JP2994688B2 - Low-temperature liquefied gas vaporizer that can produce fresh water - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for vaporizing low-temperature liquefied gas (LNG) using seawater, which is devised so that freshwater can be produced as a by-product.

[Background Art] In a low-temperature liquefied gas vaporizer, there is an open rack vaporizer that uses seawater as a heat source. This vaporizer is provided with a heat exchange panel 1a as shown in FIGS.
A trough 4a is arranged on the upper part of the tank, and the seawater sucked by the seawater pump 2a is pumped up to the header 3a, and is uniformly sprayed from the trough 4a to the heat exchange panel 1a to gasify LNG in the panel 1a.

[Problems of the prior art] However, the above-mentioned known examples have the following problems.

a. In order to equalize water spray from the trough 4a, restrictors for preventing drift are provided at various places of the header 3a. For this reason, the resistance increases, and it is necessary to increase the head of the seawater pump 2a.

b. In order to prevent breakage of the water spray film on the heat exchange panel 1a, even when the seawater temperature is high, the amount of seawater that is higher than the heat required for vaporization is pumped and flown. This results in unnecessary power costs.

c. Since seawater used for vaporization is drained as it is, there is a waste of cold heat.

An object of the present invention is to propose a low-temperature liquefied gas vaporizer capable of by-producing fresh water which does not have the problems described in the above a to c.

[Means for Solving the Problems] In order to achieve the above object, in the invention according to claim 1, heat for vaporizing a low-temperature liquefied gas having an inlet connected to an LNG inlet line and an outlet connected to an NG line is provided. A vaporizer having a built-in heat exchanger, a condensed water receiver disposed below the heat exchanger, and a seawater inlet formed below the condensed water receiver and on the inner bottom portion; A water absorption line connecting the bottom seawater inlet and the seawater pit, a bleed line attached to the upper part of the vaporizer, and a condensate once dropped in the condensate in the condensate receiver, and then the vaporizer. A freshwater recovery line leading to the outside, and a drainage pit, a drainage pump, and a drainage line for discharging seawater out of the vessel while keeping the amount of seawater introduced into the seawater introduction unit constant. Things.

Further, in the invention according to claim 2, a seawater introduction portion communicating with a seawater introduction portion formed at a bottom portion of the vaporizer through a communication port is formed at an inner bottom portion, and a tray is incorporated at a central portion, and the tray is installed at the center portion. A deaeration tower having a structure in which a water sprinkling pipe connected to a water absorption line is disposed above the water supply line is provided in front of the vaporizer.

[Action] The present invention aims to vaporize LNG by the following action, and also to desalinate seawater.

The LNG to be vaporized passes through the heat exchanger from the LNG input line, where it is heated and gasified by the heat of the steam evaporated from the seawater, and sent out from the NG line to the consumer side. On the other hand, the inside of the vaporizer is depressurized (evacuated) by the evaporation of seawater, and by this action, seawater is sucked from the seawater pit into the seawater introduction section in the vaporizer via the water absorption line.

The steam condensed by the heat of the LNG by heating the heat exchanger drops into the condensation receiver and is taken out of the condensate reservoir via the freshwater recovery line.

[Embodiment] Fig. 1 is an embodiment corresponding to the invention described in claim 1, wherein fresh water is obtained by using only a vaporizer, and reference numeral 1 denotes a vaporizer (a heat exchanger 2 incorporated therein). The seawater inlet 1a formed at the bottom of the vaporizer 1 is connected to the seawater bit 3 by a water absorption line 4. 5 is an LNG inlet line connected to the inlet of the heat exchanger 2, 6 is an NG outlet line connected to the outlet of the heat exchanger 2, 7 is disposed below the heat exchanger 2 in the vaporizer 1. A condensed water receiver, 8 is a condensed water reservoir for temporarily storing the condensed water collected by the condensed water receiver 7, 9 is a fresh water recovery line for collecting the condensed water stored outside the vaporizer 1 from the condensed water reservoir 8, 10 is This is a fresh water pump attached to the fresh water recovery line 9. Reference numeral 11 denotes a drainage pit following the seawater introduction section 1a at the bottom of the vaporizer 1, and reference numeral 12 denotes a drainage line for draining seawater from the drainage pit 11 by a drainage pump 13. 14 is an extraction line attached to the upper part of the vaporizer 1 and 15 is an extraction pump attached to the extraction line 14.

FIG. 2 shows a vaporizer with a deaeration tower provided for removing impurities in seawater at the previous stage of the same vaporizer 1 as the above-mentioned embodiment (an embodiment of the invention of claim 2). The degassing tower 16 has a seawater inlet 16a at the inner bottom, a tray 18 incorporated at the center, a sprinkling pipe 17 disposed above the tray 18, and an extraction line 14 with an extraction pump 15 at the top.
And a water absorption line 4 extended from the seawater pid 3 is connected to the sprinkler pipe 17.

Next, LNG vaporization and seawater desalination in the above two embodiments will be described.

First, LNG to be vaporized is supplied from the LNG inlet line 5 to the heat exchanger 2.
, Where it is heated and gasified by the heat of the steam evaporated from the seawater, and sent out from the NG line 6 to the consumer side. On the other hand, when the inside of the vaporizer 1 is decompressed (evacuated) due to the evaporation of seawater, the inside of the degassing tower 16 is depressurized accordingly, and seawater is sucked from the seawater pit 3 through the water absorption line 4 by this action.
The seawater is sprinkled on a tray 18 of a degassing tower 16 by a sprinkler pipe 17 and impurities are removed by the tray 18.
a → the communication port 19 → the seawater introduction section 1a, where it evaporates, and this steam heats the heat exchanger 2 to vaporize LNG.

The steam condensed by the heat of the heat exchanger 2 due to the cold heat of the LNG drops into the condensed water receiver 7 and is taken out of the condensed water reservoir 8 via the fresh water recovery line 9.

The bleeding line 14 on the side of the vaporizer 1 is used for bleeding from the carburetor 1, and the bleeding line 14 of the degassing tower 16 performs degassing from the inside of the degassing tower 16 to remove air and the like in seawater from the outside. To be discharged.

[Effects of the present invention] As described above, the present invention cools the steam of seawater evaporating in the vaporizer with the cold heat of LNG to form a vacuum state in the vaporizer and sucks seawater by this vacuum action. There is no need for seawater pumping equipment.

In addition, this seawater steam was cooled by the cold heat of LNG, condensed, and this condensed water, that is, fresh water was recovered,
Fresh water can be obtained very simply and with little cost.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the invention described in claim 1, FIG. 2 is an explanatory diagram showing an embodiment in which a degassing tower is installed in a vaporizer, showing an embodiment of the invention described in claim 2, FIG. 3 and FIG. 4 are explanatory diagrams of the open rack type vaporizer. 1 ... vaporizer 2 ... heat exchanger 3 ... seawater pit 4 ... water absorption line 7 ... condensed water receiver 8 ... condensed water reservoir 9 ... freshwater recovery line 16 ... degassing tower

Claims (2)

(57) [Claims] 1. An inlet is connected to an LNG inlet line and an outlet is NG
A heat exchanger for vaporizing low-temperature liquefied gas connected to the line is built in, and a condensed water receiver is arranged below the heat exchanger.Further, below the condensed water receiver, a seawater inlet is provided on the inner bottom part. A vaporizer having a formed configuration; a water absorption line connecting a seawater pit at a bottom portion of the vaporizer and a seawater pit; a bleeding line attached to an upper portion of the vaporizer; and condensation condensed into the condensate receiver. A freshwater recovery line for temporarily storing water in a sediment tank and then guiding the water to the outside of the vaporizer; a drainage pit and a drainage pump for discharging seawater outside the vessel while keeping the amount of seawater introduced into the seawater introduction section constant. And a drain line, and a low-temperature liquefied gas vaporizer capable of producing fresh water as a by-product. 2. A seawater introduction part, which is communicated with a seawater introduction part formed at a bottom part of a vaporizer by a communication port, is formed at an inner bottom part,
2. A low temperature capable of producing by-product fresh water according to claim 1, wherein a deaeration tower having a structure in which a tray is incorporated in a central portion and a sprinkler pipe connected to a water absorption line is disposed above the tray is provided in front of the vaporizer. Liquefied gas vaporizer.