JP2009280641A - Hotting-up apparatus by lng pump and hotting-up method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce fuel consumption in thermal powder generation equipment and reduce the amount of discharged carbon dioxide by reutilizing a hot gas not only for heat exchange but also as a fuel. <P>SOLUTION: The hotting-up apparatus includes an LNG tank 1, an LNG pump 2 for increasing the temperature and the pressure of LNG, and an LNG evaporator 3 for evaporating the LNG by increasing the temperature thereof by heat exchange with sea water and the like and is equipped with a hot gas treatment system 11 for withdrawing an evaporated LNG gas from a gas-feeding main pipe 5 at the exit side of the LNG evaporator 3 and introducing it as a hot gas into the LNG pump 2 and a hot gas recovery system 12 for sending out the evaporated LNG gas used for heat exchange as a hot gas to the gas-feeding main pipe 5 for reutilization as a fuel gas for the thermal power generation equipment P. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hot-up technology for bringing LNG (liquefied natural gas) close to room temperature, and more particularly to a hot-up device using a LNG pump provided in a thermal power generation facility and a hot-up method thereof.

  As shown in the schematic system diagram of the LNG hot-up facility in FIG. 4 and the flow diagram in FIG. 5, the LNG at −162 ° C. unloaded from the LNG carrier T at the LNG base is stored in the LNG tank 1 for cold storage. To do. The LNG stored in the LNG tank 1 is increased in pressure to a necessary pressure by the LNG pump 2, and is led to the LNG vaporizer 3 to be re-vaporized and used as a vaporized gas. In this LNG vaporizer 3, seawater etc. are pumped up by the seawater pump 4, and it vaporizes by heat exchange of this seawater. At this time, LNG is heated up to about -150 ° C.

  In this LNG pump 2, the LNG vaporized from the feed gas mother pipe 5 is used as a hot gas, which is guided to the LNG pump 2 and used for heat exchange. The LNG is heated up to 18 ° C. by heat exchange with the hot gas.

  The vaporized gas thus generated is supplied to the combustion furnace 6 of the boiler in the thermal power generation facility P and burned as fuel gas.

On the other hand, surplus gas such as BOG (Boil off gas) generated in the LNG tank 1 is burned in a flare stack (combustion tower) 7 in order to ensure the safety of the equipment. This increases the pressure in the LNG tank 1 and releases a large amount of BOG gas from the safety valve so as not to exceed the design pressure of the tank 1 and equipment.
Further, the return gas from the LNG carrier T is sent to the flare stack 7 and the BOG compressor 9 through the return gas blower 8.

Various techniques relating to a hot-up device for a low-temperature liquefied gas pump such as LNG have been proposed. For example, as shown in Japanese Patent Application Laid-Open No. 9-183986, “Hot-up device for low-temperature liquefied gas pump” in Japanese Patent Application Laid-Open No. 9-183986, LNG pump hot-up that boosts LNG in a low-temperature tank and sends it to a vaporizer Regarding the equipment, a line that leads the vaporized gas from the outlet side of the vaporizer to the inlet side of the pump, and a line that leads the vaporized gas from the outlet side of the pump to the line that discharges the vaporized gas generated in the tank to the thermal power plant , A line for introducing normal temperature nitrogen gas introduced from the nitrogen cylinder to the inlet side of the pump and a line for exhausting nitrogen gas from the outlet side of the pump to the outside of the system are provided. There has been proposed a hot-up device for a low-temperature liquefied gas pump in which a line is connected to the pump until the temperature is raised and a line is connected to the pump when a predetermined temperature is exceeded.
JP-A-9-183986

  As described above, the hot gas used to raise the temperature of the LNG is combusted in the flare stack 7 and wastes fuel. Further, the discharged hot gas is not always in a gaseous state and may be discharged as a liquid mass. When the flare stack 7 burns, there is a problem that sparks of the liquid lump easily cause misfire.

  In “Hot-up device of low-temperature liquefied gas pump” of Patent Document 1, surplus gas was discharged from the flare stack. Combustion in such a flare stack has a problem that carbon dioxide (CO2) is released to the atmosphere, which adversely affects the environment.

  The inventor of the present invention has strict gas delivery conditions such as the flow rate of vaporized gas, the delivery pressure and the amount of heat in the LNG hot-up facility used when supplying city gas to deliver to distant customers. However, in the LNG hot-up equipment that is attached to the thermal power generation equipment, it is not necessary to make the sending conditions strict, and it is important to emphasize the surrounding environment.

The present invention has been developed to solve such problems. That is, an object of the present invention is to reuse hot gas as fuel as well as heat exchange, thereby reducing fuel consumption in thermal power generation facilities and reducing carbon dioxide (CO ₂ ) emission. An object of the present invention is to provide a hot-up apparatus using an LNG pump and a hot-up method thereof.

According to the hot-up device of the present invention, the LNG is a hot-up device using an LNG pump for hot-up so that LNG can be used as the fuel gas of the combustion furnace (6) of the thermal power generation facility (P), and the LNG stores LNG. Heat exchange between the tank (1), the LNG pump (2) that raises and pressurizes the LNG extracted from the LNG tank (1), and the LNG that is heated and boosted by the LNG pump (2) with seawater and the like LNG vaporizer (3) that is heated and vaporized by the LNG vaporizer, and the LNG pump is extracted as hot gas by extracting the LNG vaporized gas from the gas supply pipe (5) on the outlet side of the LNG vaporizer (3). The hot gas processing system (11) led to (2), and the LNG vapor used for heat exchange as hot gas from the hot gas processing system (11) are converted into the thermal power generation facility (P The feed gas main pipe to re-use as a fuel gas (5) the hot gas recovery system (12) to be transmitted to, with a hot-up device according LNG pump, wherein provided that.
The hot gas recovery system (12) may be provided with a hot gas compressor (13) that boosts and raises the temperature of the hot gas used by heat exchange.

  Alternatively, a LNG pump hot-up device that heats up LNG so that it can be used as a fuel gas for a combustion furnace (6) of a thermal power generation facility (P), the LNG tank storing the LNG (1), and the LNG The LNG pump (2) that raises and raises the pressure of the LNG extracted from the tank (1), and the LNG that is heated and vaporized by heat exchange with seawater, etc., by the LNG pump (2). A vaporizer (3), a return gas from the LNG dedicated ship (T), and a BOG compressor (9) for heating and boosting the BOG naturally vaporized by heat input into the LNG tank (1), A hot gas processing system (11) for extracting LNG vaporized gas from a gas delivery pipe (5) on the outlet side of the LNG vaporizer (3) and leading it to the LNG pump (2) as hot gas; The BOG processing system (21) for leading the LNG vaporized gas used for heat exchange as hot gas from the hot gas processing system (11) to the BOG compressor (9) for re-use as fuel gas. Is.

According to the hot-up method of the present invention, the LNG stored in the LNG tank (1) is guided to the LNG pump (2) and boosted by the LNG pump (2), and the boosted LNG is converted into the LNG vaporizer ( In 3), the temperature is increased by vaporization by heat exchange with seawater and the like, and the vaporized LNG is heated by an LNG pump for hot-up so that it can be used as fuel gas for the combustion furnace (6) of the thermal power generation facility (P). LNG vaporization gas is extracted from the gas supply pipe (5) on the outlet side of the LNG vaporizer (3) and led to the LNG pump (2) as hot gas, and the LNG pump (2) The LNG pump used in the heat exchange as a hot gas is also used again as a fuel gas for the combustion furnace (6) of the thermal power generation facility (P). The law is provided.
It is preferable that the vaporized gas of LNG used for heat exchange as hot gas by the LNG pump (2) is used as fuel gas for the combustion furnace (6) of the thermal power generation facility (P) after being pressurized.

In the invention of the above configuration, the outlet side of the hot gas processing system (11) is changed from the flare stack (7) to the hot gas recovery system (12), and the fuel gas of the combustion furnace (6) of the thermal power generation facility (P) The hot gas is not burned in the flare stack (7) as in the prior art. As described above, since the fuel is consumed only by the thermal power generation facility (P), the energy efficiency of the LNG is increased. That is, fuel consumption in the thermal power generation facility (P) can be greatly reduced.
Further, since hot gas is not burned in the flare stack (7) as in the prior art, adverse effects on the environment due to the release of CO ₂ can be suppressed.
Even if the hot gas processing system (11) is changed from the flare stack (7) to the BOG processing system (21), it can be used as fuel gas for the thermal power generation facility (P).

  In the invention of the above method, the LNG vaporized gas supplied to the combustion furnace (6) of the thermal power generation facility (P) does not need to be increased above the delivery pressure as in the case of city gas, and the operation cost is reduced. Can do.

  The hot-up device of the present invention mainly comprises an LNG tank, an LNG pump, an LNG vaporizer, a hot gas processing system, and a hot gas recovery system, and uses LNG as a fuel gas for a combustion furnace of a thermal power generation facility. It is a device that is hot-up so that it can.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic system diagram illustrating a hot-up apparatus using an LNG pump according to the first embodiment. FIG. 2 is a flowchart showing hot-up by the LNG pump according to the first embodiment.
The hot-up apparatus using an LNG pump according to the present invention is an apparatus mainly composed of an LNG tank 1, an LNG pump 2, an LNG vaporizer 3, a hot gas processing system 11, and a hot gas recovery system 12.

  The LNG unloaded from the LNG carrier T at the LNG base is stored in the LNG tank 1 that is stored at a low temperature of −162 ° C. The LNG stored in the LNG tank 1 is boosted to a required pressure by the LNG pump 2, guided to the LNG vaporizer 3, and re-vaporized to be used as vaporized gas.

  In this LNG vaporizer 3, seawater etc. are pumped up by the seawater pump 4, and it vaporizes by heat exchange of this seawater. At this time, LNG at -162 ° C is heated to about -150 ° C.

  Next, in the hot gas processing system 11, a part of the LNG vaporized gas is extracted from the gas supply pipe 5 on the outlet side of the LNG vaporizer 3, and this gas is led to the LNG pump 2 as hot gas, and the LNG at −150 ° C. The temperature is raised to room temperature. LNG can be heated up to 18 ° C. by heat exchange with the hot gas.

  In the invention of the first embodiment, a hot gas recovery system 12 is provided that uses the LNG vaporized gas used as heat gas from the hot gas processing system 11 as fuel gas for the combustion furnace 6 of the thermal power generation facility P. . In the conventional hot gas recovery system 12, hot gas used for heat exchange is stored in a flare stack (tank) and is combusted in the flare stack 7. Was changed from the flare stack 7 to the gas delivery mother pipe 5 and used as a fuel for power generation.

This is because LNG hot-up facilities for supplying city gas have strict gas delivery conditions such as the flow rate of vaporized gas, delivery pressure and heat quantity. However, this is because it is not necessary to make the sending conditions strict in the LNG hot-up equipment provided in the thermal power generation equipment P. Furthermore, since the amount of CO ₂ emission can be reduced, the environment is not adversely affected.

The LNG thus hot-up is supplied to the combustion furnace 6 in the thermal power generation facility P and used as fuel gas. For example, in the hot up device of the present invention, the fuel consumption reduction amount is about 45,000 yen / unit. In addition, the CO ₂ emission reduction amount is about 6.5 t / unit.

FIG. 3 is a schematic system diagram showing a hot-up apparatus using the LNG pump according to the second embodiment.
In the hot-up apparatus using the LNG pump according to the second embodiment, in order to use the conventional BOG compressor 9, the LNG vaporized gas used for heat exchange as the hot gas from the hot gas processing system 11 is used again as the fuel gas. Therefore, a BOG processing system 21 for the BOG compressor 9 was provided.

  Even in the facility of the second embodiment, even if the outlet side of the hot gas processing system 11 is changed from the flare stack 7 to the BOG processing system 21 of the LNG tank 1, it is used as the fuel gas of the combustion furnace 6 of the thermal power generation facility P. be able to.

In the present invention, if hot gas is reused not only for heat exchange but also as fuel, the fuel consumption in the thermal power generation facility P can be reduced and the amount of carbon dioxide (CO ₂ ) released can be reduced. Of course, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  The hot-up apparatus using the LNG pump and the hot-up method thereof according to the present invention can be used in addition to thermal power generation equipment as long as it is a plant that uses the LNG vaporized gas as fuel gas adjacent to the hot-up apparatus.

1 is a schematic system diagram illustrating a hot-up device using an LNG pump according to Embodiment 1. FIG. It is a flowchart which shows the hot up by the LNG pump of Example 1. FIG. It is a schematic system diagram which shows the hot-up apparatus by the LNG pump of Example 2. It is a schematic system diagram of the conventional LNG hot-up equipment. It is a flowchart which shows the hot up of the conventional LNG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 LNG tank 2 LNG pump 3 LNG vaporizer 5 Gas supply pipe 6 Combustion furnace 9 BOG compressor 11 Hot gas processing system 12 Hot gas recovery system 13 Hot gas compressor 21 BOG processing system P Thermal power generation equipment T LNG dedicated ship

Claims (5)

A LNG pump hot-up device for hot-up so that LNG can be used as a fuel gas for a combustion furnace (6) of a thermal power generation facility (P),
An LNG tank (1) for storing LNG;
An LNG pump (2) for raising the temperature and raising the pressure of the LNG extracted from the LNG tank (1);
An LNG vaporizer (3) that raises and evaporates LNG heated and raised by the LNG pump (2) by heat exchange with seawater or the like;
A hot gas processing system (11) for extracting LNG vaporized gas from a gas delivery pipe (5) on the outlet side of the LNG vaporizer (3) and leading it to the LNG pump (2) as hot gas;
LNG vapor used for heat exchange as hot gas from the hot gas processing system (11) is sent to the gas supply pipe (5) for reuse as fuel gas for the thermal power generation facility (P). A hot-up device using an LNG pump, comprising a gas recovery system (12).   The hot-up apparatus using an LNG pump according to claim 1, wherein the hot-gas recovery system (12) is provided with a hot-gas compressor (13) that pressurizes and raises the temperature of hot gas used by heat exchange. A LNG pump hot-up device for hot-up so that LNG can be used as a fuel gas for a combustion furnace (6) of a thermal power generation facility (P),
An LNG tank (1) for storing LNG;
An LNG pump (2) for raising the temperature and raising the pressure of the LNG extracted from the LNG tank (1);
An LNG vaporizer (3) that raises the temperature of the LNG that has been heated and raised by the LNG pump (2) and vaporizes the LNG by heat exchange with seawater or the like;
A return gas from the LNG carrier (T), and a BOG compressor (9) for raising and raising the pressure of the BOG naturally vaporized by heat input into the LNG tank (1),
A hot gas processing system (11) for extracting LNG vaporized gas from a gas delivery pipe (5) on the outlet side of the LNG vaporizer (3) and leading it to the LNG pump (2) as hot gas;
A BOG treatment system (21) for leading the LNG vaporized gas used for heat exchange as hot gas from the hot gas treatment system (11) to the BOG compressor (9) for re-use as a fuel gas; A hot-up device using an LNG pump. The LNG stored in the LNG tank (1) is led to the LNG pump (2), and the pressure is increased by the LNG pump (2), and the increased LNG is exchanged with seawater or the like by the LNG vaporizer (3). It is a hot-up method using an LNG pump that heats up and vaporizes, and heats up the vaporized LNG so that it can be used as a fuel gas for the combustion furnace (6) of the thermal power generation facility (P),
The LNG vaporized gas is extracted from the gas supply pipe (5) on the outlet side of the LNG vaporizer (3) and led to the LNG pump (2) as hot gas,
The LNG pump used in the heat exchange in the LNG pump (2) as a hot gas is also reused as a fuel gas for the combustion furnace (6) of the thermal power generation facility (P). Method.   The LNG vaporized gas used for heat exchange as hot gas in the LNG pump (2) is pressurized and then used as fuel gas for the combustion furnace (6) of the thermal power generation facility (P). The hot-up method by the LNG pump of Claim 4.

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