• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a method for reliquefaction of boil-off gas generated by vaporization due to external heat in a storage tank of an LNG carrier that stores and transports LNG liquefied at a cryogenic state. According to the present invention, in a storage tank in which cryogenic LNG is stored and vaporized evaporated gas is generated due to heat transferred from the outside, the spray cooler 20 is connected to the storage tank 10 to cool the temperature of the boiled gas first, A reliquefaction compressor 30 connected to the spray cooler 20 to pressurize the first cooled evaporation gas, an evaporation gas condenser 40 connected to the reliquefaction compressor 30 to liquefy the pressurized evaporated gas, and A second valve 110 connected to the boil-off condenser 40 to transfer a portion of the liquefied boil-off gas to the spray cooler 20 and a first valve 100 connected to the boil-off gas condenser 40. A re-mixer 120 for mixing and cooling the liquefied liquefied evaporated gas with the cryogenic LNG stored in the storage tank 10 and a re-liquid connected to the re-mixer 120 to store the liquefied evaporated gas in the storage tank 10. Recovery line (130 ), A strip spray pump 140 for transporting the LNG stored in the lower portion of the storage tank 10 to the remixer 120 through the third valve 150.
    公开号:KR20030073974A
    申请号:KR1020020013772
    申请日:2002-03-14
    公开日:2003-09-19
    发明作者:배재욱；박성도；이정희；김은석；박봉운
    申请人:대우조선해양 주식회사；
    IPC主号:
    专利说明:

    Boil off gas liquefaction method and system assembly of Liquefied natural gas carrier
    [14] The present invention relates to a reliquefaction system of boil off gas (BOG) generated from a storage tank due to the amount of heat transferred from the outside during operation of a natural gas carrier, and more particularly, storage of liquefied natural gas during transportation. The evaporated gas generated in the tank is liquefied and recovered in the storage tank by using the evaporated gas reliquefaction system and the nitrogen cooling system to remove the amount of evaporated gas consumed, and the main engine of the vessel is a boiler using liquefied natural gas. The present invention relates to a boil-off gas reliquefaction system of a natural gas carrier that can reduce the cost of operating a ship by replacing it with an internal combustion engine using ship oil.
    [15] Generally, natural gas carriers (hereinafter referred to as LNG carriers) store liquefied natural gas (LNG, Liquefied Natural Gas, hereinafter referred to as LNG) by liquefying gaseous natural gas at -163 ° C. It is a ship to transport.
    [16] The storage tank of the LNG carrier is made of aluminum only because of the property of maintaining rigidity even at extremely low temperatures.
    [17] There are two types of storage tank formation methods of the LNG carrier, a spherical independent tank type and a membrane type (aka diaphragm type), and a spherical independent tank type is named Moss after the developer's name, and the membrane type is Technigas. It's called Technigas and Gas Transport.
    [18] The spherical independent tank method is a method of manufacturing a ball-shaped tank having a diameter of 40 m and then fixing it to the ship by making a ball-shaped tank having a diameter of 40 m with aluminum. It has the advantage of low stress concentration point in manufacturing or use.
    [19] However, since the ground height of the vessel is increased and receives a lot of wind during the operation of the vessel, the steering and mooring mooring device has to be strengthened.
    [20] The membrane method is a good way to keep warm on the inner wall of the cargo hold of the ship without making a separate tank, and the heat insulating surface is sealed with a thin metal plate, while the hull is reduced to an optimized size and the installation of special equipment is unnecessary It has the disadvantages that many stress concentration points are used during fabrication or use, and damage factors such as stranding in case of collision outside the hull are to be avoided.
    [21] The difference between the membrane type technigas formula and the gas transport formula lies in the construction and construction method of the insulation.
    [22] In the LNG carrier, external heat, such as direct sunlight from the sun, is transmitted to the storage tank during operation, and at this time, an evaporation gas is generated in which the LNG is partially vaporized in the storage tank.
    [23] The amount of evaporated gas evaporated in the storage tank varies depending on winter and summer, but on average, about 0.15% of the total amount of stored gas is generated in one day.
    [24] The boil-off gas is discharged through the safety valve when the safety pressure (0.25 bar) or more is set. In the existing LNG carrier, the total pressure of the liquefied natural gas evaporation is used as the fuel for the boiler and the operation of the gas storage tank. It remains stable.
    [25] However, when comparing LNG and heavy fuel oil as a propulsion fuel of a ship, since the price of the LNG is high, the operating cost of the ship is greatly consumed.
    [26] In order to solve the problems described above, the object of the present invention is to re-liquefy the evaporated gas of LNG generated in the storage tank during the operation of the LNG vessel to recover the storage tank by removing the amount of loss generated during transportation of LNG In order to reduce the operating cost of the ship, the main engine fuel of the ship is changed to the ship oil.
    [27] In order to achieve the object of the present invention as described above, an evaporative gas condenser, a remixer and a regeneration liquid recovery line equipped with a nitrogen cooling system are used to cool and compress the evaporated gas primarily by using a spray cooler and a reliquefaction two-stage compressor. The present invention provides an LNG carrier liquefaction system for storing liquefied vaporized gas in a storage tank by reliquefying gaseous vaporized gas using a strip spray pump.
    [1] 1 is a piping diagram showing a boil-off gas reliquefaction system apparatus of the LNG carrier according to an embodiment of the present invention.
    [2] 2 is a flow chart showing a procedure of the method for re-liquefying the boil-off gas of the LNG carrier according to an embodiment of the present invention.
    [3] <Explanation of symbols for the main parts of the drawings>
    [4] 10: storage tank 20: spray cooler
    [5] 30: reliquefaction compressor 40: boil off gas condenser
    [6] 50: nitrogen heat exchanger 60: first compressor
    [7] 62: second compressor 66: third compressor
    [8] 70: electric motor 80: first intermediate cooler
    [9] 82: second intermediate cooler 84: third intermediate cooler
    [10] 90 expansion turbine 100 first valve
    [11] 110: second valve 120: remixer
    [12] 130: liquid recovery line 140: strip spray pump
    [13] 150: third valve
    [28] Hereinafter, a boil-off gas reliquefaction system of an LNG carrier according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
    [29] 1 is a piping diagram showing the evaporation gas re-liquefaction system of the LNG carrier according to an embodiment of the present invention, Figure 2 is a flow chart showing the procedure of the method for re-liquefied boil-off gas of the LNG carrier according to an embodiment of the present invention. Flowchart.
    [30] As shown in the figure, LNG liquefied, stored and transported in a cryogenic state is vaporized in the storage tank 10 due to external heat such as direct sunlight of the sun during the operation of the vessel, and vaporized in the storage tank 10. When the evaporated gas becomes higher than the set safety pressure (0.25 bar), the safety valve is operated and discharged. (ST 10)
    [31] The temperature of the boil-off gas discharged through the safety valve is about -140 ° C.
    [32] The high temperature low pressure evaporated gas discharged through the safety valve is first cooled by passing through the spray cooler 20 into which the evaporated gas liquefied to cryogenic temperature is injected. (ST 20)
    [33] By passing through the spray cooler 20, the vaporized gaseous gas of which the temperature is first cooled is passed through two reliquefaction compressors 30, and the pressure is increased to about 6 bar. (ST 30)
    [34] The low temperature high pressure evaporated gas passing through the reliquefaction compressor 30 is liquefied into a low temperature low pressure liquid state while passing through the evaporative gas condenser 40 to which the nitrogen cooling system is attached.
    [35] Referring to the flow of the boil-off gas in the boil-off gas condenser 40, the low-temperature, high-pressure boil-off gas passing through the reliquefaction compressor 30 is transferred to the nitrogen heat exchanger 50 using the high-pressure nitrogen gas 2 The temperature is cooled by car (ST 40).
    [36] By passing through the nitrogen heat exchanger (50), the boil-off gas which is secondarily cooled is divided into three first, second and third compressors (60), 62 and 64 and three first, second and third intermediate coolers. By passing through (80) (82) (84) in order, the temperature is further lowered and the pressure is increased. (ST 50) (ST 60) (ST 70) (ST 80) (ST 90) (ST 100)
    [37] The low-temperature, high-pressure evaporative gas that passes through the three-stage compressor and the three-stage intermediate cooler in turn is transferred to the nitrogen heat exchanger 50 to cool the temperature. (ST 110)
    [38] The low-temperature, high-pressure evaporative gas passing through the nitrogen heat exchanger 50 passes through the expansion turbine 90 to become low-temperature low-pressure, thereby causing a phase change from gas to liquid.
    [39] The expansion turbine 90 and three compressors 60, 62, 64 are driven using an electric motor 70.
    [40] A portion of the boil-off gas liquefied by passing through the boil-off gas condenser 40 is transferred to the spray cooler 20 through the second valve 110 and the rest to the remixer 120 through the first valve 100. (ST 140)
    [41] The boil-off gas transferred to the spray cooler 20 is injected to cool the temperature of the high-temperature low-pressure boil-off gas discharged through the safety valve from the storage tank 10 firstly. (ST 130)
    [42] In the remixer 120, the liquefied boil-off gas is mixed with the cryogenic LNG stored in the storage tank 10 and cooled to -163 ° C. (ST 150)
    [43] The liquefied boil-off gas passing through the remixer 120 is injected to the lower side of the storage tank 10 through the re-liquid recovery line 130. (ST 160)
    [44] The strip spray pump 140 is mounted on the lower portion of the storage tank 10 to transfer LNG stored in the storage tank 10 to the remixer 120 through the third valve 150. The LNG is mixed with the liquefied boil-off gas introduced into the remixer 120.
    [45] According to the present invention having the above configuration, there is no loss of stored LNG during the operation of the LNG carrier, and since the main engine is replaced with a diesel type using marine oil in the boiler using the boil-off gas, the operation cost of the vessel is reduced.
    权利要求:
    Claims (3)
    [1" claim-type="Currently amended] In the method for treating boil-off gas generated by vaporization due to external heat in a storage tank of an LNG carrier that stores and transports LNG liquefied at a cryogenic state, the boil-off gas vaporized in the storage tank 10 has been set to safety. When the pressure (0.25 bar) or more is the step of operating the safety valve is discharged (ST 10), the step of reducing the temperature of the first temperature while the high-temperature low-pressure evaporated gas discharged through the safety valve passes through the spray cooler 20 ( ST 20), the step of increasing the pressure as the boil-off gas passing through the spray cooler 20 passes through the two reliquefaction compressors (ST 30), and the low temperature and high pressure through the reliquefaction compressor 30 The boil-off gas is transferred to the nitrogen heat exchanger 50 using the nitrogen gas at high pressure, and the temperature is lowered secondly (ST 40). 2, the third compressor (60) (62) (64) and three first, second and third intermediate coolers 80, 82 and 84 in order to pass temperature further down and pressure increase (ST 50) (ST 60) (ST 70) (ST 80) (ST 90) (ST 100), the low-temperature and high-pressure evaporative gas passed through the three-stage compressor and the three-stage intermediate cooler in order to lower the temperature once again to reduce the temperature In the step (ST 110) transferred to the heat exchanger (50), the low-temperature, high-pressure evaporative gas passing through the nitrogen heat exchanger (50) passes through the expansion turbine (90) to become low-temperature low-pressure, thereby causing a phase change from gas to liquid. In step ST 120, a part of the liquefied boil-off gas passing through the boil-off gas condenser 40 is transferred to the spray cooler 20 through the second valve 110 and through the safety valve of the storage tank 10. Cooling the discharged high-temperature low-pressure evaporated gas (ST 130) and the rest is transferred to the re-mixer 120 through the first valve 100 (ST 140), the liquefied boil-off gas is mixed with the cryogenic LNG stored in the storage tank 10 in the remixer 120 (ST 150), the liquefied boil-off gas passed through the remixer 120 is recovered Boiler gas reliquefaction method of the LNG carrier characterized in that it comprises a step (ST 160) is injected into the lower side of the storage tank (10) through the line (130).
    [2" claim-type="Currently amended] In the method of reliquefaction of the boil-off gas generated by vaporization due to external heat in the storage tank of the LNG carrier in which the cryogenic LNG is stored, the storage tank (10) for generating and discharge the boil-off gas vaporized by the LNG stored at cryogenic temperature, A spray cooler 20 connected to the storage tank 10 to reduce the temperature of the discharged boil-off gas first, and a reliquefaction compressor connected to the spray cooler 20 to increase the pressure of the first cooled boil-off gas ( 30), an evaporation gas condenser 40 connected to the reliquefaction compressor 30 to liquefy the high-pressure evaporation gas in a liquid state, and a portion of the evaporated gas liquefied connected to the evaporation gas condenser 40 to the spray cooler The liquefied boil-off gas transferred through the second valve 110 and the first valve 100 connected to the boil-off condenser 40 is mixed with the cryogenic LNG stored in the storage tank 10. Re-mixer 120 for cooling, the re-liquid recovery line 130 is connected to the re-mixer 120 to inject the liquefied evaporated gas to the lower side of the storage tank 10, the lower portion of the storage tank 10 Evaporation gas re-liquefaction system apparatus of the LNG carrier, characterized in that consisting of a strip spray pump 140 for transporting the LNG stored in the installation via the third valve (150) to the remixer (120).
    [3" claim-type="Currently amended] The nitrogen heat exchanger (50) of claim 2, wherein the boil-off gas condenser (40) is connected to the reliquefaction compressor (30) to lower the temperature of the boil-off gas by using nitrogen gas at a high pressure. A first compressor (60) connected to the heat exchanger (50) to increase the pressure of the cooled boil-off gas, and a first intermediate (60) connected to the first compressor (60) to cool the temperature of the boiled gas to which the pressure is increased; A cooler 80, a second compressor 62 connected to the first intermediate cooler 80, a second intermediate cooler 82 connected to the second compressor 62, and a second intermediate cooler 82 connected to the second intermediate cooler 82. A third compressor (64), a third intermediate cooler (84) connected to the third compressor (64), an expansion turbine (90) connected to the nitrogen heat exchanger (50) so that the boil-off gas changes from gas to liquid, With the electric motor 70 to drive the expansion turbine 90 and the first, second, third compressors 60, 62, 64 Boil-off gas re-liquefaction apparatus system of an LNG carrier, characterized in that the sex.
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    同族专利:
    公开号 | 公开日
    KR100441857B1|2004-07-27|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2002-03-14|Application filed by 대우조선해양 주식회사
    2002-03-14|Priority to KR20020013772A
    2003-09-19|Publication of KR20030073974A
    2004-07-27|Application granted
    2004-07-27|Publication of KR100441857B1
    优先权:
    申请号 | 申请日 | 专利标题
    KR20020013772A|KR100441857B1|2002-03-14|2002-03-14|Boil off gas rel iquefaction method and system assembly of Liquefied natural gas carrier|
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