JP2012215340A - Steam supply system and steam supply method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam supply system and method, capable of supplying high pressure steam to the outside while properly coping with variation in a supply amount of the steam supplied to the outside.SOLUTION: This steam supply system 1 includes: a coal fired boiler 2 including a superheater 9 and a reheater 12; a factory supply pipe 17 supplying some of the steam heated by the superheater 9 to the outside; a high pressure turbine 4 driven by the steam other than the steam supplied to the factory supply pipe 17 out of the steam heated by the superheater 9; a low pressure turbine 5 driven by the steam passing through the high pressure turbine 4 and reheated by the reheater 12; and a power generator 6 generating electric power by the rotation output of the high pressure turbine 4 and the low pressure turbine 5. The reheating temperature of the steam reheated in the reheater 12 is adjusted on the basis of the supply amount of the steam passing through the factory supply pipe 17 and the power generation amount required in the power generator 6.

Description

  The present invention relates to a steam supply system and a steam supply method for supplying generated steam to the outside.

  Some manufacturing facilities in factories use steam. Steam supplied to a production facility or the like is generated by a dedicated boiler (for example, an oil fired boiler) or extracted from a steam turbine of a steam turbine power generation system and sent to a factory.

  For example, Patent Document 1 discloses a technique for supplying steam to a factory or other process from a boiler provided in the middle of a bleed line while extracting steam from a steam turbine in a heat supply gas turbine combined plant. Yes.

JP-A-10-266812

  Conventionally, a dedicated oil fired boiler provided for steam supply has a large fluctuation in the price of heavy oil fuel, and is aging, resulting in poor thermal efficiency when operated alone.

  In the steam turbine power generation system, the steam extracted from the steam turbine is steam after passing through the steam turbine, and has a lower temperature and pressure than the main steam immediately after coming out of the boiler. Furthermore, when a reheat cycle is employed in the steam turbine power generation system, steam supplied from the high pressure turbine to the reheater may be extracted. However, similarly to the above, the extracted steam is the steam after passing through the high-pressure turbine, and has a low temperature and a low pressure.

  Furthermore, since the amount of steam sent to the factory varies depending on the use of the manufacturing equipment or the like, the steam supply system needs to cope with the variation in the amount of air supply.

  The present invention has been made in view of such circumstances, and is capable of supplying high-pressure steam to the outside while appropriately dealing with fluctuations in the amount of steam supplied to the outside. It is an object to provide a steam supply system and a steam supply method.

In order to solve the above-described problems, the steam supply system and the steam supply method of the present invention employ the following means.
That is, a steam supply system according to the present invention is heated by a boiler having a superheater and a reheater, an air supply pipe for supplying a part of the steam heated by the superheater to the outside, and the superheater. A first turbine that is driven by steam other than the steam supplied to the air supply pipe, a second turbine that is driven by steam that passes through the first turbine and is reheated by the reheater, A generator for generating electric power by the rotational output of the turbine and the second turbine, and the reheat temperature of the steam reheated in the reheater is required in the amount of steam supplied through the air supply pipe and in the generator It is adjusted based on the amount of power generation.

  According to the present invention, the boiler is provided with the superheater and the reheater, and the superheater heats the steam to a predetermined temperature and sends the heated steam to the air supply pipe and the first turbine. The steam passing through the air supply pipe is supplied to each facility that uses the steam installed outside, for example, a factory. Further, of the steam heated by the superheater, steam other than the steam supplied to the air supply pipe is supplied to the first turbine and drives the first turbine. And the steam which passed the 1st turbine is supplied to the reheater of a boiler, and is reheated with a reheater. The steam reheated by the reheater is supplied to the second turbine and drives the second turbine. The generator generates electricity by the rotational output generated by driving the first turbine and the second turbine.

  At this time, of the steam heated by the superheater, the flow rate of the steam supplied to the air supply pipe fluctuates depending on the steam flow required outside the air supply destination, and among the steam heated by the superheater The flow rate of the steam sent to the first turbine varies depending on the amount of power generation required in the generator. For this reason, the flow rate of the steam supplied to the reheater varies depending on the amount of steam that passes through the air pipe and the amount of power generated in the generator, but the reheat temperature of the steam passes through the air pipe. Therefore, the reheater can appropriately heat the steam in response to the fluctuation of the flow rate.

  In the above invention, the reheat temperature of the steam in the reheater is the position adjustment of the combustion zone in the boiler, the adjustment of the exhaust gas recirculation amount for introducing the exhaust gas of the boiler into the boiler, and the superheat reducer installed at the inlet of the reheater The temperature may be adjusted by at least one of the adjustment of the spray water amount.

  According to this invention, the steam reheated by the reheater is adjusted in the position of the combustion zone in the boiler, the gas temperature at the inlet of the reheater is adjusted, or the exhaust gas that introduces the boiler exhaust gas into the boiler The amount of exhaust gas passing through the reheater is adjusted by adjusting the recirculation amount, or the amount of spray water by the superheat reducer installed at the inlet of the reheater is adjusted, and the reheat steam temperature is suppressed. Therefore, the temperature is adjusted.

  In the above invention, the capacity of the reheater may be determined based on the amount of steam supplied through the air supply pipe and the amount of power required in the generator.

  According to the present invention, the flow rate of the steam supplied to the reheater varies depending on the amount of steam supplied through the air supply pipe and the amount of power required in the generator, but the capacity of the reheater is Since it is determined on the basis of the amount of steam supplied through the air supply pipe and the amount of power required by the generator, the reheater can appropriately heat the steam in response to the fluctuation of the flow rate.

  In the above invention, the air supply pipe may be provided with an air diffusion valve for releasing the passing steam to the atmosphere.

  According to this invention, it is possible to prevent the pressure of the boiler from being excessively increased by the atmospheric radiation valve provided in the air pipe being diffused to the atmosphere. In addition, when the system is activated, the air supply pipe to the outside can be warmed by causing the steam to flow backward from the outside and dissipate into the atmosphere.

  Further, the steam supply method according to the present invention includes a step of supplying a part of the steam heated by the superheater provided in the boiler to the outside through the air supply pipe, and the heating by the superheater. A step in which the first turbine is driven by steam other than the steam supplied to the air supply pipe among the steam; a step in which the second turbine is driven by the steam that passes through the first turbine and is reheated by the reheater of the boiler; The reheater reheats the generator based on the rotational output of the first turbine and the second turbine, the amount of steam supplied through the air supply pipe, and the amount of power required in the generator. Adjusting the reheat temperature of the generated steam.

  According to the present invention, the boiler is provided with the superheater and the reheater, and the superheater heats the steam to a predetermined temperature and sends the heated steam to the air supply pipe and the first turbine. The steam passing through the air supply pipe is supplied to each facility that uses the steam installed outside, for example, a factory. Of the steam generated by the superheater, steam other than the steam supplied to the air supply pipe is supplied to the first turbine and drives the first turbine. And the steam which passed the 1st turbine is supplied to the reheater of a boiler, and is reheated with a reheater. The steam reheated by the reheater is supplied to the second turbine and drives the second turbine. The generator generates electricity by the rotational output generated by driving the first turbine and the second turbine.

  At this time, of the steam heated by the superheater, the flow rate of the steam supplied to the air supply pipe fluctuates depending on the steam flow required outside the air supply destination, and among the steam heated by the superheater The flow rate of the steam sent to the first turbine varies depending on the amount of power generation required in the generator. For this reason, the flow rate of the steam supplied to the reheater varies depending on the amount of steam that passes through the air pipe and the amount of power generated in the generator, but the reheat temperature of the steam passes through the air pipe. Therefore, the reheater can appropriately heat the steam in response to the fluctuation of the flow rate.

  According to the present invention, it is possible to supply high-pressure steam to the outside while appropriately dealing with fluctuations in the amount of steam supplied to the outside.

It is a lineblock diagram showing the steam supply system concerning one embodiment of the present invention. It is a schematic block diagram which shows a boiler. It is a block diagram which shows a vapor | steam air supply system. It is a block diagram which shows a vapor | steam air supply system. It is a graph which shows the relationship between factory air supply and boiler load. It is a graph which shows the relationship between factory air supply and boiler load. It is a block diagram which shows an atmospheric release system.

Embodiments according to the present invention will be described below with reference to the drawings.
First, the structure of the vapor | steam air supply system 1 which concerns on one Embodiment of this invention is demonstrated using FIG. FIG. 1 is a configuration diagram illustrating a steam supply system 1 according to the present embodiment.

  The steam supply system 1 includes a steam turbine system and a factory supply pipe 17 that extracts the main steam from the main steam pipe 10 of the steam turbine system and supplies the steam to the outside of the factory or the like. Hereinafter, in the present specification, steam sent to the outside is also referred to as “factory steam”.

  The steam turbine system includes a coal fired boiler 2 having a superheater 9 and a reheater 12, a steam turbine 3, a generator 6, a condenser 7, a feed water pump 8, and the like.

  The coal fired boiler 2 burns coal as fuel to generate combustion gas. As shown in FIG. 2, the coal fired boiler 2 includes a burner 20, a furnace 14, a superheater 9, a reheater 12, an economizer 21, a superheater spray 22, a reheater spray 23, and an exhaust gas recirculation (GR). ) It has a damper 24 and the like. FIG. 2 is a schematic configuration diagram showing the coal fired boiler 2. The steam turbine 3 includes a high-pressure turbine 4 and a low-pressure turbine 5 as shown in FIG.

  The steam turbine system supplies steam from the high pressure turbine 4 to the reheater 12, reheats the supplied steam in the reheater 12, and supplies the reheated steam to the low pressure turbine 5 for expansion. Has been applied.

  The superheater 9 of the coal fired boiler 2 heats the water supplied from the feed water pump 8 by radiant heat transfer generated by fuel combustion and heats the steam generated by the evaporator or the like to a predetermined temperature. The steam heated by the superheater 9 is supplied to the high-pressure turbine 4 and the factory air supply pipe 17 through the main steam pipe 10.

  The high-pressure turbine 4 is an example of a first turbine and is driven by main steam supplied from the superheater 9. The steam supplied from the superheater 9 to the high-pressure turbine 4 is a part or all of the steam other than the steam supplied to the factory air supply pipe 17. The flow rate of the steam supplied to the high-pressure turbine 4 varies according to the amount of power generated in the generator 6. The high-pressure turbine 4 supplies the steam that has passed through the high-pressure turbine 4 and expanded to the reheater 12 via the low-temperature reheat steam pipe 11.

  The reheater 12 reheats the steam supplied from the high pressure turbine 4 by convective heat transfer generated by the combustion exhaust gas of the fuel, and supplies the reheated steam to the low pressure turbine 5 via the high temperature reheat steam pipe 13. Supply.

  The low-pressure turbine 5 is an example of a second turbine and is driven by steam supplied from the reheater 12. The low pressure turbine 5 discharges the steam that has passed through the low pressure turbine 5 and expanded to the condenser 7. The flow rate of the steam supplied to the low-pressure turbine 5 is equal to the flow rate of the steam supplied to the high-pressure turbine 4 if there is no extraction for warm pipes or the like in the high-pressure turbine 4. When there is extraction in the high-pressure turbine 4, the flow rate of the steam supplied to the low-pressure turbine 5 is proportional to the steam supplied to the high-pressure turbine 4.

  The generator 6 is connected to the high-pressure turbine 4 and the low-pressure turbine 5 on the same shaft, and generates electric power by the rotational outputs of the high-pressure turbine 4 and the low-pressure turbine 5.

  The condenser 7 cools the steam discharged from the low-pressure turbine 5 and returns it to water, and supplies the generated water to the feed water pump 8. The feed water pump 8 compresses the water and supplies the compressed water to the coal fired boiler 2.

  The factory air supply pipe 17 is a pipe branched from the main steam pipe 10 and supplies steam to the outside of the factory or the like. The supplied steam is used for manufacturing equipment such as a vacuum apparatus in a factory or the like. The flow rate (aeration amount) of the steam supplied to the factory air supply pipe 17 varies depending on the operating conditions of the manufacturing facility and the like.

  The factory air supply pipe 17 is provided with a factory steam pressure control valve 15, a factory steam flow measuring unit 16, an atmospheric discharge pipe 19, and the like. The factory steam pressure control valve 15 adjusts the pressure of steam supplied to the factory. The factory steam flow rate measuring unit 16 measures the flow rate of the steam flowing through the factory air supply pipe 17. The atmospheric discharge pipe 19 is provided with a factory steam atmospheric release valve 18, and the atmospheric discharge pipe 19 releases the steam flowing through the factory air supply pipe 17 to the atmosphere according to the opening degree of the factory steam atmospheric release valve 18.

  The factory air supply pipe 17 may be separately provided with a factory air supply oil fired boiler 50 according to the capacity required for the steam air supply system 1. On the other hand, when the steam can be sufficiently supplied to the factory or the like only with the steam supplied from the steam turbine system, the factory air supply oil fired boiler 50 is not necessary.

  Next, with reference to FIG. 3, control of the coal fired boiler 2 and the steam turbine 3 in the steam supply system 1 which concerns on this embodiment is demonstrated.

  The control unit 30 is, for example, a computer or control circuit including a CPU and a memory. As shown in FIG. 3, the generator output command unit 31, the turbine control unit 32, the factory air supply load calculation unit 33, and the boiler load calculation unit 34. , A BIR signal generation unit 35, a boiler control unit 36, and the like.

  The operation unit 29 is provided, for example, on a monitoring panel provided in a central operation room or the like, receives a user operation, and generates an operation signal based on the input content. The operation unit 29 sends an output (amount of power generation) requested to the generator 6 input by the user to the generator output command unit 31. The generator output command unit 31 generates an output command (MWD: Mega Watt Demand) taking into consideration the rate of change and the maximum / minimum values using the input request output as a target value. The generator output command unit 31 sends the generated output command (MWD) to the turbine control unit 32 and the boiler load calculation unit 34.

  The turbine control unit 32 generates a turbine control signal by, for example, PI control based on the output command (MWD) generated by the generator output command unit 31 and the actual output value (actual MW) in the generator 6. The turbine control unit 32 sends the generated turbine control signal to the governor 26, and the governor 26 adjusts the flow rate of the main steam flowing into the high-pressure turbine 4 of the steam turbine 3 based on the control signal.

  The factory air supply load calculation unit 33 generates an air supply load signal corresponding to the air supply amount based on the air supply amount in the factory air supply pipe 17 measured by the factory steam flow measurement unit 16. The air supply load signal is a part of a boiler master command (BM) for controlling the coal fired boiler 2. The factory air supply load calculation unit 33 sends the generated air supply load signal to the boiler load calculation unit 34.

  A main steam pressure measuring unit 27 is provided in the main steam pipe 10. The main steam pressure measuring unit 27 is a pressure transmitter, for example, and measures the pressure of the main steam flowing through the main steam pipe 10. The boiler load calculation unit 34 compares the pressure measured by the main steam pressure measurement unit 27 with a preset set value, and generates a deviation signal by PI control. If the steam pressure is high, the fuel to be input to the coal fired boiler 2 is throttled. If the steam pressure is low, the fuel to be charged to the coal fired boiler 2 is increased.

  The boiler load calculation unit 34 includes an output command (MWD) generated by the generator output command unit 31, an air supply load signal generated by the factory air supply load calculation unit 33, and a main steam pressure measurement unit 27. The above-described deviation signal based on the measured main steam pressure is added to generate a boiler master command (BM). The boiler load calculation unit 34 sends the generated boiler master command (BM) to the boiler control unit 36. The boiler control unit 36 converts the boiler master command (BM) into a required combustion amount in the coal fired boiler 2 and generates a combustion amount command (FRD). From the above, the combustion amount directive (FRD) is based on the required power generation amount, the amount of air supplied to the factory, and the pressure of the main steam.

  Moreover, the boiler load calculation part 34 produces | generates a load parameter | index (LD) based on the electric power generation amount requested | required. Further, the factory air supply load calculation unit 33 generates an air supply index (LNF) based on the air supply amount in the air supply pipe 17 measured by the steam flow rate measurement unit 16.

  The BIR signal generation unit 35 generates a BIR signal for feedforward control of the fuel to be input to the coal fired boiler 2 during a load change or a factory air supply change. The BIR signal includes, for example, a first BIR signal based on a load index (LD) and a second BIR signal based on an air supply index (LNF). The first BIR signal is generated in consideration of the load change rate and the change amount of the power generation amount (load) of the generator 6 that is predicted, and the second BIR signal is the factory steam transfer rate that is predicted to be the factory air supply flow rate change rate. It is generated taking into account the volume change. The BIR signal is used to control the amount of spray water in the reheater spray 23, control of the exhaust gas recirculation flow rate of the coal fired boiler 2, and ammonia of the denitration device in the coal fired boiler 2 in addition to the control of fuel input to the coal fired boiler 2. Also used for injection volume control.

  The boiler control unit 36 adds the combustion amount command (FRD) converted from the boiler master command (BM) generated by the boiler load calculation unit 34, the first BIR signal and the second BIR signal generated by the BIR signal generation unit 35, Based on the addition result and the actual fuel flow rate in the coal fired boiler 2, the flow rate of fuel to be input into the coal fired boiler 2 is calculated by, for example, PI control.

  As described above, the steam turbine 3 is driven based on the required power generation amount, and the generator 6 is driven to output the required power generation amount by receiving the rotation output of the steam turbine 3. . Further, the fuel input to the coal fired boiler 2 is controlled based on the required power generation amount, the air supply amount in the air supply pipe 17, and the pressure of the main steam. Further, in fuel control during load change or factory air supply flow rate change, the amount of change in power generation amount (load) and load index change rate of the generator 6, the predicted change rate of factory steam air supply amount and factory The feedforward control based on the rate of change in the air supply flow rate is performed, and control with higher responsiveness than in the case of only feedback control is performed.

  Next, the operation of the coal fired boiler 2 in the steam turbine system 1 of the steam supply system 1 according to the present embodiment will be described.

  The coal fired boiler 2 is required to be able to cope with a change in the amount of air flow of factory steam that changes in accordance with the use of a manufacturing apparatus or the like of the factory, in addition to being able to cope with a change in generator output. The operating range of the coal fired boiler 2 is as shown in the graphs shown in FIGS. 5 and 6, for example. In the graphs of FIGS. 5 and 6, the horizontal axis is the boiler load (the total ratio of heat absorption of main steam and reheat steam with the boiler maximum continuous rating (MCR) being 100%) The shaft is the factory air supply. And the operation range of the generator 6 whose rated output is 100 MW is displayed on the graphs of FIGS. In the steam supply system 1 of the present embodiment, as shown in FIGS. 5 and 6, the boiler load changes not only according to the generator output but also according to the factory supply amount.

  Hereinafter, with reference to FIG. 5 and FIG. 6, the fluctuation relationship between the factory air supply amount and the generator output and the boiler load in actual operation will be described.

1) When the generator output is constant (arrow A in FIG. 5)
As shown by arrow A in FIG. 5, when the factory air supply amount is increased or decreased while maintaining the generator output, the generator output is constant regardless of the increase or decrease in the factory air supply amount. The flow rate is constant. On the other hand, the main steam flow rate at the coal fired boiler 2 outlet increases or decreases as the factory air supply amount increases or decreases. Here, since the flow rate of the reheat steam at the inlet of the low-pressure turbine 5 is also constant, the boiler load is not changed by the reheater 12 but is changed by an increase or decrease in the heat absorption amount of the main steam of the superheater 9.

2) When both the generator output and the air flow rate change (arrow B in FIG. 5)
When the factory air supply amount is increased while increasing the generator output as indicated by the arrow B in FIG. 5, the steam flow rate at the inlet of the steam turbine 3 is increased due to the increase in the generator output, and the factory air supply amount is increased. With the increase, the main steam flow rate at the outlet of the coal fired boiler 2 increases. At this time, the reheat steam flow rate at the inlet of the low pressure turbine 5 increases as the main steam flow rate increases at the inlet of the high pressure turbine 4. The boiler load increases the total increase of the heat absorption amount of the main steam of the superheater 9 and the heat absorption amount of the reheat steam amount of the reheater 12.
On the other hand, when the factory air supply amount is reduced while reducing the generator output, the reverse movement occurs, and the boiler load is determined by the heat absorption amount of the main steam of the superheater 9 and the reheat steam amount of the reheater 12. The total decrease in heat absorption will be reduced.

3) When there is no factory air supply and is constant (arrow C in Fig. 5)
As shown by the arrow C in FIG. 5, when the generator output is increased or decreased while keeping the factory air supply at 0, the steam flow rate at the inlet of the steam turbine 3 increases or decreases as the generator output increases or decreases. At this time, the reheat steam flow rate at the inlet of the low pressure turbine 5 increases or decreases in accordance with the increase or decrease of the main steam flow rate at the inlet of the high pressure turbine 4.

4) When increasing the factory air supply while keeping the boiler load constant (arrow D in FIG. 6)
As shown by the arrow D in FIG. 6, when the factory air supply amount is increased and the generator output is decreased while keeping the boiler load constant, the main steam flow rate at the outlet of the coal fired boiler 2 is constant. However, since the factory air supply amount increases, the main steam flow rate at the inlet of the high pressure turbine 4 and the reheat steam flow rate at the inlet of the low pressure turbine 5 decrease.
At this time, the boiler load is constant, but the flow rate of the reheat steam flowing through the reheater 12 decreases, so the reheat steam temperature rises.

5) When reducing the generator output while keeping the factory air flow constant (arrow E in Fig. 6)
As shown by the arrow E in FIG. 6, when the generator output is decreased while keeping the factory air supply amount constant at a value other than 0, the main steam flow rate at the inlet of the high-pressure turbine 4 The reheat steam flow rate at the inlet of the low pressure turbine 5 decreases. However, since the factory air supply amount remains constant, the reduction rate of the reheat steam flow rate at the inlet of the low pressure turbine 5 is larger than the reduction rate of the main steam flow rate at the inlet of the high pressure turbine 4. As a result, the reheat steam temperature in the reheater 12 increases.

  According to 4) and 5) above, the reheat steam temperature tends to be high when the factory air supply is large and the generator output is low (upper left part in the shaded range in FIGS. 5 and 6). I understand that there is. Therefore, the reheater 12 in the steam supply system 1 of the present embodiment is capable of withstanding the entire operation range by determining the capacity, heat transfer area, material, etc. in consideration of the increase in the reheat steam temperature. Can be secured.

  Conventionally, the boiler reheater of the steam turbine power generation system does not need to consider the factory air supply amount, and therefore, the change in the reheat steam temperature in the case of the above 3) may be predicted. On the other hand, the reheater 12 of this embodiment must consider factory air supply. Therefore, as shown in the shaded range in FIGS. 5 and 6, it is necessary to predict the change in the reheat steam temperature two-dimensionally in the entire operation range, and the reheater 12 has an appropriate performance within the range. It is necessary to consider whether or not

Next, adjustment of the reheat steam temperature in the reheater 12 will be described with reference to FIG.
In addition to determining capacity, heat transfer area, material, etc., the reheater 12 adjusts the reheat steam temperature by controlling the temperature in the reheater 12 so that the reheater 12 can withstand the entire operation range. It may be ensured.

  The reheat steam temperature is controlled, for example, by adjusting the burner angle of the burner 20, adjusting the exhaust gas recirculation amount by the exhaust gas recirculation damper 24, charging spray water from the reheater spray 23, adjusting the opening of the air box AA damper 25, and the like. The

  The high temperature reheat steam pipe 13 is provided with a reheat steam temperature measurement unit 38, and the reheat steam temperature measurement unit 38 measures the temperature of the reheat steam flowing through the high temperature reheat steam pipe 13. The reheat steam temperature is adjusted by the control unit 30 based on the temperature of the reheat steam flowing through the high temperature reheat steam pipe 13 and the amount of factory steam flowing through the factory air supply pipe 17. For example, as indicated by an arrow D in FIG. 6, when the reheat steam temperature rises due to an increase in the factory air supply amount and a decrease in the generator output and a decrease in the reheat steam flow rate, 12 is controlled to reduce the reheat steam temperature.

  As shown in FIG. 4, the control unit 30 includes a burner angle adjustment unit 40, an exhaust gas recirculation flow rate adjustment unit 41, a spray amount adjustment unit 42, an opening degree adjustment unit 43, and the like.

  The burner angle adjustment unit 40 adjusts the angle of the burner 20 based on, for example, the boiler load (LD) and the amount of factory steam supplied. By adjusting the angle of the burner 20, the main combustion area in the coal fired boiler 2 is moved to the upper side of the furnace 14 or the lower side of the furnace 14, and the gas temperature at the outlet of the furnace 14 is adjusted. Thereby, the gas temperature at the inlet side of the reheater 12 is adjusted, and the reheat steam temperature can be adjusted.

  For example, the exhaust gas recirculation flow rate adjustment unit 41 converts the exhaust gas discharged from the economizer 21 from the bottom of the furnace 14 to the coal based on the boiler load (LD), the temperature of reheat steam, and the amount of factory steam supplied. Adjust the amount (exhaust gas recirculation flow rate) to be reintroduced into the boiler 2. The exhaust gas recirculation damper 24 adjusts the exhaust gas recirculation flow rate according to the opening degree. By adjusting the exhaust gas recirculation flow rate, the amount of exhaust gas passing through the reheater 12 can be increased or decreased, and the reheat steam temperature can be adjusted.

  The spray amount adjusting unit 42 adjusts the supply of spray water to the reheater 12 by the reheater spray 23 based on, for example, the boiler load (LD), the reheat steam temperature, and the factory steam supply amount. When the reheat steam temperature exceeds the specified temperature, the reheat steam temperature can be suppressed by introducing the spray water.

  The opening adjustment unit 43 adjusts the opening of the wind box AA damper 25 based on, for example, a boiler load (LD). The gas temperature at the outlet of the furnace 14 is adjusted by adjusting the opening degree of the air box AA damper 25. Thereby, the gas temperature at the inlet side of the reheater 12 is adjusted, and the reheat steam temperature can be adjusted.

  As described above, according to the present embodiment, the reheat steam temperature is adjusted while referring to the amount of steam supplied through the factory air supply pipe 17. As a result, the reheater 12 can appropriately heat the steam in response to fluctuations in the factory air supply without excessively increasing the reheat steam temperature.

Next, as shown in FIG. 4, the adjustment of the main steam temperature will be described.
The main steam temperature is controlled by charging spray water from the superheater spray 22 or the like. The main steam pipe 10 is provided with a main steam temperature measuring unit 37, and the main steam temperature measuring unit 37 measures the temperature of the main steam flowing through the main steam pipe 10. The main steam temperature is adjusted by the control unit 30 based on the temperature of the main steam flowing through the main steam pipe 10.

  The spray amount adjusting unit 39 adjusts the injection of spray water between the superheaters 9 by the superheater spray 22. The main steam temperature is adjusted by constantly supplying spray water between the superheaters 9. When the main steam temperature decreases, the spray water input amount is decreased, and when the main steam temperature increases, the spray water input amount is increased to adjust the temperature.

Next, the control of the atmospheric release valve 18 will be described with reference to FIG.
The coal fired boiler 2 is provided with a boiler pressure measuring unit 44, and the boiler pressure measuring unit 44 measures the pressure in the coal fired boiler 2. The atmospheric release valve control unit 45 adjusts the opening degree of the factory steam atmospheric release valve 18 based on the measured pressure. The atmospheric discharge pipe 19 may be provided with a discharge amount measuring unit 46 to measure the flow rate of steam passing through the atmospheric discharge pipe 19. The atmospheric release valve control unit 45 adjusts the opening degree of the factory vapor atmospheric release valve 18 based on the steam flow rate measured by the release amount measuring unit 46.

  As a result, the factory steam atmosphere release valve 18 can prevent the coal fired boiler 2 from being excessively pressurized by releasing the steam passing through the factory air supply pipe 17 to the atmosphere. In addition, when the system is activated, the factory air supply pipe 17 to the outside can be warmed by causing the steam to flow backward from the outside and dissipate into the atmosphere.

  As described above, according to the embodiment of the present invention, steam having good high-pressure and high-temperature conditions is supplied to a factory or the like by extracting the main steam from the main steam pipe 10 connected to the coal fired boiler 2 as factory steam. Can do. Further, by using the coal fired boiler 2 used in the steam turbine power generation system, it is possible to supply steam to the factory or the like with higher efficiency than the factory air supply oil fired boiler 50.

  Furthermore, conventional coal fired boilers have poor followability with respect to variability in steam conditions such as pressure and temperature, and are difficult to control in terms of dynamic characteristics. By considering the operation of the air, the reheat steam temperature in the reheater 12 becomes appropriate, and the amount of power generated by the generator 6 and the amount of air supplied to the factory can be changed simultaneously.

1 Steam supply system 2 Coal fired boiler
3 Steam turbine 4 High-pressure turbine (first turbine)
5 Low pressure turbine (second turbine)
6 Generator 7 Condenser 8 Water supply pump 9 Superheater 10 Main steam pipe 11 Low-temperature reheat steam pipe 12 Reheater 13 High-temperature reheat steam pipe 14 Furnace 15 Factory steam pressure control valve 16 Factory steam flow measurement unit 17 Factory feed Trachea (airpipe)
18 Factory Steam Atmospheric Release Valve 19 Atmospheric Release Pipe 20 Burner 21 Economizer 22 Superheater Spray 23 Reheater Spray (Overheat Reducer)
24 Exhaust gas recirculation damper 25 Wind box AA damper 26 Governor 27 Main steam pressure measurement unit 29 Operation unit 30 Control unit 50 Oil supply boiler for factory air supply

Claims (5)

A boiler having a superheater and a reheater;
An air supply pipe for supplying a part of the steam heated by the superheater to the outside;
A first turbine driven by steam other than the steam supplied to the air supply pipe among the steam heated by the superheater;
A second turbine driven by the steam passing through the first turbine and reheated by the reheater;
A generator for generating electric power by rotational output of the first turbine and the second turbine;
With
A steam supply system in which the reheat temperature of the steam reheated in the reheater is adjusted based on the amount of steam supplied through the air supply pipe and the amount of power generation required in the generator .   The reheat temperature of the steam in the reheater is the position adjustment of the combustion zone in the boiler, the adjustment of the exhaust gas recirculation amount for introducing the exhaust gas of the boiler into the boiler, and the superheat installed at the inlet of the reheater The steam supply system according to claim 1, wherein the temperature is adjusted by at least one of adjustment of the spray water amount by the reducer.   3. The steam supply system according to claim 1, wherein a capacity of the reheater is determined based on an amount of the steam that passes through the air supply pipe and a power generation amount required in the generator.   The steam supply system according to any one of claims 1 to 3, wherein the air supply pipe is provided with an atmospheric emission valve for releasing the vapor passing therethrough to the atmosphere. A step of supplying a part of the steam heated by a superheater provided in the boiler to the outside through an air supply pipe;
A step in which the first turbine is driven by steam other than the steam supplied to the air supply pipe among the steam heated by the superheater;
A second turbine is driven by the steam passing through the first turbine and reheated by the boiler reheater;
A step of generating power by a rotational output of the first turbine and the second turbine;
Adjusting the reheat temperature of the steam reheated in the reheater based on the amount of steam supplied through the air supply pipe and the amount of power required in the generator;
A steam insufflation method.

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