JPH10292902A - Main steam temperature controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of the rapid change of a main steam temperature by a method wherein a steam bypass pipe to bypass a superheater and a bypass flow rate regulator are provided, and a steam amount passing the superheater is regulated according to main steam. SOLUTION: A main steam temperature controller comprises a steam bypass 51 branched from a final superheater steam flow passage in a manner to bypass between the output side of a high pressure main steam temperature reducer 23 and a high pressure steam pipe 20, and a bypass steam steam flow rate regulation valve 52 to regulate a branching steam flow rate. Based on the detecting result of a main steam temperature detector 33 to detect a main steam temperature, a bypass steam flow rate regulating device 34 is operated, and based on a control signal from the bypass steam flow rate regulating device 34, the travel of a bypass steam flow rate regulating valve 52 is regulated. By the travel of a bypass steam flow rate regulation valve 52, an amount of the output substance of the high pressure main steam temperature reducer 23 fed to a high pressure second superheater 19 is regulated. Further, an amount of the output substance of the high pressure main steam temperature reducer 23 fed not through a high pressure second superheater 19 but directly to the high pressure steam pipe 20 is regulatable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to control of a main steam temperature of an exhaust heat recovery boiler of a thermal power plant (combined cycle).

[0002]

2. Description of the Related Art In recent combined cycle plants, the gas temperature at the inlet of a gas turbine has been increased in order to cope with an increase in efficiency and capacity, and the exhaust temperature of the gas turbine has also been increased. As the temperature of the gas turbine exhaust increases, the outlet steam temperature (high-pressure main steam temperature) of the exhaust heat recovery boiler also tends to increase. However, the steam turbine has optimum steam conditions according to the output from conditions such as a thick casing for using high-pressure steam and exposure of the rotor to high-temperature steam. At present, the maximum value of the steam turbine inlet main steam temperature is 538-56.
It is about 6 ° C. Therefore, when an operation state in which the main steam temperature exceeds this value occurs, the upper limit of the generated steam temperature of the exhaust heat recovery boiler is set regardless of the load, and the steam temperature is controlled to this. It is common.

The prior art will be described with reference to FIGS. 17 and 18. FIG. 17 is a diagram showing components of the exhaust heat recovery boiler and flows of water, steam, and gas.
FIG. 4 is a diagram illustrating an example of a control method.

In FIG. 17, steam worked by a steam turbine (not shown) is cooled and condensed by a condenser (not shown) and stored in a condenser hot well (not shown). The condensed water stored in the hot well is extracted by a condensate pump (not shown) and supplied to the low-pressure economizer 2 through the low-pressure water supply pipe 1. In the low-pressure economizer 2, a gas turbine (not shown) has already been used.
The entire feedwater is heated by heat exchange between the exhaust gas and the exhaust gas which has been cooled by heat exchange in the other heat exchangers.

The feed water heated by the low-pressure economizer 2 is supplied through a low-pressure connecting pipe 4 to adjust the low-pressure feed rate of the low-pressure steam drum 8 with a low-pressure feed water control valve 5 so as to keep the water level of the low-pressure steam drum 8 constant. Supplied to

On the other hand, the high pressure water is supplied to a high pressure water pump 6 through a high pressure water pump suction pipe 3 branched from the low pressure communication pipe 4.
The pressure is increased by the high-pressure water supply pump 6. The pressurized feed water is supplied to the high-pressure economizer 12 through the high-pressure feed pipe 7. The high-pressure water supplied to the high-pressure economizer 12 and exchanged heat with the exhaust gas to raise the temperature is supplied to a high-pressure water supply control valve 14 through a high-pressure communication pipe 13.
Then, the high-pressure water supply amount is adjusted so as to keep the water level of the high-pressure steam drum 15 constant, and the water is supplied to the high-pressure steam drum 15.

The feedwater supplied to the low-pressure steam drum 8 returns to the steam drum 8 while performing heat exchange with the exhaust gas in the low-pressure evaporator 9 to generate steam. It circulates while exchanging heat between the evaporators 9 to generate steam. The steam separated by the low-pressure steam drum 8 is supplied to a low-pressure superheater 11 through a low-pressure steam communication pipe 10 and exchanges heat with exhaust gas to be supplied to a low-pressure stage of a steam turbine (not shown) as superheated steam. Is done.

On the other hand, the feed water heated by the high-pressure economizer 12 and supplied to the high-pressure steam drum 15 is returned to the high-pressure steam drum 15 while performing heat exchange with exhaust gas to generate steam by the high-pressure evaporator 16. That is, the heat is circulated between the high-pressure steam drum 15 and the high-pressure evaporator 16 while exchanging heat to generate steam. The steam separated by the high-pressure steam drum 15 is supplied to a high-pressure first superheater 18 via a high-pressure steam communication pipe 17 and exchanges heat with the exhaust gas to become superheated steam. Spray water is supplied to a high pressure stage of a steam turbine (not shown).

On the other hand, the steam that has worked in the high-pressure stage of the steam turbine (not shown) is heated by heat exchange with the exhaust gas in the reheaters 21 and 22 to turn it into high-temperature steam again. Zu) is supplied to the medium-pressure paragraph. Also for this reheat steam, the maximum allowable temperature determined by the material of the steam turbine and the like is set, and the temperature of the reheat steam is controlled to be equal to or lower than the allowable temperature regardless of a change in the operation state. According to this temperature control method, the heat transfer surface of the reheater is divided, a desuperheater 26 is provided in the connecting pipe of the divided heat transfer surface, and the amount of water sprayed to the deheater 26 according to the temperature of the reheat steam. Is controlled by the reheat steam temperature control valve 27 and supplied. However, this reheater may not be installed depending on the size of the plant.

Further, a low-pressure economizer inlet feed-water temperature control pipe 28 and a low-pressure feedwater temperature control valve 29 which branch off from the high-pressure water pipe 7 on the discharge side of the high-pressure water pump 6 and circulate to the inlet of the low-pressure economizer 2 are installed. Then, the inlet temperature of the low-pressure economizer 2 is adjusted to be constant.

Generally, the main steam temperature of the exhaust heat recovery boiler is determined by characteristics such as exhaust gas inlet temperature, exhaust gas amount, steam amount, and heat transfer area. Generally, the main steam temperature of a steam turbine has an upper limit, and the superheater is divided so as not to exceed the upper limit, and the temperature is reduced in the middle of the connecting pipe connecting the heat transfer surfaces of the divided superheaters. In general, a system is provided in which a heater 23 is provided, and the amount of spray water supplied to the desuperheater 23 is adjusted by a main steam temperature control valve 25 in accordance with the main steam temperature. The source of the spray water must have a pressure higher than the steam pressure and be able to adequately cope with changes in water volume.
In the example of FIG. 17, a method of branching from the high-pressure water supply pipe 7 is shown.

FIG. 18 shows an example of conventional main steam temperature control. The pressure of the high-pressure steam drum 15 is input to a function generator 35 that calculates the lower limit value of the inlet steam temperature of the high-pressure second superheater 19, and the inlet steam of the high-pressure second heater 19 according to the pressure of the high-pressure steam drum 15. The lower limit of the temperature is calculated. The calculated value is input to the opening degree calculator 36 of the high-pressure main steam temperature control spray valve 25 together with the steam flow rate of the high-pressure steam pipe 20 and the spray water temperature of the desuperheated water supply pipe 24. The opening is calculated.

On the other hand, based on the deviation between the high-pressure steam temperature of the high-pressure steam pipe 20 and the installation value, the opening of the high-pressure main steam temperature control spray valve 25 is set by the main steam temperature controller 37 so that the deviation becomes zero. Is calculated. Further, there is provided a low value priority circuit 38 for selecting the smaller one of the calculated value and the calculated value of the opening calculated value 36 and outputting an opening command to the high-pressure main steam temperature control spray valve 25.

The main steam temperature control according to the prior art employs constant value control in which the set temperature is kept constant regardless of the load. However, the increase in the capacity of the gas turbine and the adoption of an operation method in consideration of environmental measures tend to increase the exhaust gas temperature of the gas turbine and increase the temperature rise rate of the steam temperature.

In particular, in a heat recovery steam generator having no auxiliary combustion device, the high pressure second superheater is governed by characteristics such as exhaust gas inlet temperature, exhaust gas amount, steam amount, and heat transfer area. The exit steam temperature at 19 is determined. In an operation state in which the output of a gas turbine with a small amount of steam generation is low, the steam temperature changes in temperature equivalent to the temperature rise rate of the exhaust gas.
In the case of the constant steam temperature control, the steam temperature can be controlled by the conventional technology. However, if the steam temperature rises at a rate equivalent to the temperature rise rate of the exhaust gas, the temperature rise exceeds the allowable temperature rise rate of the steam turbine, and the thermal stress of the steam turbine becomes abnormally large, resulting in an inconvenience that the life consumption increases.

On the other hand, in order to solve such inconvenience,
It is necessary to control the steam temperature by changing the set temperature at a certain temperature rise rate.

When the temperature control is performed only by adjusting the spray water amount, the injection amount of the spray water must be limited so that the spray water does not flow into the superheater in the form of water droplets and the water does not become supersaturated. General. The limit value of the spray water amount is generally set to a water amount that does not decrease below a temperature obtained by adding a margin of 30 to 50 ° C. to the saturation temperature with respect to the vapor pressure of the spray injection part.

Further, there is a large delay in controlling the main steam temperature in the spray water. For this reason, a state occurs in which the main steam temperature cannot be controlled to the set value, and as a result, the temperature rise rate also becomes higher than the initial target.

[0019]

As described above, in an operating state where the output of a gas turbine with a small amount of steam generation is low, the steam temperature changes in temperature equivalent to the temperature rise rate of the exhaust gas. In the case of the constant steam temperature control, the steam temperature can be controlled by the conventional technology.

However, if the steam temperature rises at a rate equal to the rate of temperature rise of the exhaust gas, the temperature rise exceeds the allowable temperature rise rate of the steam turbine, and the thermal stress of the steam turbine becomes abnormally large and the life consumption increases. Occurs.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art and to control the rate of increase of the main steam temperature within the allowable range of the steam turbine without changing the rate of increase in the load (fuel input) of the gas turbine. It is an object of the present invention to provide a main steam temperature control device capable of preventing a sudden change in the main steam temperature and minimizing the life consumption of a steam turbine without prolonging the start-up time of a plant.

[0022]

In order to achieve the above object, a main steam temperature control device according to a first aspect of the present invention comprises a final superheater for outputting high-pressure main steam supplied to a steam turbine, a high-pressure main steam temperature, A main steam temperature detector, a steam bypass pipe that bypasses an inlet side and an outlet side of the final superheater, and the steam bypass pipe according to the high-pressure main steam temperature detected by the main steam temperature detector. Bypass flow rate adjusting means for adjusting the flow rate of the passing steam.

Further, the second invention of the present application provides a final superheater for outputting high-pressure main steam supplied to a steam turbine, an exhaust gas temperature detector for detecting an exhaust gas temperature of a gas turbine, and an inlet side of the final superheater. A steam bypass pipe for bypassing the exhaust gas and the outlet side; and a bypass flow rate adjusting means for adjusting a steam flow rate passing through the steam bypass pipe according to the exhaust gas temperature detected by the exhaust gas temperature detector.

The third invention of the present application is a final superheater for outputting high-pressure main steam to be supplied to a steam turbine, a main steam temperature detector for detecting high-pressure main steam temperature, and a stage preceding the final superheater. A desuperheater, a steam drum that supplies steam to the desuperheater, a superheater bypass steam pipe that bypasses an outlet side of the steam drum and an outlet side of the final superheater,
A bypass flow rate adjusting means for adjusting a steam flow rate through the superheater bypass steam pipe according to the high-pressure main steam temperature detected by the main steam temperature detector.

Further, the fourth invention of the present application is directed to a final superheater for outputting high-pressure main steam supplied to the steam turbine, an exhaust gas temperature detector for detecting the exhaust gas temperature of the gas turbine, and a stage upstream of the final superheater. A steam drum for supplying steam to the cooler, a superheater bypass steam pipe for bypassing an outlet side of the steam drum and an outlet side of the final superheater, and detecting the exhaust gas temperature. And a bypass flow rate adjusting means for adjusting a steam flow rate through the superheater bypass steam pipe according to the exhaust gas temperature of the gas turbine detected by the heater.

Further, the fifth invention of the present application provides a final superheater for outputting high-pressure main steam to be supplied to a steam turbine, a gas turbine output detecting means for detecting a gas turbine output, and a reduction device located upstream of the final superheater. A heater, a steam drum that supplies steam to the desuperheater, a first steam pipe for supplying the steam of the steam drum to the desuperheater without overheating, and a heater that superheats the steam of the steam drum. A second steam pipe for supplying to the desuperheater, and a bypass flow rate adjusting means for adjusting a steam flow rate passing through the first steam pipe in accordance with the gas turbine output detected by the gas turbine output detecting means. Have.

Further, the sixth invention of the present application is directed to a final superheater for outputting high-pressure main steam supplied to a steam turbine, a gas turbine fuel flow rate detecting means for detecting a gas turbine fuel flow rate, and a stage upstream of the final superheater. A cooler, a steam drum for supplying steam to the cooler, a first steam pipe for supplying the steam of the steam drum to the cooler without overheating, and a steam for the steam drum. A second steam pipe for heating and supplying to the desuperheater; and a bypass flow rate adjusting means for adjusting a steam flow rate passing through the first steam pipe according to the gas turbine fuel flow rate detected by the gas turbine fuel flow rate detecting means. Means.

Further, the seventh invention of the present application is directed to a final superheater for outputting high-pressure main steam to be supplied to a steam turbine, a load command value output means for instructing a load command value, and a reduction device located upstream of the final superheater. A heater, a steam drum that supplies steam to the desuperheater, a first steam pipe for supplying the steam of the steam drum to the desuperheater without overheating, and a heater that superheats the steam of the steam drum. A second steam pipe for supplying to the desuperheater, and a bypass flow rate adjusting means for adjusting a steam flow rate through the first steam pipe in accordance with the load command value output from the load command value output means. Have.

The eighth invention of the present application is directed to a final superheater for outputting high-pressure main steam to be supplied to a steam turbine, a generator output detecting means for detecting a generator output, and a reduction output upstream of the final superheater. A heater, a steam drum that supplies steam to the desuperheater, a first steam pipe for supplying the steam of the steam drum to the desuperheater without overheating, and a heater that superheats the steam of the steam drum. A second steam pipe for supplying to the desuperheater, and a bypass flow rate adjusting means for adjusting a steam flow rate through the first steam pipe in accordance with the generator output detected by the generator output detecting means. Have.

More specifically, the main steam temperature control device of the first invention of the present application is provided with a steam bypass pipe 51 and a bypass flow rate regulator 52 that bypass the superheater 19, and the superheater 19 is controlled according to the main steam temperature. It is characterized in that a sudden change in the main steam temperature is prevented by adjusting the amount of passing steam.

The main steam temperature control device of the second invention is provided with a steam bypass pipe 51 for bypassing the superheater 19 and an exhaust gas temperature detector 53 to adjust the amount of steam passing through the superheater 19 according to the exhaust gas temperature. This prevents a sudden change in the main steam temperature.

The main steam temperature control device according to the third invention is provided with a main steam temperature detector 46 and a second desuperheater 47, and sprays the air supplied from the outlet of the drum 15 to the second desuperheater 47 in accordance with the main steam temperature. It is characterized in that a sudden change in the main steam temperature is prevented by adjusting the steam flow rate.

The main steam temperature control device of the fourth invention is provided with an exhaust gas temperature detector 53 and a second desuperheater 47, and a steam spray flow rate supplied from the outlet of the drum 15 to the second desuperheater 47 according to the exhaust gas temperature. By controlling the temperature, a rapid change in the main steam temperature is prevented.

The main steam temperature control device according to the fifth aspect of the present invention is provided with a gas turbine output detector 45 and adjusts the flow rate of the spray steam supplied from the drum outlet to the desuperheater 23 in accordance with the output of the gas turbine. It is characterized by preventing a rapid change in

The main steam temperature control device according to the sixth aspect of the present invention is provided with a fuel flow rate detector 41 and adjusts the flow rate of the spray steam supplied from the drum outlet to the desuperheater 23 in accordance with the fuel flow rate to thereby sharply increase the main steam temperature. Characteristic change is prevented.

The main steam temperature control device according to the seventh aspect of the present invention includes a load command value output means 42, and the temperature control device 2 according to the load command value.
By controlling the flow rate of the spray steam supplied from the outlet of the drum 15 to the outlet 3, a sudden change in the main steam temperature is prevented.

The main steam temperature control device according to the eighth aspect of the present invention is provided with a generator output detecting means 43.
The method is characterized in that the main steam temperature is prevented from changing rapidly by adjusting the flow rate of the spray steam supplied from the drum outlet to 3.

In the above-described invention, a sudden change in the high-pressure main steam temperature can be prevented by correcting and controlling the high-pressure main steam temperature at the outlet of the final superheater.

Specifically, in the first invention, if the flow rate of steam passing through the superheater is controlled by the steam branch, the amount of heat exchange from the exhaust gas to the main steam is also controlled.
A rapid change in the main steam temperature can be suppressed.

In the second invention, the operation is the same as that of the first invention, but in contrast to the first invention in which the steam flow is controlled in accordance with the main steam temperature, the steam flow is controlled in accordance with the exhaust gas temperature.

In the third aspect of the present invention, by adding a second desuperheater to adjust the flow rate of the spray steam from the drum outlet according to the main steam temperature, the response delay of the conventional main steam temperature control can be further reduced. Can be corrected.

In the fourth aspect, the operation is the same as that of the third aspect, but the spray vapor flow rate is adjusted not according to the main steam temperature but according to the exhaust gas temperature.

In the fifth aspect, the response can be made faster than in the conventional main steam temperature control by adjusting the spray steam flow rate according to the gas turbine output.

In the sixth aspect, by adjusting the spray steam flow rate according to the fuel flow rate, the response can be made faster than in the conventional main steam temperature control.

In the seventh aspect, by adjusting the spray steam flow rate according to the load command value, the response can be made faster than in the conventional main steam temperature control.

In the eighth aspect, the response can be made faster than in the conventional main steam temperature control by adjusting the spray steam flow rate according to the generator output.

[0047]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

First, an embodiment of the first invention will be described.

In the device configuration and system of the embodiment shown in FIG. 1, the same parts as those of the device configuration of the prior art shown in FIG.

The high-pressure steam from the high-pressure steam drum 15 is superheated by the high-pressure first superheater 18 through the high-pressure steam communication pipe 17. The steam superheated by the high-pressure first superheater 18 and the spray water supplied through the desuperheated water supply pipe 24 are input to the high-pressure main steam desuperheater 23, and the high-temperature main steam desuperheater 23 reduces the temperature. A mixture of the generated steam and the spray water is output.
The output of the high-pressure main steam desuperheater 23 is sent to the high-pressure second superheater 19 to be superheated to a complete steam state, and sent out to the steam turbine via the high-pressure main steam pipe 20 as main steam.

The main steam temperature detector 33 connected to the high-pressure main steam pipe 20 detects the main steam temperature. The opening degree of the high pressure main steam temperature control spray valve 25 is adjusted by the main steam temperature steam controller 32 based on the detection result, and the injection amount of spray water supplied from the desuperheated water supply pipe 24 to the high pressure main steam desuperheater 23 is reduced. Adjusted.

As shown in FIG. 2, the main steam temperature steam regulator 32 includes a function generator 35, an opening degree calculator 36, a main steam temperature regulator 37, and a low value priority circuit 38. The pressure of the high-pressure steam drum 15 is input to a function generator 35 that calculates the lower limit of the inlet steam temperature of the high-pressure second superheater 19,
High pressure second heater 19 corresponding to the pressure of high pressure steam drum 15
The lower limit of the inlet steam temperature is calculated. This calculated value is
The high-pressure main steam temperature control spray valve 25 together with the steam flow rate of the high-pressure steam pipe 20 and the spray water temperature of the cooling water supply pipe 24.
Of the high-pressure main steam temperature control spray valve 25 is calculated. On the other hand, the high pressure steam pipe 20
High-pressure main steam temperature control spray valve 25 such that the deviation becomes zero based on the deviation between the high-pressure steam temperature and its set value.
Is calculated by the main steam temperature controller 37. And
The smaller one of the calculated value and the calculated value of the opening calculated value 36 is selected, and the low value priority circuit 38 outputs an opening command to the high-pressure main steam temperature control spray valve 25.

In general, it is difficult to suppress a rise in the temperature of the high-pressure steam supplied to the steam turbine via the high-pressure main steam pipe 20 by injecting spray water supplied from the desuperheated water supply pipe 24 to the desuperheated water supply pipe 24. Because of the high-pressure second superheater 19, the effect of suppressing the increase in the high-pressure steam temperature is considerably delayed.

In FIG. 1, the flow rate of steam branched from the steam bypass 51 branched from the steam path of the final superheater is adjusted so as to bypass between the output side of the high-pressure main steam desuperheater 23 and the high-pressure steam pipe 20. And a bypass steam flow control valve 52 is newly provided. The bypass steam flow control device 34 operates based on the detection result of the main steam temperature detector 33 that detects the main steam temperature, and the bypass steam flow control device 34
The opening degree of the bypass steam flow control valve 52 is adjusted based on the control signal. The supply amount of the output of the high-pressure main steam desuperheater 23 supplied to the high-pressure second superheater 19 can be adjusted by the opening degree of the bypass steam flow control valve 52, and the output amount does not pass to the high-pressure second superheater 19. The supply amount of the output of the high-pressure main steam desuperheater 23 supplied to the high-pressure steam pipe 20 can be adjusted directly.
The temperature of the output of the high-pressure main steam desuperheater 23, which is supplied directly to the high-pressure steam pipe 20 without passing through the high-pressure second superheater 19, is equal to the high pressure supplied to the high-pressure steam pipe 20 from the high-pressure second superheater 19. Lower than main steam temperature.

In the control diagram of this embodiment shown in FIG.
When the main steam temperature rises rapidly, the bypass steam flow control valve 52 opens and closes the bypass steam flow control valve 52. The effect of suppressing the increase in high-pressure steam temperature by injection of spray water from the desuperheated water supply pipe 24 causes a considerable delay, whereas the effect of reducing the amount of heat exchanged into superheater steam by the bypass branch gradually appears, and the high-pressure main steam temperature is reduced. To the steam temperature set point.

Next, the effect of the present embodiment will be described.

The bypass flow controller 34 and the steam bypass 5
1 and a bypass steam flow control valve 52, and activates the bypass steam flow control device 34 based on the detection result of the main steam temperature detector 33. By directly adjusting the supply amount to the high-pressure steam pipe 20 without going to 19, it is possible to quickly suppress the rise in the temperature of the high-pressure steam supplied to the steam turbine.

If the steam temperature change rate such as the main steam temperature rise rate is restricted, it may not be possible to satisfy the change rate limit only by spray water control. For example, by adopting a method of reducing the amount of heat exchange by bypassing the final superheater inlet steam, it is possible to suppress an increase in the steam temperature, and to perform a desired temperature control even when a change rate restriction is required. be able to.

Next, an embodiment of the second invention will be described with reference to FIGS.

Unlike the configuration shown in FIG. 1, in this embodiment, as shown in FIG. 3, an exhaust gas temperature detector 53 for detecting the temperature of the exhaust gas of the gas turbine is provided. The bypass steam flow controller 34 operates based on the detection result of the exhaust gas temperature detector 53, not the detection result of the main steam temperature detector 33, and controls the bypass steam flow based on the control signal of the bypass steam flow controller 34. The opening of the valve 52 is adjusted.

In the control diagram shown in FIG. 4, when the exhaust gas temperature rises rapidly, the bypass flow rate regulator 34 opens and closes the bypass flow rate control valve 52.

According to the structure of this embodiment, the bypass flow rate controller 34, the steam bypass 51, and the bypass steam flow rate control valve 52 are provided, and the bypass steam flow rate control device 34 is controlled based on the detection result of the exhaust gas temperature detector 53. By operating and directly adjusting the supply amount of the output of the high-pressure main steam desuperheater 23 to the high-pressure steam pipe 20 without passing through the high-pressure second superheater 19, the high-pressure supply to the steam turbine is controlled. It is possible to quickly suppress an increase in steam temperature.

As described above, by adopting a method of reducing the amount of heat exchange by bypassing the steam at the inlet of the final superheater, it is possible to suppress an increase in the steam temperature, and even if the rate of change is required, Desired temperature control can be enabled.

Next, an embodiment of the third invention will be described with reference to FIGS.

The device configuration and system of the embodiment shown in FIG. 5 are different from the device configuration and system of the prior art shown in FIG. 17 in that a second desuperheater 47 is newly provided. Spray steam is supplied to the second desuperheater 47 via the desuperheater bypass steam pipe 30. At this time, the flow rate of the spray steam supplied to the second desuperheater 47 is adjusted by the high-pressure main steam temperature adjusting second spray valve 31 based on the control signal of the main steam temperature adjuster 46.

The main steam temperature controller 46 includes a differentiator 39 and a main steam temperature controller 40 as shown in FIG. When the high-pressure main steam temperature rises sharply, spray water is injected by the main steam temperature controller 37, and at the same time, the temperature deviation differentiated by the differentiator 39 by the other main steam temperature controller 40 also sharply increases. The amount of the saturated steam is increased to rise. At this time, the effect of suppressing the rise in high-pressure steam temperature by spray injection occurs with a considerable delay, whereas the effect of mixing saturated steam appears immediately and acts to bring the high-pressure main steam temperature to the steam temperature set value.

In the control chart shown in FIG. 6, when the main steam temperature rises rapidly, the main steam temperature controller 46 opens and closes the high-pressure main steam temperature control second spray valve 31. When the high-pressure main steam temperature control second spray valve 31 is opened, the spray steam is injected into the second desuperheater 47, and the amount of heat exchanged by the second desuperheater 47 to the superheated steam from the high-pressure second superheater 19 decreases. However, the effect of this decrease gradually appears, and acts so that the high-pressure main steam temperature becomes the steam temperature set value.

According to the configuration of the present embodiment, spray steam is injected into the newly installed second desuperheater 47 at the outlet side of the final superheater via the high-pressure main steam temperature control second spray valve 31,
By adjusting the heat exchange amount of the superheated steam by adopting a method of reducing the heat exchange amount of the desuperheater 47, it is possible to suppress an increase in the steam temperature, and even when the rate of change restriction is required, Temperature control can be performed. Further, by obtaining the heat exchange amount of the superheated steam from the differential value of the steam temperature deviation using the differentiator 39, the rise of the steam temperature can be suppressed, and even if the rate of change restriction is required, the target temperature control can be performed. It can be performed.

Next, an embodiment of the fourth invention will be described with reference to FIGS.

Unlike the configuration shown in FIG. 5, in this embodiment, as shown in FIG. 7, an exhaust gas temperature detector 53 for detecting the temperature of the exhaust gas of the gas turbine is provided. The main steam temperature controller 46 operates based on the detection result of the exhaust gas temperature detector 53 instead of the detection result of the main steam temperature detector 33, and the flow rate of the spray steam supplied to the second desuperheater 47 is The high pressure main steam temperature is adjusted by the second spray valve 31 based on the control signal of the steam temperature controller 46.

In the control chart shown in FIG. 8, when the exhaust gas temperature rises rapidly, the main steam temperature controller 46 opens and closes the high-pressure main steam temperature control second spray valve 31.
When the high pressure main steam temperature control second spray valve 31 is opened, the second
Spray steam is injected into the desuperheater 47, and the second desuperheater 47
, The amount of heat exchanged with the superheated steam from the high-pressure second superheater 19 is reduced, and the effect of this reduction gradually appears, and acts so that the high-pressure main steam temperature becomes the steam temperature set value.

According to the structure of this embodiment, the exhaust gas temperature detector 53 is provided, and the newly-developed second desuperheater 47 at the outlet of the final superheater is sprayed through the high-pressure main steam temperature control second spray valve 31. By injecting steam and adopting a method of reducing the heat exchange amount of the second desuperheater 47 and adjusting the heat exchange amount of the superheated steam, it is possible to suppress an increase in the steam temperature,
Even when the rate of change restriction is required, desired temperature control can be performed. Further, by obtaining the heat exchange amount of the superheated steam from the differential value of the steam temperature deviation using the differentiator 39, the rise of the steam temperature can be suppressed, and even if the rate of change restriction is required, the target temperature control can be performed. It can be performed.

Next, an embodiment of the fifth invention will be described with reference to FIGS. 9 and 10.

The device configuration and system of the embodiment shown in FIG. 9 are different from the device configuration and system of the prior art shown in FIG.
A gas turbine output detector 45 for detecting a gas turbine output is newly provided. The main steam temperature control device 32 is operated based on the output of the gas turbine output detector 45, the opening of the high-pressure main steam temperature control valve 25 is adjusted, and the spray steam flow rate to the high-pressure main steam desuperheater 23 is adjusted. You.

The steam sent from the high-pressure steam drum 15 to the high-pressure main steam desuperheater 23 includes steam sent to the high-pressure main steam deheater 23 after being superheated by the high-pressure first superheater 18, Steam directly to the high-pressure main steam desuperheater 23 without being superheated by the heater 18. The steam that has not passed through the high-pressure first superheater 18 is sent to the high-pressure main steam desuperheater 23 via the first steam pipe 55, and the steam superheated by the high-pressure first superheater 18 is passed through the second steam pipe 56. It is sent to the high-pressure main steam desuperheater 23. The high-pressure main steam temperature control valve 25 is provided in the first steam pipe 55.

In the control diagram shown in FIG. 10, when the gas turbine output rises sharply, the high-pressure main steam temperature control spray valve 25 is opened and closed by the main steam temperature controller 32 having the main steam temperature controller 37.

According to the configuration of the present embodiment, the gas turbine output detector 45 for detecting the gas turbine output is provided, so that the gas turbine output detector 45 is provided in accordance with the gas turbine output closely related to the temperature of the high-pressure main steam of the steam turbine. Injecting the spray steam into the high-pressure main steam desuperheater 23 at the inlet side of the final superheater, it is possible to reduce the amount of heat exchange in the high-pressure main steam desuperheater 23 and quickly suppress the rise of the main steam temperature. Thus, even when a change rate restriction is required, the desired temperature control can be performed.

Next, referring to FIG. 11 and FIG.
An embodiment of the invention will be described. The device configuration and system of the embodiment shown in FIG. 11 are different from the device configuration and system of the prior art shown in FIG. 17 in that a gas turbine fuel flow detector 41 for detecting a gas turbine fuel flow is newly provided. I have. The main steam temperature controller 32 operates based on the output of the gas turbine fuel flow rate detector 41, the opening of the high-pressure main steam temperature control valve 25 is adjusted, and the high-pressure main steam
The spray vapor flow to 3 is adjusted.

The steam sent from the high-pressure steam drum 15 to the high-pressure main steam desuperheater 23 includes steam sent to the high-pressure main steam deheater 23 after being superheated by the high-pressure first superheater 18, Steam directly to the high-pressure main steam desuperheater 23 without being superheated by the heater 18. The steam that has not passed through the high-pressure first superheater 18 is sent to the high-pressure main steam desuperheater 23 via the first steam pipe 55, and the steam superheated by the high-pressure first superheater 18 is passed through the second steam pipe 56. It is sent to the high-pressure main steam desuperheater 23. The high-pressure main steam temperature control valve 25 is provided in the first steam pipe 55.

In the control diagram shown in FIG. 12, when the gas turbine fuel flow rate rises sharply, the main steam temperature controller 3
The high-pressure main steam temperature control spray valve 25 is opened / closed by the main steam temperature controller 32 having 7.

According to the configuration of the present embodiment, the gas turbine fuel flow rate detector 41 for detecting the gas turbine fuel flow rate is provided, so that the gas turbine fuel flow rate closely related to the temperature of the high-pressure main steam of the steam turbine is provided. Accordingly, the amount of heat exchange in the high-pressure main steam desuperheater 23 can be reduced by injecting the spray steam into the high-pressure main steam desuperheater 23 on the inlet side of the final superheater, and the main steam temperature can be increased quickly. Thus, even when the rate of change is required, the desired temperature control can be performed.

Next, referring to FIG. 13 and FIG.
An embodiment of the invention will be described. The device configuration and system of the embodiment shown in FIG. 13 are different from the device configuration and system of the prior art shown in FIG. Then, the flow rate of the spray steam to the high-pressure main steam desuperheater 23 is adjusted based on the control signal of the main steam temperature adjusting device 32 according to the load command value.

The steam sent from the high-pressure steam drum 15 to the high-pressure main steam desuperheater 23 includes steam that is superheated by the high-pressure first superheater 18 and then sent to the high-pressure main steam deheater 23, Steam directly to the high-pressure main steam desuperheater 23 without being superheated by the heater 18. The steam that has not passed through the high-pressure first superheater 18 is sent to the high-pressure main steam desuperheater 23 via the first steam pipe 55, and the steam superheated by the high-pressure first superheater 18 is passed through the second steam pipe 56. It is sent to the high-pressure main steam desuperheater 23. The high-pressure main steam temperature control valve 25 is provided in the first steam pipe 55.

In FIG. 14, when the load command value rises sharply, the high-pressure main steam temperature control spray valve 25 is opened and closed by the main steam temperature controller 32 having the main steam temperature controller 37.

According to the configuration of the present embodiment, the load command value output means 42 is newly connected to the main steam temperature control device 32, so that the load command value output means 42 responds to the load command value closely related to the high-pressure main steam temperature of the steam turbine. Thus, the amount of heat exchange in the high-pressure main steam desuperheater 23 can be reduced by injecting the spray steam into the high-pressure main steam desuperheater 23 on the inlet side of the final superheater, and the increase in the main steam temperature can be suppressed quickly. The target temperature control can be performed even when the rate of change restriction is required.

Next, referring to FIG. 15 and FIG.
An embodiment of the invention will be described. The device configuration and system of the embodiment shown in FIG. 15 are different from the device configuration and system of the prior art shown in FIG. 17 in that a generator output detection means 43 for detecting a generator output is newly added to the main steam temperature controller 32. Then, the flow rate of the spray steam to the high-pressure main steam desuperheater 23 is adjusted based on the control signal of the main steam temperature adjusting device 32 according to the generator output.

The steam sent from the high-pressure steam drum 15 to the high-pressure main steam desuperheater 23 includes steam that is superheated by the high-pressure first superheater 18 and then sent to the high-pressure main steam desuperheater 23, Steam directly to the high-pressure main steam desuperheater 23 without being superheated by the heater 18. The steam that has not passed through the high-pressure first superheater 18 is sent to the high-pressure main steam desuperheater 23 via the first steam pipe 55, and the steam superheated by the high-pressure first superheater 18 is passed through the second steam pipe 56. It is sent to the high-pressure main steam desuperheater 23. The high-pressure main steam temperature control valve 25 is provided in the first steam pipe 55.

In FIG. 16, when the generator output rises sharply, the high-pressure main steam temperature control spray valve 25 is opened and closed by the main steam temperature controller 32 having the main steam temperature controller 37.

According to the configuration of the present embodiment, the generator output detection means 43 is newly connected to the main steam temperature control device 32, so that the generator output detection means 43 responds to the load command value closely related to the high-pressure main steam temperature of the steam turbine. Thus, the amount of heat exchange in the high-pressure main steam desuperheater 23 can be reduced by injecting the spray steam into the high-pressure main steam desuperheater 23 on the inlet side of the final superheater, and the increase in the main steam temperature can be suppressed quickly. The target temperature control can be performed even when the rate of change restriction is required.

[0090]

As described above, according to the configuration of the present invention, a sudden change in the high-pressure main steam temperature can be prevented by correcting and controlling the high-pressure main steam temperature at the outlet of the final superheater. As a result, a sudden change in the main steam temperature is prevented so that the rate of increase in the main steam temperature falls within the allowable range of the steam turbine without changing the load increase rate (fuel input amount) of the gas turbine, and the plant startup time is reduced. It is possible to minimize the life consumption of the steam turbine without lengthening the time.

[Brief description of the drawings]

FIG. 1 is a diagram showing a device element configuration and a system of an exhaust heat recovery boiler according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a simple block of main steam temperature control according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a device element configuration and a system of an exhaust heat recovery boiler according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a simple block of main steam temperature control according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a device element configuration and a system of an exhaust heat recovery boiler according to a third embodiment of the present invention.

FIG. 6 is a diagram showing simple blocks of main steam temperature control according to a third embodiment of the present invention.

FIG. 7 is a diagram showing a device element configuration and a system of an exhaust heat recovery boiler according to a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a simple block of main steam temperature control according to a fourth embodiment of the present invention.

FIG. 9 is a diagram showing a device element configuration and a system of an exhaust heat recovery boiler according to a fifth embodiment of the present invention.

FIG. 10 is a diagram showing a simple block of main steam temperature control according to a fifth embodiment of the present invention.

FIG. 11 is a diagram showing a device element configuration and a system of an exhaust heat recovery boiler according to a sixth embodiment of the present invention.

FIG. 12 is a diagram showing a simple block of main steam temperature control according to a sixth embodiment of the present invention.

FIG. 13 is a diagram showing a device element configuration and a system of an exhaust heat recovery boiler according to a seventh embodiment of the present invention.

FIG. 14 is a diagram showing a simple block of main steam temperature control according to a seventh embodiment of the present invention.

FIG. 15 is a diagram showing a device element configuration and a system of an exhaust heat recovery boiler according to an eighth embodiment of the present invention.

FIG. 16 is a diagram showing a simple block of main steam temperature control according to an eighth embodiment of the present invention.

FIG. 17 is a diagram showing components and a system of a conventional heat recovery steam generator.

FIG. 18 is a diagram showing an example of an exhaust gas flow rate adjusting method for controlling the main steam temperature of the exhaust heat recovery boiler shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Low-pressure water supply pipe 2 Low-pressure coal-saving pipe 3 High-pressure water suction pump suction pipe 4 Low-pressure water supply pipe 5 Low-pressure water supply control valve 6 High-pressure water supply pump 7 High-pressure water pipe 8 Low-pressure steam drum 9 Low-pressure superheater 10 Low-pressure steam liaison 11 Low-pressure superheater 12 High-pressure coal saving pipe 13 High-pressure liaison 14 High-pressure feedwater control valve 15 High-pressure steam drum 16 High-pressure evaporator 17 High-pressure steam liaison 18 High-pressure first superheater 19 High-pressure second superheater 20 High-pressure main steam pipe 21 First reheater 22 Second reheater 23 High pressure main steam desuperheater 24 Desuperheated water supply pipe 25 High pressure main steam temperature control spray valve 26 Reheat steam deheater 27 Reheat steam temperature control valve 28 Low pressure economizer inlet feedwater temperature control pipe 29 Low pressure feedwater temperature control valve 30 Superheater bypass steam pipe 31 Main steam temperature control valve 32 Main steam temperature control device 35 Function generator 36 Opening degree calculator 37 Main steam temperature controller 38 Value priority circuit 39 Differentiator 40 Main steam temperature controller 41 Gas turbine fuel flow rate detector 42 Load command output means 43 Generator output detector 45 Gas turbine output detector 46 Main steam temperature controller 47 Main steam second temperature reducer 51 steam bypass pipe 52 bypass steam flow control valve 53 exhaust gas temperature detector 55 first steam pipe 56 second steam pipe

Claims (8)

[Claims] 1. A final superheater for outputting high-pressure main steam to be supplied to a steam turbine, a main steam temperature detector for detecting high-pressure main steam temperature, and a steam for bypassing an inlet side and an outlet side of the final superheater. A main steam temperature control device comprising: a bypass pipe; and bypass flow rate adjusting means for adjusting a steam flow rate passing through the steam bypass pipe according to a high-pressure main steam temperature detected by the main steam temperature detector. 2. A final superheater for outputting high-pressure main steam supplied to a steam turbine, an exhaust gas temperature detector for detecting an exhaust gas temperature of a gas turbine, and a bypass between an inlet side and an outlet side of the final superheater. A main steam temperature control device, comprising: a steam bypass pipe for performing steam flow, and bypass flow rate adjusting means for adjusting a steam flow rate passing through the steam bypass pipe in accordance with the exhaust gas temperature detected by the exhaust gas temperature detector. . 3. A final superheater for outputting high-pressure main steam to be supplied to a steam turbine, a main steam temperature detector for detecting high-pressure main steam temperature, a desuperheater at a stage preceding the final superheater, A steam drum that supplies steam to the desuperheater; a superheater bypass steam pipe that bypasses an outlet side of the steam drum and an outlet side of the final superheater; and a high-pressure main steam temperature detected by the main steam temperature detector. And a bypass flow rate adjusting means for adjusting a steam flow rate through the superheater bypass steam pipe according to the main steam temperature control device. 4. A final superheater for outputting high-pressure main steam to be supplied to a steam turbine, an exhaust gas temperature detector for detecting an exhaust gas temperature of a gas turbine, and a desuperheater located upstream of the final superheater. A steam drum that supplies steam to the desuperheater, a superheater bypass steam pipe that bypasses an outlet side of the steam drum and an outlet side of the final superheater, and a gas turbine detected by the exhaust gas temperature detector. A bypass flow rate adjusting means for adjusting a steam flow rate passing through the superheater bypass steam pipe according to the exhaust gas temperature of the main steam temperature control apparatus. 5. A final superheater for outputting high-pressure main steam to be supplied to a steam turbine, gas turbine output detecting means for detecting a gas turbine output, a desuperheater at a stage preceding the final superheater, A steam drum for supplying steam to the heater, a first steam pipe for supplying the steam of the steam drum to the desuperheater without overheating, and a superheater of the steam of the steam drum to the desuperheater A second steam pipe for supplying; and a bypass flow rate adjusting means for adjusting a steam flow rate passing through the first steam pipe in accordance with the gas turbine output detected by the gas turbine output detecting means. Main steam temperature control device. 6. A final superheater for outputting high-pressure main steam to be supplied to a steam turbine, gas turbine fuel flow rate detecting means for detecting a gas turbine fuel flow rate, and a desuperheater located upstream of the final superheater. A steam drum for supplying steam to the temperature reducer, a first steam pipe for supplying steam to the temperature reducer without overheating the steam in the steam drum, and a temperature reduction by heating the steam in the steam drum A second steam pipe for supplying to the vessel, and a bypass flow rate adjusting means for adjusting a steam flow rate passing through the first steam pipe in accordance with the gas turbine fuel flow rate detected by the gas turbine fuel flow rate detecting means. A main steam temperature control device. 7. A final superheater for outputting high-pressure main steam to be supplied to a steam turbine, load command value output means for instructing a load command value, a desuperheater at a stage preceding the final superheater,
A steam drum for supplying steam to the temperature reducer, a first steam pipe for supplying steam to the temperature reducer without overheating the steam in the steam drum, and a temperature reduction by heating the steam in the steam drum A second steam pipe for supplying to the vessel, and bypass flow rate adjusting means for adjusting a steam flow rate passing through the first steam pipe in accordance with the load command value output by the load command value output means. Main steam temperature control device. 8. A final superheater for outputting high-pressure main steam to be supplied to a steam turbine, a generator output detecting means for detecting a generator output, a desuperheater located upstream of the final superheater,
A steam drum for supplying steam to the temperature reducer, a first steam pipe for supplying steam to the temperature reducer without overheating the steam in the steam drum, and a temperature reduction by heating the steam in the steam drum A second steam pipe for supplying to the steam generator; and a bypass flow rate adjusting means for adjusting a steam flow rate passing through the first steam pipe in accordance with the generator output detected by the generator output detecting means. Main steam temperature control device.