阅读说明：本技术 液化气气化装置及具备该液化气气化装置的浮体设备 (Liquefied gas vaporizer and float device provided with same ) 是由 中村龙太 斋藤英司 金星隆之 川波晃 松下浩市 于 2020-01-28 设计创作，主要内容包括：本发明提供一种能够不增大初期投资而将在蒸发气体焚烧处理时产生的蒸汽冷凝的液化气气化装置。液化气气化装置具备：将LNG加热而气化的气化器(25)；与气化器(25)连接,并且供二元醇循环的二元醇循环路径(38)；使在LNG箱(3)产生的BOG燃烧而生成蒸汽的再气化锅炉(30)；使在再气化锅炉(30)生成的蒸汽与在二元醇循环路径(38)循环的二元醇进行热交换的蒸汽热交换器(60)；以及进行不在气化器(25)加热LNG,而在再气化锅炉(30)对在LNG箱(3)产生的BOG进行焚烧处理的GCU模式时的控制的控制部,在GCU模式时,控制部将在再气化锅炉(30)产生的蒸汽向蒸汽热交换器(60)输送。(The invention provides a liquefied gas gasification device which can condense steam generated during incineration treatment of evaporated gas without increasing initial investment. A liquefied gas vaporizer is provided with: a vaporizer (25) for vaporizing the LNG by heating; a glycol circulation path (38) connected to the vaporizer (25) and through which glycol circulates; a regasification boiler (30) that burns BOG produced in the LNG tank (3) to generate steam; a steam heat exchanger (60) for exchanging heat between the steam generated in the re-gasification boiler (30) and the glycol circulating in the glycol circulation path (38); and a control unit for performing control in a GCU mode in which the regasification boiler (30) incinerates BOG generated in the LNG tank (3) without heating LNG in the vaporizer (25), wherein the control unit transfers steam generated in the regasification boiler (30) to the steam heat exchanger (60) in the GCU mode.)

1. A liquefied gas vaporizer is characterized by comprising:

a vaporizer for heating and vaporizing the liquefied gas;

an antifreeze circulation path connected to the vaporizer and through which antifreeze circulates;

a boiler that burns the boil-off gas generated in the liquefied gas tank to generate steam;

a steam heat exchanger for exchanging heat between steam generated in the boiler and the antifreeze circulating through the antifreeze circulation path; and

a control unit that performs control in a boil-off gas incineration mode in which boil-off gas generated in the liquefied gas tank is incinerated in the boiler without heating liquefied gas in the vaporizer,

in the boil-off gas incineration processing mode, the controller may transfer steam generated in the boiler to the steam heat exchanger.

2. A liquefied gas vaporization device as claimed in claim 1,

a seawater heat exchanger provided in the antifreeze circulation path and configured to exchange heat between the antifreeze and seawater,

in the boil-off gas incineration disposal mode, the control unit performs control so that heat is radiated from the antifreeze solution to the seawater in the seawater heat exchanger.

3. A liquefied gas vaporizing apparatus according to claim 1 or 2, comprising:

a steam turbine; and

a condenser condensing the steam discharged from the steam turbine,

in the boil-off gas incineration disposal mode, the control unit may transfer steam generated in the boiler to the condenser.

4. A floating body device is characterized by comprising:

a liquefied gas gasification apparatus as claimed in claim 1; and

the liquefied gas tank storing liquefied gas,

the vaporizer vaporizes the liquefied gas introduced from the liquefied gas tank.

Technical Field

The present invention relates to a liquefied gas vaporizer for vaporizing a liquefied gas and a float device provided with the liquefied gas vaporizer.

Background

As shown in patent document 1, a technique of regasifying LNG when LNG is supplied to the outside is known.

Documents of the prior art

Patent document

Patent document 1: japanese Kohyo publication No. 2002-506960

Technical problem to be solved by the invention

At the time of regasification, LNG in the LNG tank is consumed, and thus the pressure in the LNG tank may rise excessively. However, when the LNG is not regasified, boil-off gas (BOG) may be generated due to unavoidable heat of intrusion into the LNG tank, and the pressure in the LNG tank may excessively increase. In this case, the BOG is taken out from the LNG tank and incinerated in a GCU (Gas Combustion Unit).

When a GCU is provided as a facility for incinerating BOG, there is a problem that installation space is required and initial investment is increased. In order to solve these problems, when a facility provided with a regasification boiler (Regas boiler) is used as a heat source for regasifying LNG, it is conceivable that the regasification boiler is used as the GCU as well.

However, when the regasification boiler is used as the GCU, a large-capacity condenser for condensing the steam generated in the regasification boiler is required, and thus there is a problem in that initial investment increases.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquefied gas vaporizer capable of condensing steam generated during a boil-off gas incineration process without increasing initial investment, and a float device including the liquefied gas vaporizer.

Means for solving the problems

A liquefied gas vaporizer according to an aspect of the present invention includes: a vaporizer for heating and vaporizing the liquefied gas;

an antifreeze circulation path connected to the vaporizer and through which antifreeze circulates; a boiler that burns the boil-off gas generated in the liquefied gas tank to generate steam; a steam heat exchanger for exchanging heat between steam generated in the boiler and the antifreeze circulating through the antifreeze circulation path; and a control unit that controls an evaporation gas incineration mode in which the vaporizer does not heat the liquefied gas but the boiler incinerates the evaporation gas generated in the liquefied gas tank, and in which the control unit transfers the steam generated in the boiler to the steam heat exchanger.

In the boil-off gas incineration disposal mode, steam generated in the boiler is sent to the steam heat exchanger. In the steam heat exchanger, heat is exchanged between the steam and the antifreeze, thereby dissipating heat via the antifreeze circulating through the antifreeze circulation path. This eliminates the need for a large-sized condenser required in the boil-off gas incineration mode, and thus can suppress initial investment.

As the antifreeze, for example, glycol such as ethylene glycol can be used.

Further, in the liquefied gas gasification apparatus according to an aspect of the present invention, the control unit controls the seawater heat exchanger to radiate heat from the antifreeze solution to the seawater in the seawater heat exchanger in the evaporated gas incineration treatment mode.

The antifreeze circulation path is provided with a seawater heat exchanger, and heat is radiated from the antifreeze to the seawater through the seawater heat exchanger. This enables the heat of condensation of the steam to be efficiently dissipated to the outside.

Further, in the case where the vaporizer vaporizes the liquefied gas, the seawater heat exchanger can be used to heat the antifreeze solution after passing through the vaporizer by seawater.

Further, a liquefied gas gasification apparatus according to an aspect of the present invention includes: a steam turbine; and a condenser that condenses the steam discharged from the steam turbine, wherein the controller sends the steam generated in the boiler to the condenser in an evaporation gas incineration mode.

Steam is also supplied to the condenser, so that heat can be dissipated in the condenser as well. Since it is not necessary to condense all the steam in the condenser, it is not necessary to increase the size of the condenser. For example, the control unit may perform the following control: the steam is first condensed in the condenser, and when the amount of condensation exceeds a predetermined value, the steam is condensed in the steam heat exchanger.

In the floating body equipment according to the aspect of the present invention, the liquefied gas vaporizing device according to any of the above descriptions of the steam, the liquefied gas tank for storing the liquefied gas, and the vaporizer vaporize the liquefied gas guided from the liquefied gas tank.

By providing the liquefied gas vaporizer described above, a compact floating body device can be provided. As the float device, for example, FSRU (Floating Storage and Regasification Unit) can be cited.

The invention of this embodiment can be combined with the inventions of the above-described embodiments.

ADVANTAGEOUS EFFECTS OF INVENTION

Since heat is radiated in the antifreeze solution circulation path, steam generated during the incineration treatment of the boil-off gas can be condensed without increasing the initial investment.

Drawings

Fig. 1 is a schematic configuration diagram showing an open cycle of an LNG vaporization facility to which an FSRU according to an embodiment of the present invention is applied.

Fig. 2 is a schematic configuration diagram showing the LNG vaporization facility of fig. 1 in a combined cycle.

Fig. 3 is a schematic configuration diagram of the LNG vaporization facility of fig. 1, showing a GCU mode.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[ first embodiment ]

A first embodiment of the present invention will be explained below.

Fig. 1 shows a schematic configuration of an LNG vaporizer (liquefied gas vaporizer) 1 for vaporizing LNG (liquefied gas) as liquefied natural gas and supplying the vaporized LNG to the outside. The LNG vaporizer 1 is installed in an FSRU (Floating Storage and Regasification Unit) as a Floating body facility.

The FSRU includes an LNG tank 3 and a diesel engine (power generation engine) 5 in addition to the LNG vaporizer 1. As the Diesel Engine 5, a DFDE (Dual Fuel Diesel Engine) Engine that can use both oil Fuel and gas Fuel can be used.

LNG is stored in the LNG tank 3. BOG (boil off gas) inevitably generated by heat of intrusion or the like is accumulated above the LNG tank 3. The BOG is guided to the diesel engine 5 through a BOG supply pipe 7. The BOG supply pipe 7 is provided with a BOG compressor 9 and a BOG cooling heat exchanger 10. After the BOG is boosted to the pressure required by the diesel engine 5 by the BOG compressor 9, the BOG is cooled by the BOG cooling heat exchanger 10. The BOG cooled by the BOG cooling heat exchanger 10 is led to the diesel engine 5.

The diesel engine 5 drives a generator not shown. The generator driven by the diesel engine 5 generates the electricity required in the FSRU.

The diesel engine 5 is provided with a supercharger 12. The supercharger 12 is provided with an exhaust turbine and an air compressor, not shown. The exhaust turbine and the air compressor are coupled by a common shaft to rotate together.

The exhaust gas after passing through the exhaust turbine of the supercharger 12 is guided to the exhaust economizer 14. The exhaust bypass pipe 15 is provided to bypass the exhaust economizer 14. In the case where the exhaust economizer 14 is used, the bypass valve 15a is closed. In the present embodiment, the valve indicated by black is closed, and the valve indicated by open is open. Therefore, in the case where the exhaust economizer 14 is used, the exhaust economizer valve 14a provided on the upstream side of the exhaust economizer 14 is set to be open.

The air compressed by the air compressor of the supercharger 12 is cooled by the air cooler 16 and then guided to the diesel engine 5.

The LNG in the LNG tank 3 is guided to a gas-liquid separator 20 provided outside the LNG tank 3 by an LNG pump 18 provided in the LNG tank 3. The LNG separated from the gas-liquid separator 20 is guided to the vaporizer 25 through an LNG pipe 23 by a liquid-feeding pump (LNG pump) 22. The LNG pump 18 and the liquid feed pump 22 are electric pumps. The LNG vaporized in the vaporizer 25 is supplied to the outside through the gas supply pipe 26. The start/stop and the rotation speed of the LNG pump 18 and the liquid-sending pump 22 are controlled by a control unit, not shown.

The LNG vaporizer 1 includes, in addition to the vaporizer 25: a Regas (Regas) boiler 30, a steam turbine 32, a steam turbine generator 34, a condenser 36, and a glycol circulation path (antifreeze circulation path) 38.

A BOG supply pipe 40 for a boiler is connected to the regasification boiler (boiler) 30, and the BOG supply pipe 40 for a boiler branches off from the BOG supply pipe 7 on the downstream side of the BOG compressor 9. The regasification boiler 30 operates using the BOG guided by the boiler BOG supply pipe 40 as fuel. The regasification boiler 30 may be operated by fuel oil.

The water drum 30a of the regasification boiler 30 is connected to an evaporator 44 in the exhaust gas economizer 14 via a drum water pump 42. The water heated at the evaporator 44 is directed to the steam drum 30b of the regasification boiler 30. Water is supplied from the water supply tank 46 to the steam drum 30b through the water supply pipe 47 by the water supply pump 48.

Steam is supplied from the steam drum 30b of the regasification boiler 30 to the steam requiring unit 50 in the FSRU (in-ship) via the in-ship steam supply valve 51.

A steam pipe 52 for a steam turbine is provided between the steam drum 30b of the regasification boiler 30 and the steam turbine 32. A superheater 53 is provided at an intermediate position of the steam pipe 52 for the steam turbine. The superheater 53 is provided in the exhaust economizer 14. In the steam pipe 52 for a steam turbine, a steam stop valve 54 and a steam control valve 55 are provided between the superheater 53 and the steam turbine 32. The steam stop valve 54 and the steam control valve 55 are controlled by a control unit, not shown.

The steam pipe 52 for a steam turbine has a branch point P provided upstream of the superheater 53. A steam release pipe 57 is provided between the branch point P and the condenser 36, and the steam release pipe 57 allows the steam in the steam drum 30b to bypass the steam turbine 32 and be discharged to the condenser 36. The steam purge pipe 57 is provided with a steam purge valve 58. The steam purge valve 58 is controlled by a control unit, not shown, and is closed during normal operation.

A steam supply pipe 62 is provided between the steam drum 30b of the regasification boiler 30 and the steam heat exchanger 60 provided in the glycol circulation path 38. The steam supply pipe 62 is provided with a steam supply valve 63. The steam supply valve 63 is controlled by a control unit, not shown. The steam after the glycol is heated in the steam heat exchanger 60 becomes drain water, and is guided to the water supply tank 46 through the drain water pipe 65. Further, as the diol, for example, ethylene glycol may be used.

The steam turbine 32 is rotated by the steam and rotates about a rotation shaft 33. The rotary shaft 33 is connected to the steam turbine generator 34, and drives the steam turbine generator 34. The electric power generated by the steam turbine generator 34 is used as the required electric power in the ship, and is used for, for example, the liquid-sending pump 22 that sends LNG, the circulation pump 67 that circulates glycol.

The steam after the steam turbine 32 finishes operating is directed to the condenser 36. The condensed water condensed in the condenser 36 is guided to the water supply tank 46 via the condensed water pump 69. Seawater is directed into the condenser 36 as a thermal medium that cools the steam.

A seawater heat exchanger 72 is provided in the glycol circulation path 38. In the seawater heat exchanger 72, the seawater introduced from the seawater pump 70 through the seawater intake pipe 71 exchanges heat with the glycol. The seawater after the heat exchange in the seawater heat exchanger 72 is discharged to the ocean via the drain pipe 73. The sea water pump 70 is controlled by a control unit, not shown.

The glycol circulation path 38 includes a circulation pump 67 on the upstream side of the seawater heat exchanger 72. The glycol is circulated by the circulation pump 67 in the order of the seawater heat exchanger 72, the steam heat exchanger 60, and the vaporizer 25. The circulation pump 67 is an electric pump and is controlled by a control unit, not shown.

The control Unit includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program as an example, and the various functions are realized by reading the program into a RAM or the like by a CPU and executing processing and arithmetic processing of information. The program may be installed in advance in a ROM or another storage medium, provided in a state stored in a computer-readable storage medium, distributed via wired or wireless communication means, or the like. The computer-readable storage medium refers to: magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, etc.

< open cycle >

Next, the operation of the LNG vaporizer 1 configured as described above will be described. First, an open cycle in which the steam heat exchanger 60 is not used but the seawater heat exchanger 72 is used will be described. In the open cycle case, seawater is used as a heat source for vaporizing LNG, and the glycol is heated by the seawater using the seawater heat exchanger 72 to obtain required heat. Therefore, the open cycle is used in the sea area where the water temperature is high and in summer.

In the on-cycle, the regasification boiler 30 does not operate as a heat source for LNG vaporization. The steam drum 30b of the regasification boiler 30 is used as a gas-liquid separator. The control unit activates the water-blowing pump 42 to guide the water in the water drum 30a to the evaporator 44, and causes the water to exchange heat with the exhaust gas flowing through the exhaust gas economizer 14. The water guided to the evaporator 44 is heated and guided to the steam drum 30b to be separated into gas and liquid. The steam separated at the steam drum 30b is guided to the steam requiring part 50 and the steam turbine 32. The steam led to the steam turbine 32 is superheated by the superheater 53 of the exhaust gas economizer 14. The exhaust gas generated in the diesel engine 5 is guided to the exhaust gas economizer 14. When the amount of steam required by the steam demand section 50 is larger than the amount of steam generated by heat recovery from the exhaust gas economizer 14, the steam to be guided to the steam turbine 32 is cut off, and when the amount of steam is not sufficient, the regasification boiler 30 is operated.

The controller closes the steam supply valve 63 so that the steam does not flow into the steam heat exchanger 60. The control unit controls the operations of the liquid feed pump 22, the circulation pump 67, the sea water pump 70, and the like.

The LNG introduced from the LNG tank 3 is supplied to the vaporizer 25 through the LNG pipe 23 by the liquid feed pump 22. In the vaporizer 25, the glycol flowing through the glycol circulation path 38 is heated and vaporized. The vaporized LNG is guided to an external target via the gas supply pipe 26.

The glycol cooled by the vaporization of the LNG in the vaporizer 25 is heated by the seawater in the seawater heat exchanger 72. The glycol heated by the seawater is directed to the steam heat exchanger 60. Since the steam is not guided from the regasification boiler 30 to the steam heat exchanger 60, the glycol is guided to the vaporizer 25 without being heated in the steam heat exchanger 60.

< Combined (closed) cycle >

Next, a combined cycle or a closed cycle using the steam heat exchanger 60 will be described with reference to fig. 2. The same is true in the combined cycle and the closed cycle, in that the steam heat exchanger 60 is used. However, in the closed cycle, the seawater heat exchanger 72 is not used, and in the combined cycle, the seawater heat exchanger 72 is partially used.

The BOG is guided from the LNG tank 3 to the BOG-schemas regasification boiler 30 through a BOG supply pipe 40 for the boiler. In the regasification boiler 30, the BOG is used as fuel to form a flame in a burner (not shown), and thereby the feed water supplied through the feed water pipe 47 is heated to generate steam. The generated steam is guided from the steam drum 30b to the steam requiring part 50. The steam generated in the exhaust gas economizer 14 also assists the regasification boiler 30. The exhaust gas generated in the diesel engine 5 is guided to the exhaust gas economizer 14.

The control unit opens the steam supply valve 63 and stops the seawater pump 70. Thereby, the glycol flowing through the glycol circulation path 38 is heated by the steam heat exchanger 60.

In this way, in the closed cycle, since the seawater heat exchanger 72 is not used, the cooled seawater is not discharged to the ocean. Therefore, the environmental load can be reduced.

If necessary, a required amount of seawater may be supplied to the seawater heat exchanger 72 as a combined cycle to assist in heating the glycol.

The steam regulating valve 55 is closed at the time of the combined cycle, thereby transferring the heat of exhaust heat recovery to the FSRU side, which is advantageous in reducing the input of fuel to the regasification boiler 30.

< GCU mode >

Next, the GCU mode (the boil-off gas incineration mode) will be described with reference to fig. 3. In the GCU mode, the heating and vaporization of LNG is not performed in the vaporizer 25. That is, the LNG is not required to be vaporized from the outside. Therefore, the vaporizer 25 does not exchange heat with LNG.

Since the LNG is not sent to the outside, BOG is generated in the LNG tank 3 due to unavoidable heat intrusion, and the pressure in the LNG tank 3 rises. When the pressure in the LNG tank 3 rises to be higher than a predetermined pressure, the control unit selects the GCU mode to incinerate the BOG.

When the GCU mode is selected, the control unit supplies BOG to the regasification boiler 30. Thereby, the BOG is incinerated in the regasification boiler 30. The steam generated at this time is sent from the steam drum 30b to the steam heat exchanger 60. That is, the steam supply valve 63 is opened. At this time, the steam control valve 55 is closed, and thus the steam turbine 32 is stopped without supplying steam to the steam turbine 32.

In the glycol circulation path 38, the circulation pump 67 is started, and the glycol circulates. Further, the seawater pump 70 is started, and seawater is supplied to the seawater heat exchanger 72. Thus, the steam supplied to the steam heat exchanger 60 is cooled by the glycol, and the drain water is sent to the water supply tank 46. The glycol having cooled the steam and increased in temperature is guided to the seawater heat exchanger 72 after passing through the vaporizer 25. Since LNG is not supplied to the vaporizer 25, the glycol does not exchange heat in the vaporizer 25. However, in the seawater heat exchanger 72, the glycol is cooled by the seawater. Thereby, the condensation heat of the steam recovered in the steam heat exchanger 60 is discharged to the outside through the seawater heat exchanger 72.

< Effect of the present embodiment >

According to the present embodiment, the following operational effects are exhibited.

In the GCU mode (see fig. 3), the steam generated in the regasification boiler 30 is sent to the steam heat exchanger 60. In the steam heat exchanger 60, heat is exchanged between the steam and the glycol, thereby dissipating heat via the glycol circulating in the glycol circulation path 38. That is, by performing the purge process of the vapor in the glycol circulation path 38, it is not necessary to provide a large condenser required in the GCU mode, and initial investment can be suppressed.

The glycol circulation path 38 is provided with a seawater heat exchanger 72, and heat is radiated from the glycol to the seawater through the seawater heat exchanger 72. This enables the condensation heat of the steam generated by the BOG incineration to be efficiently dissipated to the outside.

In addition, the steam dump valve 58 may also be opened, thereby using the steam heat exchanger 60 as an aid to the condenser 36. This enables the conventional condenser 36 to be effectively used. For example, the controller opens the steam purge valve 58 while keeping the steam supply valve 63 closed in the GCU mode, thereby first condensing the steam purged in the condenser 36. The controller calculates the load of the regasification boiler 30 in the GCU mode, and when the amount of heat recovered by the condenser 36 exceeds a predetermined value, the controller opens the steam supply valve 63 while maintaining the opening degree of the steam release valve 58, thereby using the steam heat exchanger 60. This allows the heat of condensation of the steam generated by BOG combustion to be distributed to the steam heat exchanger 60 and the condenser 36, and allows the respective devices to be kept at appropriate capacities.

Description of the symbols

1 LNG gasification equipment (liquefied gas gasification equipment)

3 LNG tank (liquefied gas tank)

5 Diesel engine (Engine for power generation)

7 BOG supply piping

9 BOG compressor

10 BOG cooling heat exchanger

12 pressure booster

14 exhaust energy-saving device

14a exhaust economizer valve

15 exhaust bypass piping

15a bypass valve

16 air cooler

18 LNG pump

20 gas-liquid separator

22 liquid pump (liquefied gas pump)

23 LNG piping

25 gasifier

26 air supply pipe

30 regasification boiler (boiler)

30a water drum

30b steam drum

32 steam turbine

33 rotating shaft

34 steam turbine generator

36 coagulator

38 glycol circulation path (antifreeze circulation path)

BOG supply piping for 40-boiler

42 drum water pump

44 evaporator

46 water supply tank

47 water supply piping

48 water supply pump

50 steam requirement

51 steam supply valve in ship

Steam piping for 52 steam turbine

53 superheater

54 steam stop valve

55 steam regulating valve

57 steam vent piping

58 steam dump valve

60 steam heat exchanger

62 steam supply pipe

63 steam supply valve

65 drain water pipe

67 circulating pump

69 condensate pump

70 sea water pump

71 seawater intake pipe

72 sea water heat exchanger

73 drain pipe