KR20180043525A - Power generating and desalination composite plant - Google Patents

Abstract

The present invention provides a power generation and desalination composite plant. The power generation and desalination composite plant comprises: a liquefied natural gas storage tank; a gasifier for gasifying liquefied natural gas supplied from the storage tank; a power generation plant for producing electricity by using the gasified gas; and a desalination plant for producing fresh water by cooling sea water below a freezing point through heat exchange by using cold energy of the liquefied natural gas in the gasifier, thereby capable of improving power generation efficiency of the composite plant.

Description

{POWER GENERATION AND DESALINATION COMPOSITE PLANT}

The present invention relates to a combined power generation and desalination plant, and more particularly, to a combined power generation and desalination plant in which a power generation plant and a desalination plant are integrated into a floating structure capable of storing and vaporizing liquefied natural gas

Recently, people's living standards have been improved due to rapid industrialization, but water shortage due to drought phenomenon is frequently occurring in various places all over the world due to the climate change due to pollution of the natural environment. This phenomenon is a global trend, It is expected to become serious. In order to solve the above water shortage problem, there are dam construction and ground water development. However, in case of dam construction, it is not easy to construct the dam because damages to the natural environment and dam construction are very costly. , The groundwater resources are exhausted due to indiscreet development, and groundwater contamination is severe, so it is not easy to secure water resources and it is not a fundamental solution in the long term.

In order to solve these problems, advanced countries such as USA, Japan and Germany have already developed methods for obtaining fresh water from seawater which has been rich in water resources for a long time and use it as drinking water or industrial water. Methods for obtaining fresh water from seawater include evaporation method in which seawater is heated to obtain fresh water using evaporation and condensation properties of water, reverse osmosis method in which fresh water is obtained by separating fresh water and salt water from a seawater by using a high pressure pump, When steam is generated and steam is condensed to obtain fresh water, the sea water is cooled at the freezing point (-1.8 ℃) or lower, and the salt in the seawater is excluded from the growth interface of the ice, and crystals of ice are precipitated. And a freezing determination method in which seawater in the concentrated seawater between the surface and the crystal is separated and washed to desolate seawater.

Among these desalination facilities, the desalination of the freeze-crystallization method is performed at a low temperature, so that the corrosion of the system is minimized due to the low temperature and there is no fear of scaling or sedimentation. However, this concept of desalination has been introduced since the 1950s, and there have been studies on the system cycle using the desalination method. However, since there is no commercialized plant in the world, the main components of the desalination system Continuous research on cycle performance improvement is needed.

An object of the present invention is to provide a combined power generation and desalination plant capable of improving power generation efficiency of a complex plant as a plant in which a power generation facility and a desalination plant are combined.

An object of the present invention is to provide a combined power generation and desalination plant in which an exhaust gas treatment system of a power generation facility can be linked to a desalination plant to enhance efficiency.

An object of the present invention is to provide a combined power generation and desalination plant capable of improving desalination performance with less energy in conjunction with an electric power generation facility.

An object of the present invention is to provide a combined power generation and desalination plant capable of increasing the efficiency of reducing exhaust gas generated in a power generation facility using a desalination plant.

The problems to be solved by the present invention are not limited thereto, and other matters not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the invention, there is provided a liquefied natural gas storage tank; A vaporizer for vaporizing the liquefied natural gas provided from the storage tank; A power generation plant for generating power using the vaporized gas; And a desalination plant including a desalination plant for cooling the seawater below the freezing point through heat exchange using cold heat of liquefied natural gas in the vaporizer to produce fresh water.

The desalination plant may further include: a seawater cooler for cooling the seawater below the freezing point; A first heat exchanger for heat exchange between the seawater cooler and the vaporizer; A separator for separating the ice made in the seawater cooler from a function and a dissolver for dissolving the ice separated from the separator.

The apparatus may further include a waste heat recovery unit for dissolving ice in the desalination plant using exhaust gas discharged from the power generation plant.

The apparatus may further include a second heat exchanger for heat exchange between the dissolver and the waste heat recovering unit.

The apparatus may further include a scrubber for removing impurities contained in the exhaust gas that has passed through the waste heat recovering unit.

The apparatus may further include a seawater supply line for supplying seawater cooled in the seawater cooler to the scrubber.

The apparatus may further include a fresh water supply line for supplying fresh water dissolved in the dissolver to the scrubber.

The apparatus may further include a third heat exchanger for exchanging heat between the seawater cooled in the seawater cooler and the exhaust gas of the scrubber.

The apparatus may further include a knox oxidation device for removing nitrogen oxides (NOx) from the exhaust gas discharged from the power plant, The knox oxidation apparatus may be provided between the waste heat recoverer and the scrubber or between the power generation plant and the waste heat recoverer.

Further, a fuel cell system for generating electric power using the vaporized gas; And a steam supply line for converting the fresh water dissolved in the dissolver into water vapor through heat exchange in the waste heat recoverer and supplying the water vapor to the fuel cell facility.

According to the embodiments of the present invention, the power generation facility and the desalination facility are combined, and the power generation efficiency of the complex plant is remarkably improved.

According to the embodiment of the present invention, the exhaust gas treatment of the electric power generation facility has a remarkable effect of increasing the efficiency in connection with the desalination facility.

According to the embodiment of the present invention, there is a remarkable effect that the desalination performance can be improved with less energy.

According to the embodiments of the present invention, it is possible to enhance the efficiency of reducing the exhaust gas generated in the electric power generation facility.

 The effects of the present invention are not limited to the above-mentioned effects, and the effects not mentioned can be clearly understood by those skilled in the art from the present specification and the accompanying drawings.

1 is a configuration diagram showing a combined power generation and desalination plant according to a first embodiment of the present invention.
2 is a configuration diagram showing a first modification of the power generation and desalination complex plant according to the first embodiment of the present invention.
3 is a configuration diagram showing a second modified example of the combined power generation and desalination plant according to the first embodiment of the present invention.
4 is a configuration diagram showing a third modified example of the combined power generation and desalination plant according to the first embodiment of the present invention.
5 is a configuration diagram showing a fourth modified example of the combined power generation and desalination plant according to the first embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and will be described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout the specification and claims. The description will be omitted.

1 is a configuration diagram showing a combined power generation and desalination plant according to a first embodiment of the present invention.

Referring to FIG. 1, a combined power generation and desalination plant 10 may include a liquefied natural gas storage tank 100, a vaporizer 200, a power generation plant 300, and a desalination plant 400.

The power generation and desalination complex plant 10 may be provided in the floating structure 1000. The floating floating structure 1000 includes a hull 1100 and a liquefied natural gas storage tank 100, a vaporizer 200, a power generation plant 300 and a desalination plant 400 may be installed in the hull 110 have.

In this specification, the floating structure 1000 is a concept including both a structure and a ship which are floated at sea while having a storage tank for storing a liquid cargo to be loaded at a cryogenic temperature like LNG, for example, (LNG Regasification Vessel) as well as offshore structures such as LNG FPSO (Floating, Production, Storage and Offloading) and LNG FSRU (Floating Storage and Regasification Unit).

It is preferable that the liquefied natural gas storage tank 100 is disposed on the side of the ship 1100 and the liquefied natural gas storage tank 100 is disposed below the deck 1110 of the ship 1100 so as to improve space utilization. Although not shown, a liquefied natural gas storage tank 100 may be connected to a supply line of a liquefied natural gas carrier, and the liquefied natural gas may be supplied through the supply line and stored.

The vaporizer 200 is configured to vaporize the liquefied natural gas of the liquefied natural gas storage tank 100 and may be installed above or below the deck 1110 of the hull 1100. A liquefied natural gas supply line 110 is connected between the liquefied natural gas storage tank 100 and the vaporizer 200 and the liquefied natural gas is supplied to the liquefied natural gas storage tank 100 through the liquefied natural gas supply line 110. [ To the vaporizer (200).

It is preferable that the power generation plant 300 is arranged adjacent to the vaporizer in consideration of the arrangement relationship with the liquefied natural gas storage tank 100, the vaporizer 200 and the like, To produce power. A vaporizing gas supply line 210 is connected between the vaporizer 200 and the power generation plant 300 and vaporized gas is supplied to the power plant 300 through the vaporizing gas supply line 210.

The power generation plant 300 uses the vaporized gas generated in the vaporizer 200 as a fuel to produce electric power by burning the vaporized gas. For example, steam generated by burning a vaporized gas generates steam of high temperature and high pressure, So that the turbine can be driven to generate electric energy.

For example, the power generation plant 300 may include a power generation unit 310, a waste heat recovery unit 320, a knox oxidation unit 330, and a scrubber 340.

Although not shown, the power generation unit 310 includes a gas turbine driven by being supplied with natural gas and driven by combustion, an arrangement recovery boiler for generating steam from the exhaust gas discharged from the gas turbine as a heat source, And a generator for converting the kinetic energy of the gas turbine and the steam turbine into electrical energy.

The waste heat recovering unit 320 is preferably disposed adjacent to the power generating unit 310 and may be disposed adjacent to the desalination plant 400 using energy such as high temperature and high pressure steam, electric energy, waste heat of the exhaust gas generated in the power generating unit 310, As shown in FIG.

The knox oxidation unit 330 removes nitrogen oxides (NOx) from the exhaust gas discharged from the power generation unit 310. In other words, the knox oxidation apparatus is a device for oxidizing NO - > NO2 to remove NOx from the scrubber 340. In general, the scrubber 340 can not remove NOx. However, when the NOx removal catalyst is converted into the NO2 form by using such a device, the NOx can be removed by reacting with the H 2 O to form HNO 3. (Specific method: oxidation with NO -> NO2 using ozone, plasma, sodium hypochlorite (NaOCl)

The scrubber 340 removes impurities (for example, sulfur oxides) contained in the exhaust gas passing through the waste heat recoverer 320. In the scrubber 340, seawater and fresh water are used to cool the exhaust gas or to remove impurities, and fresh water can be used by receiving some of the cold seawater not frozen in the seawater cooler 410.

Accordingly, the efficiency of the water used for the scrubber 430 can be improved as the temperature is lower, and if the scrubber 430 is scrubbed with the seawater having a low temperature, the white smoke phenomenon can be drastically reduced.

The desalination plant (400) is a desalination plant for freezing crystal method in which fresh water is cooled by cooling the seawater below the freezing point through heat exchange using the cold heat of liquefied natural gas. The desalination plant 400 may include a seawater cooler 410, a first heat exchanger 420, an ice separator 430, a dissolver 440, and a second heat exchanger 450.

1, the seawater cooler 410 of the desalination plant 400 is operated using the cooling heat source of the vaporizer 200. As shown in FIG.

To this end, the first heat exchanging part 420 may be provided with a structure for forming a closed loop tube between the evaporator 200 and the seawater cooler 410 and for circulating the heat medium in the closed loop tube. Heat medium is a generic term used for the transfer of heat. It is a material with low freezing point such as thermal (hot) oil, glycol water or evaporative refrigerant to prevent freezing by heat exchange with cryogenic LNG. Is preferably used.

The embodiment of the present invention forms a structure for circulating the heating medium between the vaporizer 200 and the seawater cooler 410 so that a part of the cold discharged in the process of vaporizing the liquefied gas is used to cool the seawater, 400 is improved.

The seawater cooler 410 is a device for cooling seawater (about 30 degrees Celsius) to a temperature of -10 to -30 degrees Celsius, and is a device for making water (fresh water) components into sea water when cooled slowly at a temperature of -30 degrees or more . The cold heat required for seawater cooling uses the heat required to vaporize the LNG.

 In the seawater cooler 410, the seawater is heat-exchanged with the heat medium of the first heat exchanging part 420 to freeze moisture, and ice particles are generated. The ice grains produced in the seawater cooler 410 are provided to the ice separator 430. The cooling seawater supply line 412 is connected between the seawater cooler 410 and the scrubber 340 and the seawater cooled in the seawater cooler 410 is supplied to the scrubber 340 through the cooling seawater supply line 412 .

In the ice separator 430, the ice and brine are separated, and the separated ice cleans the brine on the surface of the ice granules using a portion of the fresh water produced in the dissolver 440. The cleaned ice is supplied to the dissolver 440.

In the dissolver 440, the ice particles are melted through heat exchange with the heating medium of the second heat exchanging part 450 to generate fresh water. The second heat exchanging unit 450 may be provided with a structure for forming a closed loop pipe between the waste heat recovering unit 320 and the dissolver 440 and for circulating the heating medium in the closed loop pipe.

In this way, the heat required in the dissolver 440 can be reduced by using the exhaust gas heat (200 to 300 degrees Celsius) generated in the power generation portion and used. When the temperature of the exhaust gas supplied to the scrubber 340 is low, the scrubber efficiency is increased and the volume can be reduced.

The electricity generating plant 300 may be connected to an electric power supply line 390 for supplying electric power to an electric power demanding place on the land or a desalting unit for supplying desalination water to the desalination unit 440 of the desalination plant 400. [ A supply line 490 may be connected.

FIG. 2 is a configuration diagram showing a first modification of the power generation and desalination complex plant according to the first embodiment of the present invention.

2, the combined power generation and desalination plant 10a may include a liquefied natural gas storage tank 100, a vaporizer 200, a power generation plant 300, and a desalination plant 400, The present invention is provided with substantially the same constitution and function as the illustrated power generation and desalination complex plant 10, and therefore a modified example will be described focusing on differences from the present embodiment.

In this modification, the knox oxidation unit 330 is provided between the power generation unit and the waste heat recovery unit, but there is a difference therebetween.

3 is a configuration diagram showing a second modified example of the combined power generation and desalination plant according to the first embodiment of the present invention.

3, the combined power generation and desalination plant 10b may include a liquefied natural gas storage tank 100, a vaporizer 200, a power generation plant 300, and a desalination plant 400, The present invention is provided with substantially the same constitution and function as the illustrated power generation and desalination complex plant 10, and therefore a modified example will be described focusing on differences from the present embodiment.

In this modification, the fresh water provided in the scrubber can be used by receiving some of the fresh water produced in the dissolver. At this time, if necessary, the cold water of the seawater cooled in the seawater cooler 410 can be used to cool the fresh water and supply it to the scrubber. The scrubber is supplied with fresh water and can be used for heat exchange at a temperature of 70 ° C or lower, which is necessary for the operation of the scrubber.

4 is a configuration diagram showing a third modified example of the combined power generation and desalination plant according to the first embodiment of the present invention.

4, the combined power generation and desalination plant 10c may include a liquefied natural gas storage tank 100, a vaporizer 200, a power generation plant 300, and a desalination plant 400, The present invention is provided with substantially the same constitution and function as the illustrated power generation and desalination complex plant 10, and therefore a modified example will be described focusing on differences from the present embodiment.

In this modification, the third heat exchanger 480 for heat exchange between the scrubber and the cooling seawater supply line 412 is provided. The third heat exchanging part 480 is used for heat exchange with the temperature required for operation of the scrubber 340 using the cooled seawater. For example, if the scrubber 340 is of the close type, the efficiency increases when the number of circulating scrubbers (both fresh water or seawater) is continuously increased. The necessary cold heat is supplied from the cooled seawater or seawater cooler .

This heat exchange can be expected to reduce the white smoke by lowering the relative humidity by using very dry and low temperature air (heat exchange between the cooled seawater and the air) after the completion of the scrubber.

5 is a configuration diagram showing a fourth modified example of the combined power generation and desalination plant according to the first embodiment of the present invention.

5, the combined power generation and desalination plant 10d may include a liquefied natural gas storage tank 100, a vaporizer 200, a power generation plant 300, and a desalination plant 400, The present invention is provided with substantially the same constitution and function as the illustrated power generation and desalination complex plant 10, and therefore a modified example will be described focusing on differences from the present embodiment.

In this modified example, SCR (nitrogen oxide removal equipment) 460 can be used instead of the scrubber. When the SCR 460 is used, the higher the temperature of the exhaust gas, the higher the efficiency. In this case, the waste heat recoverer described above may or may not be used.

Therefore, a fuel cell (or a turbine can also be used) 600, which is an additional eco-friendly power generation device, is installed, the exhaust gas temperature of the power generation portion is increased by using the heat of the exhaust gas, have. That is, it may include a steam supply line 470 for converting the fresh water dissolved in the dissolver 440 into water vapor through heat exchange in the waste heat recovery unit and supplying it to the fuel cell facility.

In this case, the fuel of the fuel cell 600 uses the vaporized NG, and the fresh water required to reform the NG can use the fresh water produced in the desalination plant.

The present invention can be very usefully applied to areas lacking fresh water and electricity, such as island areas and developing countries. That is, the electric energy produced by the power generation plant 300 can be supplied to the demand site on the land via the electricity supply line 390, and the fresh water produced in the desalination plant can be supplied to the demand site on the land through the desalination supply line 490 have.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: liquefied natural gas storage tank 200: vaporizer
300: Power plant 400: Desalination plant

Claims (10)

Liquefied natural gas storage tanks;
A vaporizer for vaporizing the liquefied natural gas provided from the storage tank;
A power generation plant for generating power using the vaporized gas generated in the vaporizer; And
And a desalination plant for recovering fresh water by cooling the seawater below the freezing point through heat exchange using the cold heat of liquefied natural gas in the vaporizer. The method according to claim 1,
The desalination plant
A seawater cooler for cooling the seawater below the freezing point;
A first heat exchanger for heat exchange between the seawater cooler and the vaporizer;
A separator for separating the ice made in the seawater cooler from a function;
And a dissolver for dissolving the ice separated from the separator. 3. The method of claim 2,
The power plant
A power generator for generating electricity by burning the vaporized gas; And
And a waste heat recoverer for recovering waste heat from the exhaust gas discharged from the power generation unit to dissolve ice in the desalination plant. The method of claim 3,
And a second heat exchanger for heat exchange between the dissolver and the waste heat recoverer. The method of claim 3,
The power plant
And a scrubber for removing impurities contained in the exhaust gas passing through the waste heat recoverer. 6. The method of claim 5,
And a seawater supply line for supplying seawater cooled in the seawater cooler to the scrubber. 6. The method of claim 5,
And a fresh water supply line for supplying fresh water dissolved in the dissolver to the scrubber. 6. The method of claim 5,
And a third heat exchanger for exchanging heat between the seawater cooled in the seawater cooler and the scrubber. 6. The method of claim 5,
The power plant
Further comprising a knox oxidation device for removing nitrogen oxides (NOx) from the exhaust gas discharged from the power generation section;
Wherein the knox oxidation apparatus is provided between the waste heat recovery unit and the scrubber or between the power generation unit and the waste heat recovery unit. The method of claim 3,
A fuel cell facility for producing power using the gasification gas; And
And a steam supply line for converting the fresh water dissolved in the dissolver into water vapor through heat exchange in the waste heat recoverer and supplying the water vapor to the fuel cell facility.

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