of

[Problems to be solved by the invention]

[0006] The conventional heat exchanger 5 in the upflow vaporization mode selectively uses light components that are easily vaporized until the lower header 5b is filled with liquefied natural gas and / or liquefied petroleum gas at startup. Due to evaporation, calorific value hunting occurs in the vaporized gas, and gas exceeding the set calorific value is delivered. In addition, even when the operation is stopped, the heavy component that hardly evaporates stays in the lower header, so that there is a problem that the calorific value hunting is increased again.

Similarly, if the shut-off valves for the liquefied natural gas and the liquefied petroleum gas are closed and the operation is stopped, the liquid will remain in the pipe from the mixer to the vaporizer. The remaining liquid mixture evaporates gradually due to the heat of the atmosphere around the pipe, but liquefied natural gas mixed with liquefied petroleum gas is composed of multiple components. The remaining liquid becomes heavier.

Next, when the shut-off valve is opened and the operation is resumed, the heavy residual liquid first enters the vaporizer and is vaporized, so that the heavy component having a high calorific value fluctuates the set calorific value of the vaporized gas. In general, when the calorific value of the gas fluctuates, the flame may become large or incomplete combustion may occur, which is not preferable. In particular, city gas is required to have a constant calorific value without fluctuation.

According to the present invention, in a submerged combustion type vaporizer, it is possible to prevent the occurrence of heat hunting at the time of start-up, maintain good performance as a heat exchanger, and at the time of restarting the operation due to the residual liquid when the operation is stopped. It is an object of the present invention to provide an underwater combustion type vaporizer for liquefied natural gas and / or liquefied petroleum gas configured to minimize fluctuations in calorific value.

[0010]

According to the present invention, a combustion gas generated by a burner is jetted into a water tank, and liquefied natural gas and / or liquefied petroleum gas flowing through a heat exchanger disposed in the water tank are submerged. In the heated underwater combustion type vaporizer, (a) supply of the liquefied gas to the heat exchanger in the system
Pipes should be at least as high as the water level in the aquarium
And less immediately before connecting to the header pipe (b) heat exchanger
Both increases disposed only supply pipe diameter height, the supply pipe for bypassing the supply tube portion elevated arranged and (c)
Note that a smaller diameter drain pipe was connected to the header pipe.
This is a submerged combustion type vaporizer for liquefied natural gas.

[0011]

[0012]

The submerged combustion type vaporizer according to the present invention allows liquefied natural gas and / or liquefied petroleum gas to flow from the upper header of the heat exchanger and vaporizes from the lower header by heating while lowering the meandering tubes. The adoption of a heat exchanger in the form of a down-flow vaporizer that can be sent out as a gas allows the mixed solution in the upper header to flow down and does not stay. Prevented or reduced.

Further, in the underwater combustion type vaporizer according to the present invention, when the liquefied natural gas and the liquefied petroleum gas are mixed, the liquefied gas is filled in the pipe near the mixer by the above configurations (a) and (b). As a result, a good mixing state can be obtained, and the height of the structure (b) can be minimized, so that the amount of residual liquid can be reduced as much as possible. Further, the residual liquid in the supply pipe after the shut-off valve is closed by the drain pipe having the configuration (c) flows into the header pipe of the vaporizer by gravity due to gravity, and the residual liquid is eliminated, and the residual liquid flowing down to the header pipe is retained heat in the water tank. Is vaporized over time.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of an underwater combustion type vaporizer according to the present invention will be described in detail with reference to the drawings. Here, a configuration in which caloric hunting is prevented will be described by taking as an example a case where liquefied petroleum gas is mixed with liquefied natural gas. However, a configuration that further improves the mixing state of liquefied natural gas and liquefied petroleum gas will be described.
As described above, the underwater combustion type vaporizer according to the present invention can be used for vaporization of either liquefied natural gas or liquefied petroleum gas.

The vaporizers such as the water tank 1 except for the heat exchanger 5 and the header pipe 6 are the same as those in the configuration example of FIG. In FIG. 1, 3 is an upper plate, 4 is an exhaust pipe, 1
2 is a fuel supply pipe, 13 is an air pipe, 16 is a cooler of the combustion chamber 14 using a pumping pipe 17, and 25 is a liquefied petroleum gas supply pipe. In the heat exchanger 5, a header pipe 6 from a liquefied gas supply pipe 20 is connected to an upper header 5b arranged at the upper end of a tube 5a in which a straight pipe is turned multiple times, and liquefied natural gas mixed with liquefied petroleum gas is connected. Is supplied. The mixed solution from the upper header 5b is heated while flowing down the tube 5a, and is sent out from the lower header 5c as a vaporized gas.

In the example shown in FIG. 1, the reference height of the liquefied gas supply pipe 20 is higher than the upper plate 3 of the vaporizer and is arranged at a required height (H) above the ground. The liquefied gas supply pipe 20 is provided with a mixer 21 for liquefied petroleum gas (LPG) downstream of a shutoff valve 22 for liquefied natural gas (LNG),
Between the header pipe 6 of the heat exchanger 5 and the downstream side of the mixer 21, there is provided an ascending portion 23 which is arranged to be higher than the reference height (H) by a height (h) which is equal to or more than the supply pipe diameter height. .

Immediately before connection to the header pipe 6, the arrangement is raised at least by the height of the supply pipe diameter. If the same part remains at the reference height (H), liquefaction occurs in the lower half in the supply pipe of the mixer 21. This is because a mixed liquid in a state where natural gas flows and liquefied petroleum gas falls thereon is supplied to the header pipe as it is, and the two liquids cannot be mixed uniformly. In addition, the rising height (h) needs to be minimized so that the liquefied natural gas and the liquefied petroleum gas can be maintained in a good mixed state so that the residual liquid amount can be reduced as much as possible.

Further, the liquefied gas supply pipe 20 has a rising portion 2
3, a drain pipe 24 having a smaller diameter than the supply pipe is connected to the header pipe 6.

In the above configuration, liquefied natural gas (LN
G) and liquefied petroleum gas (LPG), when the shut-off valves 22 and 26 are closed to stop the operation, the rising portion 23 of the supply pipe 20 has a minimum necessary height, so that the residual liquid amount is small and the drain pipe 24, the residual liquid after the stop naturally flows down by gravity to the header pipe of the vaporizer, and the supply pipe 2
0 and the residual liquid are eliminated in the rising portion 23. Further, the residual liquid flowing down to the header pipe 6 enters the upper header 5b of the heat exchanger 5 and immediately flows down the tube 5a.
It is heated and vaporized over time by the retained heat in the water tank 1,
It is sent out as a vaporized gas from the lower header 5c. That is, in the heat exchanger 5, the mixed solution does not stay in the upper header 5b due to the downflow vaporization mode.

[0019]

[Effect of the invention] The underwater combustion type vaporizer according to the invention is:
As is clear from the embodiment, since there is almost no residual liquid in the supply pipe after the operation is stopped and in the header of the heat exchanger, the calorific value of the vaporized gas does not fluctuate when the operation is restarted. Further, by adding a configuration in which the liquefied gas supply pipe is arranged at a predetermined height and provided with an ascending portion about the height of the supply pipe diameter, the mixing state of liquefied natural gas and liquefied petroleum gas during operation is kept constant. Can be held.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a water tank showing a configuration of an underwater combustion type vaporizer according to the present invention.

FIG. 2 is a vertical sectional view of a water tank showing a configuration of a conventional underwater combustion type vaporizer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water tank 2 Water 3 Top plate 4 Exhaust pipe 5 Heat exchanger 5a Tube 5b Upper header 5c Lower header 6 Header piping 7 Piping 8 Mixer 9,10 Shutoff valve 11 Burner 12 Fuel supply pipe 13 Air pipe 14 Combustion chamber 15 Sparge pipe 16 Cooler 17 Pumping pipe 20 Liquefied gas supply pipe 21 Mixer 22, 26 Shut-off valve 23 Up section 24 Drain pipe

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazuya Sahara 1-10 Fuso-cho, Amagasaki-shi, Hyogo Sumitomo Precision Industries, Ltd. (56) References JP-A-2-57799 (JP, A) 62-30637 (JP, Y2)

Claims (1)

(57) [Scope of request for utility model registration] An underwater combustion type vaporizer for injecting combustion gas generated by a burner into a water tank and heating liquefied natural gas and / or liquefied petroleum gas flowing in a heat exchanger disposed in the water tank. Liquefaction to the heat exchanger in the equipment
Make sure that the gas supply pipe is at least as high as the water level in the tank.
Above the same height and connected to the header pipe of the heat exchanger
Immediately before, it is arranged to rise at least by the height of the supply pipe diameter,
And smaller than the supply pipe that bypasses the supply pipe section
An underwater combustion type vaporizer for liquefied natural gas, characterized in that a drain pipe having a diameter is connected to a header pipe .