JP2006070889A - Method and device for power generation and desalination - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To desalinate seawater by utilizing a waste heat from a power generation plant and increase the efficiency of the power generation plant. <P>SOLUTION: The seawater is heated by a first heat exchanger 6 heat exchanging the exhaust gas from a gas turbine 1 driving a generator 2 with the seawater and a second heat exchanger 7 heat exchanging a compressed air extracted from the air compression stage 10 of the gas turbine with the seawater, and a fresh water is collected by flushing the seawater in a multi-stage vaporizing device 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for obtaining electricity and fresh water by combining a power generation system and a seawater desalination system, and a power generation and desalination apparatus to which this method is applied.

  Known methods for seawater desalination include a method using a reverse osmosis membrane, a method using a multi-effect evaporator, and a method and system using multi-stage flash evaporation. It is explained in detail in “Seawater Desalination Technology” issued by the association in 1978. Among them, as a desalination apparatus using a multistage flash evaporation method, for example, one described in Patent Document 1 below is known.

In this multistage flash evaporation method, for example, heated steam generated by a boiler is used as a heat source for heating seawater.
Japanese Patent Laid-Open No. 9-117753

  On the other hand, as a thermal power generation system, coal, oil, or gas is used as fuel, high pressure steam (water vapor) is generated in a boiler, the high pressure steam is overheated (the temperature is raised above the boiling point of the pressure), and the A system that generates power by rotating a steam turbine with superheated steam, or a system that generates power by rotating a turbine with combustion gas, generates superheated steam from a turbine exhaust gas in a waste heat recovery boiler, and turns the steam turbine with the superheated steam Power generation systems are well known. Hereinafter, the water vapor of the present invention includes superheated water vapor.

By the way, in various places on the earth, both fresh water (fresh water) and electricity are drastically lacking depending on the region, and there is a need to efficiently produce both fresh water and electricity. Conventionally, many technologies have been pursued for producing only fresh water efficiently and technologies for producing only electricity, but technologies for efficiently co-producing fresh water and electricity have not been pursued much. It was.
The present invention provides a technology that combines a seawater desalination system and a gas turbine power generation system to produce both fresh water and electricity efficiently for power generation.

When exhaust heat from a gas turbine power generation system is used, exhaust heat in various temperature ranges generated in each process of the power generation system is used as a heating source for the seawater desalination system, and the entire power generation system and desalination system are used. It is desirable to increase the energy use efficiency of
However, the utilization of the exhaust heat has many problems to be solved.
(1) Seawater contains components (ions) that precipitate when heated to a high temperature. When the heating surface of the heat exchanger becomes hot, scale is deposited, resulting in deterioration of heat transfer characteristics and an increase in pressure loss. As a result, it may become impossible to drive.
(2) Exhaust heat from the gas turbine has various temperature levels. When these exhaust heat is used as a heat source for desalination of seawater, the deposition of the scale (1) depends on the temperature of the exhaust heat. May cause problems.
(3) In the gas turbine power generation system, it is necessary to compress the air necessary for combustion. However, when the air is compressed, the temperature becomes high, and the energy required for the compression increases as the air temperature rises. Therefore, the compressed air is extracted in the middle, once cooled, and then compressed again. However, the heat of the compressed air was not used. Further, the heat of the exhaust gas from the gas turbine described above has not been used for other purposes as long as it is used for preheating boiler feed water after being recovered by a general exhaust heat recovery boiler.
The present invention examines the above-mentioned problems, can minimize the scale generated when heat exchange of seawater with hot gas, and further maximizes the overall energy efficiency of power generation and desalination The method was found.

  The present invention has been made in view of the above circumstances, and effectively used the exhaust heat of the power generation system while preventing the deposition of scale on the heating surface of the heat exchanger that gives heat necessary for desalination of seawater. An object of the present invention is to provide a method for efficiently obtaining electricity and fresh water by combining a power generation system and a seawater desalination system.

In order to achieve the above object, the present invention provides a method for obtaining electric electricity and fresh water by combining a gas turbine power generation system and a desalination system for obtaining fresh water from seawater using an evaporation means.
It is used as a heat source for heating seawater of the desalination system by heat exchange using compressed air extracted from an intermediate stage of an air compressor of a gas turbine as a heat source and heat exchange using exhaust gas from the gas turbine as a heat source. And
And this invention makes the temperature of the compressed air extracted from the intermediate | middle stage of the said air compressor into 480 degrees C or less, It is characterized by the above-mentioned.
Further, the present invention is characterized in that the exhaust gas temperature of the gas turbine is controlled to be lower than 480 ° C., and the exhaust gas of the gas turbine is directly exchanged with seawater.
Further, the present invention controls the exhaust gas temperature from the gas turbine to be 480 ° C. or higher, introduces the exhaust gas into a heat recovery boiler to generate water vapor, introduces the water vapor into the steam turbine, and generates electric power, All or part of the water vapor discharged from the steam turbine is used as a heat source for heating seawater in the desalination system.
The present invention also provides a method of using compressed air extracted from an intermediate stage of the air compressor as a part of a heat source for heating seawater of the desalination system and returning the compressed air to the subsequent stage before returning it to the subsequent air compressor. It is characterized by injecting.
Further, according to the present invention, the water to be jetted uses condensed air extracted from an intermediate stage of the air compressor as a part of a heat source for heating the desalination system, and is further cooled to generate condensed water and / or Or it is the fresh water manufactured with the said desalination system, It is characterized by the above-mentioned.
In addition, the present invention is characterized in that the amount of water to be injected is an amount that makes the wetness degree of air 10% or less.
Further, the present invention is characterized in that the desalination system uses a multistage flash distillation method.
Moreover, this invention is characterized by performing the pre-processing which removes bivalent ion by letting a nano filter pass before supplying seawater to the heat recovery part of a desalination system.
Further, the present invention compares the temperature of seawater heated by an external heat source with a reference value, and when the reference value is exceeded, supplies seawater treated with the nanofilter to a heat recovery unit of the desalination system or It is characterized by being mixed and supplied to seawater that is not treated with a nanofilter.

The present invention also relates to the heating of seawater flashed at the highest temperature in distillation by a multistage flash distillation method, compressed air extracted from an intermediate stage of an air compressor of a gas turbine, exhaust gas of a gas turbine, and exhaust gas of a gas turbine. It is characterized in that at least one heat source selected from the group of steam exhausted after driving the steam turbine with steam generated by recovering the heat is used.
Further, in the present invention, the heat exchange of the seawater causes the seawater to circulate in the tube and supplies the compressed air extracted from the intermediate stage of the air compressor or the exhaust gas from the gas turbine to the outside of the tube. Is performed.
Further, the present invention provides a power generation and desalination apparatus obtained by combining a gas turbine power generation system and a desalination system that obtains fresh water from seawater using an evaporation means, and the desalination system uses exhaust gas from the gas turbine as a heat source. A first heat exchanger that heats the seawater supplied to the air, and a second heat that heats the seawater supplied to the desalination system using compressed air extracted from an intermediate stage of the air compressor of the gas turbine as a heat source. It has a heat exchanger and a pipe line for returning the compressed air heat-exchanged by the second heat exchanger to an intermediate stage of the air compressor.
The present invention also relates to a power generation and desalination apparatus that combines a gas turbine power generation system and a desalination system that obtains fresh water from seawater using an evaporation means, and exhaust heat recovery using exhaust gas from the gas turbine as a heat source. Extracted from an intermediate stage of a boiler, a first heat exchanger that heats seawater supplied to the desalination system, using exhaust steam recovered from the exhaust heat recovery boiler as a heat source, and an air compressor of the gas turbine The second heat exchanger that heats seawater supplied to the desalination system using the compressed air as a heat source, and the compressed air heat-exchanged by the second heat exchanger to the intermediate stage of the air compressor And a return line.

According to the present invention, since the cooling of the extracted air of the air compressor of the gas turbine for power generation and the cooling of the turbine exhaust gas and the heating of the seawater are performed at the same time, it is possible to improve the overall efficiency of power generation and seawater desalination. it can.
Further, according to the present invention, the temperature of the extraction air of the air compressor that exchanges heat with seawater is set to 480 ° C. or lower, so the temperature of the heat transfer surface on the seawater heating side of the heat exchanger can be lowered. Scale generation can be suppressed.
In addition, when the exhaust gas temperature from the gas turbine that exchanges heat with seawater is controlled to be less than 480 ° C., even if the heat is directly exchanged between the exhaust gas and seawater, It is possible to recover heat while suppressing the generation of water.
Further, when the exhaust gas temperature is controlled so as to be 480 ° C. or higher, the exhaust gas is generated by generating steam by using the exhaust heat recovery boiler, and the steam turbine is driven by the steam to generate power 480. Heat exchange is performed between steam at the steam turbine outlet steam and seawater that has become 150 ° C. or lower, and generally 150 ° C. or lower. Therefore, the heat transfer surface of the heat exchanger is not heated to 480 ° C. or higher, and scale generation can be suppressed.
Furthermore, since the seawater used for heat exchange with the exhaust heat of the power generation apparatus can be processed by the nanofilter as necessary, divalent ions that cause scale, such as Ca ²⁺ , Mg ²⁺ , SO ₄ ^2- , the seawater from which the water has been removed can be heated, and therefore the heat source temperature of the heat exchanger, which has been limited from the viewpoint of preventing scale generation, can be increased, and the seawater can be heated with higher efficiency. .

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 shows a first embodiment. This complex plant is composed of a power generation device and a seawater desalination device.
The power generation apparatus has a basic configuration of a gas turbine 1 that is an internal combustion engine and a generator 2 that is driven by the gas turbine 1. The seawater desalination apparatus flushes the heated seawater to obtain fresh water, the seawater supplied to the multistage evaporator 5, the gas turbine exhaust gas supplied from the power plant, and the extracted air The first and second heat exchangers 6 and 7 that directly exchange heat with compressed air are used as a basic configuration.

  The gas turbine 1 of the power generation apparatus includes an air compression unit 10 and a combustion gas expansion unit 11. The fuel is burned in the combustion unit 12 using the air compressed by the air compression unit 10, and the combustion gas expansion unit 11. The thermal energy is converted into kinetic energy at, and the generator 2 is driven by this kinetic energy. The combustion gas expansion part 11 and the air compression part 10 are connected coaxially, and the air compression part 10 is driven by a part of the kinetic energy generated in the combustion gas expansion part 11.

  In the present invention, in order to control the exhaust gas temperature of the gas turbine 1 to be lower than 480 ° C., for example, the gas turbine inlet pressure is increased to a pressure of about 25 atm and combustion is performed at 1100 ° C., and the gas turbine outlet pressure is set to 1 When the pressure is 0.5 atm, the exhaust gas temperature can be controlled to about 480 ° C. The exhaust gas temperature of the gas turbine 1 has a relationship with the combustion temperature. For example, when the same 1100 ° C. combustion is performed, the gas turbine inlet pressure is further increased from 25 atm. The turbine 1 can be operated. In order to set the exhaust gas temperature of the gas turbine 1 to 480 ° C. or higher, if the combustion temperature is 1100 ° C., which is the same condition as described above, and the outlet pressure of the gas turbine is 1.5 atm, the inlet pressure is about 480 ° C. at 25 atm. However, in the present invention, the inlet pressure and temperature of the gas turbine can be appropriately selected, and an optimum configuration can be adopted under the selected conditions.

  In the gas turbine 1, the exhaust gas from the combustion gas expansion unit 11 is supplied to the first heat exchanger 6 through the exhaust pipe 60. In the heat exchanger 6, the seawater supplied from the multistage evaporator 5 through the first seawater piping 61 is heated by exchanging heat with the exhaust gas.

  The air compressor 10 of the gas turbine 1 has a plurality of stages, and the compressed air extracted from the low-pressure stage (previous stage) is supplied to the second heat exchanger 7 via the pipe line 24, Heat is exchanged with the seawater supplied from the second seawater piping 62, and then returned to the high-pressure stage (rear stage) via the pipeline 25. Further, a water injection device 26 is provided in the middle of the pipe line 25 and is generated when air is compressed in the subsequent high-pressure stage by injecting water from the nozzle into the compressed air returning to the air compression unit 10. Temperature rise is suppressed. The larger the amount of water jetted, the more effective the temperature rise is suppressed. However, when the amount is too large, the balance of the air compression blades is not good and the erosion is not adversely affected. It has been found that the amount of water to be injected is preferably such that the wetness degree of the air temperature is 10% or less. The degree of wetness in the present invention is a state quantity that expresses a state in which moisture in a mist (droplet) state is contained in the air, in addition to saturated water vapor, at the temperature, by the weight ratio of mist to air. Reference numeral 27 denotes a valve for controlling the supply of water to the water injection device 26. Note that the extracted compressed air may be further cooled by a cooler 28 installed as necessary before being returned to the high-pressure stage.

The seawater desalination apparatus is provided with a multi-stage evaporator 5 that obtains fresh water by flushing heated seawater to generate water vapor and condensing the water vapor. The multistage evaporator 5 includes an evaporator (heat recovery unit) 31 that flushes seawater at a relatively high temperature, and an evaporator 32 (heat release unit) 32 that flushes seawater at a low temperature.
A plurality of evaporation chambers are provided inside the evaporator 31, and a receiving tray 33 for receiving water condensed after flushing is provided at the top. The evaporator 31 is divided into a plurality of parts by a partition plate 34. The seawater in the evaporator is gradually reduced in temperature and pressure by repeated flashing. Similarly, the evaporator 32 is also provided with a receiving tray 33 so as to receive the condensed water vapor.

Next, a system for supplying seawater to the multistage evaporator 5 will be described.
Reference numeral 40 denotes a pump, and the seawater discharged from the pump 40 passes through the evaporator 32 through the heat exchange tube 41 of the heat release section, and cools and condenses the water vapor generated by the flash in the evaporator 32. Further, the seawater exiting the heat exchange tube 41 is branched, a part thereof is discharged through the pipe line 42, and a part is connected to the pretreatment device 43. The pretreatment device 43 includes a device for removing dissolved CO ₂ and oxygen, or adding a scale inhibitor, that is, a conventionally known deaeration device and a pretreatment device for scale suppression and prevention, It is preferable to provide a nanofilter facility. The seawater passes through the nanofilter 43 attached to the pretreatment device 43 to remove divalent ions that cause scale, such as Ca ²⁺ , Mg ²⁺ , and SO ₄ ²⁻ . Yes. The seawater from which the divalent ions have been removed through the nanofilter 43 is supplied to the heat exchange tube 45 in the evaporator 31 by the pump 44 to cool and condense the water vapor generated by the flash in the evaporator 31. After being preheated by this, the first seawater pipe 61 on the inlet side of the first heat exchanger 6 and the second seawater pipe 62 on the inlet side of the second heat exchanger 7 are connected. Although the example in which the pretreatment device is provided outside the evaporator 32 has been described, a deaeration device or the like may be provided inside the evaporator 32.

  The seawater heated by the heat exchangers 6 and 7 is sent to the evaporator 31, and is sequentially flushed in each chamber in the evaporator 31 to generate water vapor, which is cooled by the seawater in the heat exchange tube 45. Then, the water is condensed and the water droplets are collected by the receiving tray 33. The seawater in the evaporator 31 is sent to the evaporator 32 via the connecting pipe 46 and further flushed, cooled by the seawater in the heat exchange pipe 41 and condensed, and the water droplets are collected in the receiving tray 33. Is done.

  Further, the concentrated seawater (discharge brine) after being flushed in the evaporators 31 and 32 is mostly discharged to the outside by the pump 50. The fresh water collected in the tray 33 of the evaporator 31 is sent to the connecting pipe 47 by using, for example, an inclination, collected in the receiving tray 33 of the evaporator 32 from the connecting pipe 47, and further discharged from the system by the pump 51. It is sent to freshwater storage facilities.

Operation | movement of the power generation seawater desalination complex system comprised as mentioned above is demonstrated.
The raw seawater supplied by the pump 40 to the heat exchange tube 41 of the first evaporator 32 and the heat exchange tube 45 of the second evaporator 31 of the multi-stage evaporator 5 is heat-exchanged with the internal flash steam and has a temperature. To rise.

The seawater preheated through the heat exchange tube 45 is branched and sent to the seawater pipes 61 and 62 to the first and second heat exchangers 6 and 7, respectively. The seawater branched to the seawater piping 61 to the first heat exchanger 6 is heat-exchanged with the exhaust gas from the gas turbine 1 in the heat exchanger 6.
In the present invention, the exhaust gas temperature from the gas turbine 1 is a predetermined value, specifically, the equipment configuration for receiving the exhaust gas from the gas turbine 1 at a boundary of 480 ° C. is different. In this embodiment, the temperature of the exhaust gas is different. Is less than 480 ° C., a method of directly exchanging the exhaust gas of the gas turbine 1 with the seawater in the seawater piping 61 to the first heat exchanger 6 is employed. Further, the seawater branched to the seawater pipe 62 to the second heat exchanger 7 is heated by the heat exchanger 7 with heat exchanged with the compressed air extracted from the compression unit 10 of the gas turbine 1.
In some cases, the seawater preheated through the heat exchange tube 45 may be heated through the second heat exchanger 7 and further through the first heat exchanger 6 without being branched. .

  The effect of reducing the driving force of the compressor by supplying compressed air extracted from the intermediate stage of the compressor 10 to the second heat exchanger 7 and exchanging heat with seawater will be described. The required power of the compressor is generally compressed. The lower the temperature of the air, the smaller the required temperature, so that the required power of the compressor 10 is reduced by extracting the air from the intermediate stage of the compressor 10 and cooling it back to the compressor.

  In this embodiment, it is the extraction of compressed air of 480 ° C. or less from the intermediate stage of the air compressor 10, preferably 150 ° C. to 400 ° C., more preferably 180 ° C. to 260 ° C. is there. Since the compressed air is cooled by exchanging heat with seawater in this way, the required power (load of the gas turbine) of the air compressor 10 can be reduced, and this energy can be used for heating the seawater.

  If the temperature of the extracted compressed air cannot be lowered to a desired value due to the operating state of the compressor 10 or the multistage evaporator 5, the compressed air may be further cooled by a water cooling or an air cooling heat exchanger. Further, by opening the valve 27 and injecting fresh water from the water injection device 26 to the compressed air of the return pipe 25, a small amount of water can be added to the compressed air, and the temperature rise in the rear air compressor can be suppressed. For this water injection, for example, generated fresh water discharged from the pump 51 or condensed water generated when the intermediately extracted air is cooled can be used.

Next, the effect of using the nanofilter will be described.
In seawater of a general component, when the seawater temperature on the heat transfer surface exceeds 120 ° C., scale generation due to the divalent ions becomes remarkable, so the seawater heating temperature is 120 ° C. or less. However, by removing divalent ions with a nanofilter, the generation of scale can be suppressed and the temperature can be increased, and depending on how the divalent ions are removed, it can be heated to as high as 170 ° C. to 180 ° C. It is possible to perform efficient heat exchange using a high-temperature heat source.

The combined power generation and desalination system having the above configuration performs the following operations.
In the gas turbine 1, the compressed air extracted at a temperature of 480 ° C. or less extracted from the intermediate stage of the air compressor 10 is heat-exchanged directly with seawater via the second heat exchanger 7, and the cooled compressed air is converted into air. Returning to the subsequent stage of the compression unit 10, further increasing the pressure and compressing air is added to the fuel and combusted in the combustion unit 12, further expanded in the combustion gas expansion unit 11 and converted into kinetic energy, and the generator 2 is driven. To generate electricity. Further, the exhaust gas of the gas turbine 1 is controlled to be 480 ° C. or less, and the exhaust gas of 480 ° C. or less is directly heat-exchanged with seawater through the first heat exchanger 6.

  On the other hand, in the desalination apparatus, the seawater taken in by the pump 40 is heat-exchanged with the flash vapor in the multistage evaporator 5 through the heat exchange pipes 41 and 45 of the multistage evaporator 5, and the temperature is raised from room temperature. Seawater preheated by the heat exchange pipe 45 is heated by the first and second heat exchangers 6 and 7, sent to the first evaporator 314, and sequentially flushed inside. The water vapor generated by the flash is condensed and collected as water droplets in the tray 33. The seawater flushed in the first evaporator 31 is further sent to the second evaporator 32 via the connecting pipe 46 and flushed again. The water vapor generated by the flash in the evaporator 32 is cooled and condensed, collected in the receiving tray 33, and sent to a predetermined tank or the like by the pump 51 together with the generated water collected in the evaporator 31. And the seawater concentrated by generating water vapor | steam by the past heating and flushing is discharged | emitted out of the system by the pump 50 as discharge brine.

  The air extracted from the air compressor 10 in the second heat exchanger 7 is cooled by exchanging heat with seawater, thereby reducing the power required to drive the air compressor 10. As a result, the generator 2 A lot of power generation can be obtained. Further, if necessary, the valve 27 is opened and water is injected into the compressed air that returns to the compression stage 10, thereby suppressing the temperature rise during the subsequent air compression and increasing the amount of power generation.

Next, a second embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same structure as 1st Example, and description is simplified.
The second embodiment is an example in which the exhaust gas temperature of the gas turbine 1 is controlled to 480 ° C. or higher, and the exhaust heat of the gas turbine 1 is recovered before the heat exchanger 6 in the first embodiment. And a steam turbine 71 driven by steam generated by the exhaust heat recovery boiler 70 is provided.
Instead of the heat exchanger 6, an exhaust heat recovery boiler 70 is provided in the exhaust pipe 60 from which the exhaust gas of the combustion gas expansion unit 11 of the gas turbine 1 is exhausted. Steam generated by heat exchange with the exhaust gas in the heat exchange tube 72 of the exhaust heat recovery boiler 70 is supplied to the steam turbine 71 and converted into kinetic energy, and the generator 73 is driven by the steam turbine 71. And is now generating electricity.

  The steam extracted or exhausted from the steam turbine 71 is supplied to the first heat exchanger 6A. The steam supplied to the first heat exchanger 6 </ b> A undergoes heat exchange with the seawater supplied from the first seawater pipe 61 to condense, and is sent to the condensate tank 76 by the condensate pump 75. When there is more steam than is recovered by the first heat exchanger 6A, the steam exhausted from the steam turbine can be branched into the condenser 74 to be condensed. Condensate generated in the condenser 74 is sent to a condensate tank 76 by a condensate pump 77. Further, the condensate stored in the condensate tank 76 is supplied to the heat transfer tube 72 of the exhaust heat recovery boiler 70 or the boiler feed water preheater downstream thereof by the condensate pump 79 to exchange heat. .

Also in the second embodiment, by using the cooling heat of the compressed air extracted from the intermediate stage of the gas turbine 1 and the cooling heat of the steam exhausted from the steam turbine for heating the seawater, the following effects are obtained. Is obtained.
1. The intermediate cooling of the compressed air in the compression process of the gas turbine increases the thermal efficiency of the gas turbine, thereby improving the power generation efficiency.
2. The efficiency of power generation is improved by spraying condensed water onto the air flow after the intermediate cooling.
3. By increasing the gas turbine combustion pressure, the efficiency of power generation and fresh water production can be improved. From the viewpoint of thermal efficiency, it is desirable that the fuel injection pressure is 10 to 30 kg / cm 2 and the exhaust temperature of the gas turbine is 400 ° C. to 550 ° C.
Furthermore, a heat exchanger using a heat medium (for example, oil having a boiling point higher than water) may be provided in the middle of the discharge pipe 60, and seawater may be heated by this heat exchanger.

  The configuration of the present invention is not limited to the above embodiment, and in particular, the number of compression stages of the gas turbine, the number of evaporator chambers, and the like may be changed as appropriate based on the required specifications of the power generation and desalination plant. Of course it is also good.

It is a piping diagram of the power generation desalination complex plant of a 1st embodiment. It is a piping diagram of the power generation desalination complex plant of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1A Gas turbine 2 Generator 1 Generator 5 Multistage evaporator 6, 6A 1st heat exchanger 7 2nd heat exchanger 10 Air compression part 11 Combustion gas expansion part 12 Combustion part 24 Pipe line 25 Pipe line 26 Water injection device 31 Evaporator (heat recovery part)
32 Evaporator (Heat Dissipation Unit) 33 Dish 34 Partition Plate 41 Heat Exchange Tube (Heat Discharge Unit) 43 Pretreatment Device 45 Heat Exchange Tube (Heat Recovery Unit) 60 Exhaust Pipe 61 First Sea Water Pipe 62 Second Sea Water Piping 70 Waste heat recovery boiler 71 Steam turbine

Claims (14)

In a method of obtaining electricity and fresh water by combining a gas turbine power generation system and a desalination system that obtains fresh water from seawater using evaporation means,
Power generation characterized in that seawater of the desalination system is heated by heat exchange using compressed air extracted from an intermediate stage of an air compressor of a gas turbine as a heat source and heat exchange using exhaust gas from the gas turbine as a heat source , Desalination method.   The power generation and desalination method according to claim 1, wherein the temperature of the compressed air extracted from an intermediate stage of the air compressor is set to 480 ° C or lower.   3. The power generation and desalination method according to claim 1, wherein the exhaust gas temperature from the gas turbine is controlled to be less than 480 ° C., and the exhaust gas of the gas turbine is directly heat-exchanged with seawater.   The exhaust gas temperature from the gas turbine is controlled to be 480 ° C. or higher, the exhaust gas is introduced into a heat recovery boiler to generate steam, the steam is introduced into the steam turbine to generate power, and the steam turbine is discharged. 3. The power generation and desalination method according to claim 1, wherein all or part of the steam generated is used as a heat source for heating seawater in the desalination system.   Before the compressed air extracted from the intermediate stage of the air compressor is used as a part of the heat source for heating seawater of the desalination system and returned to the subsequent air compressor, water is injected into the compressed air. The power generation and desalination method according to any one of claims 1 to 4.   Condensed water and / or the desalination system produced when the water to be injected is cooled by using the compressed air extracted from the intermediate stage of the air compressor as part of a heat source for heating the desalination system. The power generation and desalination method according to claim 5, wherein the water is freshwater produced by the method described above.   6. The power generation and desalination method according to claim 5, wherein the amount of water to be injected is an amount that makes the wetness degree of air 10% or less.   The power generation and desalination method according to any one of claims 1 to 7, wherein the desalination system uses a multistage flash distillation method.   The power generation according to any one of claims 1 to 8, wherein pretreatment for removing divalent ions is performed by passing a nanofilter before supplying seawater to the heat recovery unit of the desalination system. Desalination method.   The temperature of the seawater heated by the external heat source according to claims 1 to 4 is compared with a reference value, and when the reference value is exceeded, the seawater treated with the nanofilter is supplied to the desalination system. The power generation and desalination method according to claim 9.   In the distillation by the multi-stage flash distillation method, the heat of the seawater flashed at the highest temperature is recovered by collecting the heat of the compressed air extracted from the intermediate stage of the gas turbine air compressor, the exhaust gas of the gas turbine, and the exhaust gas of the gas turbine. 5. The power generation and desalination method according to claim 4, wherein at least one heat source selected from the group of steam exhausted after driving the steam turbine with steam generated in this manner is used.   The heat exchange of the seawater is performed by circulating seawater in a tube and supplying compressed air extracted from an intermediate stage of the air compressor and exhaust gas from the gas turbine to the outside of the tube. The seawater and desalination method according to any one of claims 1 to 11, characterized in that In a power generation and desalination system that combines a gas turbine power generation system and a desalination system that obtains fresh water from seawater using evaporation means,
A first heat exchanger that heats seawater supplied to the desalination system using exhaust gas from the gas turbine as a heat source;
A second heat exchanger that heats seawater supplied to the desalination system using compressed air extracted from an intermediate stage of the air compressor of the gas turbine as a heat source;
A power generation and desalination apparatus, comprising: a conduit for returning the compressed air heat-exchanged by the second heat exchanger to an intermediate stage of the air compressor. In a power generation and desalination system that combines a gas turbine power generation system and a desalination system that obtains fresh water from seawater using evaporation means,
An exhaust heat recovery boiler that uses exhaust gas from the gas turbine as a heat source;
A first heat exchanger that heats seawater supplied to the desalination system, using exhaust steam recovered from the exhaust heat recovery boiler as a heat source;
A second heat exchanger that heats seawater supplied to the desalination system using compressed air extracted from an intermediate stage of the air compressor of the gas turbine as a heat source;
A power generation and desalination apparatus, comprising: a conduit for returning the compressed air heat-exchanged by the second heat exchanger to an intermediate stage of the air compressor.

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