KR101185872B1 - Floating structure with LNG regasification unit - Google Patents

Abstract

The present invention relates to a floating structure.
According to an aspect of the invention, the main body; A storage tank installed in the main body and storing liquefied natural gas; A boiler for generating steam by burning the boil-off gas generated in the storage tank; A regasification line for regasifying the liquefied natural gas supplied from the storage tank and supplying it to a demand destination; A first circulation line intersecting the regasification line and through which a thermal medium fluid circulates; A second circulation line connected to a ballast tank in which seawater is stored and intersecting the regasification line; A first heat exchanger installed at an intersection point of the regasification line and the first circulation line, the first heat exchanger exchanging liquefied natural gas with a heat medium fluid to regasify it into natural gas; A second heat exchanger installed at an intersection point of the regasification line and the second circulation line and heating the natural gas discharged from the first heat exchanger by heat exchange with seawater; A third heat exchanger provided in the first circulation line and heat exchanging steam supplied from the boiler with a heat medium fluid to heat the heat medium fluid flowing into the first heat exchanger; A fourth heat exchanger provided in the second circulation line and disposed between the ballast tank and the second heat exchanger, and configured to heat seawater by heat-exchanging seawater with condensate discharged from the third heat exchanger; And a fifth heat exchanger provided in the second circulation line and disposed between the ballast tank and the second heat exchanger, the fifth heat exchanger heating the seawater by exchanging fresh water and seawater used to cool the heat generating engine. A structure can be provided.

Description

Floating structure with LNG regasification unit

The present invention relates to a floating structure.

Liquefied Natural Gas (LNG) is obtained by liquefying natural gas (methane) based on methane (hereinafter referred to as "NG") by cooling it to about -162 ℃. Colorless, transparent liquid with a volume of about 1/600 compared to NG. Therefore, when liquefied and transported to LNG during the transfer of NG can be very efficiently transported, for example, an LNG carrier that can transport (transport) LNG to the sea is used.

In recent years, LNG regasification apparatuses installed in liquefied natural gas carriers or floating structures, regasifying liquefied natural gas with natural gas at sea, and supplying natural gas obtained through regasification to the land have been used.

For example, liquefied natural gas carriers include liquefied natural gas carriers, LNG liquefied natural gas regasification vessels, LNG liquefied natural gas floating storage and regasification units, and LNG liquefied natural gas floating It can be installed on floating structures including ships and offshore structures such as production, storage and off-loading.

As a method of regasifying liquefied natural gas to natural gas in the regasification apparatus, a method of using seawater or a method of using a thermal medium such as glycol water may be used.

Recently, an indirect heating method is used in which the AL medium fluid is heated with steam supplied from a boiler and then heat exchanged between the heat medium fluid and the liquefied natural gas.

However, the above conventional technology has the following problems.

There is a problem that the amount of heat contained in the steam and condensate after heating the heat medium fluid is wasted.

In addition, since the liquefied natural gas is regasified by only one heat exchange with the heat medium fluid, there is a problem that it is difficult to control the temperature of the natural gas supplied to the demand destination.

Embodiments of the present invention are to provide a floating structure that can efficiently utilize energy.

In addition, to provide a floating structure that can facilitate the temperature control of the natural gas supplied to the demand destination.

According to an aspect of the invention, the main body; A storage tank installed in the main body and storing liquefied natural gas; A boiler for generating steam by burning the boil-off gas generated in the storage tank; A regasification line for regasifying the liquefied natural gas supplied from the storage tank and supplying it to a demand destination; A first circulation line intersecting the regasification line and through which a thermal medium fluid circulates; A second circulation line connected to a ballast tank in which seawater is stored and intersecting the regasification line; A first heat exchanger installed at an intersection point of the regasification line and the first circulation line, the first heat exchanger exchanging liquefied natural gas with a heat medium fluid to regasify it into natural gas; A second heat exchanger installed at an intersection point of the regasification line and the second circulation line and heating the natural gas discharged from the first heat exchanger by heat exchange with seawater; A third heat exchanger provided in the first circulation line and heat exchanging steam supplied from the boiler with a heat medium fluid to heat the heat medium fluid flowing into the first heat exchanger; A fourth heat exchanger provided in the second circulation line and disposed between the ballast tank and the second heat exchanger, and configured to heat seawater by heat-exchanging seawater with condensate discharged from the third heat exchanger; And a fifth heat exchanger provided in the second circulation line and disposed between the ballast tank and the second heat exchanger, the fifth heat exchanger heating the seawater by exchanging fresh water and seawater used to cool the heat generating engine. A structure can be provided.

In addition, the fourth heat exchanger may provide a floating structure, which is disposed at a rear end of the fifth heat exchanger.

In addition, the second circulation line may provide a floating structure characterized in that the bypass line bypassing the ballast tank is formed.

In addition, the second circulation line may provide a floating structure characterized in that the bypass line bypassing the second heat exchanger is formed.

In addition, the thermal medium fluid may provide a floating structure, characterized in that the evaporative fluid to maintain the evaporation state at room temperature.

Embodiments of the present invention can not only save the energy required for the heating of seawater by using the steam generated in the boiler for heating the heat medium fluid and seawater, but also can effectively supply natural gas to the demand source.

In addition, the temperature of the natural gas supplied to the demand can be easily controlled by distilling the liquefied natural gas into two and regasifying and heating.

1 is a view showing the structure of a floating structure according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the 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 view showing the structure of a floating structure according to an embodiment of the present invention.

Referring to FIG. 1, a floating structure 10 according to an exemplary embodiment of the present invention includes a main body (not shown), a storage installed on the main body and storing liquefied natural gas (hereinafter referred to as “LNG”). Tank 210, boiler 250 for generating steam by using the boiled-off gas (boiled-off gas) generated in the storage tank 210, ballast tank 240, the ballast number is stored, the storage tank 210 The gas supplied from the regasification and heating may include a regasification line 101 to supply to the demand destination (300).

The floating structure 10 may be a vessel having an LNG storage tank including an LNG carrier, and also an LNG liquefied natural gas regasification vessel (RV RV), an LNG liquefied natural gas floating storage and regasification unit (FSRU), an LNG FPSO ( It may include any structure that can be equipped with an LNG regasification unit and float at sea, such as liquefied natural gas floating, production, storage and off-loading.

The regasification line 101 includes an LNG pump 171 for pumping LNG from the storage tank 210, a first heat exchanger 110 for regasifying LNG using a heat medium fluid, and regasified NG. A second heat exchanger 120 may be provided for heating to the temperature required by the customer 300.

The first heat exchanger 110 heat exchanges LNG with a heat medium fluid circulating along the first circulation line 102 to regasify LNG to natural gas (hereinafter, referred to as “NG”). That is, in the first heat exchanger 110, a phase change of LNG occurs, and LNG is regasified to NG. The first circulation line 102 is formed to intersect the regasification line 101, and the first heat exchanger 110 is an intersection point of the regasification line 101 and the first circulation line 102. Can be installed on

The heat medium fluid circulating in the first circulation line 102 may be an evaporative fluid that maintains a gaseous state at room temperature such as propane and ammonia. Here, the first circulation line 102 may be referred to as a heat medium fluid circulation line as a passage through which the heat medium fluid circulates.

The first circulation line 102 may be provided with a first circulation pump 172 for circulating a heat medium fluid and a third heat exchanger 130 for heating the heat medium fluid. The third heat exchanger 130 heats the heat medium fluid with the steam supplied from the boiler 250, and the heated heat medium fluid is heated along the first circulation line 102. 110).

The steam generated in the boiler 250 is introduced into the third heat exchanger 130 along the steam circulation line 103. Steam may be partially condensed while passing through the third heat exchanger 130, and after passing through the third heat exchanger 130, the fourth heat exchanger 140 provided in the second circulation line 104 to be described later. It can be moved to the fresh water tank 220 through.

The boiler 250 may burn the BOG supplied through the BOG supply line 211 to heat the fresh water supplied from the fresh water tank 220 to generate steam, and the boiler 250 and the fresh water tank 220. ) May be provided with a fresh water supply pump (173).

The second heat exchanger 120 may heat the NG regasified in the first heat exchanger 110 to a desired temperature. The second heat exchanger 120 is connected to the second circulation line 104 through which the seawater flows through the ballast tank 240, and heat exchanges NG and seawater circulating through the second circulation line 104 to NG. Can be heated to the desired temperature. That is, the second circulation line 104 is formed to intersect the regasification line 101, and the second heat exchanger 120 is formed of the regasification line 101 and the second circulation line 104. Can be provided at the intersection point.

The ballast tank 240 may serve as a reservoir of seawater circulating the second circulation line 104.

The second circulation line 104 is pumped by the second circulation pump 174 and the second circulation pump 174 to circulate the second circulation line 104 by pumping seawater from the ballast tank 240. The fifth heat exchanger 150 for heat-exchanging the fresh seawater with fresh water circulating in the cooling line 105 to be described later, and the seawater heated primarily by the fifth heat exchanger 150 to the third heat exchanger 130. And a fourth heat exchanger 140 that heats second heat by exchanging heat with steam that has passed through). Here, the order of the fourth heat exchanger 140 and the fifth heat exchanger 150 can be changed, and the seawater is heated twice according to the temperatures of the steam circulation line 130 and the cooling line 105. It may be appropriately changed to be supplied to the second heat exchanger 120 afterwards. In other words, a higher temperature line and heat exchanger can be arranged on the back side.

In addition, the second circulation line 104 may be referred to as a seawater circulation line as a passage through which seawater is circulated.

As described above, since LNG is primarily regasified in the first heat exchanger 110, NG may be heated in the second heat exchanger 120, and thus seawater flowing into the second heat exchanger 120 may be used. The temperature of the NG discharged from the second heat exchanger 120 can be accurately controlled by adjusting the temperature, flow rate, and the like. In particular, the temperature of the seawater supplied to the second heat exchanger 120 can also be accurately adjusted by heating twice by the fifth heat exchanger 150 and the fourth heat exchanger 140. Temperature control of the NG discharged from the machine 120 can be made more easily.

On the other hand, the fifth heat exchanger 150 may exchange heat and fresh water for cooling the heat generating engine 230, such as the engine, electronic equipment provided in the main body.

In detail, the fifth heat exchanger 150 may be connected to a cooling line 105 that passes through the heat generating engine 230 and cools the fresh water heated through the heat generating engine 230. 150 may be arranged to be supplied.

The cooling line 105 may be provided with a fresh water circulation pump 175 for circulating fresh water, and may be connected to the fresh water tank 220 in which fresh water is stored. The fresh water stored in the fresh water tank 220 is pumped by the fresh water circulation pump 175 to sequentially pass through the heat generating engine 230 and the fifth heat exchanger 150 and then back to the fresh water tank 220. You can return. In this embodiment, the boiler 250 and the cooling line 105 has been described as sharing one fresh water tank, but the spirit of the present invention is not limited thereto.

As such, the energy consumption of the floating structure 10 may be reduced by recycling waste heat contained in the fresh water used for cooling the heat generator 230 to the heating of sea water.

Meanwhile, steam or condensed water having passed through the third heat exchanger 130 may be directly supplied to the fresh water tank 220 without passing through the fourth heat exchanger 140. Pass line 103 ′ may be formed.

In addition, a bypass line 104 ′ may be formed in the second circulation line 104 to allow seawater passing through the fourth heat exchanger 140 to bypass the second heat exchanger 120. . The bypass line 104 ′ may be controlled to open or close the seawater to bypass the second heat exchanger 120 when LNG is sufficiently heated after the LNG is regasified in the first heat exchanger 110. have.

In addition, the second circulation line 104 may be supplied directly to the fifth heat exchanger 150 without being introduced into the ballast tank 240 seawater deprived of heat in the NG in the second heat exchanger 120. Bypass line 104 "may be formed to bypass the ballast tank 240 so that, for example, when the seawater is cooled in the second heat exchanger 120 more than expected, The seawater cooled by the second heat exchanger 120 may be directly supplied to the fifth heat exchanger 150.

As described above as a specific embodiment of the floating structure according to the embodiment of the present invention, but this is only an example, the present invention is not limited to this, should be construed as having the broadest range in accordance with the basic idea disclosed herein. do. Skilled artisans may implement a pattern of features that are not described in a combinatorial and / or permutational manner with the disclosed embodiments, but this is not to depart from the scope of the present invention. It will be apparent to those skilled in the art that various changes and modifications may be readily made without departing from the spirit and scope of the invention as defined by the appended claims.

10: floating structure 210: storage tank
220: fresh water tank 230: heat generating engine
240: ballast tank 250: boiler
101: regasification line 102: the first circulation line
103: steam circulation line 104: second circulation line
105: cooling line 110: first heat exchanger
120: second heat exchanger 130: third heat exchanger
140: fourth heat exchanger 150: fifth heat exchanger
171, 172, 173, 174, 175: Pump

Claims (5)

main body;
A storage tank installed in the main body and storing liquefied natural gas;
A boiler for generating steam by burning the boil-off gas generated in the storage tank;
A regasification line for regasifying the liquefied natural gas supplied from the storage tank and supplying it to a demand destination;
A first circulation line intersecting the regasification line and through which a thermal medium fluid circulates;
A second circulation line connected to a ballast tank in which seawater is stored and intersecting the regasification line;
A first heat exchanger installed at an intersection point of the regasification line and the first circulation line, the first heat exchanger exchanging liquefied natural gas with a heat medium fluid to regasify it into natural gas;
A second heat exchanger installed at an intersection point of the regasification line and the second circulation line and heating the natural gas discharged from the first heat exchanger by heat exchange with seawater;
A third heat exchanger provided in the first circulation line and heat exchanging steam supplied from the boiler with a heat medium fluid to heat the heat medium fluid flowing into the first heat exchanger;
A fourth heat exchanger provided in the second circulation line and disposed between the ballast tank and the second heat exchanger, and configured to heat seawater by heat-exchanging seawater with condensate discharged from the third heat exchanger; And
The floating structure is provided in the second circulation line, and disposed between the ballast tank and the second heat exchanger, and includes a fifth heat exchanger that heats the seawater by exchanging fresh water and seawater used to cool the heat generating engine. . The method of claim 1,
And said fourth heat exchanger is disposed at a rear end of said fifth heat exchanger. The method of claim 1,
Floating structure, characterized in that the bypass line for bypassing the ballast tank is formed in the second circulation line. The method according to any one of claims 1 to 3,
And the bypass line bypassing the second heat exchanger is formed in the second circulation line. The method of claim 1,
The thermal medium fluid is a floating structure, characterized in that the evaporative fluid to maintain the evaporation state at room temperature.

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