KR20150103207A - Liquefied-gas vaporization method, liquefied-gas vaporization system, offshore floating-body structure provided with said system - Google Patents

Abstract

The boil-off gas in the liquefied gas tank is effectively used by economical construction of the liquefied gas by the compact construction without taking seawater. A liquefied gas vaporization system (1) includes a liquefied gas vaporization unit (2) for vaporizing liquefied gas stored in a liquefied gas tank by heat exchange with a heating medium, a boil-off gas combustion unit (3) for combusting a boil- A turbine 4 rotationally driven by the energy of the combustion gas after being burned in the boil-off gas combustion section 3, and a combustion gas exhausted from the turbine 4 as the heat medium, 2 for supplying the combustion gas to the combustion chamber. The boil-off gas combustion section 3 is a pressurized combustor which is supplied with compressed air to pressurize and burn the boil-off gas. The boil-off gas combustion section 3 generates compressed air coaxially with the turbine 4, And a compressor (5) for supplying the refrigerant to the compressor (3).

Description

FIELD OF THE INVENTION [0001] The present invention relates to a liquefied gas vaporization method, a liquefied gas vaporization system, and a fluidized-

The present invention relates to a liquefied gas vaporization method, a liquefied gas vaporization system, and a marine fluidic structure equipped with the same

Liquefied gas carrier (LNG) that carries liquefied gas such as LNG, or liquefied gas introduction base (FSRU, etc.) that accepts liquefied gas from liquefied gas carrier and stores it, and supplies it to city gas line , And a liquefied gas vaporization system for vaporizing (liquefying) the liquefied gas.

In such a liquefied gas vaporization system, as a method of vaporizing liquefied gas, a number of schemes have been devised, in which a liquefied gas is flowed into an open rack-shaped vaporizer, seawater flows outside the vaporizer, Gas is heated and vaporized. However, it has been difficult to apply it in the sea area (Europe, North America, etc.) where water intake and discharge of seawater are limited for the preservation of the marine environment.

In the cold sea area, seawater may freeze or the temperature may be too low for heating water, and seawater intake itself may not be possible.

As a result, for example, as described in Patent Documents 1 and 2, it is possible to circulate the heated seawater as a heating medium in a closed loop form without discharging the seawater out of the system (outside the system) Thereby vaporizing the liquefied gas.

There is one in which the liquefied gas is vaporized by blowing the air heated by the heater to the inside of the liquefied gas vaporization unit using an air blower as described in Patent Document 3.

On the other hand, in the interior of the liquefied gas tank, the liquefied gas is vaporized by natural heat from the outside or the like, and a boil-off gas (vaporized gas) is generated. It is necessary to treat the boil-off gas so that the pressure in the tank does not exceed the design pressure by the boil-off gas. Conventionally, boil-off gas is supplied to the propulsion engine or the power generation engine of the liquefied gas carrier, , Or burned by a gas burner.

Patent Document 1: JP-A-2010-58772 Patent Document 2: JP-A-2012-17030 Patent Document 3: JP-A-2002-39695

However, as described above, conventionally, since the heating medium such as seawater or air is heated and the liquefied gas is vaporized by the heating medium, a large amount of energy is required, which is uneconomical.

In addition, a large-scale gas generation facility for heating a heating medium, an additional facility such as a boiler facility and a large-sized blower are required, and the cost of equipment investment is increased, and a large space is required for installing these facilities. Since the space for the liquefied gas carrier is very limited, it is difficult to install them.

A method of burning the boiling off gas and vaporizing the liquefied gas by using the heat of the combustion gas may be considered. However, if this combustion gas is directly supplied to the liquefied gas vaporization unit, There is a problem that the liquefied gas vaporization unit is broken due to a large temperature difference and the replacement frequency is increased due to a short life span in high temperature parts. There is also a method of diluting the combustion gas with a large amount of air for the complete discharge, but there is a problem in terms of power, facility cost, and compactness of the blower for supplying the dilution air.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a liquefied gas vaporization apparatus capable of economically vaporizing liquefied gas by effectively utilizing boiling off gas in a liquefied gas tank, A liquefied gas vaporization system, and a maritime fluidic structure equipped with the liquefied gas vaporization system.

In order to achieve the above object, the present invention provides the following means.

A liquefied gas vaporization method according to an aspect of the present invention is a liquefied gas vaporization method for promoting vaporization by exchanging liquefied gas stored in a liquefied gas tank with a heating medium to burn boiling off gas generated in the liquefied gas tank, The turbine is driven by the energy of the combustion gas, and the combustion gas after the turbine drive is used as the heating medium, thereby promoting vaporization of the liquefied gas by the heat.

According to this liquefied gas vaporization method, the combustion gas after burning the boiling off gas generated in the liquefied gas tank expands by driving the turbine, and the temperature is lowered. By the heat of the combustion gas that has been expanded and lowered in temperature, vaporization of the liquefied gas is promoted. A predetermined operation can be performed on the driven turbine.

Since the combustion gas after passing through the turbine expands and the volume increases and the temperature decreases, for example, the combustion gas after the boil-off gas is combusted is supplied to the liquefied gas vaporization unit as it is without passing through the turbine, It is possible to reduce the temperature difference with the liquefied gas vaporization unit. Thus, breakage of the liquefied gas vaporization unit and deterioration of durability can be suppressed.

Since the combustion gas after passing through the turbine maintains a high pressure, it is possible to supply the combustion gas to the liquefied gas vaporization unit without forcibly sending it by using a blower or the like, thereby simplifying the structure of the liquefied gas vaporization system. The liquefied gas can be efficiently vaporized while effectively using the boil-off gas in the liquefied gas tank.

As described above, since the liquefied gas can be vaporized without difficulty by the heat of the combustion gas burning the boiling off gas, it is not necessary to heat the heating medium such as seawater or air, and no other energy is required. Rather, since the turbine can be operated and energy can be taken out, the liquefied gas can be vaporized very economically.

According to an aspect of the present invention, there is provided a liquefied gas vaporization system including a liquefied gas vaporization unit for vaporizing liquefied gas stored in a liquefied gas tank by heat exchange with a heating medium, and a boil-off gas combustion unit A turbine that is rotationally driven by the energy of the combustion gas after being burned in the boil-off gas combustion unit to perform a predetermined operation; and a control unit that supplies the combustion gas discharged from the turbine to the liquefied gas vaporization unit as the heating medium And a combustion gas supply unit.

According to the liquefied gas vaporization system of the above construction, the boil-off gas generated in the liquefied gas tank is combusted in the boil-off gas combustion section, the turbine is driven by the combustion gas, and the combustion gas after the turbine drive is supplied Is supplied as a heating medium to the liquefied gas vaporization unit, and vaporization of the liquefied gas is promoted. In addition, the turbine can perform a predetermined operation.

Since the combustion gas after the turbine drive expands and the temperature decreases, for example, the combustion gas discharged from the boil-off gas combustion section is supplied to the liquefied gas vaporization unit as it is without being passed through the turbine to vaporize the liquefied gas This makes it possible to reduce the temperature difference between the liquefied gas vaporizing unit and the liquefied gas vaporizing unit, and to suppress the breakage of the liquefied gas vaporizing unit and the deterioration of durability.

Since the combustion gas after passing through the turbine maintains a high pressure, it is not necessary to forcibly supply the combustion gas to the liquefied gas vaporization unit by using a blower or the like, thereby simplifying the construction. Further, since the liquefied gas can be vaporized by the heat of the combustion gas burning the boil-off gas without any difficulty, energy can be taken out by operating the turbine on the contrary without requiring any other energy, It can be vaporized.

In the above configuration, the boil-off gas combustor is a pressurized combustor supplied with compressed air to combust the boil-off gas, and generates the compressed air coaxial with the turbine, And a compressor for supplying the gas to the gas combustion unit.

According to the liquefied gas vaporization system of the above configuration, since the boil-off gas combustion unit, which is a pressurized combustor, pressurizes and burns the boil-off gas while compressed air is supplied from a compressor provided coaxially with the turbine, The size of the furnace or the flue can be reduced to make the liquefied gas vaporization system compact.

In the liquefied gas vaporization system, the boil-off gas combustion section may include a combustion gas dilution section for mixing a part of the compressed air supplied from the compressor with the combustion gas to dilute the combustion gas.

According to the liquefied gas vaporization system of the above configuration, the combustion gas discharged from the boil-off gas combustion section is diluted with the compressed air in the combustion gas dilution section, and the volume is increased. This diluted combustion gas expands as it passes through the turbine, and further increases in volume, and is supplied to the liquefied gas vaporization unit in a state in which the temperature is lowered. Therefore, it is possible to effectively vaporize the liquefied gas by introducing a large amount of diluted combustion gas at a proper temperature into the liquefied gas vaporization unit, and also to reduce the temperature difference between the liquefied gas vaporization unit and the breakage and durability Can be suppressed.

In the above configuration, the combustion gas supply unit may include an air eductor for mixing the dilution air with the combustion gas to dilute the combustion gas.

According to the liquefied gas vaporization system of the above construction, when the combustion gas passing through the turbine passes through the air eductor, dilution air is mixed to increase the volume, and the temperature is supplied to the liquefied gas vaporization unit. This makes it possible to effectively vaporize the liquefied gas by introducing a large amount of dilute combustion gas at a proper temperature into the liquefied gas vaporization unit and to reduce the temperature difference between the liquefied gas vaporization unit and the liquefied gas vaporization unit, Can be suppressed.

In the above configuration, in the air eductor, the mixing ratio of the dilution air may be set so that the temperature of the combustion gas after dilution supplied to the liquefied gas vaporization unit becomes 100 캜 or lower.

According to the liquefied gas vaporization system of the above construction, since the temperature of the diluted combustion gas supplied to the liquefied gas vaporization unit becomes 100 DEG C or less, the temperature difference between the liquefied gas vaporization unit and the liquefied gas vaporization unit is reduced, It is possible to suppress the decrease in durability.

In the above arrangement, it is preferable that a dilution air supply unit for adding a portion of the compressed air generated by the compressor to supply the compressed air to the air eductor as the dilution air, and a flow rate adjusting valve for adjusting the flow rate of the dilution air May be provided.

According to the liquefied gas vaporization system of the above construction, a part of the compressed air generated by the compressor is sucked, and the sucked compressed air is supplied to the air eductor as dilution air by adjusting the flow rate to the flow rate regulating valve, Dilute. Thereby, there is no need to control the flow rate of the dilution air on the side of the turbine or the boil-off gas combustion unit, and the control can be facilitated.

In the above configuration, the liquefied gas vaporization unit is configured such that a vaporizing tube through which the liquefied gas flows is arranged inside the case along the vertical direction, and the combustion gas flows in from the upper portion of the case and is discharged from the lower portion .

Since the combustion gas burning the boiling off gas of the liquefied gas always contains moisture, when this combustion gas is supplied to the liquefied gas vaporization unit, heat exchange with the liquefied gas at a low temperature results in generation of condensed water, According to the liquefied gas vaporization system of the above construction, since condensed water is discharged from the lower portion of the liquefied gas vaporization unit, freezing is hardly caused, and liquefied gas can be efficiently vaporized.

The above configuration may further comprise a compressed air supply unit for adding a portion of the compressed air generated by the compressor and injecting the compressed air to the vicinity of the inlet of the liquefied gas in the liquefied gas vaporization unit.

According to the liquefied gas vaporization system of the above construction, since the high-temperature compressed air is injected into the liquefied gas inlet portion of the liquefied gas vaporization unit in which condensation water is likely to freeze, freezing is difficult to occur and even if iced, You can blow away the ice. This prevents freezing of the liquefied gas vaporization unit and efficiently vaporizes the liquefied gas.

The dilution combustion gas supply unit may further include a dilution combustion gas supply unit for adding a portion of the diluted combustion gas supplied to the liquefied gas vaporization unit and supplying the diluted combustion gas to the compressor.

According to the liquefied gas vaporization system having the above configuration, since the diluted combustion gas diluted with the compressed air and containing a large amount of oxygen and cooled by heat exchange with the liquefied gas in the liquefied gas vaporization unit is supplied to the compressor, So that the compressor efficiency can be improved.

In the above configuration, the diluted combustion gas supply unit may supply the combustion gas added from the liquefied gas vaporization unit to the air eductor.

According to the liquefied gas vaporization system of the above configuration, by supplying the lean burn gas separated (dehumidified) by heat exchange with the liquefied gas at a low temperature in the liquefied gas vaporization unit to the air eductor, And consequently the condensation amount of the combustion gas entering the liquefied gas vaporization unit is reduced to prevent freezing of the liquefied gas vaporization unit and to vaporize the liquefied gas efficiently.

The floating structure according to an embodiment of the present invention may include a liquefied gas vaporization system having any of the above configurations.

According to the floating structure of the above-described structure, the liquefied gas vaporization system can be compactly constructed regardless of whether the liquefied gas carrier is a liquefied gas carrier or a liquefied gas introduction base, and the boiling off gas in the liquefied gas tank The liquefied gas can be economically vaporized without difficulty by the heat of the burned combustion gas.

As described above, according to the liquefied gas vaporization method, the liquefied gasification system, and the maritime superstructures equipped with the liquefied gas vaporization system of the present invention, it is possible to provide a liquefied gas- The liquefied gas can be economically vaporized by effectively using the boil-off gas.

In addition, since liquefied gas can be vaporized without taking seawater, it can contribute to the preservation of the marine environment.

1 is a schematic configuration diagram of a liquefied gas vaporization system showing Embodiment 1 of the present invention.
2 is a cross-sectional view schematically showing a configuration of an air eductor.
3 is a schematic configuration diagram of a liquefied gas vaporization system showing Embodiment 2 of the present invention.

[Embodiment 1]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a liquefied gas vaporization method and a liquefied gas vaporization system according to the present invention will be described with reference to the drawings.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic configuration diagram of a liquefied gas vaporization system showing Embodiment 1 of the present invention. FIG. The liquefied gas vaporization system 1 is mounted on a liquefied gas carrier such as an LNG carrier or a liquefied gas introduction station such as a floating storage and regasification unit (FSRU). The liquefied gas stored in a liquefied gas tank The boil-off gas generated in the liquefied gas tank is combusted, and vaporization of the liquefied gas is promoted by using the heat of the combustion gas.

The liquefied gas vaporization system 1 includes a liquefied gas vaporization unit 2, a boil-off gas combustion unit 3, a turbine 4, a compressor 5 provided coaxially with the turbine 4, 6, the start portion 7, the combustion gas supply portion 8, the air trunks 9, 10, the compressed air supply portion 11, the chimney 12 and the dilution combustion gas supply portion 13 Respectively.

The liquefied gas vaporizing unit 2 is configured to vaporize the liquefied gas stored in the liquefied gas tank by heat exchange with the combustion gas (heat medium) of the boiling off gas. In the case 15, (16) are arranged along the vertical direction. The vaporizing tube 16 is, for example, a structure in which a plurality of air pins 16b extending in the vertical direction are provided around the center tube 16a to increase the surface area. An inlet conduit 17 is connected to the upstream side of the group of the vaporizing tubes 16 and an outlet conduit 18 is connected to the downstream side of the group of the vaporizing conduits 16. The liquefied gas flows from the inlet conduit 17, passes through the inside of the vaporizing conduit 16, and flows out of the outlet conduit 18.

As described later, the combustion gas of the boil-off gas flows from the upper part of the case 15 of the liquefied gas vaporization unit 2 as a heating medium, flows downward along the vaporizing pipe 16 extending in the vertical direction, So that the liquefied gas is vaporized and then discharged to the outside through the discharge port 19 provided in the lower portion of the case 15. [

The turbine 4 is rotationally driven by the energy of the combustion gas after being burned in the boil-off gas combustion section 3 to perform a predetermined operation. Herein, the turbine 4 drives the compressor 5 and the generator 6 provided on the coaxial axis so that the compressed air of about 3 atmospheres generated in the compressor 5 passes through the compressed air supply pipe 21, And is supplied to the boil-off gas combustion section 3 as combustion air and dilution air. An air trunk 9 is connected to the intake side of the compressor 5 through an outside air supply pipe 22. The outside air entering the air trunk 9 through the intake port 9a is rectified and supplied to the compressor 5. [

The boil-off gas combustion section 3 is configured to pressurize and burn the boil-off gas generated in the liquefied gas tank while supplying the compressed air from the compressor 5, And a cylindrical combustion gas diluting section 3b surrounding the outer periphery of the combustion chamber 3a. The combustion gas dilution section 3b is formed by mixing a part of the combustion gas and diluting the combustion gas. A compressed air supply pipe 21 extending from the compressor 5 is connected to one end of the combustion gas dilution part 3b and the compressed air supplied from the compressed air supply pipe 21 flows into both the combustion chamber 3a and the combustion gas dilution part 3b . A merging exhaust port 3c is provided at the other end of the combustion chamber 3a and the combustion gas dilution section 3b.

Off gas supply line 25 extending from a liquefied gas tank (not shown) is arranged so as to diffuse the boil-off gas inside the combustion chamber 3a of the boil-off gas combustion portion 3. In the combustion chamber 3a, the compressed air supplied from the compressor 5 and the boil-off gas are mixed and combusted at a predetermined ratio, and the combustion gas flows in the combustion gas dilution section 3b at the merging exhaust port 3c And is supplied to the turbine 4 through the exhaust gas supply pipe 26. [0033]

The startup section 7 drives the auxiliary compressor 29 with the electric motor 28 in place of the compressor 5 which has not yet been operated at startup of the liquefied gas vaporization system 1 and generates the starting compressed air To supply compressed air to the boil-off gas combustion section (3) from the starting air supply pipe (30). The starting air supply pipe 30 joins the compressed air supply pipe 21 so that check valves 31 and 32 are provided in the respective pipelines 21 and 30, respectively.

The compressor 5 is forcibly driven by supplying the generator 6 in place of the electric motor by energizing the generator 6 when the liquefied gas vaporization system 1 is started without providing the starting unit 7, And the compressed air may be supplied to the combustion section 3.

The combustion gas supply unit 8 is a conduit for supplying the combustion gas discharged from the turbine 4 to the liquefied gas vaporization unit 2 as a heating medium. The combustion gas supply section 8 extends from the turbine 4 and then diverges in this direction so that the air trunk 10 is connected in the middle of the one branch duct 8a and the other branch duct 8b is connected to the chimney (Not shown). The branch passage 8a is connected to the upper portion of the case 15 of the liquefied gas vaporization unit 2 after branched through the air trunk 10 as a distribution pipe 8c.

The liquefied gas vaporization system 1 is started at the starting section 7 to operate the compressor 5 and then the temperature at which the gas 5 is discharged from the gas turbine 4 The combustion gas with unstable pressure is led to the chimney 12 via the branch passage 8b and is discarded. When the driving of the compressor 5 is stabilized, the combustion gas is supplied to the air eductor 35 via the branch passage 8a. Further, even when the amount of the combustion gas is excessively large, surplus combustion gas is discarded from the chimney 12. The switching of the branch passages (8a, 8b) is performed by opening and closing the partitioning valve.

An air duct 35 is provided inside the air trunk 10. The air eductor 35 mixes the outside air entering the air trunk 10 from the air intake port 10a as air for dilution into the combustion gas flowing from the combustion gas supply section 8, dilutes the combustion gas, To increase the amount.

Specifically, as shown in Fig. 2, the branch passage 8a of the combustion gas supply unit 8 is bent at right angles inside the air trunk 10, and a dilution air pipe 36 are opened. The other end of the dilution air pipe (36) opens into the air trunk (10). Therefore, when the combustion gas passes through the refraction portion 8R of the combustion gas supply portion 8, the inside of the air trunk 10 is drawn from the dilution air pipe 36 into the combustion gas supply portion 8 by the negative pressure Is mixed with the combustion gas, and the combustion gas is diluted.

As described above, the combustion gas diluted with the air mixed by the air eductor 35 in the air trunk 10 flows continuously to the side of the liquefied gas vaporization unit 2 through the combustion gas supply unit 8. [ In the air eductor 35, the temperature of the diluted combustion gas supplied to the liquefied gas vaporization unit 2 is set to be not more than 100 DEG C, preferably about 90 DEG C, and the combustion gas is diluted The mixing ratio of the air for use is set.

The compressed air supply unit 11 adds a part of the compressed air generated in the compressor 5 from the compressed air supply pipe 21 to the vicinity of the inlet of the liquefied gas inside the liquefied gas vaporization unit 2 (For example, a vaporizing pipe 16 disposed at a position close to the evaporator 17), and the flow rate of the compressed air supplied to the liquefied gas vaporization unit 2 by the flow rate adjusting valve 38 provided in the middle thereof So that the flow rate can be adjusted.

The dilution combustion gas supply unit 13 supplies a part of the combustion gas diluted to a concentration close to the air after being supplied to the liquefied gas vaporization unit 2 from the case 15 to the compressor 5 And an air duct 35 (air trunk 10). That is, the combustion gas supply pipe 13a extending from the case 15 of the liquefied gas vaporization unit 2 is branched to the two branch pipes 13b and 13c on the downstream side thereof, and one branch pipe 13b is branched from the air And the other branch pipe 13c is connected to the air trunk 10, as shown in Fig. The branch pipes 13b and 13c are respectively provided with flow rate adjusting valves 41 and 42 so that the amount of dilution of the combustion gas can be adjusted. When the flow regulating valve 41 is opened, the diluted combustion gas is supplied to the compressor 5 via the air trunk 9. When the flow regulating valve 42 is opened, the diluted combustion gas flows into the air trunk 10, And then flows back to the liquefied gas vaporization unit 2.

The liquefied gas vaporization system 1 configured as described above operates as follows.

First, since the compressor 5 is not operating at the startup of the liquefied gas vaporization system 1, the electric motor 28 of the starting section 7 drives the auxiliary compressor 29, And supplies the compressed air to the combustion chamber 3a of the boil-off gas combustion section 3 and the combustion gas dilution section 3b from the starting air supply pipe 30.

At the same time, the boil-off gas is diffused and supplied from the liquefied gas tank (not shown) through the boil-off gas supply pipe 25 into the combustion chamber 3a. The boil-off gas is burned together with the compressed air, and the combustion gas and the compressed air passing through the combustion gas diluting section 3b are mixed at the merging exhaust port 3c, The gas is supplied to the turbine 4 via the exhaust gas supply pipe 26, and the turbine 4 is driven. The pressure and temperature of the combustion gas discharged from the boil-off gas combustion section 3 are, for example, 3 atm and 500 deg.

The compressor 5 provided on the coaxial axis of the turbine 4 is activated by the drive of the turbine 4 so that outside air is introduced from the air trunk 9 to generate compressed air, Compressed air is supplied to the combustion chamber 3a of the gas combustion section 3 and the combustion gas dilution section 3b. At this point of time, the electric motor 28 and the auxiliary compressor 29 of the starting section 7 are stopped, but the boil-off gas combustion section 3 continues to supply the boil- Combustion and dilution of the combustion gas are performed.

The combustion gas discharged from the turbine 4 is supplied to the liquefied gas vaporization unit 2 through the combustion gas supply unit 8 but is supplied to the liquefied gas vaporization unit 2 in the middle of the air trunk 10 by the air eductor 35 The outside air is mixed and diluted. As a result, the temperature of the combustion gas, which was about 0.5 atm and 200 ° C, dropped to 100 ° C or less at the time when it was discharged from the turbine 4, and the concentration of the combustion gas became closer to the air.

The combustion gas diluted with air and thus lowered in temperature is introduced into the case 15 from the upper portion of the case 15 of the liquefied gas vaporization unit 2 and dispersed therein. ) And flows downward along the vaporizing tube 16 to heat-exchange with the liquefied gas flowing in the vaporizing tube 16 to vaporize the liquefied gas. Thereafter, the combustion gas is discharged from the discharge port 19 to the outside.

The liquefied gas flowing into the liquefied gas vaporization unit 2 from the inlet line 17 is vaporized inside the vaporizing line 16 as described above to be gaseous and flows out from the outlet line 18, And the like. Particularly, at a position close to the inlet line 17, a large amount of water contained in the combustion gas is heat-exchanged with the liquefied gas at a low temperature to cause condensation. This condensed water may freeze and significantly deteriorate the vaporization performance of the liquefied gas vaporization unit 2. For this reason, for example, the flow rate adjustment valve 38 of the compressed air supply unit 11 is opened at a predetermined interval, A part of the high temperature compressed air generated in the liquefied gas generating unit 5 is injected into the liquefied gas inlet portion (in particular, the upstream portion of the vaporizing tube 16) of the liquefied gas vaporization unit 2. As a result, freezing ice can be blown off or removed, or freezing of the ice can be prevented by heating the part with the heat of compressed air in advance, and vaporization performance of the liquefied gas vaporization unit 2 can be maintained satisfactorily, thereby efficiently vaporizing the liquefied gas .

The flow regulating valve 41 of the branch pipe 13b is opened out of the two branch pipes 13b and 13c branching from the combustion gas supply pipe 13a of the diluted combustion gas supply unit 13 so that the liquefied gas vaporizing unit 2 A part of the combustion gas diluted to a concentration close to the air is supplied to the air trunk 9 and sucked into the compressor 5. [ Since the lean burn gas is cooled to room temperature or lower by heat exchange with the liquefied gas, the intake air temperature of the compressor 5 can be lowered and the compressor efficiency can be improved. Off gas is supplied to the boil-off gas combustion section 3 through the compressor 5, the boil-off gas is prevented from burning because it is diluted with air and contains a large amount of oxygen.

A part of the combustion gas after being supplied to the liquefied gas vaporization unit 2 is supplied to the air trunk 10 by the opening of the flow rate adjusting valve 42 of the branch pipe 13c, And mixed with the combustion gas as air. In the liquefied gas vaporization unit 2, the condensed water is separated by heat exchange with the liquefied gas at a low temperature, and the dehumidified lean burn gas passes through the air trunk 10 (air eductor 35) The condensation amount of the combustion gas entering the liquefied gas vaporization unit 2 is reduced to prevent freezing of the liquefied gas vaporization unit 2 and to efficiently vaporize the liquefied gas .

As described above, this liquefied gas vaporization system and the liquefied gas vaporization system 1 are capable of vaporizing the liquefied gas stored in the liquefied gas tank in the liquefied gas vaporization unit 2, Off gas combustion section 3 and drives the turbine 4 with the energy of the combustion gas to generate heat of the liquefied gas in the liquefied gas vaporization unit 2 by the heat of the combustion gas after the drive of the turbine 4 Promotes vaporization.

According to the liquefied gas vaporization method and the liquefied gas vaporization system 1, the combustion gas after burning the boiling off gas generated in the liquefied gas tank expands by driving the turbine 4, and the temperature is lowered. The vaporization of the liquefied gas in the liquefied gas vaporization unit 2 is promoted by the heat of the combustion gas that has been expanded and lowered in temperature. The driven turbine 4 can be driven to perform a predetermined operation, that is, the compressor 5 and the generator 6 in the present embodiment.

Since the combustion gas after passing through the turbine 4 expands and the volume increases and the temperature decreases greatly, for example, the combustion gas after burning the boiling off gas does not pass through the turbine 4, The temperature difference with the liquefied gas vaporizing unit 2 can be reduced as compared with the case where the liquefied gas is supplied to the vaporizing unit 2 to vaporize the liquefied gas. As a result, breakage of the liquefied gas vaporization unit 2 and deterioration of durability can be suppressed.

Since the combustion gas after passing through the turbine 4 maintains a high pressure, it is possible to supply the combustion gas to the liquefied gas vaporization unit 2 without forcibly sending it by using a blower or the like, The configuration can be simplified.

As described above, since the liquefied gas can be vaporized without difficulty by the heat of the combustion gas burning the boil-off gas, it is not necessary to heat the heating medium such as seawater or air by the different energy, . Rather, since the turbine 4 can be operated to perform a predetermined operation (air compression, power generation, etc.), the liquefied gas can be vaporized very economically while effectively using the boil-off gas in the liquefied gas tank.

This liquefied gas vaporization system 1 is a pressurized type combustor in which the boil-off gas combustion section 3 is supplied with compressed air from a compressor 5 provided coaxially with the turbine 4 to burn the boil-off gas. This reduces the size of the flame at the time of combustion compared to the case where the boil-off gas is combusted at atmospheric pressure, thereby reducing the size of the boil-off gas combustion section 3 and the flue gas, It can make a great contribution to compactness.

The boil-off gas combustion section 3 includes a combustion chamber 3a for pressurizing and burning a boil-off gas, a combustion gas dilution section 3 for mixing a part of the compressed air supplied from the compressor 5 into a combustion gas, The combustion gas discharged from the combustion chamber 3a is diluted with the compressed air in the combustion gas dilution section 3b and the volume thereof is increased.

The diluted combustion gas expands as it passes through the turbine 4 and is supplied to the liquefied gas vaporization unit 2 in a state in which the volume is further increased and the temperature is lowered. Therefore, the liquefied gas can be efficiently vaporized by introducing a large amount of the diluted combustion gas at a proper temperature into the liquefied gas vaporization unit 2, and the temperature difference between the liquefied gas vaporization unit 2 and the liquefied gas The breakage of the vaporizing unit 2 and deterioration of durability can be suppressed.

An air eductor 35 is provided in the air trunk 10 provided in the combustion gas supply section 8 and the air for dilution is mixed with the combustion gas after the turbine 4 is driven by the air eductor 35 The combustion gas is diluted and the temperature of the diluted combustion gas is controlled to be 100 占 폚 or lower, preferably about 90 占 폚, and then supplied to the liquefied gas vaporization unit 2. Therefore, when the combustion gas passing through the turbine 4 passes through the air eductor 35, the dilution air is mixed to further increase the volume and lower the temperature to 100 DEG C or lower, and the liquefied gas vaporization unit 2 .

Therefore, it is possible to effectively vaporize the liquefied gas by introducing a larger amount of the diluted combustion gas at a proper amount and also to the liquefied gas vaporization unit 2, and also to control the temperature difference between the liquefied gas vaporization unit 2 So that breakage of the liquefied gas vaporizing unit 2 and deterioration of durability can be suppressed.

The liquefied gas vaporizing unit 2 is provided with a vaporizing pipe 16 through which a liquefied gas flows in a vertical direction in the case 15 so that the combustion gas flows in from the upper part of the case 15, 19). Therefore, even if the water contained in the combustion gas necessarily undergoes heat exchange with the low-temperature vaporizing pipe 16 (liquefied gas) to generate condensed water, the condensed water is condensed in the inside of the case 15 from the upper side to the lower side And flows downwardly by the combustion gas flowing along the vaporizing tube 16 and is easily discharged from the discharge port 19. Therefore, the condensed water freezes around the vaporizing tube 16 to reduce the possibility of deteriorating the heat exchange performance, and the liquefied gas can be efficiently vaporized.

By providing the liquefied gas vaporization system 1 configured as described above on a liquefied gas carrier or a floating fluid structure such as an FSRU, the liquefied gas vaporization system 1 can be compactly constructed and the boil- The liquefied gas can be economically vaporized without difficulty by the heat of the burned combustion gas.

[Embodiment 2]

Next, Embodiment 2 of the liquefied gas vaporization system according to the present invention will be described with reference to Fig. In the liquefied gas vaporization system 51 shown in Fig. 3, the same components as those of the liquefied gas vaporization system 1 of the first embodiment shown in Fig. 1 are denoted by the same reference numerals and the description thereof is omitted.

In the liquefied gas vaporization system 51, the compressed air supply pipe 21 extending from the compressor 5 driven by the turbine 4 is diverted in this direction, and one of the branch passages 21a is provided in the first embodiment Off gas combustion section 3 and the other branch passage 21b (diluted air supply section) is connected to the air trunk 10 (air eductor 35) through the flow rate control valve 43 Respectively.

A part of the compressed air of about 3 atmospheres generated in the compressor 5 is added to the branch passage 21b and the flow rate is adjusted to the flow rate adjusting valve 43 to be supplied to the air trunk 10. In the same manner as the liquefied gas vaporization system 1 of the first embodiment, in the interior of the air trunk 10, after the turbine 4 flowing from the combustion gas supply section 8 (branch passage 8a) is driven Mixed with the combustion gas as dilution air, and the combustion gas is diluted.

The atmospheric pressure of the diluted combustion gas sent out from the air eductor 35 is controlled to be about 1 atm and the temperature is 100 캜 or less to supply the combustion gas to the liquefied gas vaporization unit 2.

In the liquefied gas vaporization system 1 of Embodiment 1, a combustion gas is supplied to the gas turbine side (the boil-off gas combustion unit 3, the turbine 4, the compressor 5, etc.) and the air eductor 35 (Diluted air) supplied to the liquefied gas unit 2 is controlled by adjusting the flow rate regulating valve 42,

On the other hand, in the liquefied gas vaporization system 51 of the second embodiment, a part of the compressed air generated by the compressor 5 is added and the flow rate of the compressed air is adjusted by adjusting the flow rate (pressure) (35) to dilute the combustion gas.

Thus, in this liquefied gas vaporization system 51, there is no need to control the flow rate of the dilution air on the side of the gas turbine, and the control can be facilitated.

As described above, according to the liquefied gas vaporization method and the liquefied gas vaporization system (1, 51) of the present invention and the marine fluidic structure equipped with the liquefied gas vaporization system (1, 51), it is possible to provide a very compact structure Thus, the boil-off gas in the liquefied gas tank can be effectively used to economically vaporize the liquefied gas.

Since liquefied gas can be vaporized without taking seawater, it can contribute to the preservation of the marine environment.

It is possible to easily carry out the retrofit work for replacing the conventional liquefied gas vaporization system for vaporizing the liquefied gas by using the heated seawater or air as the heating medium with the liquefied gas vaporization system according to the present invention.

The present invention is not limited to the configurations of the first and second embodiments, but can be modified or improved as appropriate without departing from the gist of the present invention. And are included in the scope of the invention.

For example, it is conceivable that the air trunk 9 and the air trunk 10 (air duct 35) are omitted.

In the first and second embodiments, the dilution gas in which the combustion gas burning the boil-off gas is diluted with air is directly supplied to the liquefied gas vaporization unit 2, but as a modification, the liquefaction gas The vaporizing unit 2 may be replaced by an open rack type vaporizer in which a liquefied gas is passed through and the vaporizer is vaporized by heated seawater flowing through the closed loop circuit or a heating medium such as air to heat the heating medium It is conceivable that the heat of the combustion gas after burning the boiling off gas is used.

It is also conceivable that the liquefied gas vaporization system 1 of the first embodiment and the liquefied gas vaporization system 51 of the second embodiment are combined.

1, 51 liquefied gas vaporization system
2 liquefied gas vaporization unit
3 boil-off gas combustion unit
3a combustion chamber
3b Combustion gas dilution part
4 Turbines
5 Compressor
8 Combustion gas supply part
11 Compressed air supply
13 dilution flue gas supply
15 cases
16 Wreaths
19 outlet
21b branch (dilution air supply)
35 Air eductor
43 Flow regulating valve

Claims (12)

A liquefied gas vaporization method for promoting vaporization by heat-exchanging liquefied gas stored in a liquefied gas tank with a heating medium,
Off gas generated in the liquefied gas tank is burned to drive the turbine with the energy of the combustion gas and the combustion gas after the turbine drive is used as the heat medium to accelerate vaporization of the liquefied gas with the heat, Way. A liquefied gas vaporization unit for vaporizing the liquefied gas stored in the liquefied gas tank by heat exchange with the heating medium,
A boil-off gas combustion unit for combusting the boil-off gas generated in the liquefied gas tank,
A turbine which is rotationally driven by the energy of the combustion gas after being burned in the boil-off gas combustion section to perform a predetermined operation;
A combustion gas supply unit for supplying the combustion gas discharged from the turbine to the liquefied gas vaporization unit as the heating medium,
And the liquefied gas vaporizing system is constructed so as to include the liquefied gas. 3. The method of claim 2,
The boil-off gas combustion section is a pressurized type combustor which is supplied with compressed air to pressurize and burn the boil-off gas,
And a compressor for generating the compressed air coaxially with the turbine and supplying the compressed air to the boil-off gas combustion unit as pressurized combustion air. The method of claim 3,
Wherein the boil-off gas combustion section includes a combustion gas dilution section for diluting the combustion gas by mixing a part of the compressed air supplied from the compressor with the combustion gas. 5. The method according to any one of claims 2 to 4,
Wherein the combustion gas supply unit includes an air eductor for mixing the combustion gas with dilution air to dilute the combustion gas. 6. The method of claim 5,
Wherein the mixing ratio of the dilution air is set so that the temperature of the diluted combustion gas supplied to the liquefied gas vaporization unit becomes 100 DEG C or lower in the air eductor. The method according to claim 5 or 6,
A diluting air supply unit for supplying a portion of the compressed air generated by the compressor to the air eductor as the diluting air;
A flow rate adjusting valve for adjusting the flow rate of the dilution air;
Further comprising: a liquefied gas vaporization system comprising: 7. The method according to any one of claims 2 to 6,
Wherein the liquefied gas vaporizing unit is configured such that a vaporizing tube through which the liquefied gas flows is arranged in a vertical direction inside the case and the combustion gas flows from an upper portion of the case and is discharged from a lower portion thereof. 8. The method according to any one of claims 3 to 7,
Further comprising a compressed air supply unit for adding a portion of the compressed air generated by the compressor and injecting the compressed air to the vicinity of the inlet of the liquefied gas in the liquefied gas vaporization unit. 9. The method according to any one of claims 3 to 8,
And a diluted combustion gas supply unit for adding a portion of the diluted combustion gas supplied to the liquefied gas vaporization unit and supplying the diluted combustion gas to the compressor. 10. The method of claim 9,
Wherein the diluted combustion gas supply unit is capable of supplying the combustion gas added from the liquefied gas vaporization unit to the air eductor. 12. A maritime superficial structure with a liquefied gas vaporization system according to any one of claims 2 to 11.

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