KR102505858B1 - Liquefied gas regasification system - Google Patents

Abstract

The present invention provides a liquefied gas regasification system. The liquefied gas regasification system of the present invention includes a first heat exchanger and a second heat exchanger that sequentially exchange heat between the liquefied gas supplied from the storage tank and the heat medium; a regasification line supplying the liquefied gas vaporized through the first heat exchanger and the second heat exchanger to a customer; a first circulation line for circulating a first heat medium among heat mediums supplied from the suction drum to the suction drum through the first heat exchanger; a second circulation line branched off from the first circulation line to circulate a second heat medium among the heat medium to the suction drum through the second heat exchanger and the first heat exchanger sequentially; and an exhaust gas line having a preheater for preheating a heat source that exchanges heat with the first heat medium and the second heat medium by using waste heat of the exhaust gas generated from the demand side.

Description

Liquefied gas regasification system {LIQUEFIED GAS REGASIFICATION SYSTEM}

The present invention relates to a liquefied gas regasification system.

Liquefied natural gas is a colorless and transparent cryogenic liquid that reduces its volume to 1/600 by cooling natural gas collected from a gas field to a cryogenic temperature of about -162 degrees Celsius. Liquefied natural gas is transported and unloaded over a long distance from a production site to a consumer by a liquefied natural gas carrier. The unloaded liquefied natural gas is regasified by the liquefied natural gas regasification facility installed in the land terminal and then supplied to consumers such as homes and industrial complexes.

An onshore terminal equipped with such a regasification facility can be economically advantageous if it is built in a place where the natural gas market and demand are stable. However, in the case of demand destinations where demand for natural gas is seasonal, short-term or periodically limited, construction of an onshore terminal is uneconomical due to high installation and maintenance costs.

In recent years, in order to regasify liquefied natural gas at sea and supply natural gas directly to consumers, a liquefied natural gas regasification vessel (LNG RV, LNG Regasification Vessel) or floating liquefaction vessel with a regasification system installed on a liquefied natural gas carrier is installed. Natural gas storage and regasification facilities (FSRU, Floating Storage and Regasification Unit) have been developed and operated.

Such a regasification system or regasification facility vaporizes liquefied natural gas by exchanging heat with a heat source such as seawater to cryogenic liquefied natural gas stored in a storage tank.

However, when seawater is directly heat-exchanged with liquefied natural gas, there is a problem in that the durability of the regasification facility is greatly reduced due to freezing of seawater or corrosion of equipment due to salt. In addition, since the temperature of the seawater is not constant, the reliability of the liquefied natural gas regasification performance may deteriorate. As a related technology, please refer to Korean Patent Publication No. 10-2008-0085284 (published on September 24, 2008).

Korean Patent Publication No. 10-2008-0085284 (published on September 24, 2008)

An embodiment of the present invention is to provide a liquefied gas regasification system that improves regasification efficiency and performance of liquefied gas and generates electricity by using a circulating heat medium for heat exchange with liquefied gas.

An embodiment of the present invention is to provide a liquefied gas regasification system that produces electricity by utilizing waste heat generated in a consumer.

The problem to be solved by the present invention is not limited thereto, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to one aspect of the present invention, a first heat exchanger and a second heat exchanger for sequentially performing heat exchange between the liquefied gas supplied from the storage tank and the heat medium; a regasification line supplying the liquefied gas vaporized through the first heat exchanger and the second heat exchanger to a customer; a first circulation line for circulating a first heat medium among heat mediums supplied from the suction drum to the suction drum through the first heat exchanger; a second circulation line branched off from the first circulation line to circulate a second heat medium among the heat medium to the suction drum through the second heat exchanger and the first heat exchanger sequentially; and an exhaust gas line having a preheater for preheating a heat source that exchanges heat with the first heat medium and the second heat medium by using waste heat of the exhaust gas generated from the demand side. .

In addition, a first heater provided in the first circulation line and exchanging heat between the heat source preheated in the preheater and the first heat medium; a first expander that expands the heat-exchanged first heat medium and sends it to the first heat exchanger; And it may include a first generator connected to the first expander to generate electricity.

In addition, a first vaporizer provided between the first heater and the first expander and vaporizing the first heat medium by using waste heat of the exhaust gas supplied from the exhaust gas line may be further included.

In addition, a second heater provided in the second circulation line, heat-exchanging the heat source preheated in the pre-heater and the second heat medium and sending it to the second heat exchanger; may be included.

In addition, a second expander provided at a rear end of the second heat exchanger in the second circulation line, expands the second heat medium passing through the second heat exchanger, and sends it to the first heat exchanger; And it may further include a second generator connected to the second expander to generate electricity.

In addition, a second vaporizer provided between the second heater and the second expander and vaporizing the second heat medium using waste heat of the exhaust gas supplied from the exhaust gas line may be further included.

In addition, a pressure pump for pressurizing the heat medium supplied from the suction drum; Based on at least one of the internal pressure of the suction drum, the temperature of the heat medium supplied from the suction drum to the pressure pump, and the temperature of the first heat medium that has passed through the first heat exchanger through the first circulation line, the first circulation It may further include a first control valve for adjusting the supply amount and the degree of pressure reduction of the first heat medium supplied to the first heater through the line.

In addition, a second control valve for adjusting the supply amount of the second heat medium supplied to the second heater through the second circulation line based on the temperature of the vaporized liquefied gas that has passed through the second heat exchanger of the regasification line. may further include.

In addition, a pressure measuring device provided at the rear end of the second heater in the second circulation line and measuring the pressure of the second heat medium vaporized by the second heater, and provided between the pressure measuring device and the second heat exchanger, , Based on the measured pressure of the second heat medium, it may further include a third control valve for adjusting the pressure of the second heat medium so that the second heat medium maintains a gaseous state even after passing through the second heat exchanger. .

In addition, a third expander provided between the first heat exchanger and the second heat exchanger of the regasification line and primarily expanding the liquefied gas vaporized by the first heat exchanger; A third generator connected to the third expander to produce electricity; a fourth expander provided at a rear end of the second heat exchanger in the regasification line and secondarily expanding the vaporized liquefied gas heated by the second heat exchanger; and a fourth generator connected to the fourth expander to generate electricity.

In addition, it may further include a third heat exchanger for performing heat exchange between the vaporized liquefied gas secondarily expanded by the fourth expander and a heat source to adjust the temperature according to the fuel supply conditions of the customer.

According to an embodiment of the present invention, it is possible to improve regasification efficiency and performance of liquefied gas, and to generate electricity using a circulating heat medium for heat exchange with liquefied gas.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 shows a liquefied gas regasification system according to an embodiment of the present invention.

Since the present invention can apply various transformations and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, it should be understood that this is not intended to limit the present invention to specific embodiments, and includes all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. description is omitted.

1 shows a liquefied gas regasification system according to an embodiment of the present invention.

Referring to FIG. 1, the liquefied gas regasification system 100 according to an embodiment of the present invention includes a first heat exchanger 101 that sequentially exchanges heat between the liquefied gas supplied from the storage tank 12 and a heat medium, and A regasification line (L10) for supplying the liquefied gas vaporized through the second heat exchanger (102), the first heat exchanger (101) and the second heat exchanger (102) to the consumer (14), and the suction drum (110) The first circulation line (L11) circulates the first heat medium among the heat medium supplied from the first heat exchanger (101) to the suction drum (110), and is branched off from the first circulation line (L11), and the suction drum (110) ) A second circulation line (L12) for circulating the second heat medium among the heat medium supplied from the second heat exchanger 102 and the first heat exchanger 101 sequentially to the suction drum 110, and the first circulation line (L11), the first heater 201 for exchanging heat with the heat source, and the first heat medium vaporized by the first heater 201 is expanded and sent to the first heat exchanger 101. It is provided in the expander 301, the first generator G1 connected to the first expander 301 to produce electricity, and the second circulation line L12, and heat exchanges the second heat medium with the heat source to form a second heat exchanger. and a second heater 202 directed to 102.

In addition, the liquefied gas regasification system 100 is provided at the rear end of the second heat exchanger 102 in the second circulation line L12, and expands the second heat medium passing through the second heat exchanger 102 to exchange the first heat. It includes a second expander 302 sent to the machine 101 and a second generator G2 connected to the second expander 302 to generate electricity.

In addition, the liquefied gas regasification system 100 is provided between the first heat exchanger 101 and the second heat exchanger 102 of the regasification line L10, and the liquefied gas vaporized by the first heat exchanger 101 The third expander 303 for primary expansion of gas, the third generator G3 connected to the third expander 303 to generate electricity, and the rear end of the second heat exchanger 102 of the regasification line L10 , a fourth expander 304 for secondarily expanding the vaporized liquefied gas heated by the second heat exchanger 102, and a fourth generator G4 connected to the fourth expander 304 to produce electricity. ) and a third heat exchanger 103 that performs heat exchange between the vaporized liquefied gas secondarily expanded by the fourth expander 304 and the heat source to adjust the temperature according to the fuel supply conditions of the customer.

In addition, the liquefied gas regasification system 100 includes a pressure pump 112 that pressurizes the heat medium of the suction drum 110, and the internal pressure of the suction drum 110 is supplied from the suction drum 110 to the pressure pump 112. The first heater 201 through the first circulation line (L11) based on at least one of the temperature of the heat medium and the temperature of the first heat medium that has passed through the first heat exchanger 101 through the first circulation line (L11). Based on the temperature of the vaporized liquefied gas that has passed through the first control valve (V1) for controlling the supply amount and the degree of pressure reduction of the first heat medium supplied to and the second heat exchanger (102) of the regasification line (L10), A second control valve (V2) for controlling the supply amount of the heating medium supplied to the second heater (202) and a second circulation line (L12) provided at the rear end of the second heater (202), A pressure measuring device (P2) for measuring the pressure of the second heat medium vaporized by the pressure measuring device (P2), provided between the pressure measuring device (P2) and the second heat exchanger (102), the vaporized second heat medium measured by the pressure measuring device (P2) Based on the pressure of the second heat exchanger 102, it includes a third control valve (V3) for adjusting the pressure of the second heat medium to maintain a gaseous state even after passing through.

In addition, the liquefied gas regasification system 100 is a preheater that preheats a heat source that exchanges heat with the first heat medium and the second heat medium by using waste heat of exhaust gas generated from a consumer (eg, a generator, an engine, etc.) ( exhaust gas line 910 having 902 .

The exhaust gas line 910 may include a main line 912 , a first branch line 914 , and a second branch line 916 .

A preheater 902 is installed on the main line 912. The first branch line 914 provides exhaust gas to the first vaporizer 920 that vaporizes the first heating medium. The first vaporizer 920 is provided on the first circulation line L11 between the first heater 201 and the first expander 301, and uses waste heat of the exhaust gas supplied from the exhaust gas line 910 to The first heat medium is vaporized.

The second branch line 916 supplies exhaust gas to the second vaporizer 930 that vaporizes the second heat medium. The second vaporizer 930 is provided on the second circulation line L12 between the second heater 202 and the second expander 302, and uses the waste heat of the exhaust gas supplied from the exhaust gas line to generate the second heat medium. vaporize

In this embodiment, the first branch line is illustrated as branching from the second branch line, but is not limited thereto, and the first branch line may branch from the main line.

Meanwhile, control valves V5 to V7 are installed in the main line 912, the first branch line 914, and the second branch line 916, and these may be controlled by the control unit 990. That is, efficiency in operation can be maximized by selectively controlling the heat exchange between the exhaust gas and the heating medium through the control unit 990 according to the system situation (when a lot of electricity to be recovered is required or when it is no longer needed). there is.

This liquefied gas regasification system 100 is a variety of liquefied fuel carriers, liquefied fuel RV (Regasification Vessel), container ships, general merchant ships, LNG FPSO (Floating, Production, Storage and Off-loading), LNG FSRU (Floating Storage and Regasification) Unit), etc. can be applied to ships.

In the above-described liquefied gas regasification system 100, the heat source (for example, sea water) used for heat exchange in the first heater, the second heater, and the third heat exchanger 103 has a temperature limit (sea water temperature is Since the temperature is maintained within a certain range), to compensate for this, heat exchangeability is improved by utilizing the waste heat of the exhaust gas generated from the customer as a way to supplement additional heat. For reference, the waste heat from the demand source (generator) is a high temperature of about 500-800 degrees, and if the heat source is used, an increase in electricity production of more than 10% can be expected compared to using simple seawater. It is also possible to configure the system smaller than the facility.

Hereinafter, each component will be described in detail.

The storage tank 12 may include a membrane type tank, an SPB type tank, and the like for storing fuel in a liquefied state while maintaining an adiabatic state. The liquefied gas stored in the storage tank 12 may be any one of LNG (Liquefied Natural Gas), LPG (Liquefied Petroleum Gas), DME (Dimethylether), and Ethane that can be stored in a liquefied state, but is not limited thereto .

The first heat exchanger 101 performs heat exchange with the liquefied gas supplied from the storage tank 12 and the first heat medium and the second heat medium supplied through the first circulation line L11 and the second circulation line L12. regasification of liquefied gas. Here, the first and second heat mediums may be condensable heat mediums capable of easily changing phases between a gas phase and a liquid phase, and may be provided with, for example, propane. Propane is easy to obtain in terms of cost, and phase change between gaseous and liquid phases is easy. The vaporized liquefied gas that has passed through the first heat exchanger 101 is expanded by the third expander 303 .

The third expander 303 is provided between the first heat exchanger 101 and the second heat exchanger 102, and primarily expands the liquefied gas vaporized by the first heat exchanger 101. The third expander 303 is connected to the third generator G3 that produces electricity. That is, the third generator G3 may generate electricity by using the force generated while the vaporized liquefied gas expands by the third expander 303 . This can also be applied to the electricity generation method between the fourth expander 304 and the fourth generator G4 in the embodiment of the present invention.

The second heat exchanger 102 heats the vaporized liquefied gas that has passed through the third expander 303 by exchanging heat with the second heat medium supplied through the second circulation line L12.

The vaporized liquefied gas that has passed through the second heat exchanger 102 is expanded by the fourth expander 304 .

The fourth expander 304 is provided between the second heat exchanger 102 and the third heat exchanger 103 of the regasification line L10, and converts the vaporized liquefied gas heated by the second heat exchanger 102 to second expansion. The fourth expander 304 is connected to the fourth generator G4 that produces electricity.

The third heat exchanger 103 may perform heat exchange between the vaporized liquefied gas that has passed through the fourth expander 304 and the heat source, thereby increasing the temperature of the vaporized liquefied gas according to the fuel supply conditions required by the consumer 14. The heat source may include seawater, steam, and the like. In an embodiment of the present invention, an example in which seawater is used as a heat source will be described.

The first circulation line L11 circulates the first heat medium among the heat medium supplied from the suction drum 110 to the suction drum 110 via the first heat exchanger 101 .

The suction drum 110 accommodates the heating medium. At this time, a pressure pump 112 is provided in the first circulation line L11 to pressurize the heat medium supplied from the suction drum 110 .

The pressure pump 112 is provided to operate by receiving a liquid heat medium to prevent malfunctions and failures and to stably pressurize the heat medium. Accordingly, the inlet end of the first circulation line L11 is connected to the lower part of the suction drum 110 to supply only the liquid heat medium to the pressure pump 112 .

Among the heat medium pressurized by the pressure pump 112, the first heat medium is supplied to the first heater 201 through the first control valve V1.

The first control valve V1 controls the pressure inside the suction drum 110 measured by the pressure measuring device P1 and the heat medium supplied to the pressure pump 112 from the suction drum 110 measured by the temperature sensor T2. Based on one or more of the temperature of the first heat medium passing through the first heat exchanger 101 through the first circulation line L11 measured by the temperature sensor T1, the first circulation line L11 The supply amount of the first heating medium supplied to the first heater 201 and the degree of pressure reduction are controlled through the.

The first heater 201 heat-exchanges the first heat medium that has passed through the first control valve V1 with the heat source.

The first heat medium primarily vaporized by the first heater 201 is vaporized by exchanging heat with the heat source of the exhaust gas in the first vaporizer 920 . As such, in the present invention, efficiency can be maximized by vaporizing the first heat medium through heat exchange with seawater and exhaust gas twice.

The first heat medium vaporized in the first vaporizer 920 is expanded by the first expander 301 . The first expander 301 is connected to a first generator G1 that generates electricity. That is, the first generator G1 can generate electricity by using the force generated while the gaseous first heat medium expands by the first expander 301 . This can also be applied to the electricity generation method between the second expander 302 and the second generator G2 in the embodiment of the present invention.

The first heat medium that has passed through the first expander 301 is sent to the above-described first heat exchanger 101 in a gas-liquid state and exchanges heat with liquefied gas. The first heat medium that has passed through the first heat exchanger 101 is liquefied and stored in the suction drum 110 .

Among the heat medium pressurized by the pressure pump 112, the second heat medium is supplied to the second heater 202 through the second control valve V2.

The second control valve (V2) is based on the temperature of the vaporized liquefied gas that has passed through the second heat exchanger (102) of the regasification line (L10) measured by the temperature sensor (T3), the second heater (202) Adjust the supply amount of the heating medium supplied to

The second heater 202 exchanges heat between the second heat medium passing through the second control valve V2 and the heat source.

The pressure measuring device P2 measures the pressure of the second heating medium vaporized through the second heater 202 .

And, based on the pressure of the vaporized second heat medium measured by the pressure measuring device (P2), the third control valve (V3) maintains the gaseous state even after the second heat medium passes through the second heat exchanger (102). Adjust the pressure of the second heat medium.

That is, if the heat exchange is performed in the second heat exchanger 102 in a state where the pressure of the second heat medium is too high, it may change to a liquid phase before reaching the second expander 302, and power generation may be impossible, and the first heat exchanger ( 101), the efficiency can be very low during heat exchange with liquefied gas.

The second heat medium primarily vaporized by the second heater 202 is vaporized by exchanging heat with the heat source of the exhaust gas in the second vaporizer 930 . The second heat medium vaporized in the second vaporizer 930 is expanded by the second expander 302 . The second heat medium passed through the second expander 302 is stored in the suction drum 110 after being liquefied through the first heat exchanger 101 in a gas-liquid state.

In this way, the liquefied gas regasification system 100 performing the above process can improve the regasification efficiency and performance of liquefied gas through heat exchange with a heat medium without using existing seawater.

In addition, the force generated while expanding after the heat exchange process between the liquefied gas and the heat medium or between the heat medium and the heat source can be effectively recovered through electricity generation.

The above description is merely an example of the technical idea of the present invention, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed according to the claims below, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

100: liquefied gas regasification system
12: storage tank 14: demand place
101 to 103: heat exchanger 110: suction drum
112: pressure pump 201, 202: heater
301 to 304: expander G1 to G4: generator
L10: regasification line L11: first circulation line
L12: 2nd circulation line P1, P2: pressure measuring device
T1~T3: Temperature sensor V1~V7: Control valve
910: exhaust gas line 912: main line
914: first branch line 916: second branch line
920: first vaporizer 930: second vaporizer
990: control unit

Claims (12)

A first heat exchanger and a second heat exchanger sequentially performing heat exchange between the liquefied gas supplied from the storage tank and the heat medium;
a regasification line supplying the liquefied gas vaporized through the first heat exchanger and the second heat exchanger to a customer;
a first circulation line for circulating a first heat medium among heat mediums supplied from the suction drum to the suction drum through the first heat exchanger;
a second circulation line branched off from the first circulation line to circulate a second heat medium among the heat medium to the suction drum through the second heat exchanger and the first heat exchanger sequentially;
an exhaust gas line having a preheater for preheating a heat source that exchanges heat with the first heat medium and the second heat medium by using waste heat of the exhaust gas generated from the demand side;
a first heater provided in the first circulation line and exchanging heat between the heat source preheated in the preheater and the first heat medium;
a first expander that expands the first heat medium heated by the first heater and sends it to the first heat exchanger;
and a first vaporizer provided between the first heater and the first expander and vaporizing the first heating medium using the exhaust gas supplied from the exhaust gas line. According to claim 1,
The liquefied gas regasification system further comprises a first generator connected to the first expander to produce electricity. delete According to claim 1,
The liquefied gas regasification system further includes a second heater provided in the second circulation line and exchanging heat between the heat source preheated in the preheater and the second heat medium and sending the second heat exchanger to the second heat exchanger. According to claim 4,
a second expander provided at a rear end of the second heat exchanger in the second circulation line to expand the second heat medium passing through the second heat exchanger and send it to the first heat exchanger; and
A liquefied gas regasification system further comprising a second generator connected to the second expander to produce electricity. According to claim 5,
and a second vaporizer disposed between the second heater and the second expander to vaporize the second heat medium using waste heat of the exhaust gas supplied from the exhaust gas line. According to claim 1,
a pressure pump for pressurizing the heat medium supplied from the suction drum;
Based on at least one of the internal pressure of the suction drum, the temperature of the heat medium supplied from the suction drum to the pressure pump, and the temperature of the first heat medium that has passed through the first heat exchanger through the first circulation line, the first circulation The liquefied gas regasification system further comprises a first control valve for adjusting the supply amount and the degree of pressure reduction of the first heating medium supplied to the first heater through the line. According to claim 5,
A second control valve for adjusting the supply amount of the second heat medium supplied to the second heater through the second circulation line based on the temperature of the vaporized liquefied gas that has passed through the second heat exchanger of the regasification line. Liquefied gas regasification system. According to claim 5,
A pressure meter provided at a rear end of the second heater in the second circulation line and measuring a pressure of the second heat medium vaporized by the second heater;
It is provided between the pressure measuring device and the second heat exchanger, and based on the measured pressure of the second heat medium, the pressure of the second heat medium is maintained in a gaseous state even after the second heat medium passes through the second heat exchanger. A liquefied gas regasification system further comprising a third control valve for controlling. According to claim 1,
a third expander provided between the first heat exchanger and the second heat exchanger of the regasification line and primarily expanding the liquefied gas vaporized by the first heat exchanger;
A third generator connected to the third expander to produce electricity;
a fourth expander provided at a rear end of the second heat exchanger in the regasification line and secondarily expanding the vaporized liquefied gas heated by the second heat exchanger; and
A liquefied gas regasification system further comprising a fourth generator connected to the fourth expander to produce electricity. According to claim 10,
and a third heat exchanger for performing heat exchange between the vaporized liquefied gas secondarily expanded by the fourth expander and a heat source to adjust a temperature according to a fuel supply condition of the customer. A vessel comprising the liquefied gas regasification system according to any one of claims 1, 2, and 4 to 11.

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