JP2023032523A - Start-up control device and start-up control method for combined cycle power generation plant - Google Patents

Abstract

To provide a start-up control device and a start-up control method for a combined cycle power generation plant capable of shortening the plant start-up time compared with conventional ones.SOLUTION: The start-up control device includes: a converter for inputting a high-pressure steam outlet pressure signal of an exhaust heat recovery boiler and outputting a saturation temperature signal; a rise rate setting circuit that outputs a saturation temperature rise set value to start the exhaust heat recovery boiler at a certain temperature rise rate in response to the saturation temperature signal; a converter that converts the saturation temperature rise set value and outputs a steam pressure set value; and a valve opening degree setting device that outputs an opening degree signal for a high-pressure turbine bypass valve from the steam pressure set value and the high-pressure steam outlet pressure signal. The valve opening degree setting device controls an opening degree of the high-pressure turbine bypass valve, and steam is recovered to a condenser until steam conditions are met for inflow to the steam turbine, and then switched to inflow into the steam turbine after the steam conditions are met.SELECTED DRAWING: Figure 1

Description

An embodiment of the present invention relates to a start-up control device and a start-up control method for a combined cycle power plant.

A combined cycle power plant is capable of power generation operation that matches the power demand. Depending on the power demand, the gas turbine is stopped and restarted when the power is needed in a DSS (Daily Start Stop) operation. is being implemented.

Here, the restrictions on the start-up of the combined cycle power plant include the start-up time of the gas turbine, the start-up time of the heat recovery steam generator, and the start-up time of the steam turbine. In particular, at the start-up of the plant, the time required to satisfy the conditions of the steam supplied to the steam turbine has an effect, and the start-up time element of the heat recovery boiler is a major factor of the time. Therefore, there is a demand for shortening the start-up time of the heat recovery boiler.

JP 2012-57585 A

In order to establish the pressure and temperature conditions for starting power generation with a steam turbine, it is necessary to quickly raise the temperature of the steam generated by the heat recovery boiler. If the speed is increased, the thermal fatigue of equipment including piping will increase, and there is a risk of serious accidents due to damage to steam pipes and the like.

For this reason, when the conventional combined cycle power plant starts up, the steam pressure of the high pressure steam drum that separates the moisture from the steam generated by the heat recovery boiler is monitored, and the high pressure turbine bypass control that recovers the steam to the condenser is used. , the rate of steam temperature rise was controlled by limiting the rate of steam pressure rise.

In the high-pressure turbine bypass control, the pressure rise speed is suppressed at a constant speed depending on the pressure condition of the high-pressure drum, and the temperature rise speed is limited. However, the specified value of the temperature rise from the high-pressure steam drum is generally a constant temperature rise rate, and the saturation function of temperature and pressure cannot be expressed by a linear function expression. The temperature rise was set at a low rate of rise, requiring a significant excess of plant start-up time.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a start-up control apparatus and a start-up control method for a combined cycle power plant, which can shorten the plant start-up time compared with the prior art.

A start-up control device for a combined cycle power plant according to an embodiment includes a gas turbine driven by burning fuel, a gas turbine generator driven by the gas turbine to generate electricity, and recovering the heat of flue gas generated by the gas turbine. a heat recovery boiler for generating main steam, a high pressure steam drum and a low pressure steam drum for separating moisture from the steam generated by the heat recovery steam generator, a steam turbine driven by the steam, and a steam turbine driven by the steam turbine. a steam turbine generator for generating electricity; a main steam pipe for supplying steam generated by the heat recovery boiler to the steam turbine; and a high-pressure turbine bypass valve for controlling the pressure of the steam generated by the heat recovery boiler. a condenser for cooling steam back to water, the start-up control device for a combined cycle power plant comprising: measuring the high pressure steam outlet pressure of the heat recovery boiler and outputting a high pressure steam outlet pressure signal. a pressure transmitter, a steam pressure-to-saturation temperature converter that receives the high-pressure steam outlet pressure signal and outputs a saturation temperature signal, and the heat recovery steam generator at a constant rate of temperature rise with respect to the saturation temperature signal. and a saturation temperature rise rate setting circuit that outputs a saturation temperature rise set value for activating the saturation temperature rise set value, and a steam pressure set value that converts the saturation temperature rise set value to steam pressure and outputs the steam pressure set value from the saturation temperature to the steam pressure. a converter; and a high-pressure turbine bypass valve opening setting device for outputting an opening signal of the high-pressure turbine bypass valve from the steam pressure set value and the high-pressure steam outlet pressure signal, wherein the high-pressure turbine bypass valve The degree of opening of the high-pressure turbine bypass valve is controlled by an degree-of-opening setter, the steam is recovered into the condenser until the conditions for the steam flowing into the steam turbine are satisfied, and the recovery is performed after the conditions for the steam are satisfied. It is characterized by switching from recovery to a water vessel to inflow to the steam turbine.

ADVANTAGE OF THE INVENTION According to this invention, the control apparatus and control method of a combined cycle power plant which can shorten plant start-up time compared with the past can be provided.

1 is a diagram showing a schematic configuration of a start-up control device for a combined cycle power plant according to a first embodiment; FIG. The figure which shows schematic structure of the start-up control apparatus of the combined cycle power plant which concerns on 2nd Embodiment. Graph showing the relationship between steam saturation temperature and pressure. The figure which shows schematic structure of the start-up control apparatus of the conventional combined cycle power plant.

Hereinafter, a start control device and a start control method for a combined cycle power plant according to embodiments will be described with reference to the drawings.

(First embodiment)
First, a first embodiment will be described with reference to FIG. As shown in FIG. 1, the combined cycle power plant according to the embodiment includes a gas turbine (GT) 1 driven by burning fuel and a steam turbine (ST) 11 driven by steam.

Around the gas turbine 1, there are an air compressor (COMP) 2 that supplies air to the gas turbine 1, a gas turbine generator (GTG) 3 that drives and generates electricity together with the gas turbine 1, and combustion generated in the gas turbine 1. A heat recovery steam generator (HRSG) 4 is provided for recovering exhaust gas heat and generating main steam for driving the steam turbine 11 .

The heat recovery boiler 4 includes a high pressure steam drum (HP DRUM) 5 and a low pressure steam drum (LP DRUM) 6 for separating moisture from the steam generated by the heat recovery boiler 4, and the steam generated by the heat recovery boiler 4. is provided to the steam turbine 11 as main steam.

The main steam pipe 7 is provided with an atmospheric release line 8 for releasing steam from the main steam pipe 7 to the atmosphere in order to raise the pressure of the heat recovery boiler 4 to a specified pressure at the initial start of the heat recovery boiler 4. , a high-pressure turbine bypass valve 9 for controlling the pressure of steam generated by the heat recovery boiler 4, and a main steam stop valve and adjustment for controlling the supply of main steam supplied from the main steam pipe 7 to the steam turbine 11. A valve 10 is provided.

A condenser (CONDENSER) 12 is connected to the steam turbine 11 , and steam from the high-pressure turbine bypass valve 9 also flows into the condenser 12 . The steam turbine 11 is also provided with a steam turbine generator (STG) 13 that is driven by the steam turbine 11 to generate power.

A high-pressure steam outlet pressure detection source 14 is provided in the vicinity of the connecting portion of the main steam pipe 7 with the heat recovery boiler 4, and the high-pressure steam outlet pressure detection source 14 is provided with a pressure transmitter 15. . A high-pressure steam outlet pressure signal (PV) 16 from the pressure transmitter 15 is input to the control device 50, and a high-pressure turbine bypass valve opening command signal (MV) 18 is input to the high-pressure turbine bypass valve 9 from the control device 50. , whose opening is controlled.

A pipe connecting the high-pressure turbine bypass valve 9 and the condenser 12 is provided with a high-pressure turbine bypass valve outlet temperature detection source 19 for monitoring the outlet temperature of the high-pressure turbine bypass valve 9. A temperature detector 20 is provided. A high-pressure turbine bypass valve outlet temperature detection signal (PV) 21 from the temperature detector 20 is input to a temperature regulation controller 22 .

The temperature adjustment controller 22 includes a temperature set value controller 221 and a high pressure turbine bypass spray control valve opening degree setter 222 . The temperature set value controller 221 outputs a temperature set value (SV) to the high pressure turbine bypass spray control valve opening degree setter 222 based on the high pressure turbine bypass valve outlet temperature detection signal 21 . A high-pressure turbine bypass spray control valve opening setting device 222 generates a high-pressure turbine bypass spray control valve opening command signal (MV) from the deviation between this temperature setting value (SV) and the high-pressure turbine bypass valve outlet temperature detection signal (PV) 21. 23 is calculated.

Then, a high-pressure turbine bypass spray control valve opening command signal (MV) 23 from a high-pressure turbine bypass spray control valve opening setting device 222 is input to the high-pressure turbine bypass spray control valve 24, and by adjusting the opening, The supply of cooling water to the high pressure turbine bypass valve 9 from the high pressure turbine bypass valve spray line 25 and the gland steam condenser water line 26 is adjusted to control its temperature.

The aforementioned control device 50 includes a steam pressure-to-saturation temperature converter 501, a saturation temperature rise rate setting device 503, a saturation temperature-to-steam pressure converter 505, and a high-pressure turbine bypass valve opening degree setting device 507. is equipped with

A steam pressure-to-saturation temperature converter 501 multiplies the high-pressure steam outlet pressure signal 16 of the heat recovery boiler 4 detected by the pressure transmitter 15 by a multiplier for calculating the saturation temperature, and converts the steam pressure to the saturation temperature. Convert to saturation temperature. Then, this saturation temperature signal 502 is input to a saturation temperature rise rate setting device 503 .

A saturation temperature rise rate setter 503 calculates a saturation temperature rise set value 504 for starting the exhaust heat recovery boiler 4 at a constant temperature rise rate with respect to the input saturation temperature signal 502, and determines steam from the saturation temperature. Input to converter 505 to pressure.

After the conditions for the steam flowing into the steam turbine 11 are established, the opening command of the high-pressure turbine bypass valve 9 for switching the main steam from being recovered in the condenser 12 to flowing into the steam turbine 11 is determined by the main steam pressure. do. Therefore, the saturation temperature to steam pressure converter 505 multiplies the saturation temperature rise setting value 504 output from the saturation temperature rise rate setting device 503 by a multiplier for calculating the steam pressure, and converts the saturation temperature to the steam pressure. After conversion, this steam pressure set value 506 is input to the high pressure turbine bypass valve opening degree setter 507 .

The high-pressure turbine bypass valve opening setting device 507 performs PID calculation based on the difference between the input steam pressure set value 506 and the high-pressure steam outlet pressure signal 16 detected by the pressure transmitter 15, and determines the opening of the high-pressure turbine bypass valve 9. A high pressure turbine bypass valve opening command signal 18 for control is generated and input to the high pressure turbine bypass valve 9 .

As described above, in the control device 50, the input high-pressure steam outlet pressure signal 16 is input to the steam pressure-to-saturation temperature converter 501 to calculate the saturation temperature. Using this calculated saturation temperature, the saturation temperature rise rate setting device 503 calculates the temperature rise rate of the heat recovery boiler 4 at a constant rise rate, and the converter 505 from the saturation temperature to the steam pressure , is converted into steam pressure again to enable control, and the temperature and pressure of the steam are increased until the steam conditions for flowing into the steam turbine 11 are satisfied.

Then, when the steam conditions for flowing into the steam turbine 11 are established, the high-pressure turbine bypass valve opening degree setting device 507 is operated to switch the recovery of the main steam in the condenser 12 to the flow into the steam turbine 11 . The valve 9 is closed. Along with this, the main steam stop valve and control valve 10 are opened, the main steam is introduced into the steam turbine 11, and the steam turbine 11 is driven to generate power by the steam turbine generator 13.

For comparison, FIG. 4 shows a conventional start-up control device and start-up control method for a combined cycle power plant. In FIG. 4, parts corresponding to those in FIG. 1 are given the same reference numerals, and redundant explanations are omitted. As shown in FIG. 4 , the control device 17 that performs conventional start-up control comprises a pressure rise rate calculator 171 and a turbine bypass valve opening degree setter 172 .

Based on the high-pressure steam outlet pressure signal 16, a pressure rise rate calculator 171 calculates a pressure rise rate 173 for increasing pressure at a constant speed, and a turbine bypass valve opening setting device 172 calculates the pressure rise rate 173 and the high-pressure steam outlet pressure. By the deviation of the signal 16, the pressure rise speed is suppressed to a constant speed, and the temperature rise speed is limited. According to this, since the pressure rise is set to be constant, as shown in FIG. 3, the relationship between the temperature rise speed and the pressure rise speed does not become a linear function, so the temperature rise rate increases at low pressure. , the temperature rise drops dramatically as the pressure rises. For this reason, the plant start-up time has become long.

On the other hand, in the first embodiment shown in FIG. 1, by using temperature conversion, it is possible to set the temperature change rate by replacing the pressure change with the temperature change, and generally it takes about 3 hours. It is possible to shorten the startup time by about 30 minutes. Since the steam temperature is raised at a constant rate of increase in this manner, the start-up time of the heat recovery boiler 4 can be shortened, and the main steam generated by the heat recovery boiler 4 starts to flow into the steam turbine 11. It is possible to shorten the time until

(Second embodiment)
Next, a second embodiment will be described with reference to FIG. In addition, the same code|symbol is attached|subjected to the part corresponding to 1st Embodiment shown in FIG. 1, and the overlapping description is abbreviate|omitted.

As shown in FIG. 2, in the second embodiment, a deviation monitor 508 between the actual value of the steam pressure and the set value and a temperature setting rise limiter 510 are added to the control device 50a. In the deviation monitor 508 between the actual value and the set value of the steam pressure, the steam pressure set value 506 and the high-pressure steam outlet pressure signal 16 converted by the converter 505 from the saturated temperature to the steam pressure described in the first embodiment. monitor the deviation of A deviation signal 509 between the actual steam pressure value and the set value, which is this output, is input to the temperature setting rise limiter 510, and when the deviation value is less than a predetermined value, for example, less than 0 The set temperature increase limiter 510 is turned on, and the temperature set value increase stop/restart signal 511 from the temperature set value increase limiter 510 temporarily stops the rise of the temperature set value in the saturation temperature rise rate setter 503 . On the other hand, when the deviation value is equal to or greater than a predetermined value, for example, equal to or greater than 0 (zero or plus), the temperature setting increase limiter 510 is turned off, and the saturation temperature increase rate setting device 503 resumes increasing the temperature setting value. do.

In other words, when the saturation temperature signal 502 output from the steam pressure-to-saturation temperature converter 501 exceeds the saturation temperature rise setpoint 504 output from the saturation temperature rise rate setter 503, saturation is reached. The rise of the saturation temperature rise set value 504 in the temperature rise rate setter 503 is temporarily stopped, and the rise of the saturation temperature rise set value 504 is resumed when the saturation temperature signal 502 becomes equal to or less than the saturation temperature rise set value 504 . Thus, the saturation temperature rise is controlled.

If the temperature rise rate of the steam generated by the heat recovery boiler 4 is accelerated, the thermal fatigue of the equipment including the piping will increase, and there is a risk that the main steam piping 7 will be damaged, resulting in a serious accident. Therefore, when the rise of the saturation temperature signal 502 exceeds the set value 504 of rise in saturation temperature, the rise of the set value 504 of saturation temperature rise is temporarily stopped. By controlling the rise of the saturation temperature rise set value 504 in this way, it is possible to control the rise of the high-pressure steam outlet pressure signal 16 due to the continued rise of the steam pressure set value 506, and the temperature rise rate allowed by the boiler ( different values depending on the boiler tube material) can be satisfied.

As described above, according to the second embodiment, the same effects as those of the first embodiment can be obtained, and in addition, a rapid temperature rise that damages equipment including piping due to thermal fatigue can be prevented. can be suppressed. As a result, it is possible to suppress accident factors of the heat recovery boiler 4 .

Although several embodiments of the invention have been described above, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

1 gas turbine, 2 air compressor, 3 gas turbine generator, 4 exhaust heat recovery boiler, 5 high-pressure steam drum, 6 low-pressure steam drum, 7 main steam piping, 8...Atmospheric release line, 9...High pressure turbine bypass valve, 10...Main steam stop valve and control valve, 11...Steam turbine, 12...Condenser, 13...Steam turbine generator, 14... High-pressure steam outlet pressure detection source 15 Pressure transmitter 16 High-pressure steam outlet pressure signal 17 Control device 18 High-pressure turbine bypass valve opening command signal 19 High-pressure turbine bypass valve outlet temperature detection 20 Temperature detector 21 High-pressure turbine bypass valve outlet temperature detection signal 22 Temperature adjustment controller 23 High-pressure turbine bypass spray control valve opening command signal 24 High-pressure turbine bypass spray Control valve 25 High-pressure turbine bypass valve spray line 26 Grand steam condenser water supply line 50 Controller 221 Temperature setpoint controller 222 High-pressure turbine bypass spray control valve opening Setting device 501 ... Converter from steam pressure to saturation temperature 502 ... Saturation temperature signal 503 ... Saturation temperature rise rate setter 504 ... Saturation temperature rise set value 505 ... Saturation temperature to steam pressure converter, 506 ... steam pressure set value, 507 ... high-pressure turbine bypass valve opening setting device, 508 ... deviation monitor between actual value and set value of steam pressure, 509 ... actual value of steam pressure and Deviation signal of set value, 510 Temperature setting increase limiter, 511 Temperature set value increase stop/restart signal.

Claims (6)

a gas turbine driven by burning fuel;
a gas turbine generator driven by the gas turbine to generate electricity;
an exhaust heat recovery boiler that recovers the heat of the flue gas generated by the gas turbine and generates main steam;
a high-pressure steam drum and a low-pressure steam drum for separating moisture from the steam generated by the heat recovery steam generator;
a steam turbine driven by steam;
a steam turbine generator driven by the steam turbine to generate electricity;
a main steam pipe for supplying the steam generated by the heat recovery steam generator to the steam turbine;
a high-pressure turbine bypass valve that controls the pressure of the steam generated by the heat recovery steam generator;
a condenser that cools the steam back to water;
A start-up control device for a combined cycle power plant comprising
a pressure transmitter for measuring the high-pressure steam outlet pressure of the heat recovery boiler and outputting a high-pressure steam outlet pressure signal;
a steam pressure to saturation temperature converter receiving said high pressure steam outlet pressure signal and outputting a saturation temperature signal;
a saturation temperature rise rate setting circuit for outputting a saturation temperature rise set value for starting the heat recovery boiler at a constant temperature rise rate in response to the saturation temperature signal;
a saturation temperature to steam pressure converter that converts the saturation temperature rise setpoint to steam pressure and outputs a steam pressure setpoint;
a high-pressure turbine bypass valve opening setting device that outputs an opening signal of the high-pressure turbine bypass valve based on the steam pressure set value and the high-pressure steam outlet pressure signal,
The opening of the high-pressure turbine bypass valve is controlled by the high-pressure turbine bypass valve opening setting device, and the steam is recovered to the condenser until the steam condition for flowing into the steam turbine is satisfied, and the steam condition is satisfied. A start-up control device for a combined cycle power plant, characterized by switching from recovery to the condenser to inflow to the steam turbine after establishment.
A startup control device for a combined cycle power plant according to claim 1,
a steam pressure deviation monitor that outputs a deviation signal between the high-pressure steam outlet pressure signal and the steam pressure set value;
When the value of the deviation signal calculated by the deviation monitor of the steam pressure is less than a predetermined value, the steam pressure set value is stopped increasing, and when the value of the deviation signal is greater than or equal to the predetermined value, the steam pressure is set. a temperature setpoint increase controller to resume increasing the value;
A startup control device for a combined cycle power plant, comprising:
A startup control device for a combined cycle power plant according to claim 2,
When the predetermined value is zero and the value of the deviation signal is negative, the increase of the steam pressure setpoint is stopped, and when the value of the deviation signal is zero or positive, the increase of the steam pressure setpoint is resumed. A start-up control device for a combined cycle power plant characterized by:
a gas turbine driven by burning fuel;
a gas turbine generator driven together with the gas turbine to generate electricity;
an exhaust heat recovery boiler that recovers the heat of the flue gas generated by the gas turbine and generates main steam;
a high-pressure steam drum and a low-pressure steam drum for separating moisture from the steam generated by the heat recovery steam generator;
a steam turbine driven by steam;
a steam turbine generator driven by the steam turbine to generate electricity;
a main steam pipe for supplying the steam generated by the heat recovery steam generator to the steam turbine;
a high-pressure turbine bypass valve that controls the pressure of the steam generated by the heat recovery steam generator;
a condenser that cools the steam back to water;
A start-up control method for a combined cycle power plant comprising
a pressure measuring step of measuring the high-pressure steam outlet pressure of the heat recovery boiler and outputting a high-pressure steam outlet pressure signal;
a steam pressure to saturation temperature conversion step of inputting the high pressure steam outlet pressure signal and outputting a saturation temperature signal;
a saturation temperature rise rate setting step of outputting a saturation temperature rise set value for starting the heat recovery boiler at a constant temperature rise rate with respect to the saturation temperature signal;
a saturation temperature-to-steam pressure conversion step of converting the saturation temperature rise setpoint into steam pressure and outputting the steam pressure setpoint;
a high-pressure turbine bypass valve opening degree setting step of outputting an opening degree signal of the high-pressure turbine bypass valve from the steam pressure set value and the high-pressure steam outlet pressure signal;
The opening degree of the high pressure turbine bypass valve is controlled by the high pressure turbine bypass valve opening degree setting step, and the steam is recovered to the condenser until the steam conditions for flowing into the steam turbine are satisfied, and the steam conditions are satisfied. A start-up control method for a combined cycle power plant, characterized by switching from recovery to the condenser to inflow to the steam turbine after establishment.
A startup control method for a combined cycle power plant according to claim 4,
a steam pressure deviation monitoring step of outputting a deviation signal between the high-pressure steam outlet pressure signal and the steam pressure set value;
If the value of the deviation signal calculated in the deviation monitoring step of the steam pressure is less than a predetermined value, the steam pressure setting value is stopped, and if the value of the deviation signal is equal to or greater than the predetermined value, the steam pressure is set. a temperature setpoint increase control step for restarting the increase of the value;
A startup control method for a combined cycle power plant, comprising:
A startup control method for a combined cycle power plant according to claim 5,
When the predetermined value is zero and the value of the deviation signal is negative, the increase of the steam pressure setpoint is stopped, and when the value of the deviation signal is zero or positive, the increase of the steam pressure setpoint is resumed. A start-up control method for a combined cycle power plant, characterized by:

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