JPH05118203A - Power generation control device in exhaust heat utilization system - Google Patents

Abstract

PURPOSE:To enable the compensation control for a secondary delay in advance in relation to a load change by detecting the temperature pressure and the like of respective parts in the respective systems of exhaust heat, medium and cooling and adjusting the respective flow rate after a comparative calculation with respective set values. CONSTITUTION:In relation to an electric power load setting, a flow rate adjust valve 16 is controlled by the result added/subtracted a bias signal (a) based on the exhaust heat temperature deviation between the entrance/exit of an evaporator 5 and a bias signal (b) based on the medium temperature deviation between the entrance of a hotwell tank 11/the exit of the evaporator 5 to/from the deviation signal between the set value and the exhaust heat flow rate. In relation to the gas pressure setting of a medium, a pressure adjust valve 24 is controlled by the result added/subtracted a bias signal (c) based on the exhaust heat flow rate deviation to/from the deviation signal between the set value and the medium pressure of the evaporator 5. In relation to a medium level setting, a level adjust valve 23 is controlled by the result added/subtracted the signal (c) to/from the deviation signal between the set value and the level of the evaporator 5. Further in relation to the medium temperature setting, a flow rate control valve 25 is controlled by the result added/subtracted the signal (c) to/from a bias signal (d) based on the deviation between a temperature in the tank 11 and an exhaust gas temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust heat utilization system power generation control device utilizing high temperature hot water and exhaust heat and a low boiling point medium.

[0002]

2. Description of the Related Art Generally, an exhaust heat utilization system power generation control device utilizes exhaust heat generated in an industrial production process or the like, and uses the exhaust heat of the low boiling point medium exchanged with this exhaust heat to generate an outlet pressure of a medium turbine power generator. It controls for the machine set load.

In this type of control device, the medium flow rate is controlled with respect to the exhaust heat temperature fluctuation, and the inlet pressure of the medium turbine is controlled by the pressure adjusting valve of the medium turbine bypass piping system. Next, the flow rate of the cooling water is controlled so that the exhaust gas spent for driving the medium turbine generator has a specified value in the condenser. In the electric power load control of an exhaust heat utilization power plant, basically, the maximum power is operated, and the output of the medium turbine generator fluctuates due to fluctuations in the exhaust heat flow rate, temperature fluctuations, evaporation pressure of the medium in the evaporator, and the like.

[0004]

However, the above-mentioned conventional control device has the following problems.

First, when the exhaust heat flow rate and exhaust heat temperature of the primary system fluctuate during power load control, the output of the turbine generator is greatly influenced by the heat exchange performance of the preheater and the performance of the evaporator. It In other words, the medium evaporation amount level of the evaporator fluctuates due to the transient exhaust heat flow rate and temperature fluctuation,
Along with this, the vaporized gas pressure of the medium also fluctuates significantly. Therefore, there is a problem that the inlet flow rate and pressure of the medium turbine fluctuate, and the output of the medium turbine generator fluctuates significantly.

Secondly, as the load of the medium turbine generator fluctuates, the exhaust gas spent for driving the medium turbine becomes a transient flow rate and temperature fluctuation, and the cooling temperature of the medium also fluctuates due to the secondary delay of the condenser. To do. In this way, with the transient changes in exhaust heat temperature and exhaust gas flow rate, the flow rate of the medium flow rate for heat exchange fluctuates, which causes a secondary delay when heat is exchanged in the preheater and the evaporator. There is a problem that the output fluctuates and the control system becomes unstable.

Therefore, the present invention reduces the cause of the secondary delay of the heat exchanger due to the exhaust heat temperature and flow rate fluctuations of the exhaust heat system, the medium temperature and flow rate fluctuations of the medium system, and supplies the exhaust heat of the medium turbine and the condenser. It is an object of the present invention to provide an exhaust heat utilization system power generation control device capable of preventing the output fluctuation of the medium turbine generator by reducing the secondary delay factor of the condenser when exchanging heat with the generated cooling water.

[0008]

According to the present invention, high-temperature hot water and exhaust heat are supplied to an evaporator and a preheater by an exhaust heat pump, and an exhaust heat system for exchanging heat with a medium and a heat exchange in the evaporator. The supplied medium gas is supplied to the medium turbine, the exhaust gas of the medium turbine is cooled by the condenser and collected in the hot well tank, and the medium is supplied to the preheater and the evaporator by the medium pump and circulates. In the exhaust heat utilization system power generation control device that controls the power generation plant consisting of the cooling water system that cools the exhaust gas of the medium turbine with the cooling water by the condenser, the flow rate detector that detects the exhaust heat flow rate of the exhaust heat system, and the evaporation A first temperature detector for detecting the exhaust heat temperature at the inlet of the evaporator and a second temperature detector for detecting the exhaust heat temperature at the outlet of the evaporator
Temperature detector and a first flow rate control valve for adjusting the exhaust heat flow rate are arranged in the exhaust heat system, and a third temperature detector for detecting the temperature inside the hot well tank and an evaporator for the medium system are arranged. Temperature detector for detecting the inlet temperature of the evaporator, a pressure detector for detecting the pressure at the outlet of the evaporator, a pressure control valve for adjusting the pressure at the outlet of the evaporator, and a level for detecting the level of the evaporator A detector and a level control valve to control the level of the evaporator,
A fifth temperature detector for detecting the exhaust gas temperature of the medium turbine is arranged in the medium system, and further, a second flow rate control valve is arranged in the cooling water system to output a generator power setting signal of the medium turbine. Of the power setting means for calculating the deviation between the power setting signal and the detection signal of the flow rate detector and outputting the deviation signal, and the detection signal of the first temperature detector and the detection signal of the second temperature detector. The difference is calculated, and the first signal is calculated based on the calculated signal.
First bias setting means for outputting the bias signal of
Deviation between the power setting means and the second bias setting means that calculates the difference between the detection signal of the third temperature detector and the fourth temperature detector and outputs the second bias signal based on this calculated value. A first addition / subtraction means for adding / subtracting the signal, the first bias signal, and the second bias signal, and an output signal of the first addition / subtraction means are input to open / close the first flow rate control valve to discharge the first flow control valve. A first control means including a control calculation means for outputting a control signal for controlling the heat flow rate; and a medium pressure setting signal for the evaporator, which outputs the medium pressure setting signal and the detection signal for the pressure detector. The pressure setting means for calculating the deviation and outputting the deviation signal, the third bias setting means for outputting the third bias signal based on the output signal of the first addition / subtraction means, the deviation signal of the pressure setting means and the third Second addition and subtraction with the bias signal of 3 Evaporation control means for inputting an output signal of the second addition / subtraction means and a control calculation means for opening / closing the pressure control valve to control the medium pressure; and evaporation. Output the medium level setting signal of the container, calculate the deviation between the medium level setting signal and the detection signal of the level detector, and output the deviation signal, and the deviation signal of the level setting means and the third signal. It comprises a third addition / subtraction means for adding / subtracting the bias signal, and a control calculation means for inputting the output signal of the third addition / subtraction means to open / close the level control valve and output a control signal for level control. A third control means, a temperature setting means for outputting a temperature setting signal of the hot well, calculating a deviation between the temperature setting signal and a detection signal of the third temperature detector, and outputting a deviation signal; Three Deviation between the temperature setting means and the fourth bias setting means for calculating the difference between the detection signal of the temperature detector and the detection signal of the fifth temperature detector and outputting the fourth bias signal based on the calculated signal. A fourth adding / subtracting means for adding / subtracting the signal, the third bias signal and the fourth bias signal, and an output signal of the fourth adding / subtracting means to open and close the second flow rate control valve to control the temperature. And a fourth control means composed of a control calculation means for outputting the control signal.

[0009]

With the above structure, first, the first control means opens and closes the flow rate control valve to control the exhaust heat flow rate by following the power set value. In this state, when the system process fluctuates, the first bias signal based on the deviation signal between the first temperature detector at the evaporator inlet and the second temperature detector at the evaporator outlet of the exhaust heat system A second bias signal based on a third temperature detector in the hot well tank device of the medium system and a deviation signal of the fourth temperature detector at the inlet of the evaporator is preceded by the first addition / subtraction means. Added. This compensates for the secondary delay when heat is exchanged in the evaporator and the preheater, follows the set power of the steam turbine generator, and the opening degree of the fourth exhaust heat flow control valve at the preheater outlet is adjusted. It is controlled to the set value.
Next, the second control means opens and closes the pressure control valve to control the pressure so as to reach the pressure set value. In this state, when the process of the system fluctuates, the third bias signal based on the output signal of the first addition / subtraction means is added to the second addition / subtraction means in advance. Therefore, the evaporator and the preheater follow the set value of the gas pressure to control the opening of the pressure control valve to the set value. Next, the third control means opens and closes the level control valve to control the level of the evaporator to the level set value. When a variation occurs in the process of the system, the third bias signal based on the output signal of the first addition / subtraction means is added to the third addition / subtraction means in advance.
Therefore, the secondary delay when heat is exchanged by the evaporator and the preheater is compensated, the medium level of the evaporator follows the set value, and the opening of the level control valve at the preheater inlet becomes the set value. Controlled. Next, the fourth control means opens and closes the second flow rate control valve to control the temperature of the hot well to the temperature set value. When the process of the system fluctuates, a fourth bias signal and a fourth bias signal based on a deviation signal between the fifth temperature detector detecting the exhaust gas temperature and the third temperature detector detecting the temperature inside the hot well tank device The bias signal of 3 is applied to the fourth adding / subtracting means in advance. Therefore, the medium cooling temperature is controlled to a specified value, and the opening of the second flow rate control valve at the condenser inlet is controlled so that the temperature inside the hot well tank device becomes the set value. Therefore, the secondary delay of heat exchange of the evaporator, preheater, and condenser is compensated in advance by following the power load setting of the medium turbine, and the transient exhaust heat flow rate and temperature fluctuation, low boiling point medium Stable control can be achieved against fluctuations in flow rate and temperature, cooling water temperature, and cooling water flow rate.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall system diagram of an exhaust heat utilization system power generation control device showing an embodiment of the present invention. This system comprises an exhaust heat system 1, a medium system 2, and a cooling water system 3.

In the exhaust heat system 1, high-temperature hot water and exhaust heat are supplied by the exhaust heat pump 4, heat-exchanged with the medium in the evaporator 5, and then flow to the preheater 6 for further heat exchange. In the medium system 2, the medium is supplied to the preheater 6 by the medium pump 7, where heat is exchanged with the high-temperature hot water and the exhaust heat, and further, the medium is supplied to the evaporator 5 and the high-temperature hot water and the exhaust heat and the heat are exchanged. The exchanged medium gas is supplied to the medium turbine 8 so that the generator 9
And then the medium gas flows into the condenser 10 and is heat-exchanged with the cooling water to become a medium to become the hot well tank 11
Are collected and circulated. Further, the medium gas bypasses the turbine bypass system 12 under a predetermined condition. The cooling system 3 causes cooling water to flow through the condenser 10. As the medium, a substance with a low boiling point such as CFC is used.

The exhaust heat system 1 includes a flow rate detector 13,
A temperature detector 14, a temperature detector 15, and a flow rate control valve 16 are arranged, and these are connected to the control device 17 shown in FIG. The medium system 2 includes a level detector 18, a pressure detector 19, a temperature detector 20, a temperature detector 21, and a temperature detector 2.
2. A level control valve 23 and a pressure control 24 are arranged, which are connected to the control device 17. In the cooling system 3,
A regulating valve 25 is arranged and connected to the control device 17.

In the present embodiment, first, as a first control means, a deviation signal from the exhaust heat flow rate of the exhaust heat system 1 with respect to the setting of the electric power load of the generator 9 is preceded by the inlet / outlet of the evaporator 5. The first bias signal a based on the exhaust heat temperature deviation signal at the outlet and the second bias signal b based on the medium temperature deviation signal at the inlet / evaporator 5 outlet of the hot well tank 11 of the medium system 2 are added and subtracted, These addition / subtraction deviation signals are input to the PID controller 29 as exhaust heat flow rate deviation signals for controlling the opening / closing of the flow rate control valve 16.

As a second control means, the deviation signal from the medium pressure of the evaporator 5 with respect to the evaporative gas pressure setting of the medium of the evaporator 5 is preceded by the exhaust heat flow rate deviation signal of the first control means. The third bias signal c based on the above is added and subtracted, and these added and subtracted deviation signals are input to the PID controller 42 as pressure deviation signals for controlling the opening and closing of the pressure adjusting valve 24.

As the third control means, the deviation signal from the medium level of the evaporator 5 with respect to the level setting of the medium level in the evaporator 5 is preceded by the exhaust heat flow deviation of the first control means. The third bias signal c based on the signal is added / subtracted, and the added / subtracted deviation signal is input to the PID controller 46 as a level deviation signal for controlling the opening / closing of the level adjusting valve 23.

As a fourth control means, the hot well tank 11 is set for the medium temperature setting of the hot well tank 11.
A deviation signal from the medium temperature of the first bias signal based on the deviation signal of the medium temperature signal of the hot well tank 11 and the deviation signal of the exhaust gas temperature signal of the medium turbine 8 in advance, and the deviation signal of the first control means. A third bias signal c based on the exhaust heat flow rate deviation signal is added / subtracted, and the adjusted deviation signal is input to the PID controller 53 as a temperature deviation signal for controlling the opening / closing of the flow rate control valve 25 of the cooling water system 3. I am trying.

With the above structure, first, the exhaust heat flow rate of the exhaust heat system 1 is controlled by the first control means of the controller 17 as follows.

In the control device 17, the detection signal of the flow rate detector 13 is converted into a linear signal by the square root calculator 26, and this signal is compared by the power setting device 27. This deviation signal is applied to the addition / subtraction calculator 28. Further, the addition / subtraction calculator 28 is
The following first bias signal and second bias signal are input, added / subtracted by the reference symbols, and input to the PID controller 29.

That is, in the addition / subtraction calculator 32, the temperature detector 1
A signal obtained by converting the detection signal of No. 4 into a current signal by the temperature converter 30 and the detection signal of the temperature detector 15 by the temperature converter 31.
The signal converted into the current signal is added / subtracted by this, and this addition / subtraction calculation signal is applied to the first bias signal a by the bias unit 33.
This signal is input to the addition / subtraction calculator 28.
Further, in the addition / subtraction calculator 34, a signal obtained by converting the detection signal of the temperature detector 22 at the inlet of the evaporator 5 into a current signal by the temperature converter 35 and the temperature detector 2 of the hot well tank 11
A signal obtained by converting the detection signal of 0 into a current signal by the temperature converter 36 is subjected to addition / subtraction calculation, and this addition / subtraction calculation signal is input to the addition / subtraction calculator 28 as the second bias signal b by the bias device 37.

The PID controller 29 is the electropneumatic converter 3.
At 8, the current signal is converted into an air signal to control the opening of the flow rate control valve 16 at the outlet of the preheater 6. As a result, the exhaust heat flow rate is controlled by following the power set value of the generator 9 of the medium turbine 8.

Next, in the second control means, the detection signal of the pressure detector 19 at the outlet of the evaporator 5 of the medium system 2 is compared with the pressure set value of the pressure setter 39, and the deviation signal is added / subtracted by the addition / subtraction calculator 40. Added to. Further, the third bias signal c from the bias setter 41 is applied to the addition / subtraction calculator 40. The third bias signal c is set by the bias setter 41 based on the exhaust heat flow rate deviation signal of the addition / subtraction calculator 28.

The output signal of the adder / subtractor 40 is the PID
The control signal is input to the controller 42 and the control signal is input to the electropneumatic converter 43.
Is converted into an air signal, and the pressure is adjusted by controlling the opening / closing of the pressure adjusting 24 of the turbine bypass system 12.

Next, in the third control means, the detection signal of the level detector 18 of the evaporator 5 is compared with the medium level set value in the evaporator 5 by the level setter 44, and the deviation signal thereof is adjusted. Is added to the container 45. Further, the addition / subtraction calculator 45
The third bias signal c is input to. The output signal of the adder / subtractor calculator 45 is input to the PID controller 46,
The control signal is converted into an air signal by the electropneumatic converter 47,
The level of the evaporator 5 is controlled by increasing or decreasing the opening degree of the level control valve 23.

Next, in the fourth control means, the signal obtained by converting the detection signal of the temperature detector 20 of the medium of the hot well tank 11 by the temperature converter 36 is the medium temperature set value of the hot well tank of the temperature setter 48. The temperature deviation signal is added to the addition / subtraction calculator 49. Further, the addition / subtraction calculator 49
The third bias signal c and the next fourth bias signal d are input to the.

That is, the addition / subtraction calculator 50 has a current signal obtained by converting the detection signal of the medium temperature detector 20 of the hot well tank 11 by the temperature converter 36 and a detection signal of the temperature detector 21 at the outlet of the medium turbine 8. Is added to the current signal converted by the temperature converter 51, and this addition / subtraction calculation signal is used as the fourth bias signal d by the bias device 52.

The output signal of the addition / subtraction calculator 49 is P
The control signal is input to the ID controller 53 and the control signal is sent to the electropneumatic converter 54.
Is converted into an air signal, and the amount of cooling water in the cooling water system 3 is controlled by the flow rate adjusting valve 25 by increasing or decreasing the opening degree.

In this way, the first control means is based on the deviation between the temperature at the evaporator inlet and the temperature at the evaporator outlet of the drainage system in the control of making the exhaust heat flow rate of the exhaust heat system follow the power load setting. Second based on the first bias signal and the deviation between the temperature inside the hot well tank of the medium system and the temperature at the outlet of the preheater
And the bias signal of 1 are added as bias signals in advance. This compensates for the secondary delay when heat is exchanged in the evaporator and preheater. Therefore, the electric power of the turbine generator transiently follows the load change and is stably controlled.

In the second control means for controlling the medium pressure of the medium system, the third bias signal based on the exhaust heat flow rate deviation signal is added in advance to the deviation of the medium pressure control system. This compensates for the secondary delay when heat is exchanged in the evaporator and preheater. Therefore, it is possible to perform stable control by following transient changes in the vaporized gas pressure of the evaporator.

In the third control means for controlling the medium level in the evaporator, the third bias signal based on the exhaust heat flow rate deviation signal is added to the deviation of the medium level in advance.
This compensates for the secondary delay when heat is exchanged in the evaporator and preheater. Therefore, the medium level of the evaporator can follow the set value and be stably controlled.

In the fourth control means for controlling the amount of cooling water at the condenser inlet of the cooling water system, the third bias signal based on the exhaust heat flow rate deviation signal, the exhaust gas temperature at the medium turbine outlet, and the internal temperature of the hot well tank are used. And a fourth bias signal based on the deviation between and are added to the cooling water system temperature deviation in advance.
Thereby, the medium cooling water temperature can follow the transient fluctuation of the medium gas amount.

Therefore, by following the power load setting of the medium turbine, the secondary delay amount during heat exchange of the evaporator, preheater and condenser is compensated in advance, and the transient exhaust heat flow rate and temperature fluctuation, Stable control can be achieved against fluctuations in low boiling point medium flow rate and temperature, cooling water temperature, and flow rate.

[0033]

As described above, according to the present invention, it is possible to prevent the medium evaporation pressure of the evaporator from fluctuating due to the exhaust heat flow rate of the evaporator to the exhaust heat system and the temperature change with respect to the power setting load. Further, control is performed so as to prevent fluctuation due to secondary delay at the time of exhaust heat in the preheater and heat exchange of the medium, and to prevent transient load fluctuation. As a result, control can be achieved by following the set power of the medium turbine generator, and fluctuations in the inlet pressure of the medium turbine can be minimized. Therefore, by improving the heat exchange rates of the condensers of the exhaust heat system, the medium system, and the cooling water system, it is possible to stably control transient load fluctuations and operate with high efficiency.

[Brief description of drawings]

FIG. 1 is an overall system diagram of an exhaust heat utilization system power generation control device showing an embodiment of the present invention.

FIG. 2 is a block configuration diagram of the control device in FIG.

[Explanation of symbols]

 13 Flow Rate Detector 14 Temperature Detector 15 Temperature Detector 16 Flow Rate Control Valve 17 Control Device 18 Level Detector 19 Pressure Detector 20 Temperature Detector 21 Temperature Detector 22 Temperature Detector 23 Level Control Valve 24 Pressure Control Valve 25 Flow Rate Control Valve 27 Electric power setting device 28 Adjusting / calculating device 39 Pressure setting device 40 Adjusting / calculating device 44 Level setting device 45 Adjusting / calculating device 48 Temperature setting device 49 Adjusting / calculating device

Claims (1)

[Claims] 1. An exhaust heat system in which high-temperature hot water and exhaust heat are supplied to an evaporator and a preheater by an exhaust heat pump to exchange heat with a medium, and a medium gas heat-exchanged in the evaporator is supplied to a medium turbine. The exhaust gas of the medium turbine is cooled in the condenser and recovered in the hot well tank, and the medium is supplied to the preheater and the evaporator by the medium pump and circulates, and the condenser in the medium system. In the exhaust heat utilization system power generation control device for controlling a power plant comprising a cooling water system for cooling exhaust gas of a medium turbine with cooling water, a flow rate detector for detecting an exhaust heat flow rate of the exhaust heat system, and an evaporator A first temperature detector for detecting the exhaust heat temperature at the inlet, a second temperature detector for detecting the exhaust heat temperature at the outlet of the evaporator, and a first flow rate control valve for adjusting the exhaust heat flow rate In front A third temperature detector which is arranged in an exhaust heat system and detects an internal temperature of the hot well tank; a fourth temperature detector which detects an inlet temperature of the evaporator of the medium system; and an evaporator. Detector for detecting the pressure at the outlet of the evaporator, a pressure control valve for adjusting the pressure at the outlet of the evaporator, a level detector for detecting the level of the evaporator, and a level adjustment for adjusting the level of the evaporator A valve and a fifth temperature detector for detecting the exhaust gas temperature of the medium turbine are arranged in the medium system, and a second flow control valve is arranged in the cooling water system, and the generator of the medium turbine is arranged. A power setting signal that outputs a power setting signal, calculates a deviation between the power setting signal and the detection signal of the flow rate detector, and outputs a deviation signal, a detection signal of the first temperature detector, and the second temperature detector. The difference with the detection signal of the temperature detector of And calculating a difference between the first bias setting means for calculating and outputting the first bias signal based on the calculated signal, the detection signal of the third temperature detector and the fourth temperature detector, Second bias setting means for outputting a second bias signal based on the calculation signal, and a first bias signal for adding / subtracting the deviation signal of the power setting means, the first bias signal, and the second bias signal. A first addition / subtraction means, and a control calculation means for inputting an output signal of the first addition / subtraction means to output a control signal for opening / closing the first flow rate control valve to control the exhaust heat flow rate And a pressure setting means for outputting a medium pressure setting signal of the evaporator, calculating a deviation between the medium pressure setting signal and a detection signal of the pressure detector, and outputting a deviation signal. Based on the output signal of the adder / subtractor of And a third bias setting means for outputting a third bias signal, a second addition / subtraction means for adding / subtracting the deviation signal of the pressure setting means and the third bias signal, and an output of the second addition / subtraction means. A second control means comprising a control calculation means for inputting a signal to open and close the pressure control valve to control the medium pressure, and to output a medium level setting signal for the evaporator, A level setting means for calculating a deviation between the medium level setting signal and the detection signal of the level detector and outputting the deviation signal, and a third for adding / subtracting the deviation signal of the level setting means and the third bias signal. Of the third addition and subtraction means and a control calculation means for inputting an output signal of the third addition and subtraction means and outputting a control signal for opening and closing the level control valve to perform level control. And a temperature setting means for outputting a temperature setting signal of the hot well, calculating a deviation between the temperature setting signal and a detection signal of the third temperature detector, and outputting a deviation signal, and the third temperature. The fourth bias setting means for calculating the difference between the detection signal of the detector and the detection signal of the fifth temperature detector, and outputting the fourth bias signal based on the calculated signal, and the temperature setting means. Fourth addition / subtraction means for adding / subtracting the deviation signal, the third bias signal, and the fourth bias signal, and an output signal of the fourth addition / subtraction means are input to open / close the second flow rate control valve. An exhaust heat utilization system power generation control device comprising: a fourth control unit including a control calculation unit that outputs a control signal for temperature control.