JPH10184316A - Power generation control device utilizing exhaust heat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always provide stable generator output irrespective of variation of exhaust heat amount and temperature by suppressing fluctuation of a steam to be flowed into a steam turbine through a steam flow amount control system in respect to an power set load of an exhaust heat utilizing generation plant, and suppressing fluctuation of steam pressure by a steam pressure control system. SOLUTION: Exhaust heated steam is flowed into high, medium, low pressure steam separators 2a, 2b, 2c whereby steam is separated from hot water. The separated hot water is introduced into a heat exchanger 17, while steam is introduced into a steam turbine 6. A flow amount of the steam is controlled such that an output of a generator 8 is in a set value. Outlet pressure values of the separators 2 are switched and adjusted according to pressure deviation thereof, so as to obtain set values. The hot water level of the steam separators 2 are controlled so as to obtain set values. The temperature of the excessive hot water in the heat separators 2 at the outlet of the heat exchanger is adjusted to obtain a set value by controlling an amount of cooling water to the heat exchanger 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power generation control device utilizing waste heat utilizing waste heat (geothermal) obtained from waste heat steam or underground steam of an industrial plant or the like.

[0002]

2. Description of the Related Art In general, there are various types of power generation in addition to thermal power generation, hydroelectric power generation, nuclear power generation, and the like. As one of the special power generation methods, there is a power generation method using waste heat obtained from an industrial plant or an underground.

[0003] In such a power generation system utilizing waste heat, similarly to thermal power generation, a steam turbine is driven by steam to generate power. However, since steam is generated by exhaust heat, steam is generated in comparison with thermal power generation. Significant savings in fuel costs to run the turbine. For this reason, in recent years, it has begun to attract attention in terms of resource utilization.

[0004]

In such a conventional power generation control apparatus utilizing waste heat, the flow rate of the waste heat is not always fixed, so that the flow rate of the waste heat must be controlled particularly. Instead, all the exhaust heat obtained from an industrial plant or the like is used for driving the steam turbine, and basically, the electric power is maximally operated.

However, in such a conventional power generation control system using waste heat, when the flow rate or temperature of the waste heat from an industrial plant or the like changes, the output of the generator also changes immediately, so that it is possible to control the power generation by itself. There was a problem.

Accordingly, an object of the present invention is to provide a power generation control device utilizing waste heat capable of always obtaining a stable generator output irrespective of changes in the flow rate or temperature of waste heat from an industrial plant or the like. To provide.

[0007]

According to a first aspect of the present invention, there is provided a power generation control apparatus utilizing waste heat, which includes a low pressure, a medium pressure, and a high pressure for separating low pressure, medium pressure, and high pressure waste heat steam into steam and hot water. A steam separator, a steam turbine driven by steam from the steam separator, a generator driven by the steam turbine to generate power, and a condenser for condensing steam after working in the steam turbine into condensate. A cooling tower for cooling the condensed water with a cooling tower fan and then exchanging heat with the hot water from each of the steam separators in a heat exchanger, and replenishing the cooling water with makeup water. In a power generation control device utilizing waste heat, a steam flow control system that controls a flow rate of steam flowing into the steam turbine so that an output of the generator becomes a predetermined power load set value, and an inlet pressure of the steam turbine is increased. Set to a predetermined pressure set value A steam pressure control system for controlling the inlet pressure of the steam turbine based on a control signal obtained by adding each deviation of the outlet pressure of each of the high, medium and low pressure steam separators as a bias signal; A hot water level control system that preferentially controls each hot water level based on a signal on the higher value side of each level deviation so that each hot water level becomes a predetermined level set value, and a high-, medium-, and low-pressure steam separator. A hot water temperature control system for cooling and controlling the excess hot water with the cooling water of the cooling tower so that the temperature of the surplus hot water becomes a predetermined temperature set value at the heat exchanger outlet, and a water level level of the condenser A condenser level control system for controlling the cooling water amount based on a control signal added as a bias signal so as to be a predetermined water level level setting value, and a water level level of the cooling tower being a predetermined level setting value So the high pressure A replenishing water amount control system for controlling a replenishing water amount replenished to the cooling tower based on a signal on the high side of the water level of the medium pressure and low pressure hot water separators and a control signal obtained by adding the steam flow signal as a bias signal A cooling tower internal temperature control system that controls the number of rotations of the cooling tower fan per unit time so that the cooling water temperature of the cooling tower becomes a predetermined temperature set value. I do.

According to the present invention, the exhaust heat steam flowing into each of the high-, medium-, and low-pressure steam separators is separated into steam and hot water by these steam separators, and the hot water is introduced into the heat exchanger. Meanwhile, the steam is introduced into a steam turbine. The amount of steam introduced into the steam turbine is controlled by a steam flow control system such that the output of the generator reaches a predetermined power set value.

The steam pressure at the inlet of the steam turbine is controlled by a steam pressure control system according to the pressure deviations of the high, medium and low pressure steam separators so as to reach a predetermined pressure set value. Is controlled by switching control.

[0010] The hot water level of each of the high-, medium-, and low-pressure steam separators is controlled by a hot-water level control system to a predetermined value.

The temperature at the heat exchanger outlet of the excess hot water of each of the high-, medium-, and low-pressure steam separators is cooled by the hot-water temperature control system so that the temperature becomes a predetermined temperature set value. It is controlled by controlling the amount of water.

The temperature of the cooling water of the cooling tower is controlled by controlling the number of rotations of the cooling fan of the cooling tower per unit time by a cooling water temperature control system so as to reach a predetermined temperature set value.

[0013] The water level of the cooling tower is controlled by controlling the amount of water supplied to the cooling tower by a make-up water amount control system so as to reach a predetermined cooling tower water level set value.

According to a second aspect of the present invention, the steam pressure control system compares the steam pressure deviations of the high-pressure, medium-pressure, and low-pressure steam separators with the respective deviation limiters. When the turbine inlet pressure is higher than the set value, the pressure is automatically switched to the outlet pressure control of the medium-pressure and low-pressure steam separators based on the comparison signal of the deviation limiter, and the steam turbine inlet pressure is set in advance. If the steam turbine inlet pressure is lower than the set value, on the other hand, the pressure is automatically switched to the high-pressure / medium-pressure steam separator outlet pressure control based on the comparison signal of the deviation limiter, and A control system for controlling the steam turbine inlet pressure to a set value.

According to the present invention, the steam pressure is controlled by the steam pressure control system so that the pressure of the steam turbine becomes a predetermined set value. Pressure control is performed in three stages of high-pressure, medium-pressure, and low-pressure steam. The pressure control switching method compares the deviation signal between the steam turbine inlet pressure set value and the steam turbine inlet pressure with the limit value of the deviation limiter, and when the pressure deviation signal is large (that is, when the steam turbine pressure is very high). ) Controls the inlet pressure of the steam turbine with the outlet pressure of the low-pressure steam separator, and switches to the medium-pressure / low-pressure steam separator pressure control when the pressure deviation decreases slightly. Conversely, when the inlet pressure of the steam turbine tends to decrease, the difference signal between the steam turbine inlet pressure set value and the steam turbine inlet pressure is similarly compared with the limit value using the deviation limit value. Switch to the pressure control of the steam separator, and if the deviation signal further decreases,
Automatically switches to medium- and low-pressure steam separators.

According to a third aspect of the present invention, the hot water level control system comprises:
The difference signal between the hot water level of each steam separator and its set value is compared by the high value priority circuit, and the hot water level is controlled preferentially based on the signal on the high value side, and the signal of the steam flow rate of the steam turbine is preceded. A control system for controlling the hot water level to follow an increase or a decrease in the power load based on a control signal added as a bias.

According to the present invention, the hot water level of each steam separator is controlled by its control system so as to be a preset hot water level set value of the steam separator. However, the steam obtained from industrial waste heat and geothermal heat has different steam conditions, and the high-pressure, medium-pressure, and low-pressure steam separators convert the steam and hot moisture according to the pressure conditions of each steam. To separate. However, when the heat and moisture rise, the blades of the steam turbine are damaged by erosion. In addition, since the hot water level of each steam separator varies depending on the set value of the electric power load, the deviation between each of these hot water levels and each set value of the high-, medium-, and low-pressure steam separator has a higher priority. The high-pressure, medium-pressure, and low-pressure steam separator hot water levels are controlled based on the control signal added in advance by using the steam flow control signal of the steam turbine as a bias signal to give priority to the high value signal in the circuit. I do. Thereby, erosion of the blades of the steam turbine can be reduced.

According to a fourth aspect of the present invention, in the hot water temperature control system, a deviation signal between a condenser internal temperature and a heat exchanger outlet temperature, and a hot water level control signal are added in advance as bias signals. A control system for controlling the amount of cooling water based on the control signal is provided.

According to the present invention, the temperature of the surplus hot water at the time of controlling the hot water level of the high-, medium-, and low-pressure steam separators is controlled by the control means in accordance with a preset hot-water temperature set value. You. However, this hot water is first heat-exchanged with cooling water from a cooling tower in a heat exchanger and cooled, and then sent to the cooling tower. And the cooling water used in the heat exchanger is
Although sent to the condenser, if the temperature of the cooling water is high, the cooling capacity of the condenser decreases, and the generator output fluctuates due to a decrease in the condenser vacuum.

Therefore, the amount of cooling water in the cooling tower is controlled based on a deviation signal between the inside temperature of the condenser and the temperature at the outlet of the heat exchanger and a control signal to which a hot water level control signal is added in advance as a bias signal. By doing so, the rise in the internal temperature of the condenser is suppressed. Therefore, it is possible to reduce or prevent a decrease in the degree of vacuum of the condenser and a change in the generator output due to the decrease.

According to a fifth aspect of the present invention, there is provided a cooling tower internal temperature control system, comprising: a heat exchanger outlet temperature, a cooling tower internal temperature signal,
A control system for controlling the number of revolutions of the cooling tower fan per unit time based on a control signal to which a level control signal of an excess amount of hot water of the steam separator is added in advance as a bias signal is provided.

According to the present invention, the temperature of the cooling water of the cooling tower is controlled by the control means in accordance with a preset cooling water temperature set value of the cooling tower. However, if the temperature of the cooling water rises due to the cooling of the hot water of the heat exchanger or the condensing cooling of the condenser, the performance of the condenser decreases due to the cooling water, and the generator output Leads to a decrease in

Therefore, the cooling fan of the cooling tower is controlled based on a control signal in which the hot water level control signal, the hot water temperature control signal, the condenser internal temperature and the cooling water temperature deviation signal of the cooling tower are added as bias signals in advance. By controlling the number of rotations of the motor per unit time, a rise in the temperature of the cooling water is suppressed. As a result, it is possible to suppress a decrease in performance due to a rise in the temperature of the condenser and suppress or prevent a decrease in generator output.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG. In these figures, the same or corresponding parts are denoted by the same reference characters.

FIG. 1 is a block diagram of a main part of a power generation control apparatus using waste heat according to one embodiment of the present invention, and FIG. 2 is a system showing an entire configuration of one embodiment of the present invention including main parts shown in FIG. FIG.

As shown in FIG. 2, a power generation control device utilizing waste heat is provided with a waste heat of an industrial plant or waste heat steam obtained from an underground hot water layer or a high-pressure waste heat steam passage for passing waste heat water. 1
a, the medium-pressure exhaust heat steam channel 1b and the low-pressure exhaust heat channel 1c are connected to the high-pressure steam separator 2a, the medium-pressure steam separator 2b, and the low-pressure steam separator 2c, respectively.

High pressure steam separator 2a, medium pressure steam separator 2
b, the low-pressure steam separator 2c separates steam and hot water, and the separated steam passes through a flow path provided with a high-pressure control valve 3a, a medium-pressure control valve 3b, and a low-pressure control valve 3c, respectively. Through the steam header 4.

The steam header 4 is connected to an inlet of a steam turbine 6 through a waste heat steam passage 5, and a flow control valve 7 is interposed in the waste heat steam passage 5. A generator 8 is connected to the rotating shaft of the steam turbine 6 by, for example, a direct connection.
Can be generated by the rotation of.

The steam outlet side of the steam turbine 6 is connected to the exhaust heat passage 9
Is connected to the inlet side of the condenser 10. Condenser 1
0 is a condensate flow path 1 with a condensate pump 11
2 is connected to the condensate inlet of the cooling tower 13.

The cooling tower 13 cools the condensed water introduced therein by the blowing of a cooling tower fan 14 and stores it in a tank of the cooling tower 13.

The cooling water outlet of the cooling tower 13 is connected to the heat exchanger 1 through a cooling water passage 16 provided with a cooling water pump 15.
7 is connected to a cooling water inlet of the heat exchanger 17.
Inside, heat exchange is performed with hot water exiting from the high-pressure steam separator 2a, the medium-pressure steam separator 2b, and the low-pressure steam separator 2c. Here, the outlet of the hot water to be cooled by heat exchange is connected to the hot water inlet of the cooling tower 13 through the cooling channel 18.

The hot water outlets of the high-pressure steam separator 2a, the medium-pressure steam separator 2b, and the low-pressure steam separator 2c are connected to the hot water inlet of the heat exchanger 17 through a waste heat treatment channel 19. I have. On the other hand, the makeup water inlet of the cooling tower 13 is connected to a makeup water flow path 21 provided with a makeup water pump 20 so that makeup water is supplied to the cooling tower 13.

The power generation plant utilizing waste heat configured as described above is provided with the control device 22 shown in FIGS. 1 and 3, while the exhaust heat steam flow path 5 has a flow rate for detecting the waste heat steam flow rate. A detector 23a and a pressure detector 23b for detecting the pressure of the exhaust heat steam are provided. The high, medium, and low pressure steam separators 2a to 2c have high, medium, and low pressure control valves 3a,
3b, 3c and steam pressure detectors 24a, 24b, 24c
And level detectors 25a, 25b, and 25c, respectively.

Further, a hot water level control valve 26 for controlling the flow rate of surplus hot water is provided in the waste heat treatment flow path 19, and a hot water temperature detector for detecting hot water temperature is provided at a hot water outlet side of the heat exchanger 17. 27 are provided. The cooling water flow path 16 and the condensing water flow path 12 are provided with flow control valves 28 and 29, respectively, the cooling tower 13 is provided with a level detector 30 and a temperature detector 31, and the makeup water flow path 2 is provided.
1 is provided with a makeup water flow control valve 32. The condenser 10 has a condenser temperature detector 33a and a condenser level detector 33a.
b is provided.

As shown in FIGS. 1 and 3, the control device 22 includes a flow rate detector 23a, an inlet pressure detector 23b, and a respective steam pressure detector 24a of each of the steam separators 2a to 2c on its signal input side. ~ 24c, each hot water level detector 25a ~ 2
5c, hot water temperature detector 27, cooling tower level detector 30,
The temperature detector 31, the temperature detector 33a of the condenser 10 and the level detector 33b are connected respectively.

On the other hand, the flow control valve 7, the hot water level control valve 26, and the steam separators 2a to 2c are connected to the output side of the control device 22 via the electropneumatic converters 34a, 34b, 34c.
, A cooling water flow control valve 28, a condensed water flow control valve 29, and a make-up water flow control valve 32, and a cooling tower fan 14 through a thyristor switch 35.
Are electrically connected.

The control device 22 includes a steam flow control system,
Steam separator level control system, steam pressure control system, hot water temperature control system at the heat exchanger outlet, water level control system of the condenser 10,
It has a water level control system for the cooling tower 13 and an internal temperature control system for the cooling tower 13.

The steam flow control system is a control system that adjusts the opening of the flow control valve 7 at the inlet of the steam turbine 6 so that the steam flow introduced into the steam turbine 6 becomes a power set value.

That is, the flow rate of the steam flowing through the exhaust heat steam flow path 5 is detected by the flow rate detector 23a, the detection signal is smoothed by the square root calculator 36, and the steam flow rate is calculated by the power calculated by the function of the steam flow rate. The set value is compared with the power setter 37,
The deviation signal is subjected to PID calculation by a PID controller 38 to obtain a control signal. This control signal is further provided to the electropneumatic converter 34a, where the electric signal of the control signal is converted into an air signal. The opening of the pneumatically actuated flow control valve 7 is controlled by this air signal. Thus, the amount of steam flowing into the steam turbine can be controlled by following the power set value of the generator 8.

The steam separator level control system gives priority to the higher value signal among the deviation signals between the hot water level of each of the steam separators 2a, 2b and 2c and the set value of the hot water level, and gives priority to each steam separator. This is a control system for adjusting the hot water level of 2 a to 2 c by adjusting the opening of the hot water level control valve 26.

That is, the waste heat steam flowing through the high-pressure waste heat steam passage 1a is separated into hot water and steam by the high-pressure steam separator 2a, and the hot water is separated by the hot water level detector 25a of the high-pressure steam separator 2a. Is detected. This detection signal is compared with the set value by the level setting unit 39, and the difference signal between the two is input to the high value priority circuit 40.

Similarly, the waste heat steam flowing through the medium pressure waste heat flow path 1b is separated into hot water and steam by the medium pressure steam separator 2b, and the hot water is separated by the hot water level detector 25b of the medium pressure steam separator 1b. Is detected. This detection signal is output from the level setting device 41.
The deviation signal is compared with the set value and the high-value priority circuit 4
Input to 0.

Further, the exhaust heat steam flowing through the low-pressure exhaust heat flow path 1c is separated into hot water and steam by the low-pressure steam separator 2c, and the hot water is detected by the hot water level detector 25c of the low-pressure steam separator 1c. . This detection signal is output from a level setting unit 42.
The deviation signal is compared with the set value and the high-value priority circuit 4
Input to 0.

In the high-value priority circuit 40, the signal on the high value side among these input signals is selected with priority and input to the addition / subtraction operation unit 43. The addition / subtraction operation unit 43 obtains a control signal obtained by adding a signal obtained by biasing the PID operation control signal from the steam flow rate control PID controller 38 by the bias unit 44 to the high value side signal. The control signal is PID-calculated by the PID controller 43a to obtain a control signal.

Further, this control signal is transmitted to the electropneumatic converter 34b.
Converts the electric signal into an air signal. By controlling the opening of the hot water level control valve 26 by this air signal, the corresponding high-pressure, medium-pressure, and low-pressure steam separators 2a to 2a
Control is performed so that the hot water level of c does not exceed the set value.

The steam turbine inlet pressure control system includes a pressure control valve 3a of the high-pressure steam separator 2a, a pressure control valve 3b of the medium-pressure steam separator 2b, and a low-pressure steam separator so that the inlet pressure of the steam turbine 6 becomes a set value. It is a control system for adjusting the opening of the pressure control valve 3c of the vessel 2c.

That is, the detection signal of the inlet pressure detector 23b of the steam turbine 6 is input to the pressure setting device 45, a deviation signal from the pressure setting value is obtained, and the signal is given to the switching device 46. On the other hand, the detection signal of the inlet pressure detector 23b and the detection signal of the high-pressure steam pressure detector 24a are input to the adjustment calculator 47,
The deviation signal is compared by a limiter 48 with a limit value.

When the limit value is α1 or less (−), the signal is switched to the terminal b in the drawing by the switch 46, the detection signal of the inlet pressure detector 23 b is input to the pressure setting device 45, and the deviation signal is added / subtracted. The PID controller 49 inputs a bias signal from the bias unit 44 and then performs a PID operation in the PID controller 50 to obtain a control signal.

The control signal is transmitted to the electropneumatic converter 34c.
Converts the electric signal into an air signal. By controlling the opening degree of the high-pressure control valve 3a for controlling the outlet pressure of the high-pressure steam separator 2a by the air signal, the steam turbine inlet pressure is controlled to follow the set pressure value.

On the other hand, when the inlet pressure deviation of the steam turbine 6 is compared with the set value of the setter 45, the limit value is α1 or more (+)
In the case of, the detection signal of the inlet pressure detector 23b and the detection signal of the steam pressure detector 24b of the intermediate-pressure steam separator 2b are input to the adjustment calculator 51, and the deviation signal is compared with the limit value by the limiter 52. I do.

When the limit value is equal to or smaller than α2, the switch 53
To the terminal b, and the inlet pressure detector 2 of the steam turbine 6
3b is input to the pressure setting device 45, and the deviation signal is input to the addition / subtraction operation unit 54, where the bias unit 44
After adding the bias signal from, a PID operation is further performed by the PID controller 55 to obtain a control signal.

The control signal is transmitted to the electropneumatic converter 34d.
Converts the electric signal into an air signal, and controls the opening degree of the medium-pressure pressure control valve 3b for controlling the outlet pressure of the medium-pressure steam separator 2b by the air signal, thereby setting the steam turbine inlet pressure to a pressure set value. Is controlled by following.

When the inlet pressure deviation of the steam turbine 6 is larger than the set value of the setting device 45 and the limit value is equal to or more than α2, the detection signal of the steam turbine inlet pressure detector 23b is
The detection signal of the steam pressure detector 24c of the low-pressure steam separator 2c is input to an addition / subtraction calculator 56, and the deviation signal is input to a limiter 57.
To compare with the limit value.

When the limit value is equal to or smaller than α3, the switch 58
To the terminal b, and the inlet pressure detector 2 of the steam turbine 6
The detection signal of 3b is input to the pressure setting device 45 to obtain a deviation signal. Further, the deviation signal is input to the addition / subtraction operation unit 59, where the bias signal from the bias unit 44 is added.
An ID operation is performed to obtain a control signal.

The control signal is transmitted to the electropneumatic converter 34e.
Converts the electric signal into an air signal, and controls the opening degree of the low-pressure pressure control valve 3c for controlling the outlet pressure of the low-pressure steam separator 2c according to the air signal so that the steam turbine inlet pressure follows the pressure set value. Let control.

The hot water temperature control system at the heat exchanger outlet has a cooling water flow control valve 28 at the cooling water inlet side of the heat exchanger 17 so that the hot water temperature at the outlet side of the heat exchanger 17 has a set value. Is to adjust the degree of opening.

That is, the detection signal of the hot water temperature detector 27 on the outlet side of the heat exchanger 17 flowing through the waste heat treatment flow path 19 is converted into an electric signal by the temperature converter 61, and this temperature electric signal is converted into a temperature setter 62. And the adder / subtractor 64. Setting device 6
In step 2, the temperature signal is compared with a set value, and the deviation signal is input to the adder / subtractor 63.

On the other hand, the adder / subtractor 64 is a signal obtained by converting the signal converted by the temperature converter 61 into an electric signal and the signal detected by the condensate temperature detector 33a of the condenser 10 into an electric signal by the temperature converter 65. And the deviation of both signals.

Further, this deviation signal is compared with a limit value by a limiter 66, and when this limit value is equal to or more than α4, the deviation signal is used as a bias signal by a bias unit 67 to add / subtract an arithmetic unit 6
3 and a PID controller 38 for controlling the steam flow rate.
A signal obtained by biasing the calculated control signal by the bias unit 44 is added by the addition / subtraction unit 63, and this signal is further added to the PID
The control signal is obtained by performing the PID operation in the controller 68.

The control signal is transmitted to the electropneumatic converter 34f.
The electric signal is converted into an air signal by the air signal, the opening degree of the cooling water flow control valve 28 is controlled by the air signal, and the cooling water flow at the outlet side of the cooling water pump 15 is controlled. by this,
The cooling water amount is adjusted so that the condensing water temperature of the condenser 10 does not rise, and the outlet water temperature of the heat exchanger 17 can be controlled by following the set value.

The condenser level control system is a control system for adjusting the opening of the level control valve 29 at the outlet of the condenser 10 so that the water level of the condenser 10 becomes a set value.

That is, the condensate flowing through the condensate flow path 12
The detection signal from the water level detector 33b of the condenser 10 is compared with the set value by the level setter 69 of the condenser 10 and the deviation signal is given to the addition / subtraction calculator 70.

Further, the addition / subtraction arithmetic unit 70 includes a signal obtained by biasing the control signal PID-calculated by the PID controller 38 for controlling the steam flow rate by the bias unit 44 and a PID controller for controlling the cooling water amount of the heat exchanger 17. 68 to which a signal biased by the bias unit 72 is added to the PID controller 7
3 to obtain a control signal by performing a PID operation.

Then, this control signal is transmitted to the electropneumatic converter 34g.
Converts the electric signal into an air signal. The opening of the pneumatically operated level control valve 29 on the outlet side of the condensate pump 11 is controlled by this air signal. As a result, the condenser water level of the condenser 10 is changed to the electric power load and the steam separators 2a and 2a.
The flow rate of the condensate water can be controlled by following the level set value of the condenser 10 in accordance with the increase or decrease in the exhaust heat levels b and 2c.

The water level control system of the cooling tower 13 is a control system for adjusting the opening of the level control valve 32 of the cooling tower 13 on the outlet side of the makeup water pump 20.

That is, the level detector 30 of the cooling tower 13
Is supplied to the level setting device 74 of the cooling tower 13, where it is compared with the level setting value to obtain a deviation signal. Further, this deviation signal is supplied to an addition / subtraction arithmetic unit 75, where a P for controlling the level of the exhaust heat hot water of the steam separators 2a, 2b, 2c is provided.
A signal obtained by adding a signal biased by the bias unit 76 of the ID adjuster 43a and a bias signal of the bias unit 76 of the PID adjuster 73 of the condenser water level is subjected to PID calculation by the PID adjuster 77 and controlled. Get the signal.

The control signal is transmitted to the electropneumatic converter 34h.
Converts the electric signal into an air signal, and controls the opening of the level control valve 32 of the cooling tower 13 with the air signal.
Accordingly, the level of the cooling tower 13 follows the set value with respect to the increase / decrease of the exhaust heat steam amount of each of the steam separators 2a, 2b, and 2c and the condensed water amount of the condenser 10, so that the replenished water amount is set in advance. Can be controlled.

The internal temperature control system of the cooling tower 13 includes the cooling tower 1
3, the flow rate of the exhaust heat from the cooling flow path 18, the flow rate of the condensed water in the condensate flow path 12, the flow rate of the make-up water flow in the make-up water flow path 21, and the flow rate of the cooling water flow out of the cooling tower 13.
3 is a control system for controlling the number of rotations of the cooling tower fan 14 per unit time so that the in-machine temperature becomes a set value.

That is, the internal temperature detector 3 of the cooling tower 13
The detection signal detected in 1 is converted into an electric signal by the temperature converter 78. Further, the electric signal is given to the temperature setting device 79 and the adjustment calculator 71 of the cooling tower 13, respectively. The temperature setter 79 compares the detected value from the temperature detector 31 with the temperature set value, and provides a deviation signal to the addition / subtraction calculator 80.

In the addition / subtraction unit 80, a temperature setting unit 79
And a bias signal of the addition / subtraction operation signal from the addition / subtraction unit 71 and a bias unit 76 of the PID controller 43a of the PID controller 43a of the exhaust heat water level of the steam separators 2a, 2b, 2c. And a control signal from the cooling water amount control PID controller 68 and a signal biased by the bias unit 72 are added to obtain a control signal.

Then, the control signal is subjected to PID calculation by the PID controller 82 for the temperature inside the cooling tower, and then given to the thyristor switch 35.

Thus, the thyristor 35 controls the number of revolutions per unit time by controlling the current supplied to the cooling tower fan 14, and controls the temperature inside the cooling tower 13 according to the set value.

[0073]

As described above, according to the present invention, the steam flow control system can suppress the fluctuation of the steam flow rate flowing into the steam turbine with respect to the power setting load of the waste heat utilizing power plant. Fluctuations in steam pressure at the steam turbine inlet due to fluctuations in the flow rate and pressure of the exhaust heat steam in the exhaust heat steam passage can be reduced or prevented by the steam pressure control system.

Further, the exhaust heat steam is divided into high-pressure, medium-pressure, and low-pressure steam separators according to steam conditions, and stable pressure control can be performed in accordance with the pressure fluctuation of the steam turbine.
Medium- and low-pressure exhaust heat steam can be stored according to the steam conditions, and the exhaust heat steam can be used effectively.

Further, the hot water level control system gives priority to the hot water level of the high-pressure, medium-pressure, and low-pressure steam separators by a high-priority circuit for the level fluctuation due to the power load fluctuation and the pressure fluctuation. Can be prevented from rising sharply. Also, in order to prevent fluctuations in the condenser's internal temperature due to fluctuations in the flow rate of the residual heat excess steam, a deviation signal between the exhaust heat temperature of the heat exchange of the exhaust heat and the condenser's internal temperature and the level signal of the steam generator are biased. In advance to stably control the inside temperature of the condenser to prevent a decrease in condenser vacuum.

Furthermore, a condenser level control system adds a deviation signal between the amount of cooling water, the temperature at the outlet of the exhaust heat exchanger and the temperature inside the condenser as a bias signal in advance to stabilize the condenser level. Can be controlled.

To prevent fluctuations in the level of the cooling tower, a level control signal for the condenser and a control signal for the hot water level of the steam generator are added in advance as bias signals to stabilize the level of the cooling tower. Can be controlled.

Further, the cooling tower internal temperature control system
The internal temperature of the condenser, the internal temperature deviation signal of the cooling tower, and the cooling temperature signal of the waste heat surplus hot water are each added as a bias signal, and the rotational speed is controlled by controlling the current supplied to the cooling tower fan in advance. This can reduce or prevent the temperature fluctuation inside the cooling tower. Therefore, stable control can be performed by following the set power of the steam turbine generator, and stable control is performed even for transient load fluctuations so that the inlet pressure fluctuation of the steam turbine is minimized. Thus, high-efficiency operation using exhaust heat steam effectively can be achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a main part of a control system of a power generation control device using waste heat according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a power generation plant using waste heat to which the present invention is applied.

FIG. 3 is a schematic diagram showing input and output of the control device shown in FIG. 1;

[Explanation of symbols]

1a, 1b, 1c High, medium, low pressure exhaust heat steam flow path 2a, 2b, 2c High, medium, low pressure steam separator 3a, 3b, 3c Pressure control valve 4 Steam header 5 Waste heat steam flow path 6 Steam turbine 7 Flow control valve 8 Generator 10 Condenser 11 Condenser pump 12 Condenser flow path 13 Cooling tower 14 Cooling tower fan 15 Cooling water pump 16 Cooling water flow path 17 Heat exchanger 18 Cooling flow path 19 Waste heat treatment flow path 20 Make-up water Pump 22 Controller 23a Flow rate detector 23b Inlet pressure detector 24a, 24b, 24c Pressure detector of each steam separator 25a, 25b, 25c Hot water level detector of each steam separator 26 Hot water level control valve 27 Hot water Temperature detector 28 Cooling water flow control valve 29 Condensate flow control valve 30 Cooling tower level detector 31 Temperature detector 32 Makeup water flow control valve 33a Condenser temperature detector 33b Condenser level detector

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F01K 7/24 F01K 7/24 H 27/02 27/02 D F03G 4/00 511 F03G 4/00 511

Claims (5)

[Claims] 1. Low-, medium-, and high-pressure steam separators for separating low-, medium-, and high-pressure exhaust heat steam into steam and hot water, and a steam turbine driven by the steam from the steam separators A generator for generating power by being driven by the steam turbine, a condenser for condensing steam after working in the steam turbine into condensate, and cooling the condensate with a cooling tower fan. In a power generation control device utilizing waste heat, which has a cooling tower that replenishes the cooling water with make-up water while causing heat exchange with hot water from the steam separator and the heat exchanger, the output of the generator is predetermined. A steam flow control system for controlling a flow rate of steam flowing into the steam turbine so as to have a power load set value; and a high-pressure, medium-pressure, and low-pressure control so that an inlet pressure of the steam turbine has a predetermined pressure set value. Each deviation of the outlet pressure of each steam separator is covered. A steam pressure control system for controlling an inlet pressure of the steam turbine based on a control signal added as an EAS signal; and a level deviation for each of the hot water levels of the steam separators to be a predetermined level set value. A hot water level control system for controlling preferentially on the basis of a signal on the high value side, and a temperature set value determined at the outlet of the heat exchanger at a temperature of the excess hot water of each of the high-pressure, medium-pressure and low-pressure steam separators. And a hot water temperature control system for controlling by cooling with the cooling water of the cooling tower, and adding the cooling water amount as a bias signal so that the water level of the condenser becomes a predetermined water level set value. A condenser level control system for controlling the water level of the cooling tower to a predetermined level set value, and a high level of the water level of the high-, medium-, and low-pressure hot water separators. Side signal and the steam And replenishing water control system for controlling the replenishing amount of water to be supplied to the cooling tower based on a flow rate signal to the control signal added as a bias signal,
A cooling tower internal temperature control system that controls the number of rotations of the cooling tower fan per unit time so that the cooling water temperature of the cooling tower becomes a predetermined temperature set value. Power generation control device using waste heat. 2. The steam pressure control system compares the steam pressure deviations of the high-pressure, medium-pressure, and low-pressure steam separators with respective deviation limiters, and when the pressure deviation is large, that is, the steam turbine inlet pressure is set. If the pressure is higher than the value, the pressure is automatically switched to the outlet pressure control of the medium-pressure and low-pressure steam separators based on the comparison signal of the deviation limiter, and the steam turbine inlet pressure is controlled in advance to the set value. On the contrary, when the steam turbine inlet pressure is lower than the set value, the steam turbine inlet pressure is automatically switched to the high pressure / medium pressure steam separator outlet pressure control based on the comparison signal of the deviation limiter. The power generation control device using waste heat according to claim 1, further comprising a control system that controls the pressure to be a set value. 3. A hot water level control system compares a deviation signal between the hot water level of each steam separator and its set value by a high value priority circuit, and preferentially determines the hot water level based on the signal on the high value side. 2. A control system, comprising: a control system for controlling and controlling a hot water level following an increase or a decrease in an electric power load based on a control signal to which a signal of a steam flow rate of a steam turbine is preliminarily added as a bias. Or the power generation control device utilizing waste heat described in 2. 4. A hot water temperature control system based on a deviation signal between a condenser internal temperature and a heat exchanger outlet temperature, and a control signal to which a control signal of a hot water level is added in advance as a bias signal. The power generation control device using waste heat according to any one of claims 1 to 3, further comprising a control system for controlling a cooling water amount. 5. The cooling tower internal temperature control system includes a control in which an outlet temperature of a heat exchanger, a cooling tower internal temperature signal, and a level control signal of a surplus hot water amount of a steam separator are added in advance as a bias signal. 5. The power generation control device utilizing waste heat according to claim 1, further comprising a control system for controlling the number of revolutions of the cooling tower fan per unit time based on the signal.