KR101224915B1 - Lng regasification system - Google Patents

Abstract

A regasification system of LNG is disclosed.
One embodiment of the present invention is a regasification line providing a path for LNG to move for regasification by the pumping force of the LNG pump, and a first heating for heating the LNG passing through the regasification line by heat exchange with seawater And a second heating section for heating the LNG passing through the regasification line by heat exchange with the fruit.

Description

LNG REGASIFICATION SYSTEM

The present invention relates to a regasification system of LNG.

Recently, LNG carriers for delivering liquefied natural gas (hereinafter referred to as 'LNG') are equipped with a separate regasification system to supply natural gas to consumers at sea. In addition to forms, structures that are constructed to carry out the same role by mounting a regasification system on top of offshore structures are also emerging.

The regasification system mounted on such a ship or offshore structure may use various facilities for vaporizing LNG using seawater or other fruits, depending on the method of vaporizing LNG.

In the conventional regasification system, the direct vaporization method using the fruit was mainly applied, but indirect vaporization method using the fruit is recently used due to environmental regulations. As a fruit, an antifreeze such as propane or glycol may be used, and is used in the form of a mixed refrigerant.

The regasification system of the indirect vaporization method is mainly used as a heat source for heating the fruit by receiving heat from a separate device, has the advantage that does not discharge the sea water in terms of environment.

However, this indirect gasification regasification system has a disadvantage in that the loss in terms of thermal efficiency, the sea water is not available when regasification in the sea where there is no discharge regulation.

In addition, due to the one-time heat exchange between the LNG and the fruit had a problem having a limit to increase the regasification efficiency.

Embodiment of the present invention by applying a direct vaporization method to increase the thermal efficiency when regasifying LNG, and to control the temperature of the seawater used for the regasification of LNG by controlling the use and discharge of seawater according to the operation type of the system I want to increase flexibility.

According to an aspect of the present invention, a regasification line for providing a movement path for regasification of LNG, a first heating unit for heating the LNG passing through the regasification line by heat exchange with sea water, and the regasification A regasification system of LNG may be provided that includes a second heating portion that heats LNG or cold NG passing through the line by heat exchange with fruit.

The first heating unit may include a seawater storage tank for storing seawater, a seawater circulation line providing a path for circulating and supplying seawater of the seawater storage tank to the regasification line, and seawater circulated and supplied through the seawater circulation line. And a first heat exchanger installed in the regasification line to heat exchange the LNG moving in the regasification line.

In addition, the second heating unit circulates through a boiler for generating steam which is a part of the fruit, a steam condensation water circulation line providing a path for circulating and supplying steam of the boiler to the regasification line, and the steam condensation water circulation line. Installed in the regasification line to heat exchange the supplied steam and LNG or cold NG moving through the regasification line, and generate condensed water which is another part of the fruit by heat exchange between the steam and the LNG or cold NG. It may comprise a second heat exchanger.

In addition, the second heating unit is installed in a path through which the seawater of the first heating unit moves, and by heat exchange with steam supplied from the steam condensation water circulation line, or heat exchange with condensate generated and supplied from the second heat exchanger. It may further include a third heat exchanger for heating the seawater by.

In addition, a first bypass line for installing LNG in the regasification line to bypass the first heating section, and a first bypass valve section for selecting whether to bypass the LNG provided in the first bypass line and the regasification line. And a second bypass line in which the LNG or cold NG is installed in the regasification line to bypass the second heating part, and installed in the second bypass line and the regasification line to select whether to bypass the LNG or cold NG. The apparatus may further include a second bypass valve unit.

In addition, it is installed to measure the temperature of the sea water of the seawater storage tank and / or the temperature of the rear end of the first heat exchanger of the regasification line and / or the temperature of the rear end of the second heat exchanger of the regasification line to output the detection signal The control unit may further include a temperature sensing unit and a sensing signal received from the temperature sensing unit and controlling the first and second bypass valve units, respectively.

The gas detector may further include a gas detector configured to be installed in the seawater storage tank to detect natural gas from the seawater and output a detection signal to the controller.

In addition, the first heating unit is a third bypass line where seawater is installed to bypass the third heat exchanger, and a third bypass valve installed on the third bypass line and the seawater moving path to select whether to bypass the seawater. The control unit may further include a unit, and the third bypass valve unit may receive a detection signal for the temperature of the seawater from the temperature sensor.

The embodiment of the present invention can increase the thermal efficiency when regasification of LNG by applying a direct vaporization method.

In addition, it is possible to control the temperature of the seawater used for the regasification of LNG, it is possible to increase the flexibility for the use and discharge of seawater according to the operating mode of the system.

1 is a block diagram showing a regasification system of LNG according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 is a block diagram showing a regasification system of LNG according to an embodiment of the present invention.

As shown in FIG. 1, the LNG regasification system 100 according to an embodiment of the present invention includes a LNG regasification line 110 that provides a movement path of LNG, and an LNG that passes through the regasification line 110. Heat through the first heating unit 120 and the first heating unit 120 bypassed by the first heating unit 120 as passing through the first heating unit 120 and the regasification line 110 to heat by heat exchange with seawater. The second heating unit 130 for heating the cold NG according to the heat exchange with the fruit may be included.

Regasification line 110 provides a path for the LNG to move for regasification by the pumping force of the LNG pump 111 from the LNG tank (1).

In order to heat and vaporize LNG, the first heating unit 120 recovers the seawater storage tank 121 in which seawater is stored, and the seawater in the seawater storage tank 121 by the pumping force of the seawater pump 122. By heat-exchanging the cryogenic LNG moving through the seawater circulation line 123 and the recirculation line 110 and the seawater circulated through the seawater circulation line 123 to provide a path for circulation supply to the fire line 110 side It may include a first heat exchanger 124 is installed in the regasification line 110 to be made of cold NG.

On the other hand, the seawater storage tank 121 may have a seawater line 126 is provided with an on-off valve 125 is installed for the discharge or supply of seawater in the sea area and the like can be discharged.

The second heating unit 130 may use, for example, steam or condensed water as a fruit to heat and vaporize the LNG. For this purpose, the second heating unit 130 may vaporize the steam of the boiler 131 and the boiler 131 to generate steam. Steam condensed water circulation line 132 that provides a path for circulation supply to the line 110 side, and the LNG or cold NG moving through the steam and regasification line 110 circulated through the steam condensation water circulation line 132 The heat exchanger may include a second heat exchanger 133 installed in the regasification line 110 to make a warm NG (warm NG).

Alternatively, in the second heat exchanger 133, the LNG and steam passing through the first bypass line 141 and the cold NG exiting from the first heat exchanger 124 without passing through the first bypass line 141 may be used. Steam may exchange heat to produce condensate. At this time, the condensed water has a higher temperature than that of seawater, so it can be used for heating seawater.

In addition, the second heating unit 130 may further include a third heat exchanger 134 to heat seawater using steam or condensed water.

That is, the third heat exchanger 134 is an intersection point of the seawater circulation line 123, which is a path through which the seawater of the first heating unit 120 moves, and the steam condensation water circulation line 132, which is a path through which steam or condensate moves. It is connected to and installed in the steam condensed water circulation line 132 by receiving the condensed water generated by the steam or the second heat exchanger 133 passed through the second heat exchanger 133 to heat the sea water.

The LNG regasification system 100 according to the present invention includes first and second bypass lines 141 and 143 to select LNG seawater and steam heating according to environmental constraints or operational conditions of the sea area. The apparatus may further include first and second bypass valve units 142 and 144 for determining the bypass.

The first bypass line 141 is installed in the regasification line 110 so that LNG bypasses the first heating unit 120, specifically, the first heat exchanger 124.

The first bypass valve unit 142 is installed in the first bypass line 141 and the regasification line 110 to select whether to bypass the LNG, as in the present embodiment is made of a three-way valve, or otherwise It may consist of multiple two-way valves.

The second bypass line 143 is installed in the steam condensation water circulation line 132 so that steam bypasses the second heating unit 130, specifically, the second heat exchanger 133.

The second bypass valve unit 144 is installed in the second bypass line 143 and the steam condensation water circulation line 132 to select whether the steam is bypassed, or as a three-way valve as in this embodiment, Alternatively it may consist of multiple two-way valves.

The first and second bypass valve units 142 and 144 or the following third bypass valve unit 128 may be manual valves, but may be made of electronic control valves controlled by the controller 146.

In the present embodiment, the temperature of the seawater in the seawater storage tank 121 and / or the temperature of the rear end of the first heat exchanger 124 of the regasification line 110 and / or the second heat exchanger of the regasification line 110 ( 133) The temperature sensing units 145, 145a and 145b which are installed to measure the temperature of the rear stage and output the sensing signal, and receive the detection signals from the temperature sensing units 145, 145a and 145b, and the first and second The control unit 146 may further control the bypass valve units 142 and 144 or the third bypass valve unit 128, respectively.

The control unit 146 controls the temperature of the cold NG or the worm NG regasified from LNG by adjusting the opening / closing flow rate or opening / closing timing of the first bypass valve unit 142 and / or the second bypass valve unit 144. Can be.

For example, the controller 146 compares and checks the detection signal with a preset temperature corresponding to the cold NG, the warm NG, or the steam, and then the first bypass valve unit 142 and / or the second bypass valve unit 144. It can be configured to adjust the opening and closing flow rate or the opening and closing timing of.

In addition, the seawater storage tank 121 may further include a gas detector 147 for detecting natural gas from the stored seawater and outputting a detection signal to the controller 146. Accordingly, when the control unit 146 receives the detection signal from the gas detecting unit 147, the control unit 146 outputs a control signal to generate an alarm by determining that leakage of LNG occurs in the regasification line 110, or regasification line ( An open / close valve (not shown) of the LNG may be controlled to suppress the movement of the LNG through the 110.

Meanwhile, the first heating unit 120 includes a third bypass line 127 and a third bypass line 127 installed in the seawater circulation line 123 so that seawater bypasses the third heat exchanger 134. And a third bypass valve unit 128 installed in the seawater circulation line 123 which is a movement path of the seawater to select whether the seawater is bypassed. Here, the third bypass valve unit 128 may be made of a three-way valve or a plurality of two-way valves as in the present embodiment, and receives the detection signal for the temperature of the seawater from the temperature sensor 145. The controller 146 may be controlled to perform the bypass operation when the seawater is above a certain temperature, for example, 20 degrees Celsius or more.

Referring to the operation of the LNG regasification system according to the present invention having such a configuration as an example.

The LNG stored in the LNG tank 1 is transferred to and pressurized by the LNG pump 111, which is a high pressure pump, and the pressurized LNG is transported along the regasification line 110 to be primarily connected to the sea water in the first heating part 120. It vaporizes by heat exchange, and it vaporizes by heat exchange with steam which is a fruit by the 2nd heating part 130 secondly. In this way, by adopting a multi-stage heat exchange method for LNG, it is possible to easily control the temperature of the vaporized natural gas.

In addition, the control unit 146 allows the LNG to bypass all or part of the first heat exchanger 124 when the seawater measured by the temperature sensing unit 145 has a predetermined temperature, for example, 20 ° C. or less. The first bypass valve unit 142 may be controlled such that LNG passes through all or most of the second heat exchanger 133.

For example, when the temperature of the sea water exceeds a predetermined temperature, for example, 20 degrees Celsius, the first bypass valve unit 142 is controlled so that the LNG passes through all or most of the first heat exchanger 124, and steam is supplied to the second heat exchanger. The second bypass valve unit 144 may be controlled to bypass all or part of the device 133.

In the meantime, the control unit 146 controls the opening / closing flow rate or the opening / closing timing of the first bypass valve unit 142 and / or the second bypass valve unit 144 according to a preset temperature corresponding to the cold NG or the warm NG. By fine adjustment, the temperature of each NG regasified can be controlled.

As such, when the LNG is vaporized by applying a direct heating method by sea water and steam rather than an indirect heating method, the thermal efficiency is high, and LNG or cold by allowing the sea water of low temperature to exchange heat with steam condensate in the third heat exchanger 134. Not only temperature control of the seawater after heat exchange with NG is possible, but also the temperature of the seawater storage tank 121 can be kept constant at all times. When the seawater temperature of the seawater storage tank 121 is too high, the controller 146 that recognizes the seawater temperature through the temperature sensing unit 145 controls the third bypass valve unit 128 to control the seawater. Heat exchange with LNG is performed only in the first heat exchanger 124 without heat exchange with the steam condensate in the gas 134.

In addition, the LNG can be regasified by the discharge and suction of seawater through the seawater storage tank 121, the seawater is circulated in the seawater storage tank 121 when there is an environmental constraint in the sea area being operated, LNG vaporization The heat source required for is to use the steam supplied from the boiler 131. At this time, when the boiler 131 breaks down, freezing may occur in the system, and LNG may be vaporized by the heat capacity of seawater in the seawater storage tank 121 to prevent freezing.

In addition, when leakage occurs in the first and second heat exchangers 124 and 133 and natural gas flows into the seawater, the gas detecting unit 147 detects the leakage and may respond quickly to the natural gas leakage.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand. For example, those skilled in the art can change the material, size, etc. of each component according to the application field, or combine or substitute the disclosed embodiments in a form that is not clearly disclosed in the embodiments of the present invention, but this also It does not depart from the scope of the invention. Therefore, it should be understood that the above-described embodiments are to be considered in all respects as illustrative and not restrictive, and that such modified embodiments are included in the technical idea described in the claims of the present invention.

110: regasification line 111: LNG pump
120: first heating portion 121: seawater storage tank
122: seawater pump 123: seawater circulation line
124: first heat exchanger 125: on-off valve
126: seawater line 127: third bypass line
128: third bypass valve portion 130: second heating portion
131: boiler 132: steam condensation water circulation line
133: second heat exchanger 134: third heat exchanger
141: first bypass line 142: first bypass valve portion
143: second bypass line 144: second bypass valve portion
145, 145a, 145b: temperature sensing unit 146: control unit
147: gas detection unit

Claims (8)

A regasification line providing a movement path for regasification of LNG,
A first heating unit for heating LNG passing through the regasification line by heat exchange with sea water;
A second heating unit for heating the LNG or cold NG passing through the regasification line by heat exchange with the fruit,
The first heating unit
A seawater storage tank in which seawater is stored,
A seawater circulation line providing a path for circulating and supplying seawater of the seawater storage tank to the regasification line;
And a first heat exchanger installed in the regasification line to heat-exchange the seawater circulated and supplied through the seawater circulation line and the LNG moving in the regasification line.
LNG regasification system.
delete The method of claim 1,
The second heating unit
A boiler for generating steam which is part of the fruit;
A steam condensation water circulation line providing a path for circulating and supplying steam of the boiler to the regasification line;
It is installed in the regasification line to heat exchange the LNG circulated through the steam condensation water circulation line and the LNG or cold NG moving the regasification line, the fruit by the heat exchange of the steam and the LNG or the cold NG A second heat exchanger for producing condensate which is another part of the
LNG regasification system.
The method of claim 3, wherein
The second heating unit
The seawater is installed in a path through which the seawater of the first heating unit moves and heats the seawater by heat exchange with steam supplied from the steam condensation water circulation line or by heat exchange with condensate water generated and supplied from the second heat exchanger. Further comprising a third heat exchanger
LNG regasification system.
The method according to any one of claims 1, 3, and 4,
A first bypass line installed in the regasification line so that LNG bypasses the first heating unit;
A first bypass valve unit installed at the first bypass line and the regasification line to select whether to bypass the LNG;
A second bypass line installed in the steam condensation circulation line so that steam bypasses the second heating unit;
And a second bypass valve unit installed at the second bypass line and the steam condensation water circulation line to select whether to bypass steam.
LNG regasification system.
The method of claim 5, wherein
A temperature installed to output a detection signal by measuring any one of a temperature of seawater of the seawater storage tank, a temperature of the rear end of the first heat exchanger of the regasification line, and a temperature of the rear end of the second heat exchanger of the regasification line; Detection unit,
Receiving a detection signal from the temperature sensing unit, and further comprising a control unit for controlling the first and second bypass valve unit, respectively
LNG regasification system. The method according to claim 6,
Installed in the seawater storage tank further comprises a gas detection unit for detecting the natural gas from the seawater and outputs a detection signal to the control unit
LNG regasification system.
The method of claim 4, wherein
The first heating unit
A third bypass line installed so that sea water bypasses the third heat exchanger;
A third bypass valve unit installed in the third bypass line and a seawater path to select whether to bypass the seawater;
The third bypass valve unit is controlled by a control unit for receiving a detection signal for the temperature of the sea water from the temperature detection unit
LNG regasification system.

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