JP2021046989A - Feedwater heating system, power generation plant equipped with the same, and operation method of feedwater heating system - Google Patents

Abstract

To provide a feedwater heating system capable of effectively using steam generated in a boiler for feedwater heating over a wide load range in a power generation plant.SOLUTION: A feedwater heating system 6 used for a power generation plant 1 equipped with a boiler 3, a steam turbine 5 driven by steam generated by the boiler 3, a power generator driven by the steam turbine 5, and a plurality of feedwater heaters 50 and 54 for heating feedwater fed to the boiler 3 by extraction steam extracted from a plurality of positions of the steam turbine 5 includes: a boiler 7 for heating feedwater for heating feedwater fed to the boiler 3; two or more steam pipes 62a and 62b for heating feedwater that can supply the steam generated by the boiler 7 for heating feedwater to two or more feedwater heaters 54a and 54c respectively as steam for heating; and a control part 30 for selecting the steam pipes 62a and 62b for heating feedwater for circulating the steam for heating according to a load of the power generation plant 1.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a water supply heating system, a power plant equipped with the water supply heating system, and a method of operating the water supply heating system.

Large boilers such as coal-fired boilers have a hollow fireplace that is installed in the vertical direction, and a plurality of combustion burners are arranged along the circumferential direction of the fireplace on the wall of the fireplace. In the coal-fired boiler, a flue is connected vertically above the fireplace, and a heat exchanger for generating steam is arranged in this flue. Then, the combustion burner injects a mixture of fuel and air (oxidizing gas) into the fireplace to form a flame, and combustion gas is generated and flows into the flue. A heat exchanger is installed in the area where the combustion gas flows, and superheated steam is generated by heating the water or steam flowing in the heat transfer tube constituting the heat exchanger.

In a power plant equipped with a boiler as described above, superheated steam generated by the boiler is sent to a steam turbine, and the steam turbine is rotationally driven. The rotational driving force obtained by the steam turbine is transmitted to the generator, and the generator generates electricity.

Patent Document 1 includes an independent heat exchanger provided with a power plant and an additional water supply heating boiler (biomass boiler), and steam (external steam) from the water supply heating boiler is provided at the economizer inlet of the water supply system of the existing power plant. A configuration is disclosed in which the water is supplied to the water supply to heat the water supply.
Patent Document 2 discloses an invention that controls the amount of steam recovered by a feed water heater when the amount of heat of external steam fluctuates.
Patent Document 3 discloses an invention in which the amount of external steam is controlled so that the water supply temperature or the water supply pressure at the inlet of the economizer becomes constant.
Patent Document 4 discloses an invention in which external steam is supplied to a low-pressure feed water heater to control the internal pressure inside the low-pressure feed water heater.

Japanese Patent No. 6224858 Japanese Patent No. 64198888 Japanese Patent No. 6342539 Japanese Unexamined Patent Publication No. 2004-190546

Although the publicly known techniques described in the above patent documents disclose that the boiler water supply of the power plant is heated by using external steam, the power plant is operated with a constant predetermined load (predetermined power generation amount). Is assumed. However, a power plant operates in a wide load range from the rated load (rated power generation amount) to the minimum load, and biomass that generates steam using biomass fuel for such a wide load range. How to use the external steam generated by the water supply heating boiler such as a boiler has not been examined.

When the power plant is operated with a partial load, it is conceivable that the external steam generated by the feed water heater boiler is not supplied to the feed water heater and the heat is not recovered. Alternatively, it is conceivable to limit the operation of the feed water heating boiler to the amount of heat of external steam that can be recovered by the feed water heater even with a partial load.

However, such an operation has a problem in that the effective use of the external steam of the water supply heating boiler is limited. Therefore, even in a power plant that is operated in a wide range of loads, it is desired to operate the power plant so that the external steam can be recovered by the feed water heater without waste.

The present disclosure has been made in view of such circumstances, and includes a water supply heating system capable of effectively utilizing steam generated in a water supply heating boiler over a wide load range of a power plant, and a water supply heating system thereof. It is an object of the present invention to provide a method of operating a power plant and a water supply heating system.

The water supply heating system according to one aspect of the present disclosure includes a boiler, a steam turbine driven by the steam generated by the boiler, a generator driven by the steam turbine, and extraction air from a plurality of positions of the steam turbine. A water supply heating system used in a power generation plant including a plurality of water supply heaters for heating the water supply supplied to the boiler by the extracted steam, and water supply heating for heating the water supply supplied to the boiler. Depending on the power supply boiler, two or more water supply heating steam pipes that can supply the steam generated by the water supply heating boiler as heating steam to two or more water supply heaters, respectively, and the load of the power generation plant. A control unit for selecting the water supply heating steam pipe through which the heating steam is circulated is provided.

A method of operating the water supply heating system according to one aspect of the present disclosure includes a boiler, a steam turbine driven by the steam generated by the boiler, a generator driven by the steam turbine, and a plurality of the steam turbines. A method of operating a water supply heating system used in a power generation plant including a plurality of water supply heaters for heating the water supply supplied to the boiler by the extracted steam extracted from a position, wherein the water supply heating system is the said. Two or more water supply heaters that can supply the water supply heating boiler that heats the water supply supplied to the boiler and the steam generated by the water supply heating boiler as heating steam to two or more water supply heaters, respectively. The steam pipe for heating the water supply, which is provided with the steam pipe for heating, and which distributes the steam for heating is selected according to the load of the power plant.

The steam generated by the water supply heating boiler can be effectively used over a wide load range of the power plant.

It is the 1st Embodiment of the power plant of this disclosure, and is the schematic block diagram which showed the state at the time of 100% load. It is a schematic block diagram which corresponds to FIG. 1 and shows the state at the time of 50% load. It is a schematic block diagram which corresponds to FIG. 1 and shows the state at the time of a load of 30%. It is the 2nd Embodiment of the power plant of this disclosure, and is the schematic block diagram which showed the state at the time of 100% load. It is a schematic block diagram which showed the control of the deaerator side control valve of FIG. It is a schematic block diagram which showed the modification of FIG. It is a schematic block diagram which showed the power plant which provided the thermostat with respect to FIG.

Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings.
[First Embodiment]
FIG. 1 shows a power plant 1 according to the first embodiment. The power plant 1 includes a boiler 3, a steam turbine 5, and a biomass boiler (boiler for water supply and heating) 7. In this embodiment, an example using the biomass boiler 7 that burns the biomass fuel is shown, but the present invention is not limited to the biomass boiler, as long as the water supply is heated to generate a predetermined steam. It does not limit the fuel or heat source to be burned.

The boiler 3 is provided with a burner (not shown) that forms a flame using fossil fuels such as coal and oil in the furnace of the boiler main body 3a. The furnace wall forming the fireplace is a water-cooled wall composed of heat transfer tubes and fins, and the water heated by the water-cooled wall is guided to the steam drum. A water drum is provided on the vertically lower side of the water cooling wall (not shown). In this embodiment, a subcritical pressure boiler having a drum is taken as an example, but it can also be applied to a supercritical pressure boiler having no drum.

The combustion exhaust gas generated by the flame of the burner flows to the vertically upper side of the fireplace and is guided to the superheater 13. A reheater 17 and an economizer (enomizer) 18 are provided in this order on the downstream side of the combustion exhaust gas flow of the superheater 13.

A water supply pipe 24 for supplying water supply (water) is connected to the economizer 18. The water supplied through the water supply pipe 24 is supplied to the economizer 18 after being heated by the steam generated in the biomass boiler 7, as will be described later. The water supply to the economizer 18 can be controlled so that the water (water supply) after heating with the economizer 18 does not vaporize (steam) beyond the saturation temperature while achieving the highest possible water supply temperature. preferable.

An exhaust gas duct connected to the boiler main body 3a is provided on the downstream side of the combustion exhaust gas flow that has passed through the economizer 18. A denitration device (not shown) for removing NOx in the combustion gas is provided at an intermediate position of the exhaust gas duct. The combustion exhaust gas that has passed through the denitration device is, for example, heat exchanged by an air preheater (not shown), and SOx and the like are removed by a desulfurization device (not shown) in order to remove SOx in the combustion gas. Later, on the downstream side, a dust treatment device (not shown), an induced Draft Fan (IDF), and the like are provided as needed, and the gas is discharged from the chimney at the downstream end of the exhaust gas duct to the atmosphere.

As shown in FIG. 1, the superheated steam leaving the superheater 13 is guided to the steam turbine 5 through the main steam pipe 32. In the present embodiment, the steam turbine 5 includes, for example, a high-pressure turbine 34, a medium-pressure turbine 35, and a low-pressure turbine 36. A generator (not shown) is rotationally driven by the rotational power generated by the turbines 34, 35, and 36 to generate electricity.

The main steam pipe 32 is connected to the inlet of the high pressure turbine 34. A high-pressure turbine outlet pipe 38 is connected to the exhaust side of the high-pressure turbine 34. The downstream end of the high-pressure turbine outlet pipe 38 is connected to the reheater 17, so that steam that has completed the work of performing predetermined expansion in the high-pressure turbine 34 to rotationally drive the turbine is guided to the reheater 17. It has become.

A reheat steam supply pipe 40 for supplying reheat steam to the medium pressure turbine 35 is provided between the steam outlet side of the reheater 17 and the medium pressure turbine 35.

A medium pressure turbine outlet pipe 42 is connected to the exhaust side of the medium pressure turbine 35. The downstream end of the medium-pressure turbine outlet pipe 42 is connected to the inlet of the low-pressure turbine 36, and steam that has completed the work of performing predetermined expansion in the medium-pressure turbine 35 to rotationally drive the turbine is guided to the low-pressure turbine 36. It has become like.

A low-pressure turbine outlet pipe 44 is connected to the exhaust side of the low-pressure turbine 36. The downstream end of the low pressure turbine outlet pipe 44 is connected to the condenser 46. In the condenser 46, steam is cooled under vacuum by cooling water (not shown) to condense. The condensate liquefied by the condensate 46 becomes water supply and is guided to the low-pressure feed water heater 50 by the condensate pump 48.

In the present embodiment, for example, four low-pressure feed water heaters 50 are, in order from the upstream side of the feed water flow, a fourth low-pressure feed water heater 50d, a third low-pressure feed water heater 50c, a second low-pressure feed water heater 50b, and a first low-pressure heater. A feed water heater 50a is provided in series. In each low-pressure feed water heater 50, the feed water guided from the condenser 46 is heated by the low-pressure steam guided from the low-pressure turbine 36 via the low-pressure bleed steam pipes 52a, 52b, 52c, 52d.

The feed water heated by the first low-pressure feed water heater 50a is guided to the deaerator 53. In the deaerator 53, the gas phase component (air, especially oxygen) is removed from the water supply by using the medium pressure steam extracted from the medium pressure turbine 35 via the degassing air extraction pipe 53a, and the predetermined water quality is stable. Is secured.

The water supply degassed by the deaerator 53 is guided to the high-pressure feed water heater 54 through the water supply pump 51. In the present embodiment, for example, the three high-pressure water supply heaters 54 are arranged in the order of the first high-pressure water supply heater 54a and the second high-pressure water supply heater 54b (lower pressure side than the first high-pressure water supply heater 54a) from the downstream side of the water supply flow. The first low-pressure side water supply heater) and the third high-pressure water supply heater 54c (the second low-pressure side water supply heater on the lower pressure side than the second high-pressure water supply heater 54b) are provided. In the third high-pressure feed water heater 54c, the feed water is heated by the medium-pressure turbine bleed steam extracted from the medium-pressure turbine 35 via the third high-pressure bleed pipe 55c. The third high-pressure bleeding pipe 55c is provided with a third high-pressure bleeding valve 56c whose opening degree is controlled by the control unit 30. A third high-pressure check valve 57c is provided on the downstream side of the bleed steam flow of the third high-pressure bleed valve 56c. The third high-pressure check valve 57c allows the bleed steam flow toward the third high-pressure feed water heater 54c and limits the flow in the opposite direction.

The feed water heated by the third high-pressure feed water heater 54c (second low-pressure side feed water heater) is the second high-pressure feed water heater 54b (first low-pressure side feed water heater) and the first high-pressure feed water heater in the order of water supply flow. It is guided to the vessel 54a.

The high-pressure steam guided to the second high-pressure feed water heater 54b is guided through the second high-pressure bleeding pipe 55b. The second high-pressure bleeding pipe 55b is provided with a second high-pressure bleeding valve 56b whose opening degree is controlled by the control unit 30. A second high-pressure check valve 57b is provided on the downstream side of the bleed steam flow of the second high-pressure bleed valve 56b. The second high-pressure check valve 57b allows the bleed steam flow toward the second high-pressure feed water heater 54b and limits the flow in the opposite direction.

The high-pressure steam guided to the first high-pressure feed water heater 54a is guided through the first high-pressure bleeding pipe 55a. The first high-pressure bleeding pipe 55a is provided with a first high-pressure bleeding valve 56a whose opening degree is controlled by the control unit 30. A first high-pressure check valve 57a is provided on the downstream side of the bleed steam flow of the first high-pressure bleed valve 56a. The first high-pressure check valve 57a allows the bleed steam flow toward the first high-pressure feed water heater 54a and limits the flow in the opposite direction.

In the present embodiment, since the first high-pressure bleeding pipe 55a is connected to the upstream side (high-pressure side) of the high-pressure turbine 34 with respect to the second high-pressure bleeding pipe 55b, the high-pressure steam guided by the first high-pressure bleeding pipe 55a The pressure is higher than the pressure of the high pressure steam guided by the second high pressure bleeding pipe 55b. Further, the pressure of the high-pressure steam guided by the second high-pressure bleed pipe 55b is higher than the pressure of the high-pressure steam guided by the third high-pressure bleed pipe 55c. Therefore, the pressure of the high-pressure feed water heater 54 increases in the order of the third high-pressure feed water heater 54c, the second high-pressure feed water heater 54b, and the first high-pressure feed water heater 54a.

The steam after being used for heating in the high-pressure feed water heater 54 becomes drain water, which is sequentially sent to the high-pressure feed water heater 54 in the low-pressure stage via the drain water system (not shown), and finally. It is collected by the deaerator 53. Further, the steam after being used for heating in the low-pressure feed water heater 50 becomes drain water, which is sequentially sent to the low-pressure feed water heater 50 in the low-pressure stage via the drain water system (not shown), and finally. Is collected in the return pipe via a drain pump (not shown).

The water supply after being heated by the first high-pressure feed water heater 54a is guided to the economizer 18 through the feed water pipe 24.

The control unit 30 is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. Then, as an example, a series of processes for realizing various functions are stored in a storage medium or the like in the form of a program, and the CPU reads this program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program is installed in a ROM or other storage medium in advance, is provided in a state of being stored in a computer-readable storage medium, or is distributed via a wired or wireless communication means. Etc. may be applied. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, and the like.

<Water supply heating system>
Next, the water supply heating system 6 provided in the power plant 1 described above will be described.
The feed water heating system 6 mainly includes a biomass boiler 7 in addition to the feed water heaters 50 and 54 described above.

The biomass boiler 7 is provided with a biomass boiler water supply pipe 60. In the present embodiment, the upstream end of the biomass boiler water supply pipe 60 is connected to the water supply pipe 24 between the downstream side of the water supply pump 51 and the third high-pressure water supply heater 54c. Further, depending on the steam generation capacity of the biomass boiler 7, it may be connected between the third high-pressure feed water heater 54c and the second high-pressure feed water heater 54b. The biomass boiler water supply pipe 60 may be appropriately provided with an on-off valve, a flow rate adjusting valve, or the like. A part of the water supply discharged from the water supply pump 51 is guided to the biomass boiler 7 by the biomass boiler water supply pipe 60.

The biomass boiler 7 heats the supply water by burning the biomass fuel to generate steam. The amount of evaporation of the biomass boiler 7 in the present embodiment is, for example, 30% or less, preferably 20% or less of that of the boiler 3. The amount of steam that is the output of the biomass boiler 7 is controlled by the control unit 30. Specifically, the control unit 30 controls the supply amount of biomass fuel to be charged into the biomass boiler 7, the flow rate of combustion air, the supply amount of generated steam, and the like.

The steam generated in the biomass boiler 7 is output from the water supply heating steam pipe 62 as heating steam for heating the water supply supplied to the boiler 3. The water supply heating steam pipe 62 is branched into a first water supply heating steam pipe 62a on the high pressure side and a second water supply heating steam pipe 62b on the low pressure side. The heating steam generated in the biomass boiler 7 is an external steam generated outside the boiler 3, and will be simply referred to as "external steam" hereafter.

The downstream end of the first water supply heating steam pipe 62a is connected to the first high-pressure bleeding pipe 55a. The first water supply heating steam pipe 62a is provided with a first control valve 63a whose opening degree is controlled by the control unit 30.

The downstream end of the second water supply heating steam pipe 62b is connected to the third high-pressure bleeding pipe 55c. The steam pipe 62b for heating the second water supply is provided with a second control valve 63b whose opening degree is controlled by the control unit 30.

Generally, the high-pressure feed water heater 54 is designed to have a larger amount of energy of the turbine bleed steam than the low-pressure feed water heater 50, and the heat exchange amount is larger. Therefore, as in the present embodiment, in order to effectively utilize the steam energy generated in the biomass boiler 7, the external steam generated in the biomass boiler 7 can be supplied to the high-pressure bleeding pipes 55a and 55c of the high-pressure feed water heater 54. preferable.

The power plant 1 provided with the water supply heating system 6 having the above configuration operates as follows.
The superheated steam generated by the superheater 13 of the boiler 3 is guided to the high-pressure turbine 34 of the steam turbine 5, and after rotationally driving the high-pressure turbine 34, it is guided to the reheater 17. The steam led to the reheater 17 is reheated by the boiler 3 and led to the medium pressure turbine 35 as reheated steam. After the medium pressure turbine 35 is rotationally driven, the reheated steam is guided to the low pressure turbine 36 to rotationally drive the low pressure turbine 36. The generator 37 is rotationally driven by the rotational power obtained in this way to generate electricity.

The steam that has completed the work of rotating and driving the turbine by performing a predetermined expansion in the low-pressure turbine 36 is condensed in the condenser 46, and the low-pressure feed water heater 50, the deaerator 53, and the high-pressure feed water heater 54 are used as water supply. It is heated by passing through sequentially. After that, the water supply is supplied to the economizer 18 of the boiler 3.

The operation according to the load (ratio to the rated load) of the power plant 1 will be described.
The load of the power generation plant 1 is input to the control unit 30 by, for example, a higher-level control system or operator that adjusts the amount of power supplied and supplied in the power supply system.

The biomass boiler 7 is operated with a predetermined load that generates a constant amount of steam, such as the rated evaporation amount of the biomass boiler 7.
The states of the bleeding valves 56a, 56b, 56c and the control valves 63a, 63b are as shown in Table 1. In Table 1, 100% load, 75% load, 50% load, and 30% load of the power plant are shown as an example. In each figure, the valves shown in black indicate the closed state, and the valves shown in white indicate the open state.

<100% load>
When the power plant 1 has a 100% load (rated load), the first high-pressure bleed valve 56a is fully closed and the first control valve 63a is adjusted and opened. The second high-pressure bleed valve 56b is fully open, the third high-pressure bleed valve 56c is fully open, and the second control valve 63b is fully closed.

The external steam (heating steam) generated in the biomass boiler 7 passes through the water supply heating steam pipe 62 and the first water supply heating steam pipe 62a, and is guided to the first high-pressure bleeding pipe 55a. The first control valve 63a is opened (adjusted open) so as to have a desired pressure, and then has a constant opening degree.
Since the first high-pressure bleed valve 56a is fully closed, steam is not extracted from the high-pressure turbine 34, and the bleed steam is saved. Further, by fully closing the first high-pressure bleed valve 56a, chattering of the first high-pressure check valve 57a can be prevented.

On the other hand, the second control valve 63b is fully closed. Therefore, the external steam generated by the biomass boiler 7 is not supplied from the second water supply heating steam pipe 62b to the third high-pressure bleeding pipe 55c. As a result, the entire amount of steam generated in the biomass boiler 7 is supplied to the first high-pressure feed water heater 54a.

<75% load>
When the power plant 1 has a 75% load, the operation is the same as the 100% load. The steam conditions of the external steam generated in the biomass boiler 7 are also the same as those at 100% load. As a result, it is possible to suppress a decrease in the power generation efficiency of the power generation plant 1 without lowering the water supply temperature. On the other hand, in the operation of the conventional power plant that does not use the external steam for heating the feed water, the turbine extraction pressure decreases due to the decrease in the load of the power plant 1, so that the outlet water supply temperature of the first high-pressure feed water heater 54a (that is, the economizer 18 The inlet water supply temperature) also decreased, which was a factor in reducing power generation efficiency.

<50% load>
FIG. 2 shows an operation method when the power plant 1 has a 50% load (first low load).
Even when the power plant 1 is 50%, the steam conditions of the external steam generated in the biomass boiler 7 are the same as when the load is 100%.

When the power plant 1 has a 50% load, the first high-pressure bleed valve 56a is fully closed and the first control valve 63a is adjusted and opened. The third high-pressure bleed valve 56c is fully open, and the second control valve 63b is fully closed. However, unlike the 100% load and the 75% load, the second high-pressure bleed valve 56b is fully closed.

When the power plant 1 is loaded at 50%, the outlet water supply temperature of the first high-pressure feed water heater 54a rises too much when all the external steam is recovered by the first high-pressure feed water heater 54a due to the decrease in the feed water flow rate due to the load reduction. There is a risk of exceeding the limit value. If the limit value is exceeded, steaming will occur in which the water supply evaporates in the economizer 18. Therefore, in order to lower the inlet water supply temperature of the first high-pressure feed water heater 54a, the second high-pressure bleeding valve 56b is fully closed to stop the bleeding from the high-pressure turbine 34 to the second high-pressure feed water heater 54b.

<30% load>
FIG. 3 shows an operation method when the power plant 1 has a 30% load (second low load).
Even when the power plant 1 has a 30% load, the steam conditions of the external steam generated in the biomass boiler 7 are the same as when the load is 100%.

When the power plant 1 has a 30% load, the first high-pressure bleed valve 56a is fully closed and the first control valve 63a is adjusted and opened. The second high-pressure bleed valve 56b is fully closed. However, unlike the case of 50% load, the third high-pressure bleed valve 56c is fully closed and the second control valve 63b is adjusted and opened.

When the power plant 1 is loaded at 30%, the water supply flow rate of the power plant 1 is smaller than that at the time of 50% load. Therefore, the outlet water supply temperature of the first high-pressure feed water heater 54a is further limited by the economizer 18 so as not to cause steaming. It should be kept within the value. Therefore, by fully closing the third high-pressure bleeding valve 56c, the bleeding from the medium-pressure turbine 35 to the third high-pressure feed water heater 54c was stopped.
If all the external steam generated in the biomass boiler 7 is recovered in the first high-pressure feed water heater 54a, the increase value of the feed water temperature in the first high-pressure feed water heater 54a exceeds the limit value and the first high-pressure feed water heater There is a risk of damaging the 54a. Therefore, by adjusting and opening the second control valve 63b, the external steam generated by the biomass boiler 7 is distributed and supplied to the third high-pressure feed water heater 54c, so that the feed water temperature per feed water heater is supplied. It was decided to reduce the increase value of. The valve opening degree of the second control valve 63b is set to a constant opening degree after being opened (adjusted open) so as to have a desired pressure, for example.

The effects of the present embodiment described above are as follows.
Depending on the load of the power plant 1, the steam pipes 62a and 62b for heating the water supply to which the external steam generated in the biomass boiler 7 is circulated were selected. As a result, external steam can be supplied to the high-pressure feed water heater 54 in an appropriate amount according to the feed water heating amount required for the load of the power plant 1. As a result, the external steam generated in the biomass boiler 7 can be used as much as possible, and the extracted steam extracted from the steam turbine 5 can be reduced accordingly. Then, by reducing the extracted steam, it is possible to reduce the amount of fuel used for the boiler 3 (for example, fossil fuel such as coal) and the amount of carbon dioxide generated by the combustion of the fuel in the boiler 3.
Therefore, the steam generated in the biomass boiler 7 can be effectively used over a wide load range of the power plant 1.

When the power plant 1 has a high load such as 100% load or 75% load, the first feed water heater steam pipe 62a connected to the first high pressure feed water heater 54a is selected, and the biomass boiler 7 is selected. The high-pressure, high-temperature external steam generated in the above is effectively used to heat the feed water.
When the power plant 1 has a 50% load, the first high-pressure feed water heater 54a does not need as much heating as when the load is high, as the feed water flow rate decreases due to the load reduction. At this time, the second high-pressure bleeding valve 56b is fully closed to stop the bleeding from the high-pressure turbine 34, and the heating of the feed water in the second high-pressure feed water heater 54b is stopped. As a result, the required amount of external steam supplied to the first high-pressure feed water heater 54a increases, so that the external steam generated by the biomass boiler 7 can be used without waste.
Further, while achieving the highest possible feed water temperature for the water supplied to the economizer 18, steaming in the economizer 18 is prevented by avoiding an excessive rise in the outlet feed water temperature of the first high-pressure feed water heater 54a. Can be done.

When the power plant is loaded with 30%, the first high-pressure feed water heater 54a does not require as much heating as when the load is high, so that it is for the second feed water heater connected to the third high-pressure feed water heater 54c. The steam pipe 62b is further selected. As a result, the external steam generated by the biomass boiler 7 can be distributed to the plurality of feed water heaters 54a and 54c, so that the external steam can be used without waste.
Further, by distributing and supplying the external steam generated by the biomass boiler 7 to the third high-pressure feed water heater 54c, the feed water temperature rise value per feed water heater is lowered, and the specified temperature of the feed water heater is lowered. It is possible to prevent the damage from exceeding the above.

By opening and closing the high-pressure bleeding valves 56a, 56b, 56c while selecting the steam pipes 62a, 62b for heating the water supply as described above, the load of the biomass boiler 7 is kept constant regardless of the load of the power plant 1. It can be operated, and the biomass boiler 7 can be operated efficiently.

[Second Embodiment]
Next, the second embodiment of the present disclosure will be described with reference to FIG.
This embodiment is different from the first embodiment in that a steam pipe 70 for heating on the deaerator side for guiding external steam to the deaerator 53 is provided. Other than that, it is the same as that of the first embodiment, and the description thereof will be omitted. The states of the bleed valves 56a, 56b, 56c and the control valves 63a, 63b at 100% load, 75% load, 50% load, and 30% load of the power plant 1 are the same as those in the first embodiment.

As shown in FIG. 4, the steam pipe 70 for heating on the deaerator side is provided so as to branch from the steam pipe 62b for heating the second water supply. The downstream end of the steam pipe 70 for heating on the deaerator side is connected to the deaerator 53. The steam pipe 70 for heating on the deaerator side is provided with a control valve 70a on the deaerator side. The deaerator side control valve 70a is controlled to a desired opening degree by the control unit 30.

Generally, the feed water heaters 50 and 54 have an operating characteristic in which the heat transfer amount (heat receiving amount) on the water supply side and the heat transfer amount (heat dissipation amount) on the extracted steam side are always balanced. That is, the extracted steam flow rate is extracted from the steam turbine 5 so that the amount of heat transferred to the feed water is balanced, and is supplied to the feed water heaters 50 and 54. More specifically, of the steam flowing through the steam turbine 5, the amount of steam required for the feed water heaters 50 and 54 is always extracted from the steam turbine 5 and supplied to the feed water heaters 50 and 54.

On the other hand, since the entire amount of steam generated in the biomass boiler 7 is supplied as external steam to the first high-pressure feed water heater 54a and the third high-pressure feed water heater 54c, the external steam is supplied from the biomass boiler 7 to the feed water heaters 50 and 54. It is difficult to balance the required amount of heated steam depending on the state of each feed water heater 50, 54 with respect to the load of the power plant 1.

Therefore, it was generated in the biomass boiler 7 so as to be able to cope with the feed water heaters 50 and 54 that fluctuate according to the load (for example, so that the increase value of the feed water temperature in the feed water heaters 50 and 54 does not exceed the limit value). It was decided to control the supply destination of external steam.

In the present embodiment, among the external steam generated in the biomass boiler 7, the required amount of steam for which the heating amount is balanced is recovered as the heating steam of the first high-pressure feed water heater 54a and / or the third high-pressure feed water heater 54c. It was decided to discharge the surplus steam to the deaerator 53 to adjust the flow rate. As a result, the load (steam generation amount) of the biomass boiler 7 can be made constant, and the biomass boiler 7 can be operated efficiently.

There is also a method of controlling the amount of external steam generated in the biomass boiler 7 by a control valve provided in each of the high-pressure bleeding pipes 55a and 55c. However, since it is assumed that steam is distributed to a plurality of high-pressure feed water heaters 54, excess steam is used to prevent the steam flow rate control from becoming unstable due to interference between the operations of the plurality of control valves. It is preferable to control the amount to be discharged to the deaerator 53.

As shown in FIG. 5, the deaerator side control valve 70a is controlled based on the pressure of the fluid (heating side fluid) on the body side of the third high-pressure feed water heater 54c. The body-side pressure of the third high-pressure feed water heater 54c is measured by a pressure sensor 72 installed in the third high-pressure bleed pipe 55c. The pressure sensor 72 is installed closer to the third high-pressure feed water heater 54c than the third high-pressure bleed valve 56c. The output of the pressure sensor 72 is transmitted to the control unit 30.

When the flow rate of the external steam generated in the biomass boiler 7 becomes larger than the steam flow rate required for feed water heating, the steam recovered by the first high-pressure feed water heater 54a and the third high-pressure feed water heater 54c becomes surplus, and the third The pressure on the body side of the high-pressure feed water heater 54c rises more than when the steam recovered is not surplus. This pressure fluctuation is measured by the pressure sensor 72, and the control unit 30 regards it as a preceding signal of steam imbalance, and controls to open the opening degree of the deaerator side control valve 70a. As a result, the steam flow rates are balanced in the first high-pressure feed water heater 54a and the third high-pressure feed water heater 54c.

The steam pipe 70 for heating on the deaerator side is provided in the steam pipe 62a for heating the first feed water heater, and the pressure of the fluid on the body side (fluid on the heating side) of the first high-pressure feed water heater 54a is measured and controlled. You may.

Instead of the configuration of FIG. 5, as shown in FIG. 6, the deaerator side control valve 70a may be controlled based on the temperature sensor 74 that measures the outlet water supply temperature of the first high-pressure feed water heater 54a. In the figure, the steam pipe 70 for heating on the deaerator side is connected to the steam pipe 62a for heating the first water supply.
The temperature sensor 74 is installed in the water supply pipe 24 on the outlet side of the first high-pressure feed water heater 54a. The output of the temperature sensor 74 is transmitted to the control unit 30.
When the steam recovered by the first high-pressure feed water heater 54a becomes surplus and the body pressure of the first high-pressure feed water heater 54a rises, the outlet water supply temperature of the first high-pressure feed water heater 54a also rises. The control unit 30 regards this temperature fluctuation as a preceding signal of steam imbalance, and controls to open the opening degree of the deaerator side control valve 70a. As a result, the steam flow rates are balanced in the first high-pressure feed water heater 54a and the third high-pressure feed water heater 54c.

The steam pipe 70 for heating on the deaerator side may be provided in the steam pipe 62b for heating the second feed water heater, and the outlet water supply temperature of the third high pressure feed water heater 54c may be measured and controlled.

In each of the above-described embodiments, the high-pressure bleed valves 56a, 56b, 56c are fully closed to prevent chattering of the high-pressure check valves 57a, 57b, 57c when the bleed flow rate of the turbine bleed system decreases. However, the high-pressure bleeding valves 56a, 56b, 56c may be opened without completely stopping the bleeding as long as the operation can be performed with the bleeding flow rate without chattering.

In each of the above-described embodiments, the operating state is switched for each load condition on the condition of the load set value of the power plant 1 given to the control unit 30. In the present embodiment, examples of 100% load, 75% load, 50% load, and 30% load of the power plant 1 are shown, but the switching of the operating state is not limited to the ratio value of this load, and can be arbitrarily set. It may be set. Instead of this, thermometers are provided at the inlet and outlet of the first high-pressure feed water heater 54a, and the outlet water supply temperature of the first high-pressure feed water heater 54a and the water supply temperature rise value in the first high-pressure feed water heater 54a (the first). 1) The control may be such that the ratio value of the load is estimated and the operation state is switched on the condition of the outlet temperature of the high-pressure feed water heater 54a-the inlet temperature).

It was decided to supply the entire amount of the external steam generated by the biomass boiler 7 to the first high-pressure feed water heater 54a during the rated operation of the power plant 1 (during 100% load operation). However, depending on the steam conditions of the external steam generated in the biomass boiler 7 and the conditions of the applicable plant, external steam for heating may be supplied to other feed water heaters or a plurality of feed water heaters.
Further, the supply destination of the external steam for heating when the power plant 1 is partially loaded is not limited to the high-pressure feed water heater 54, but a part of the low-pressure feed water heater 50 and the external steam for heating are not limited to the high-pressure feed water heater 54. May be supplied to other equipment that can be used as a heat source.

Considering the design temperature of the bleeding pipes 55a, 55b, 55c of the power plant 1, the external steam is supplied to the first high-pressure bleeding pipe 55a and the third high-pressure bleeding pipe 55c. However, steam may be supplied to other feed water heaters.

As shown in FIG. 7, depending on the temperature conditions, the external steam generated in the biomass boiler 7 may be cooled by the heater 65 and supplied to the high-pressure bleeding pipes 55a and 55c. As the fluid supplied to the cooler 65, for example, water supplied from the water supply pump 51 can be used. Water supply of external steam for heating By providing a heater 65 in the middle of the steam pipe 62 for heating, it is possible to adjust the temperature of the external steam without exceeding the design temperature of the high-pressure bleeding pipes 55a and 55c. Become. The warmer 65 can also be used for the second embodiment shown in FIG.

The drain of the external steam supplied to the first high-pressure feed water heater 54a and the third high-pressure feed water heater 54c is collected in the deaerator 53 of the power plant 1. Therefore, when adding a water supply heating system 6 to an existing power plant, the water supply system (boiler water treatment system such as a chemical injection device) and condensate system of the biomass boiler 7 are used to supply water to the existing power plant. It is possible to use a part of the condensate system as well, and it is possible to simplify the system that requires additional installation.

The supply flow rate of the external steam for heating supplied to the first high-pressure feed water heater 54a and the third high-pressure feed water heater 54c depends on the pressure of the external steam or the outlet water supply temperature of each feed water heater 50, 54 in advance by simulation. By setting the planned flow rate, the flow rate of the external steam supplied from the biomass boiler 7 may be set appropriately.

In each of the above-described embodiments, the biomass boiler 7 is used as an additional steam generator for heating the water supply, but it is not always necessary to use biomass as the fuel. As the fuel, for example, garbage, combustible waste, fossil fuel and the like can be used. Further, as the external steam, steam supplied from the outside such as a steam generator using factory exhaust heat as a heat source or a regional common heat source can be used.

The operation method of the water supply heating system described in each of the above-described embodiments, the power plant provided with the water supply heating system, and the water supply heating system is grasped as follows, for example.

The water supply heating system (6) according to one embodiment of the present disclosure is composed of a boiler (3), a steam turbine (5) driven by the steam generated by the boiler (3), and the steam turbine (5). A generator to be driven and a plurality of water supply heaters (50, 54) for heating the supply water supplied to the boiler (3) by the extracted steam extracted from a plurality of positions of the steam turbine (5) are provided. A water supply heating system (6) used in the power generation plant (1), the water supply heating boiler (7) for heating a part of the water supply supplied to the boiler (3), and the water supply heating boiler. Two or more water supply heating steam pipes (62a, 62b) capable of supplying the steam generated in (7) as heating steam to two or more water supply heaters (54a, 54c), respectively, and the power generation plant. It is provided with a control unit (30) that selects the water supply heating steam pipes (62a, 62b) through which the heating steam is circulated according to the load of (1).

The steam generated in the feed water heating boiler is used as heating steam (external steam) for heating the feed water in the feed water heater. The heating steam is connected to two or more feed water heaters via two or more feed water heating steam pipes. According to the load of the power plant, the steam pipe for heating the water supply that circulates the steam for heating was selected. As a result, heating steam can be supplied to the feed water heater in an appropriate amount according to the feed water heating amount required for the load of the power plant. As a result, the heating steam generated in the water supply heating boiler can be used as much as possible, and the extracted steam extracted from the steam turbine can be reduced accordingly. Then, by reducing the extracted steam, it is possible to reduce the amount of fuel used for the boiler (for example, fossil fuel such as coal) and the amount of carbon dioxide generated by the combustion of the fuel in the boiler.
Therefore, the steam generated in the water supply heating boiler can be effectively used over a wide load range of the power plant.

In the feed water heater system (6) according to one embodiment of the present disclosure, the feed water heater (54) is composed of a high pressure side feed water heater (54a) provided on the high pressure side and the high pressure side feed water heater (54a). Also provided with a first low-pressure side feed water heater (54b) provided on the low-pressure side, and the water supply heating steam pipes (62a, 62b) are connected to the high-pressure side water supply heater (54a) on the high-pressure side. A steam pipe (62a) for heating feed water is provided, and the bleed pipe (55b) for connecting the first low-pressure side water heater (54b) and the steam turbine (34) and the bleed pipe (55b) are provided. A steam extraction valve (56b) is provided, and the control unit (30) selects the high-pressure side feed water heater steam pipe (62a) when the power generation plant (1) has a high load of a predetermined value or more. However, when the power generation plant (1) has a first low load (50% load) lower than the high load, the feed water heater steam connected to the high-pressure side feed water heater (54a). The pipe (62a) is selected, and the bleed valve (56b) is changed from the open state to the closed state.

If the power plant is to be operated with a high load of more than a predetermined value, select the steam pipe for high pressure side feed water heater connected to the high pressure side feed water heater, and select the high pressure side high temperature water supply heating boiler generated by the water supply heating boiler. Effectively use heating steam to heat feed water.
When the power plant is to be operated with a first low load lower than a high load of a predetermined value or more, the high-pressure side feed water heater does not require as much heating as when the load is high. At this time, the extraction valve provided in the extraction pipe connected to the first low-pressure side feed water heater is closed, and the heating of the first low-pressure side feed water heater is stopped. As a result, the required amount of heating steam supplied to the high-pressure side feed water heater increases, so that the heating steam generated in the feed water heating boiler can be used without waste.
By opening and closing the bleed valve while selecting the steam pipe for water supply and heating as described above, it is possible to operate with a constant load of the water supply and heating boiler regardless of the load of the power generation boiler, which is efficient. The boiler for heating water supply can be operated. For high loads above the specified value, even if the entire amount of heating steam is supplied to the high-pressure side feed water heater and used to heat the feed water, the high-pressure side feed water heater outlet water supply temperature rises excessively (steaming in the economizer). ) Does not occur.

In the feed water heater system (6) according to one embodiment of the present disclosure, the feed water heater (54) is composed of a high pressure side water heater (54a) provided on the high pressure side and the high pressure side water heater (54a). Also provided with a second low-pressure side feed water heater (54c) provided on the low-pressure side, and the water supply heating steam pipes (62a, 62b) are connected to the high-pressure side water supply heater (54a) on the high-pressure side. A feed water heater steam pipe (62a) and a low pressure side feed water heater steam pipe (62b) connected to the second low pressure side feed water heater (54c) are provided, and the control unit (30) generates the power generation. When the plant (1) has a high load equal to or higher than a predetermined value, the high-pressure side feed water heater steam pipe (62a) is selected, and the power generation plant (1) has a second low load lower than the high load. When the load (30% load) is set, the low-pressure side feed water heater steam pipe (62b) is selected in addition to the high-pressure side feed water heater steam pipe (62a).

When the power plant has a high load of more than a predetermined value, select the steam pipe for high-pressure side feed water heating connected to the high-pressure side feed water heater, and use it for high-pressure and high-temperature heating generated by the feed water heating boiler. Use steam effectively to heat feed water.
If the power plant has a second low load that is lower than the high load above a predetermined value or lower than the first low load, the high-pressure side feed water heater does not require as much heating as when the load is high. The steam pipe for heating the low pressure side feed water heater connected to the second low pressure side feed water heater is further selected. As a result, the heating steam generated by the feed water heating boiler can be distributed to a plurality of feed water heaters so that the heating steam can be used without waste.
By selecting the steam pipe for water supply and heating as described above, the load of the water supply and heating boiler can be kept constant regardless of the load of the power generation boiler, and the water supply and heating boiler can be operated efficiently. It becomes.
By setting the first low load and the second low load, it is preferable that the first low load is higher than the second low load. By making the first low load higher than the second low load, when the first low load is applied, a large amount of heating steam is increased without supplying the heating steam to the second low load side feed water heater. It can be supplied to the load side feed water heater. As a result, steam for heating at a higher pressure and a higher temperature can be effectively used for heating the feed water.

In the water supply heating system (6) according to one embodiment of the present disclosure, the deaerator (53) for degassing the water supply and the steam generated by the water supply heating boiler (7) are sent to the deaerator (53). It is provided with a steam pipe (70) for heating on the deaerator side to guide.

If the heating steam generated in the feed water heater boiler is used for heating the feed water heater and becomes surplus, use the steam pipe for heating on the deaerator side to remove the surplus steam for heating. It was decided to lead it to the air conditioner and collect it. As a result, it is possible to heat the feed water beyond the specifications of the high-pressure feed water heater and prevent steaming in the economizer, so that the operation of the feed water heating boiler can be kept constant and the biomass boiler can be operated efficiently. can do.

In the feed water heater system (6) according to one embodiment of the present disclosure, the deaerator side control valve (70a) provided in the deaerator side heating steam pipe (70) is provided, and the control unit (30) is provided. , The pressure of the feed water heater (54a, 54b) to which the steam pipe for water supply heating (62a, 62b) is connected, or the feed water heater (62a, 62b) to which the steam pipe (62a, 62b) for heating water supply is connected. The opening degree of the deaerator side control valve (70a) is controlled based on the feed water temperature at the outlets of 54a and 54b).

When the heating steam supplied to the feed water heater becomes surplus, the pressure on the heating fluid side of the feed water heater rises and / or the water supply temperature at the outlet of the feed water heater rises as compared with the case where there is no surplus. Therefore, based on the pressure of the fluid on the heating side of the feed water heater and the water supply temperature at the outlet of the feed water heater, the opening of the control valve on the deaerator side is controlled to adjust the steam flow rate led to the deaerator. did. As a result, the amount of heating steam supplied to each feed water heater can be maintained appropriately.

The water supply heating system (6) according to one embodiment of the present disclosure includes a heater (65) for cooling the heating steam circulating in the water supply heating steam pipe (62).

By providing a heater, the temperature of steam can be adjusted without exceeding the design temperature of the steam pipe for heating water supply.

In the water supply heating system (6) according to one embodiment of the present disclosure, the water supply heating boiler (7) is a biomass boiler (7) that uses biomass fuel as a main fuel.

By using the biomass fuel as the main fuel for the water supply heating boiler, it is possible to exclusively burn the biomass fuel in the water supply heating boiler without co-firing the biomass fuel in the boiler. Therefore, it is possible to increase the ratio of biomass fuel used to fossil fuel, for example, which is burned in a boiler. In addition, inexpensive biomass fuel containing a corrosive component can be used without affecting the combustion in the boiler body, the amount of fossil fuel used can be reduced, and highly efficient power generation can be performed.

The power plant (1) according to one embodiment of the present disclosure includes the water supply heating system (6) according to any one of the above.

The operation method of the water supply heating system (6) according to one embodiment of the present disclosure includes a boiler (3), a steam turbine (5) driven by the steam generated by the boiler (3), and the steam turbine ( A generator driven by 5) and a plurality of water supply heaters (50, 54) for heating the supply water supplied to the boiler (3) by the extracted steam extracted from a plurality of positions of the steam turbine (5). A method of operating the water supply heating system (6) used in the power generation plant (1) provided with the above, wherein the water supply heating system (6) heats the water supply to be supplied to the boiler (3). Two or more water supply heating steam pipes that supply the water supply boiler (7) and the steam generated by the water supply heating boiler (7) as heating steam to two or more water supply heaters (54a, 54c), respectively. (62a, 62b), and the water supply heating steam pipe (62a, 62b) for circulating the heating steam is selected according to the load of the power generation plant (1).

1 Power plant 3 Boiler 3a Boiler body 5 Steam turbine 6 Water supply heating system 7 Biomass boiler (boiler for water supply heating)
13 Superheater 17 Reheater 18 Economizer 24 Feed water pipe 30 Control unit 32 Main steam pipe 34 High pressure turbine 35 Medium pressure turbine 36 Low pressure turbine 38 High pressure turbine outlet pipe 40 Reheat steam supply pipe 42 Medium pressure turbine outlet pipe 44 Low pressure turbine outlet Pipe 46 Water recovery device 48 Water recovery pump 50 Low pressure water supply heater 50a First low pressure water supply heater 50b Second low pressure water supply heater 50c Third low pressure water supply heater 50d Fourth low pressure water supply heater 51 Water supply pump 52a, 52b, 52c , 52d Low pressure bleeding steam pipe 53 Deaerator 53a Degassing bleeding pipe 54 High pressure feed water heater 54a First high pressure feed water heater (high pressure side feed water heater)
54b 2nd high pressure feed water heater (1st low pressure side feed water heater)
54c 3rd high pressure feed water heater (2nd low pressure side feed water heater)
55a 1st high pressure bleeding pipe 55b 2nd high pressure bleeding pipe 55c 3rd high pressure bleeding pipe 56a 1st high pressure bleeding valve 56b 2nd high pressure bleeding valve 56c 3rd high pressure bleeding valve 57a 1st high pressure check valve 57b 2nd high pressure check valve 57c Third high-pressure check valve 60 Biomass boiler water supply piping 62 Water supply heating steam piping 62a First water supply heating steam piping (water supply heating steam piping)
62b 2nd steam pipe for heating water supply (steam pipe for heating water supply)
63a 1st control valve 63b 2nd control valve 65 Heat reducer 70 Steam pipe for heating on the deaerator side 70a Deaerator side control valve 72 Pressure sensor 74 Temperature sensor

Claims (9)

With a boiler
A steam turbine driven by the steam generated in the boiler,
The generator driven by the steam turbine and
A plurality of feed water heaters that heat the feed water supplied to the boiler by the extracted steam extracted from the plurality of positions of the steam turbine, and
It is a water supply heating system used in a power plant equipped with
A water supply heating boiler that heats the water supply supplied to the boiler, and
Two or more feed water heating steam pipes that can supply steam generated by the feed water heating boiler as heating steam to two or more feed water heaters, respectively.
A control unit that selects the steam supply steam pipe for circulating the heating steam according to the load of the power plant, and a control unit.
The water supply heating system is equipped with. The feed water heater includes a high pressure side feed water heater provided on the high pressure side and a first low pressure side feed water heater provided on the low pressure side of the high pressure side feed water heater.
The steam pipe for heating water supply includes a steam pipe for heating water supply on the high pressure side connected to the feed water heater on the high pressure side.
An air extraction pipe connecting the first low-pressure side feed water heater and the steam turbine, and
The bleeding valve provided in the bleeding pipe and
With
When the power plant has a high load of a predetermined value or more, the control unit selects the steam pipe for heating the high-pressure side feed water heater, and the power plant has a first low load lower than the high load. The water supply heating system according to claim 1, wherein the steam pipe for heating the water supply connected to the high-pressure side water supply heater is selected, and the bleed valve is closed from the open state. The feed water heater includes a high pressure side feed water heater provided on the high pressure side and a second low pressure side feed water heater provided on the low pressure side of the high pressure side feed water heater.
The water supply heating steam pipe includes a high pressure side water supply heating steam pipe connected to the high pressure side water supply heater and a low pressure side water supply heating steam pipe connected to the second low pressure side water supply heater. ,
When the power plant has a high load of a predetermined value or more, the control unit selects the steam pipe for heating the high-pressure side water supply, and the power plant has a second low load lower than the high load. The water supply heating system according to claim 1 or 2, wherein the steam pipe for high pressure side water supply heating is selected in addition to the steam pipe for high pressure side water supply heating. An deaerator that degass the water supply and
The steam pipe for heating on the deaerator side that guides the steam generated in the water supply heating boiler to the deaerator,
The water supply heating system according to any one of claims 1 to 3. The deaerator side control valve provided in the steam pipe for heating on the deaerator side is provided.
The control unit degass based on the pressure of the feed water heater to which the steam pipe for heating water supply is connected or the water supply temperature at the outlet of the feed water heater to which the steam pipe for heating water supply is connected. The feed water heater according to claim 4, wherein the opening degree of the control valve on the device side is controlled. The water supply heating system according to any one of claims 1 to 5, further comprising a heater for cooling the heating steam circulating in the water supply heating steam pipe. The water supply heating system according to any one of claims 1 to 6, wherein the water supply heating boiler is a biomass boiler that uses biomass fuel as a main fuel. A power plant comprising the water supply heating system according to any one of claims 1 to 7. With a boiler
A steam turbine driven by the steam generated in the boiler,
The generator driven by the steam turbine and
A plurality of feed water heaters that heat the feed water supplied to the boiler by the extracted steam extracted from the plurality of positions of the steam turbine, and
It is an operation method of the water supply heating system used in the power plant equipped with
The water supply heating system includes a water supply heating boiler that heats the water supply supplied to the boiler to generate available steam.
Two or more feed water heating steam pipes that can supply steam generated by the feed water heating boiler as heating steam to two or more feed water heaters, respectively.
With
A method of operating a water supply heating system that selects the water supply heating steam pipe that distributes the heating steam according to the load of the power plant.

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