JP6740059B2 - Water collection device for thermal power plant - Google Patents

Description

The present invention relates to a water collecting device for a thermal power plant that uses fossil fuels such as liquefied natural gas (LNG), coal, and petroleum.

For example, a large amount of pure water is required in an LNG-only burning thermal power plant. In this thermal power plant, heat of combustion gas generated by burning LNG causes steam to be generated by a boiler, and this steam drives a steam turbine to rotate a generator to generate electricity. In such a thermal power plant, as a water supply for steam turbines, water for cooling equipment in the plant, domestic water in the plant, water for air conditioning in the plant, etc. Use water.

As these water sources, river water, industrial water, city water (clean water), etc. are treated and used as pure water. However, the cost of purchasing water is high when these water sources are used, and high cost is required for pure water production. Further, the water quality of river water and industrial water is poor, and advanced treatment is required as pure water treatment. Also, city water (clean water) has a relatively good quality, but is very expensive.

In addition, the water intake itself may be restricted due to various regulations such as environmental regulations, and when the water becomes insufficient due to the weather, the water supply is restricted by the local government that is the supplier. If the water supply is restricted, the operation of the thermal power plant will be seriously hindered and the operation may be stopped. In areas where water is not available in the first place, the construction of thermal power plants may not be approved.

In particular, in a thermal power plant that uses LNG as a fuel, including LNG-only combustion, hydrocarbons (mostly methane) that are gas components are combusted, and a large amount of steam is generated together with the combustion gas. In the current thermal power plant, all the steam generated by this combustion is released together with carbon dioxide gas and nitrogen gas, and there is no device for recovering this water.

JP-A-8-260909 JP, 2014-129731, A

In the background art mentioned above, particularly when a thermal power plant is installed in an environment where it is difficult to take in industrial water or tap water, there are cases where it is not possible to secure sufficient water for use in this thermal power plant, The problem is that there is no technology that can sufficiently cope with it. By securing a new water source in the thermal power plant, it may be possible to construct and operate the thermal power plant even in a location where it was conventionally impossible to construct.

The object of the present invention was made in consideration of the above circumstances, and even if there are restrictions on the use of water resources in the location of a thermal power plant, sufficient water is secured in this thermal power plant. An object is to provide a water collecting device for a thermal power plant that can be used.

The water collecting device of a thermal power plant according to the present invention performs power generation using combustion gas generated by combustion of fossil fuel, and collects water vapor by collecting steam from exhaust gas after the combustion gas contributes to power generation. Together with a water collecting device of a thermal power plant having a boiler that supplies driving steam to a steam turbine used for power generation, the exhaust gas cooling device on the upstream side on the way to the exhaust gas chimney for exhaust to the atmosphere, water recovery device is disposed respectively on the downstream side, the exhaust gas cooling device, while by spraying water into the exhaust gas Ru configured to cool the exhaust gas directly, the water that has absorbed heat by cooling the exhaust gas Is guided to a heat exchanger, the boiler water sent to the boiler is configured to heat-exchange by the heat exchanger to raise the temperature, and the water cooled by raising the temperature of the boiler water, It is guided to a cooling device and further cooled to be guided to the exhaust gas cooling device, and is configured to cool the exhaust gas, and the water recovery device is provided on the surface of a recovery element arranged along the flow direction of the exhaust gas. A structure in which water in the exhaust gas cooled by the exhaust gas cooling device is attached and separated and recovered , and the recovered water is replenished to the water sent from the cooling device to the exhaust gas cooling device. The exhaust gas cooling device or the water recovery device is configured to cool the exhaust gas containing the water vapor to a temperature below the dew point.

According to the present invention, the exhaust gas cooling device or the water recovery device cools the exhaust gas containing water vapor to a temperature below the dew point, whereby water vapor in the exhaust gas is condensed and water is produced. As a result, a water source can be secured in the thermal power plant, so that even if there is a constraint on the use of water resources at the location of the thermal power plant, sufficient water required in the thermal power plant can be secured.

1 is a system diagram showing a combined cycle type thermal power plant to which a first embodiment of a water collection device of a thermal power plant according to the present invention is applied. Sectional drawing which shows the water recovery apparatus of FIG. Sectional drawing which follows the III-III line of FIG. FIG. 4 is a vertical cross-sectional view showing the recovery unit of FIGS. 2 and 3, and (B) and (C) are cross-sectional views taken along lines IVB-IVB and IVC-IVC of FIG. 4A. FIG. 4 is a vertical cross-sectional view showing another example of the water recovery device in FIG. 1. Sectional drawing which follows the VI-VI line of FIG. The collection pipe of FIG. 5 and FIG. 6 is shown, (A) is the longitudinal cross-sectional view, (B) is sectional drawing which follows the VIIB-VIIB line of FIG. 7(A). A system diagram showing a combined cycle type thermal power plant to which a second embodiment of a water collection device of a thermal power plant according to the present invention is applied. The systematic diagram which shows the conventional combined cycle system thermal power plant. A system diagram showing another conventional combined cycle system thermal power plant.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
[A] First embodiment (FIGS. 1 to 7)
FIG. 1 is a system diagram showing a combined cycle type thermal power plant to which a first embodiment of a water collection device for a thermal power plant according to the present invention is applied. This thermal power plant 10 uses fossil fuels such as liquefied natural gas (LNG), coal, and petroleum as fuel, and in particular, combustion gas generated by combustion of LNG rotationally drives a gas turbine 12 to generate electricity. After that, the heat of the exhaust gas from the gas turbine 12 is used to generate steam in the exhaust heat recovery boiler 14, and the steam (driving steam) rotates the steam turbine 15 to generate electric power, which is a combined cycle thermal power generation. It is a plant.

That is, LNG, which is fossil fuel, is stored in a liquid state in the storage tank, vaporized, mixed with compressed air, and sent to the combustor 11. The combustor 11 burns the vaporized LNG to generate high-temperature combustion gas of, for example, 1000° C. or higher, and sends the combustion gas to the gas turbine 12.

The gas turbine 12 is rotationally driven by the combustion gas from the combustor 11, and rotates the connected generator 13 to generate electric power. The combustion gas that has finished its work in the gas turbine 12 becomes exhaust gas of about 500° C. to 600° C. and is sent to the exhaust heat recovery boiler 14.

The exhaust heat recovery boiler 14 heats the sent water (boiler water) by exchanging heat with the exhaust gas while removing nitrogen oxides (NOx) inside, to generate superheated steam. It is supplied to the steam turbine 15 as driving steam. The exhaust gas that has exchanged heat with the boiler water in the exhaust heat recovery boiler 14 is exhausted from the chimney 18 into the atmosphere via the exhaust gas cooling device 16 and the water recovery device 17 described later.

The steam turbine 15 is rotationally driven by the driving steam from the exhaust heat recovery boiler 14, and rotates the connected generator 19 to generate electric power. The generator 19 may be the same as the generator 13 or may be a different one. The steam (driving steam) that has finished its work in the steam turbine 15 is sent to the condenser 20. The condenser 20 cools the fed steam while depressurizing it, condenses it and returns it to water, thereby increasing the pressure difference between the front and rear of the steam turbine 15, thereby generating electric power that is rotated by the steam turbine 15. The power output of the machine 19 is increased. The water generated in the condenser 20 is sent as boiler water to the exhaust heat recovery boiler 14 via the heat exchanger 21.

Here, as shown in FIG. 9, in the conventional thermal power plant 100, the boiler water from the condenser 20 is directly fed to the exhaust heat recovery boiler 14, but the boiler water is cooled by the condenser 20. When the exhaust heat recovery boiler 14 flows into the exhaust heat recovery boiler 14 at the controlled low temperature, dew condensation occurs on the surface of a heat exchanger (not shown) in the exhaust heat recovery boiler 14, which is one of the causes of corrosion of members including the heat exchanger. Become. Note that, in FIG. 9 and FIG. 10 described next, the same reference numerals are given to the same devices and apparatuses as in the present embodiment.

On the other hand, in each of the other conventional power generation plants 110 shown in FIG. 10, a part of the superheated steam (driving steam) generated in the exhaust heat recovery boiler 14 is branched and guided to the heat exchanger 111, and this heat exchange is performed. In the vessel 111, the boiler water from the condenser 20 and a part of the superheated steam are mixed to raise the temperature of the boiler water. As a result, it is possible to prevent the occurrence of dew condensation in the exhaust heat recovery boiler 14 by the boiler water sent to the exhaust heat recovery boiler 14, and to prevent the corrosion of the members in the exhaust heat recovery boiler 14. However, in this thermal power plant 110, part of the superheated steam generated in the exhaust heat recovery boiler 14 is used to raise the temperature of the boiler water sent to the exhaust heat recovery boiler 14, so that steam The superheated steam (driving steam) supplied to the turbine 15 decreases, and the power generation output of the generator 19 connected to the steam turbine 15 decreases.

On the other hand, in the thermal power plant 10 of the present embodiment, the exhaust gas cooling device 16 is installed on the upstream side and the water recovery device 17 is installed on the downstream side in the middle of the exhaust system of the exhaust gas flowing from the exhaust heat recovery boiler 14 to the chimney 18. The exhaust gas cooling device 16 and the water recovery device 17 cool the exhaust gas discharged from the exhaust heat recovery boiler 14, condense and collect water vapor (moisture) from the exhaust gas, and collect the exhaust gas cooling device. 16 and the heat exchanger 21 use the water that has absorbed the heat by cooling the exhaust gas to raise the temperature of the boiler water sent to the exhaust heat recovery boiler 14.

As described above, in the thermal power plant 10 of the present embodiment, the water source is secured in the thermal power plant 10 by condensing the water vapor by condensing the water vapor in the exhaust gas generated together with the combustion gas by the combustion of the fossil fuel. It becomes possible to do. Further, the temperature of the boiler water sent to the exhaust heat recovery boiler 14 is raised by utilizing the heat of the exhaust gas discharged from the exhaust heat recovery boiler 14, so that the generator 19 connected to the steam turbine 15 is used. It becomes possible to secure the power generation output and prevent the occurrence of corrosion in the exhaust heat recovery boiler 14.

Hereinafter, the exhaust gas cooling device 16, the water recovery device 17, the cooling device 21, and the recovery water tank 22 and the cooling device 23, which constitute the water collection device 25 of the thermal power plant 10, will be described in detail. Here, the water collecting device 25 collects the steam generated together with the combustion gas by the combustion of the fossil fuel from the exhaust gas after the combustion gas contributes to power generation, specifically, the exhaust gas discharged from the exhaust heat recovery boiler 14. In addition to collecting water, the heat of the exhaust gas is recovered to raise the temperature of the boiler water sent to the exhaust heat recovery boiler 14.

The exhaust gas cooling device 16 sprays water of 20° C. to 40° C. using the spray nozzle 26 on the exhaust gas of about 80° C. to 120° C. discharged from the exhaust heat recovery boiler 14, thereby directly cooling the exhaust gas. The exhaust gas is cooled to about 30°C to 60°C. The water sprayed from the spray nozzle 26 absorbs heat from the exhaust gas, the temperature of the water is increased, and the water is further vaporized. Therefore, the humidity of the exhaust gas is about several% to several tens% at the outlet A of the exhaust heat recovery boiler 14, but the outlet B of the exhaust gas cooling device 16 becomes wet steam containing a large amount of water. The exhaust gas that has become the wet steam is sent to the water recovery device 17. Further, the water that has absorbed the heat of the exhaust gas and has risen in temperature is sent to the heat exchanger 21.

The spray nozzle 26 is installed on the upper portion of the exhaust gas cooling device 16 and is configured to be capable of spraying a mist of water of several μm to several tens of μm. The mist of water sprayed from the spray nozzle 26 is set to several μm to several tens of μm because the finer the mist of water sprayed, the higher the heat exchange efficiency with the exhaust gas and the more the amount of water to be sprayed can be suppressed. Since the driving force for transporting water to the height of the spray nozzle 26 can be reduced, and because the sprayed water does not include solid matter, the heat transfer coefficient of mist is high and the exhaust gas cooling device 16 itself can be miniaturized. This is because it can be done.

Further, in the exhaust gas cooling device 16, since nitrogen oxides (NOx) contained in the exhaust gas sent from the exhaust heat recovery boiler 14 are absorbed by water, a neutralization facility and a desalination facility are provided as necessary. To be Even when these facilities are provided, the exhaust gas cooling device 16 is configured to pass the exhaust gas with a low pressure loss in order to secure the power generation output by the generator 13 driven by the gas turbine 10.

The water recovery device 17 is provided on the surface of the recovery element 27 (the stacked flat plates 27A shown in FIG. 4 or the fiber mist separator 27B shown in FIG. 7) arranged along the flow of the exhaust gas, and The moisture in the exhaust gas, which has been cooled and turned into wet steam, is attached as water droplets, separated from the exhaust gas, collected, and collected. Further, the water recovery device 17 has a cooling function of cooling the exhaust gas of the moist steam containing water vapor to a dew point (about 30° C.) or lower, if necessary.

The case where the water recovery device 17 has a cooling function is a case where the temperature of the exhaust gas guided from the exhaust gas cooling device 16 is higher than the dew point. By the above-described cooling function of the water recovery device 17 or by cooling the exhaust gas to the dew point by the exhaust gas cooling device 16, water vapor derived from fossil fuel (LNG in the present embodiment) contained in the exhaust gas is condensed to recover the water. Water droplets can be attached to the collection element 27 of the device 17 and collected. From the outlet C of the water recovery device 17, the exhaust gas from which water vapor has been removed and which has been cooled to about 30° C. is discharged to the chimney 18 and discharged from the chimney 18 to the atmosphere. In this embodiment, a case where the water recovery device 17 has a cooling function will be described.

That is, as shown in FIGS. 2 to 4, the water recovery device 17 having the flat plate 27A as the recovery element 27 includes the recovery unit 28 that accommodates the flat plate 27A. As shown in FIG. 4, this recovery unit 28 is configured so as to be shielded from the outside air, and a plurality of flat plates 27A are stacked inside with a space (not shown) in between, and along the exhaust gas flow direction X. Arrange in parallel. Exhaust gas flows between the flat plates 27A in the recovery unit 28 to cause water droplets to adhere to the surface of the flat plate 27A, and the water droplets that have grown and dropped due to the action of gravity are attached to the lower portion of the recovery unit 28. A water receiver 29 for receiving is formed. The water receiver 29 is connected to the recovery water tank 22 via a water supply tube 30, and the water in the water receiver 29 is guided to the recovery water tank 22 via the water supply tube 30 by the action of gravity.

As shown in FIG. 2 and FIG. 3, a plurality of or one recovery unit 28 is installed in the casing 31 of the water recovery device 17 with an air passage 32 therebetween. An introducing duct 33 for guiding the exhaust gas from the exhaust gas cooling device 16 and a guiding duct 34 for guiding the exhaust gas to the chimney 18 are connected to the recovery unit 28 in an airtight state. An air inlet 35 is formed at the bottom of the casing 31, an air outlet 36 is formed at the top, and a blower fan 37 is installed near the air outlet 36. By the rotation of the blower fan 37, the outside air flows into the casing 31 from the air inlet port 35, flows in the Y direction in the air passage 32, and flows out from the air outlet port 36, so that the inside of the recovery unit 28 is in the X direction (above-mentioned). The exhaust gas flowing along the direction (perpendicular to the Y direction) is heat-exchanged with the outside air and cooled to a temperature below the dew point.

Further, as shown in FIGS. 5 to 7, the water recovery device 17 having the fiber mist separator 27B as the recovery element 27 includes a recovery pipe 38 that accommodates the mist separator 27B. As shown in FIG. 7, the recovery pipe 38 is configured to be shielded from the outside air, and has a plurality of mist separators 27B arranged in a straight line inside the exhaust gas flow direction X. The mist separator 27B may be stacked in the recovery pipe 38 with a gap interposed therebetween, as shown by the chain double-dashed line. At the bottom of the recovery pipe 38, for example, a water supply tube 39 is connected to the downstream position of the most downstream mist separator 27B, and the water supply tube 39 is connected to the recovery water tank 22. By the exhaust gas flowing along the mist separator 27 in the recovery pipe 38, water droplets adhere to the surfaces of these mist separators 27, and the adhered water droplets grow and fall by the action of gravity, and then pass through the water supply tube 39. It is led to the recovery water tank 22.

As shown in FIGS. 5 and 6, one or a plurality of recovery pipes 38 are arranged in the casing 41 of the water recovery device 17. An introduction duct 43 for guiding the exhaust gas from the exhaust gas cooling device 16 and a discharge duct 44 for guiding the exhaust gas to the chimney 18 are connected to the recovery pipe 38 in an airtight state. The casing 41 has an air inlet 35 at the bottom and an air outlet 36 at the top, and a blower fan 37 is installed near the air outlet 36. By the rotation of the blower fan 37, the outside air flows into the casing 41 from the air inlet 35, flows in the casing 41 in the Y direction, and flows out from the air outlet 36, so that the inside of the recovery pipe 38 is in the X direction (the above-mentioned). The exhaust gas flowing along the direction (perpendicular to the Y direction) is heat-exchanged with the outside air and cooled to a temperature below the dew point.

In the water recovery device 17 including the flat plate 27A or the mist separator 27B as described above, the flat plate 27A is arranged in the recovery unit 28, and the mist separators 27B are arranged in the recovery pipe 38 along the flow direction X of the exhaust gas, Further, the exhaust gas flow path in each of the recovery unit 28 and the recovery pipe 38 has a flow path configuration in which the expansion and contraction of the flow path cross-sectional area is small, and the exhaust gas is excellent in straightness, and the like. The pressure loss of the exhaust gas flowing through each of the pipes 38 is reduced, whereby the power generation output of the generator 13 driven by the gas turbine 12 is secured. Further, the water droplets attached to the flat plate 27A drop to the water receiver 29 by the action of gravity, and are further guided to the recovery water tank 22 via the water supply tube 30, and the water droplets attached to the mist separator 27B also deliver the water by the action of gravity. By being guided to the recovery water tank 22 via the tube 39, power for recovering water in the water recovery device 17 and the recovery water tank 22 becomes unnecessary.

As shown in FIG. 1, the recovered water that is recovered by the water recovery device 17 and guided to the recovered water tank 22 is purified as necessary, and a part of the makeup water is water to be sprayed by the exhaust gas cooling device 16. And the rest is supplied into the thermal power plant 10. Purification of the above-mentioned recovered water is performed as follows.

That is, the recovered water led to the exhaust heat recovery boiler 14 becomes acidic water due to the dissolution of nitrogen oxides (NOx). Therefore, for example, removal of anions by an ion exchange resin or addition of a neutralizing agent causes the pH to decrease. Is neutral. As the neutralizing agent, slaked lime, sodium hydroxide, sodium hydrogen carbonate, sodium carbonate or the like is used. If this neutralized recovered water is made into pure water by performing a desalting process using a reverse osmosis membrane or an ion exchange resin and removing particles using an ultrafiltration membrane, it can be used as boiler water. Become. Further, this pure water can also be used as washing water after maintenance of the thermal power plant 10.

Water that has absorbed the heat of the exhaust gas and has risen in temperature by the exhaust gas cooling device 16 shown in FIG. 1 is guided to the heat exchanger 21. The heat exchanger 21 heats the boiler water sent from the condenser 20 to the exhaust heat recovery boiler 14 by exchanging heat with the water that has absorbed the heat by cooling the exhaust gas from the exhaust gas cooling device 16. As a result, it is possible to replace the temperature rise of the boiler water for preventing the corrosion of the internal components of the exhaust heat recovery boiler 14 which was performed by the heat exchanger 111 of FIG. 10, and the power generation of the generator 19 accompanying the installation of the heat exchanger 111. The decrease in output can be suppressed. Further, although it depends on the adjustment of the heat balance, by making the rising temperature of the boiler water by the heat exchanger 21 higher than the rising temperature of the boiler water by the heat exchanger 111, the thermal efficiency is improved and the steam turbine 15 is connected. It is possible to increase the power generation output by the generated generator 19.

The water cooled by raising the temperature of the boiler water by the heat exchanger 21 is guided to the cooling device 23, and is further cooled by the cooling device 23 if necessary. This cooling device 23 uses a cooling tower (water cooling type cooling tower) that uses a large amount of water whose water quality is controlled in view of the fact that the thermal power plant 10 is located in an environment where it is difficult to take in water such as tap water or industrial water. This is inappropriate, and an air cooling method or a cooling method using environmental water such as seawater is preferable. The water cooled as necessary by the cooling device 23 is guided to the exhaust gas cooling device 16 and sprayed from the spray nozzle 26 of the exhaust gas cooling device 16.

The water sent from the cooling device 23 to the exhaust gas cooling device 16 is sprayed in the exhaust gas cooling device 16 and evaporated, so that it is appropriately replenished from the recovery water tank 22. However, when the exhaust gas cooling device 16 cools the exhaust gas to the dew point (about 30° C.), the exhaust gas cooling device 16 condenses water vapor in the exhaust gas and collects a large amount of water. Therefore, in this case, since a large amount of water flows from the exhaust gas cooling device 16 to the cooling device 23 via the heat exchanger 21, a part of the water sent from the cooling device 23 to the exhaust gas cooling device 16 is appropriately recovered. It will be stored in the water tank 22.

With the above-described configuration, according to the first embodiment, the following effects (1) and (2) are obtained.
(1) As shown in FIG. 1, the exhaust gas cooling device 16 or the water recovery device 17 cools the exhaust gas containing water vapor to a temperature below the dew point, whereby the water vapor in the exhaust gas is condensed and water is produced. As a result, since a water source is secured in the thermal power plant 10, even if it is difficult to take in clean water, industrial water, etc. at the location of the thermal power plant 10 and there is a restriction on the use of water resources, this thermal power plant Sufficient water can be secured within 10.

(2) The boiler water sent to the exhaust heat recovery boiler 14 is heated in the heat exchanger 21 by exchanging heat with the water that has absorbed heat by cooling the exhaust gas by the exhaust gas cooling device 16. Therefore, firstly, it is possible to prevent dew condensation that occurs in the exhaust heat recovery boiler 14 when the low-temperature boiler water from the condenser 20 flows into the exhaust heat recovery boiler 14, and therefore, the exhaust heat generated by this dew condensation can be prevented. It is possible to prevent corrosion of members inside the recovery boiler 14.

Secondly, since the temperature of the boiler water is raised by utilizing the heat absorbed in the exhaust gas cooling device 16 from the exhaust gas originally discharged from the chimney 18, the thermal efficiency can be improved. Further, since the temperature rise of the boiler water does not utilize a part of the superheated steam generated in the exhaust heat recovery boiler 14 and supplied to the steam turbine 15, the power generator 19 driven by the steam turbine 15 is operated. The power generation output can be suitably secured.

[B] Second embodiment (FIG. 8)
FIG. 8 is a system diagram showing a combined cycle type thermal power plant to which the second embodiment of the water collection device of the thermal power plant according to the present invention is applied. In the second embodiment, the same parts as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment to simplify or omit the description.

The point that the water collecting device 51 of the thermal power plant 50 in the second embodiment is different from that in the first embodiment is that a plurality of exhaust gas cooling devices 16 are connected in series and configured in a multi-stage structure, and the downstream side in the flow direction of the exhaust gas. This is a point that the exhaust gas cooling device 16 cools the exhaust gas and absorbs heat, and the water is sprayed by the exhaust gas cooling device 16 on the upstream side in the exhaust gas flow direction.

That is, for example, when three exhaust gas cooling devices 16A, 16B, and 16C are connected in series, the water cooled by the cooling device 23 is sprayed in the exhaust gas cooling device 16C on the most downstream side, and the exhaust gas cooling device 16C is sprayed. In the exhaust gas cooling device 16B on the upstream side, the water that has absorbed heat from the exhaust gas is guided to be sprayed, and the water that has absorbed heat from the exhaust gas in this exhaust gas cooling device 16B is guided to the exhaust gas cooling device 16A that is the most upstream side. Spray. Therefore, relatively cool water is sprayed in the exhaust gas cooling device 16 on the downstream side (particularly, the exhaust gas cooling device 16C on the most downstream side), and relatively hot water is sprayed on the upstream side (particularly, the exhaust gas cooling device 16A on the most upstream side). Will be sprayed. As a result, the temperature of the water that has absorbed heat from the exhaust gas in the exhaust gas cooling device 16 (16A) on the most upstream side absorbs heat from the exhaust gas when the exhaust gas cooling device 16 is in a single stage (that is, when the exhaust gas cooling device 16C is the only one). The temperature of the generated water becomes higher than that of the generated water, and the heat of the exhaust gas from the exhaust heat recovery boiler 14 can be recovered more efficiently.

Therefore, according to the second embodiment, in addition to the same effects as the effects (1) and (2) of the first embodiment, the following effect (3) is achieved.

(3) A plurality of exhaust gas cooling devices 16 (for example, exhaust gas cooling devices 16A, 16B, 16C) are connected in series to have a multi-stage structure, and the exhaust gas cooling device 16 on the downstream side in the exhaust gas flow direction cools the exhaust gas. Since the heat-absorbed water is sprayed by the exhaust gas cooling device on the upstream side in the exhaust gas flow direction, the temperature of the water that has absorbed heat from the exhaust gas in the exhaust gas cooling device 16 on the most upstream side in the exhaust gas flow direction is When the exhaust gas cooling device 16 has a single stage, the temperature can be higher than the temperature of water that has absorbed heat from the exhaust gas. As described above, since the exhaust gas cooling device 16 has the multi-stage structure as described above, the heat of the exhaust gas can be efficiently recovered. Therefore, the condenser 20 is provided by the multi-stage exhaust gas cooling device 16 and the heat exchanger 21. The boiler water sent from the exhaust heat recovery boiler 14 to the exhaust heat recovery boiler 14 can be set to a higher temperature, and the power generation output by the generator 19 connected to the steam turbine 15 can be improved.

Although some embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention, and the replacements and changes thereof can be performed. Is included in the scope and gist of the invention, and is also included in the invention described in the claims and its equivalent scope.

For example, in both of the above-described embodiments, the present invention is applied to the combined cycle type thermal power plant 10 including the gas turbine 12, the exhaust heat recovery boiler 14, and the steam turbine 15, but is generated by burning fossil fuel. In a thermal power plant that drives a gas turbine with combustion gas to generate electric power, the present invention may be applied to exhaust gas discharged from the gas turbine. Furthermore, in a thermal power plant in which combustion gas generated by burning fossil fuel is guided to a boiler to generate steam, and a steam turbine is driven by this steam to generate electric power, the present invention is applied to exhaust gas discharged from the boiler. You may apply.

10... Thermal power plant, 12... Gas turbine, 13... Generator, 14... Exhaust heat recovery boiler, 16... Exhaust gas cooling device, 16A, 16B, 16C... Exhaust gas cooling device, 17... Water recovery device, 18... Chimney, 19 ... generator, 21... heat exchanger, 22... recovery water tank, 25... water collecting device, 26... spray nozzle, 27... recovery element, 27A... flat plate, 27B... mist separator, 50... thermal power plant, 51... water collection apparatus.

Claims (4)

Power generation is performed by using combustion gas generated by combustion of fossil fuel, and steam is collected from the exhaust gas after the combustion gas contributes to power generation and water is collected , and driving steam is supplied to the steam turbine used for power generation. A water collecting device for a thermal power plant equipped with a boiler for supplying ,
The exhaust gas cooling device is installed on the upstream side of the exhaust gas on the way to the chimney for exhausting to the atmosphere, and the water recovery device is installed on the downstream side, respectively.
The exhaust gas cooling device, while by spraying water into the exhaust gas Ru configured to cool the exhaust gas directly,
The water that has absorbed the heat by cooling the exhaust gas is guided to a heat exchanger, the boiler water sent to the boiler is configured to heat exchange by the heat exchanger to raise the temperature,
The water cooled by raising the temperature of the boiler water is guided to a cooling device, further cooled and guided to the exhaust gas cooling device, and configured to cool the exhaust gas,
The water recovery device, on the surface of the recovery element arranged along the flow direction of the exhaust gas, the water in the exhaust gas cooled by the exhaust gas cooling device is attached and separated, and the recovered water is collected. Is configured to replenish the water sent from the cooling device to the exhaust gas cooling device ,
The water collecting device of a thermal power plant, wherein the exhaust gas cooling device or the water recovery device is configured to cool the exhaust gas containing the water vapor to a temperature below a dew point. The water collecting device of a thermal power plant according to claim 1 , wherein the collecting element of the water collecting device is a laminated flat plate or a mist separator made of fiber. The exhaust gas cooling device is configured in a multi-stage structure in which a plurality of units are connected in series, water that has absorbed heat by cooling the exhaust gas in the exhaust gas cooling device on the downstream side is sprayed to the exhaust gas cooling device on the upstream side. water collecting device thermal power plant according to claim 1 or 2, characterized in that configured. The boiler is an exhaust heat recovery boiler that introduces exhaust gas from a gas turbine that is driven by combustion gas to rotate a generator and heats the sent water by exchanging heat with the exhaust gas to heat it to drive steam. The water collecting device for a thermal power plant according to any one of claims 1 to 3 , wherein:

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