JP6833908B2 - Floating equipment on the water - Google Patents

Description

The present invention relates to floating floating equipment.

Generally, a vessel that transports LNG (liquefied natural gas) is known (see, for example, Patent Document 1). LNG transported by such a ship is regasified using the heat of seawater via FSRU (floating storage regasification unit) and sent to onshore equipment. .. It is known that the electric power required for the operation as FSRU is generated by using a diesel generator using fossil fuel or the like.

JP-A-2019-34665

However, if the cold heat of LNG is warmed with seawater and the cooled seawater flows out into the sea as it is, there is a concern that it may affect the natural environment such as the ecosystem. In addition, if the exhaust heat is cooled by seawater using a diesel generator for operation and the seawater flows out, there is also a concern about the impact on the natural environment.

An object of the embodiment of the present invention is to provide a floating floating device that functions as an FSRU that utilizes water in a natural environment and suppresses an influence on the natural environment.

The floating floating equipment according to the viewpoint of the present invention includes a tank for storing a liquid gas, a vaporizing means for vaporizing the gas stored in the tank, and the gas vaporized by the vaporizing means on land. A Rankine cycle that generates power by the Rankine cycle based on the temperature difference between the gas delivery means to be sent to the equipment, the water uptake means for taking in water in the natural environment, and the water taken in by the gas and the water uptake means. A power generation means, a first heating means for heating the Rankine cycle medium used in the Rankine cycle based on the water taken in by the water intake means, and another power generation means different from the Rankine cycle power generation means. , The fresh water is cooled based on the second heating means for heating the Rankine cycle medium based on the fresh water used for cooling the other power generation means and the water taken in by the water intake means. Provided with cooling means .

According to an embodiment of the present invention, it is an object of the present invention to provide a floating floating device that functions as an FSRU that utilizes water in a natural environment and suppresses an influence on the natural environment.

The block diagram which shows the structure of the floating body type equipment which concerns on embodiment of this invention. The Ts diagram which shows the temperature / specific enthalpy of ORC which concerns on this embodiment.

(Embodiment)
FIG. 1 is a configuration diagram showing a configuration of a floating floating equipment 1 according to an embodiment of the present invention.
The water-floating equipment 1 is a water-floating (offshore floating) LNG terminal that stores LNG, regass the stored LNG, and sends high-pressure gas to equipment on land (for example, a gas pipe). That is, the floating floating equipment 1 is an FSRU. Further, the floating floating equipment 1 is a navigable mobile body (for example, a ship).

The floating device 1 has a function of storing a liquid gas (for example, LNG), regasifying (vaporizing) the gas, and sending it to land, and water such as seawater, river water, or lake water. Any shape and structure may be used as long as the equipment floats on the surface. For example, the floating floating equipment 1 does not have to be in the shape of a ship, and may not have a propulsion equipment. Here, the floating floating equipment 1 will be described mainly as a vessel that navigates the ocean.

The floating body type equipment 1 includes a turbo generator 3, an LNG vaporizer 4, an organic medium circulation pump 5, a first heat exchanger 6, a second heat exchanger 7, a third heat exchanger 8, and a fourth heat exchanger 9. , 5th heat exchanger 10, diesel generator 11, recondenser (reliquefaction device) 12, LNG booster pump 13, trim heater (heat exchanger for regas temperature adjustment) 14, LNG tank 15, feed pump ) 16, BOG (boil off gas) compressor 17, heating seawater pump 18, heating medium circulation pump 19, cooling seawater pump 20, cooling fresh water booster pump 21, organic medium piping L1, LNG piping L2, BOG piping L3, A seawater pipe L4, a heating medium pipe L5, a cooling fresh water pipe L6, and a regas pipe L7 are provided.

The organic medium pipe L1 is a pipe through which the organic medium used in the power generation system 2 flows. The organic medium pipe L1 is configured such that the organic medium circulates between the LNG vaporizer 4 and the turbo generator 3. The organic medium pipe L1 includes a path from the LNG vaporizer 4 to the turbo generator 3 sequentially passing through the first heat exchanger 6 and the second heat exchanger 7, and from the LNG vaporizer 4 to the first heat exchanger 6. The path is configured to branch into a path that passes through the third heat exchanger 8 and a path that does not pass through the third heat exchanger 8 (bypass). While the BOG compressor 17 is operating, the organic medium flows through a path that passes through the third heat exchanger 8, and while the BOG compressor 17 is stopped, the organic medium flows through a path that does not pass through the third heat exchanger 8. It flows. The order in which the organic medium passes through the three heat exchangers 6 to 8 may be configured in any order. The organic medium is, for example, propane, but it may not be a flammable medium but a non-flammable medium having thermal characteristics close to those of propane.

The LNG pipe L2 is configured so that LNG is sent from the LNG tank 15 to the recondenser 12. LNG may have any composition.
The BOG pipe L3 is configured such that BOG (boil off gas) is sequentially sent from the upper part of the LNG tank 15 to the recondenser 12 via the BOG compressor 17 and the third heat exchanger 8. Further, the BOG pipe L3 is provided with a path for sending the BOG for fuel supply of the diesel generator 11. BOG is a gaseous natural gas in which a part of LNG accumulated in the LNG tank 15 is vaporized by heat input.

In the seawater pipe L4, seawater taken in from outside the ship is sent to each of the 4th heat exchanger 9 and the 5th heat exchanger 10, and is heated or heated from each of the 4th heat exchanger 9 and the 5th heat exchanger 10. The seawater used for cooling is configured to be discharged overboard.

The heating medium pipe L5 is a pipe through which the heating medium flows. In the heating medium pipe L5, the heating medium circulates between the fourth heat exchanger 9 and the trim heater 14 and between the fourth heat exchanger 9 and the first heat exchanger 6. It is configured to include a route to do so. The heating medium is used to heat the organic medium by the first heat exchanger 6, and is also used as the heating medium of the trim heater 14.

Here, if the organic medium is directly heated with seawater, there is a risk that the seawater freezes in the first heat exchanger 6. Therefore, a heating medium, which is an antifreeze heat medium, is used as an intermediate medium between the organic medium and seawater. For example, the heating medium is an aqueous ethylene glycol solution (glycol water), but other media such as propane may also be used.

The cooling fresh water pipe L6 is a pipe through which fresh water flows to cool the engine supply air with an air cooler of the diesel generator 11. The cooling fresh water pipe L6 is configured so that fresh water flows and circulates in sequence through the fifth heat exchanger 10, the diesel generator 11, and the second heat exchanger 7.
The regas pipe L7 is configured so that vaporized (regasified) natural gas is sent from the LNG vaporizer 4 to the onshore equipment via the trim heater 14.

The power generation system 2 includes a turbo generator 3, an LNG vaporizer 4, an organic medium circulation pump 5, a first heat exchanger 6, a second heat exchanger 7, a third heat exchanger 8, and an organic medium pipe L1. Will be done.
The power generation system 2 is an organic Rankine cycle (ORC) type power generation system that generates power by a Rankine cycle using an organic medium. Power is generated by the turbo generator 3 by utilizing the temperature difference between the LNG cold heat and other heat sources.

The outline of the operation of the power generation system 2 is as follows. Each heat exchanger 6 to 8 heats (vaporizes) an organic medium to produce superheated steam. The turbo generator 3 rotates the turbine by expanding the superheated steam produced by the heat exchangers 6 to 8 in the turbine. The turbo generator 3 generates electricity by this rotational force (work). The organic medium that has worked in the turbine of the turbo generator 3 is cooled by the LNG vaporizer 4 in a gas state or a gas-liquid mixed state to be condensed and liquefied, and returns to each of the heat exchangers 6 to 8. The power generation system 2 repeats this series of operations to perform a cycle for generating power.

The turbo generator 3 has a configuration in which a turbine rotor having wings is connected to the generator. The turbo generator 3 is a generator that uses a polymer organic medium instead of steam.
The LNG vaporizer 4 is a heat exchanger for absorbing heat from the organic medium flowing through the organic medium pipe L1 to vaporize (regasify) LNG. For example, the LNG vaporizer 4 is a shell & tube type, but other types may be used.

The organic medium circulation pump 5 is a pump for boosting the pressure of the condensed and liquefied organic medium cooled by the LNG vaporizer 4 and circulating the organic medium in the organic medium piping L1 of the power generation system 2. A tank for temporarily storing the liquefied organic medium may be provided on the upstream side of the organic medium circulation pump 5 (the wake side of the LNG vaporizer 4).

The first heat exchanger 6 heats the organic medium with the heating medium by exchanging heat between the organic medium flowing through the organic medium pipe L1 and the heating medium flowing through the heating medium pipe L5. The first heat exchanger 6 may or may not be used. In this case, the power generation system 2 uses the second heat exchanger 7 and the third heat exchanger 8 to perform the Rankine cycle by waste heat of the diesel generator 11 and heat recovery of the BOG compressor 17. Therefore, the floating floating equipment 1 may reduce the amount of seawater used.

The second heat exchanger 7 heats the organic medium with fresh water by exchanging heat between the organic medium flowing through the organic medium pipe L1 and the fresh water flowing through the cooling fresh water pipe L6. As a result, the second heat exchanger 7 heats the organic medium by utilizing the waste heat of the diesel generator 11.

The third heat exchanger 8 heats the organic medium with the BOG by exchanging heat between the organic medium flowing through the organic medium pipe L1 and the BOG flowing through the BOG pipe L3.
The fourth heat exchanger 9 heats the heating medium with seawater by exchanging heat between the seawater flowing through the seawater pipe L4 and the heating medium flowing through the heating medium pipe L5.
The fifth heat exchanger 10 cools the fresh water with seawater by exchanging heat between the seawater flowing through the seawater pipe L4 and the fresh water flowing through the cooling fresh water pipe L6.

The diesel generator 11 is a generator for supplying the electric power required for the regasification process (for example, the power source of the LNG booster pump 13, the BOG compressor 17, or the heating seawater pump 18) on board. .. The diesel generator 11 is a dual fuel-fired diesel generator that generates electricity by burning heavy oil and BOG supplied from the BOG compressor 17 as fuel. The diesel generator 11 may be another generator that does not use a diesel engine.

The recondenser 12 is a pressure vessel for reliquefying (recondensing) a part of the BOG supplied from the BOG compressor 17. The recondenser 12 reliquefies (recondenses) a part of the BOG by utilizing the latent heat of vaporization caused by spraying LNG on the BOG inside the pressurized state. The reliquefied BOG is mixed with the sprayed LNG and sent to the LNG vaporizer 4 by the LNG booster pump 13. The reliquefied BOG may be returned to the LNG tank 15.

The LNG booster pump 13 is a pump for boosting LNG (including reliquefied BOG) supplied from the recondenser 12 and sending it to onshore equipment via the LNG vaporizer 4. The LNG booster pump 13 determines the design discharge pressure according to the required pressure on the land side. The LNG booster pump 13 has a role as a suction drum that keeps the liquid level above a certain level in order to prevent idle operation.

The trim heater 14 heats the regas with the heating medium by exchanging heat between the heating medium flowing through the heating medium pipe L5 and the regas flowing through the regas pipe L7. Since the heating medium is heated by seawater by the fourth heat exchanger 9, the trim heater 14 is a heat exchanger that uses seawater as a heat source for heating. The trim heater 14 heats the regas sent from the LNG vaporizer 4 to the regas pipe L7 to adjust the temperature of the regas. The capacity of the trim heater 14 is determined to meet the required pressure on the land side.

The LNG tank 15 is a tank for storing LNG. BOG in which a part of LNG is evaporated and vaporized is accumulated in the upper part of the LNG tank 15.

The feed pump 16 is installed on the bottom surface of the LNG tank 15 and is connected to the LNG pipe L2. The feed pump 16 is a pump for sending an amount of LNG required for regas from the LNG tank 15 to the recondenser 12.

The BOG compressor 17 is a gas compressor that sucks in the BOG accumulated in the upper part of the LNG tank 15, compresses it, and sends it to the recondenser 12. The BOG compressor 17 is used for pressure control of the LNG tank 15. As the BOG continues to increase, the internal pressure of the LNG tank 15 rises, so the BOG compressor 17 compresses the BOG in order to protect the LNG tank 15. The compressed BOG is sent to the recondenser 12 or incinerated as fuel for the diesel generator 11.

The seawater pump 18 for heating is provided in the seawater pipe L4. The heating seawater pump 18 is a pump for taking in seawater from the outboard and sending it to the fourth heat exchanger 9.

The heating medium circulation pump 19 is a pump for boosting and circulating the heating medium. The heating medium circulation pump 19 is provided in the heating medium pipe L5.

The cooling seawater pump 20 is provided in the seawater pipe L4. The cooling seawater pump 20 is a pump for taking in seawater from the outboard and sending it to the fifth heat exchanger 10.

The cooling fresh water booster pump 21 is provided in the cooling fresh water pipe L6. The cooling fresh water booster pump 21 boosts the fresh water used for cooling the diesel generator 11 to sequentially circulate the diesel generator 11, the second heat exchanger 7 of the power generation system 2, and the fifth heat exchanger 10. It is a pump of.

Next, the power generation system 2 will be described.
The power generation system 2 is formed by a closed cycle of the organic medium flowing through the organic medium pipe L1. The organic medium is heated and vaporized by the heat recovered from the gas wake of the BOG compressor 17, the heat obtained from seawater, and the heat obtained from the waste heat of the diesel generator 11. The difference between those heats and the cold heat obtained from LNG liquefies the organic medium to generate expansion force. The turbo generator 3 converts this expansion force into rotational energy to generate electricity.

The organic medium is boosted by the organic medium circulation pump 5 and circulates in the organic medium pipe L1. As the primary heating of the organic medium, the third heat exchanger 8 recovers the excess heat given to the BOG pipe L3 by the BOG compressor 17. As the secondary heating of the organic medium, the first heat exchanger 6 takes in heat from seawater through the heating medium. This heating medium takes in heat from seawater via the fourth heat exchanger 9. As the tertiary heating (and vaporization) of the organic medium, the second heat exchanger 7 recovers the waste heat given to the fresh water for cooling the diesel generator 11. Through these heating and vaporization processes, the organic medium is given the energy required for power generation, and by passing through the turbo generator 3, the power generation system 2 obtains electric power.

FIG. 2 is a Ts diagram showing the temperature / specific enthalpy of the organic medium used in the ORC of the power generation system 2 according to the present embodiment. Further, FIG. 2 shows the saturation curve Cs of the organic medium.
The organic medium output from the LNG vaporizer 4 is boosted by the organic medium circulation pump 5 to circulate the organic medium pipe L1 so as to execute ORC (state P5).

The organic medium is heated in two phases of liquid or gas-liquid by the first heat exchanger 6 and the third heat exchanger 8 (states P6 and P8). While the BOG compressor 17 is in operation, the organic medium passes through the third heat exchanger 8 in order to recover the heat of the wake of the BOG compressor 17 (state P8). While the BOG compressor 17 is stopped, the organic medium passes through a bypass that does not pass through the third heat exchanger 8.

The organic medium is heated by the second heat exchanger 7 that utilizes the waste heat of the diesel generator 11. As a result, at least a part of the liquid state (state P7a) is finally vaporized (state P7b). The vaporized organic medium enters the turbo generator 3 in a high temperature and high pressure state (state P3), performs work (power generation), and returns to the LNG vaporizer 4. At this time, the organic medium returns from the gaseous state (state P4a) to the liquid state (state P4b).

Next, the operation in which LNG is regasified and sent to equipment on land will be described.
When regasifying LNG by the LNG vaporizer 4, the LNG in the LNG tank 15 is sent to the recondenser 12 by the feed pump 16. Further, the BOG accumulated in the upper part of the LNG tank 15 is sent to the recondenser 12 via the third heat exchanger 8 by the BOG compressor 17. Therefore, the temperature of the BOG is lowered by the third heat exchanger 8 before being sent to the recondenser 12.

In the recondenser 12, the LNG sent by the feed pump 16 is sprayed, and a part of the BOG sent from the BOG compressor 17 is reliquefied. At this time, since the temperature of the BOG is lowered in advance, the reliquefaction efficiency is improved, and the recondenser 12 can reliquefy more BOG.

The reliquefied BOG and the LNG sent from the LNG tank 15 are boosted to a predetermined pressure by the LNG booster pump 13 and sent to the LNG vaporizer 4. The LNG vaporizer 4 regasses the sent LNG and sends it to the trim heater 14. The trim heater 14 regulates the temperature of the sent natural gas and sends it to the equipment on land.

According to this embodiment, the following effects can be obtained.
The power generation system 2 is a closed-loop type that heats LNG using steam as a heat source, but an indirect heating system that regasifies an organic medium by using the heat source of seawater (water in the natural environment) via an intermediate medium. Since it is adopted, it also has the advantage of an open loop type.

Specifically, fuel consumption and carbon dioxide emissions can be suppressed as compared with the closed-loop type that regasifies without using the heat source of seawater. Further, by adopting the indirect heating system, it is possible to suppress the influence on the natural environment (for example, the ecosystem) due to the decrease in seawater temperature due to the cold heat of LNG. Further, it is possible to avoid the risk of seawater circulating in each device (LNG vaporizer 4 or the like) of the floating floating equipment 1 (for example, damage to the tube due to freezing of seawater).

Further, since the power generation system 2 performs LNG cryogenic power generation using LNG cold heat, the LNG cold heat flowing into the seawater can be further reduced.
Further, by providing a second heat exchanger 7 for heating the organic medium with fresh water for cooling the diesel generator 11, the energy efficiency of the power generation system 2 is improved, and the diesel generator 11 is discharged as seawater. Waste heat can be reduced. As a result, it is possible to suppress the influence on the natural environment due to the rise in seawater temperature.

Here, it is necessary to operate the BOG compressor 17 in order to send the surplus BOG to the recondenser 12. This raises the temperature of the BOG and gives the BOG extra heat for the reliquefaction process. Due to this extra heat input, the reliquefaction efficiency decreases and the rate of increase in the internal pressure of the LNG tank 15 increases. When the internal pressure of the LNG tank 15 rises above a certain level, it is necessary to incinerate the BOG to protect the LNG tank 15. As a result, the energy efficiency of the floating floating equipment 1 as a whole is reduced, and the amount of carbon dioxide generated is increased.

Therefore, in the floating body type equipment 1, the energy efficiency of the power generation system 2 is improved and the reliquefaction efficiency by the recondenser 12 is improved by providing the third heat exchanger 8 for heating the organic medium by BOG. Can be done. As a result, the internal pressure of the LNG tank 15 can be efficiently reduced, and the amount of BOG incinerated can be reduced.

Therefore, by applying the power generation system 2 that utilizes LNG cold heat to the FSRU, the floating body type equipment 1 can suppress the influence on the natural environment and reduce the energy required for the operation as the FSRU.

1 ... floating equipment, 2 ... power generation system, 3 ... turbo generator, 4 ... LNG vaporizer, 5 ... organic medium circulation pump, 6-10 ... heat exchanger, 11 ... diesel generator, 12 ... recondenser, 13 ... LNG booster pump, 14 ... trim heater, 15 ... LNG tank, 16 ... feed pump, 17 ... BOG compressor, 18 ... heating seawater pump, 19 ... heating medium circulation pump, 20 ... cooling seawater pump, 21 ... Cooling fresh water booster pump, L1 ... Organic medium piping, L2 ... LNG piping, L3 ... BOG piping, L4 ... Seawater piping, L5 ... Heating medium piping, L6 ... Cooling fresh water piping, L7 ... Regas piping.

Claims (10)

A tank for storing liquid gas and
A vaporizing means for vaporizing the gas stored in the tank and
A gas delivery means for delivering the gas vaporized by the vaporization means to equipment on land, and a gas delivery means.
Water intake means for taking in water in the natural environment,
A Rankine cycle power generation means that generates electricity by the Rankine cycle based on the temperature difference between the gas and the water taken in by the water intake means .
A first heating means for heating the Rankine cycle medium used in the Rankine cycle based on the water taken in by the water uptake means, and
With other power generation means different from the Rankine cycle power generation means,
A second heating means for heating the Rankine cycle medium based on fresh water used for cooling the other power generation means, and
A floating device on the water, comprising a cooling means for cooling the fresh water based on the water taken in by the water taking-in means. A compression means for compressing the vaporized gas generated inside the tank, and
The floating device on water according to claim 1 , further comprising a liquefaction means for liquefying the gas compressed by the compression means. The floating device on water according to claim 2 , further comprising a third heating means for heating the Rankine cycle medium with the gas compressed by the compression means. A tank for storing liquid gas and
A vaporizing means for vaporizing the gas stored in the tank and
A gas delivery means for delivering the gas vaporized by the vaporization means to equipment on land, and a gas delivery means.
Water intake means for taking in water in the natural environment,
A Rankine cycle power generation means that generates electricity by the Rankine cycle based on the temperature difference between the gas and the water taken in by the water intake means .
A first heating means for heating the Rankine cycle medium used in the Rankine cycle based on the water taken in by the water uptake means, and
A compression means for compressing the vaporized gas generated inside the tank, and
A liquefaction means for liquefying the gas compressed by the compression means,
A floating device on the water , comprising a second heating means for heating the Rankine cycle medium with the gas compressed by the compression means. With other power generation means different from the Rankine cycle power generation means,
The floating floating equipment according to claim 4 , further comprising a third heating means for heating the Rankine cycle medium based on fresh water used for cooling the other power generation means. The floating floating equipment according to claim 5 , further comprising a cooling means for cooling the fresh water based on the water taken in by the water taking-in means. The first heating means heats the Rankine cycle medium using the intermediate medium heated by the water.
The floating floating equipment according to claim 1 or 4. The other power generation means, water floating facility according to claim 1 or claim 5, characterized in that the vaporized the gas generated within the tank and fuel. The water surface according to claim 1 or 4 , further comprising a temperature adjusting means for adjusting the temperature of the gas vaporized by the vaporizing means based on the water taken in by the water taking means. Floating equipment. The floating floating equipment according to claim 1 or 4 , wherein the facility has a function of moving on water.

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