JPS6033982B2 - Turbine plant control device - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a turbine plant control device, and more specifically, a fluid pressure control device that controls the pressure of fluid flowing out from a fluid pressure source such as a reactor, and a turbine plant control device. A turbine plant control system that works in coordination with the control device to enable the turbine plant to be operated safely even in the face of disturbances to the pressure source and changes in the turbine operating status without any adverse effects on the pressure source. Regarding equipment.

[Prior art]

FIG. 4 shows an example of the configuration of a conventional blast furnace gas energy recovery turbine plant in which a turbine plant is attached to the exhaust gas system of the blast furnace plant.

In the blast furnace plant 1 , exhaust gas from the blast furnace 2 is collected by a dust collector 3 and then sent downstream via a pressure regulating valve 7 . In this case, the furnace top pressure of the blast furnace 2 is detected by the furnace top pressure detector 4, and the furnace top pressure regulator 6 controls the pressure regulating valve 7 so that the pressure is maintained at the value set by the furnace top pressure setting device 5. The opening degree is calculated, and the output signal drives the pressure regulating valve 7 to adjust the opening degree to a desired value, thereby controlling the top pressure of the blast furnace 2. On the other hand, in the energy recovery pin plant 11, high-pressure exhaust gas that has passed through the dust collector 3 is passed through the regulating valve 12 to the turbine 1.
3, and the energy recovered there is converted into energy such as mechanical energy or electric power, and then supplied to the load 14.

In this case, the rotation speed of the output shaft of the turbine 13 is detected by the speed detector 16, and the speed controller 18 calculates and maintains the speed at the value set by the speed setting device 17, and adjusts the speed using the output signal. By driving the speed valve 12, the turbine 1
3 rotational speed is controlled. In such an energy recovery turbine plant, a pressure regulating valve upstream is used to respond to disturbances applied to the blast furnace from the turbine side, including fluctuations in the outflow amount of fluid such as exhaust gas due to charging of blast furnace raw materials and blow-through, and startup and shutdown of the turbine. The disadvantage is that the fluid pressure cannot be maintained at a set value.

Additionally, there is the problem of not being able to direct as much fluid as possible to the turbine to increase energy recovery. [Object of the invention] The present invention was made in view of the above-mentioned problems, and its purpose is to:
By increasing the energy generation rate of turbine plants, it is possible to adjust the gas flow rate led to the turbine even in response to fluctuations in gas flow rate, and in addition, it is possible to prevent abnormal pressure increases in the pressure source due to sudden changes in the turbine. It is an object of the present invention to provide a control device for a turbine plant that can perform the following steps.

More specifically, the first objective is to improve the energy generation efficiency of the turbine even if the pressure of the fluid flowing out from the pressure source is controlled as follows.

■When the turbine is stopped, it is controlled by a "fluid pressure control device using a pressure regulating valve barb pressure regulating valve installed in the flow." ■When the turbine is operating, the pressure regulating valve is kept fully closed, and the entire amount of fluid flowing out from the pressure source is guided to the turbine. Under normal conditions, the regulating valve is fully open, and the variable stator vane is operated as a "turbine-based fluid pressure control device." It is controlled by driving with a control signal from ``. ■When there is a large pressure fluctuation that exceeds the control range of the variable stator vanes, control is performed by driving the speed governor or pressure regulating valve. The second is ``When the turbine is in an abnormal state and a sudden change such as tripping or load shedding occurs, feedforward compensation is calculated from the theoretical valve opening and stator vane angle just before the change occurs. The purpose is to prevent an abnormal pressure rise in the pressure source by generating a signal and opening the pressure regulating valve prior to the rise in pressure in the pressure source. [Structure of the Invention] The features of the present invention are explained in accordance with FIG. To explain, the pressure deviation setting part 31 and the pressure are used to maintain the pressure of the fluid upstream of the pressure regulating valve 7 at a pressure setting value slightly lower than the pressure setting value of the "fluid pressure control device using a pressure regulating valve" 8. a pressure control means 30 having an adjustment section 32; a signal dividing means 40 for dividing the furnace pressure control signal f from the pressure control means; and receiving one of the divided signals and outputting a variable stator vane drive signal v. A stator vane drive signal selection means 50 consisting of a stator vane hand setting section 51 and a signal selection section 52, and a stator vane drive signal selection means 50 for driving the variable stator vane 15 of the turbine with the output signal of this stator vane drive signal selection means. The driving means 25 is provided with a regulating valve drive signal selection means 90 that receives the other divided signal and outputs a regulating valve drive signal G.

In addition to the above-described structure, another invention provides that when the abnormal signal E is issued, the immediately preceding speed governor drive signal G (-0) is stored in the storage means 60, and the pressure is adjusted in response to the abnormal signal E. Valve 7
The feedforward signal calculation setting section 71 and the feedforward signal transmitting section 7 are used to calculate the increase in the opening of the
2 and a feedforward signal calculation means.

〔Example〕

Hereinafter, the present invention will be explained in detail based on examples thereof.

FIG. 2 is a control system diagram of the blast furnace gas energy recovery turbine plant. The furnace pressure regulator 6 of the “fluid pressure control device using a pressure regulating valve” 8 in the blast furnace plant Kawasaki is connected to the blast furnace 2.
The furnace top pressure PB detected by the furnace top pressure detector 4 installed at the top of the blast furnace This is to control the furnace pressure of the blast furnace 2 by driving the pressure regulating valve 7 interposed in a path through which the exhaust gas of the blast furnace 2 can flow.On the other hand, the energy recovery turbine plant 11 is installed in parallel with the pressure regulating valve 7. A turbine 13 having a governor valve 12 and variable stator vanes 15, and a "turbine-based fluid pressure control device" 26 that drives the governor valve 12 and variable stator vanes 15 and controls the fluid pressure upstream thereof. be done.

This "fluid pressure control device using a turbine" 26 includes a pressure control means 30, a signal dividing means 40, a stator vane drive signal selection means 50, a storage means 60, a feedforward signal calculation means 70, a governor valve lock calculation means 80, and a It has governor valve drive signal selection means 90.

The pressure control means 30 that controls the furnace top pressure receives the furnace top pressure setting value PBS set by the furnace top pressure setting device 5 and adjusts the pressure deviation ΔP.
a pressure adjustment section 32 that compares and subtracts this output from the furnace top force PB detected by the furnace top pressure detector 4, and performs calculations such as proportional, integral, and differential calculations. The furnace high pressure control signal from the turbine 13 is outputted to four signal dividing means.

The signal dividing means 4 divides the furnace top pressure control signal into the stator vane automatic control signal 8v and the governor valve automatic control signal OG, and each of them is also connected to the stator vane drive signal selection means 50 and the governor valve lock calculation means 80. This is what is output.

The stator blade drive signal selection means 50 includes a stator blade manual setting section 51 and a signal selection section 52.

The stator vane means setting section 51 has a function of setting the pitch angle of the variable stator vanes 16 to an arbitrary angle. The signal selection unit 52
The stator blade automatic control signal 8v that drives the variable stator blade 15 to the pressure control means 30 up to the output signal and the stator blade manual control signal 8w from the stator blade manual setting section 51 are applied to the stator blade automatic manual switch which is applied from the outside. It has a function of selecting one of them based on the signal C, and also has a function of outputting a signal that holds the stator blade 15 at its pitch angle, in addition to a stator blade hold signal applied from the outside. And, between these signals, the unselected signals always follow the fluctuations of the selected signals and fluctuate, so that there is no shock during the cutting process. Therefore, continuous switching is possible even when the signals av and ow are switched and when the hold signal is applied and released. However, in the normal state, the stationary blade automatic control signal 8v is selected and passed through as is. Storage means 60
'Well, when an abnormality signal E indicating that an abnormality has occurred in the blast furnace plant or the energy recovery turbine plant 11 is issued, the governor valve 1 immediately before the abnormality signal E is issued.
It has a function of storing the governor valve drive layer number G (10) which commands the opening degree of 2.

The feedforward signal calculation means 7 consists of a feedforward signal calculation setting section 71 and a feedforward signal transmission section 72.

The feed forward signal calculation setting section 71 stores the storage means 6.
The output signal G (10) from 0, the governor drive signal G (10) that changed after the abnormal signal E was issued, and the abnormal signal E
When the stator vane drive signal selection means 5 is issued, the stator vane hold signal applied to the stator vane drive signal selector 5 causes the held variable stator vane drive signal v to be input, and the flow rate of the governor valve 12 and the pressure regulating valve 7 is Based on the characteristics, the amount of change in the gas flow rate passing through the turbine 13 before and after the issuance of the abnormal signal E is calculated, and the increase in the opening of the pressure regulating valve 7 corresponding to the amount of change in the gas flow rate is calculated. The feed forward signal transmitting section 72 receives the pressure regulating valve opening setting signal output from the feed forward signal calculation setting section 71 only when the abnormal signal E is issued. It has a function of continuing to output an open signal to the pressure regulating valve 7 until the pressure regulating valve actual pressure signal and the pressure regulating valve actual relationship signal match. When the dovetail valve lock command signal L is received, in addition to cutting off the circuit of the signal aG for controlling the furnace top pressure by the governor valve 12, the signal is fed back from the output side of the governor valve drive signal selection means 90 to the input side. This is to put the circuit flea 2 in a conductive state.

Therefore, it has a function of stopping the furnace pressure control function by the speed regulating valve 12 and at the same time maintaining the opening degree of the speed regulating valve 12. Note that the valve lock command signal is now released when the furnace top pressure PB is restored. The speed control valve drive signal selection means 901 has a low level signal selection function, and has a speed control valve automatic control signal OG.
A speed valve function limit signal fL and a rotation speed control signal N are input. Among these input signals, the lowest signal is automatically selected and output as the governor valve reversal signal G that commands the opening degree of the governor valve 12. The valve function limit signal fL or the rotation speed control signal N is selected only in special operating conditions such as when starting or stopping the energy recovery turbine plant 11. According to the above configuration, the energy recovery turbine plant 11 Control of the turbine plant 11 is performed as follows.

First, we will explain the control of the furnace top pressure.The control of the furnace top pressure here refers to reducing the flow rate of the exhaust gas passing through the pressure regulating valve 7 as much as possible, in order to efficiently recover the energy retained in the blast furnace exhaust gas. The valve is fully opened to supply as much exhaust gas as possible to the turbine 13 via the speed governor 12, and in addition, the pressure drop at the speed governor 12 is kept as low as possible in order to more effectively recover the energy of the exhaust gas supplied to the turbine 13. However, under suitable circumstances, the flow rate should be adjusted using the variable stator vane 15 by fully opening it.Furthermore, for large fluctuations in the exhaust gas flow rate that exceed the control range of the variable stator vane 15, the speed governor valve 12 or the pressure regulating valve should be opened. 7 to supplement the control range. Therefore, in response to fluctuations in the exhaust gas flow rate that occur on the normal blast furnace 2 side, the furnace top pressure is controlled by the variable stator vanes 15, and the governor valve 12 and The pressure regulating valve 7 is kept on standby in a state where its control system is utilized. To describe this operation specifically, the furnace top pressure of the blast furnace 2 of the blast furnace Plato 1 is as follows.
The furnace top pressure PB detected by the furnace top pressure detector 4 constituting the "fluid pressure control device using a pressure regulating valve" 8 is made to match the furnace top pressure set value P set by the furnace top pressure setting device 5. Also, the furnace top pressure regulator 6 is controlled by driving the pressure regulating valve T.

On the other hand, in the "fluid pressure control device using a turbine" 26 of the energy recovery turbine plant 1, the pressure control means 30 is set to the furnace top pressure setting value P set by the furnace top pressure setting device 5.
In response to the unevenness, the pressure deviation △P is set by the pressure deviation setting section 31.
Furthermore, the furnace top pressure PB is reduced in the pressure adjustment section 32.
A fluid pressure control signal for controlling the furnace top pressure due to the turbine blade 3 is outputted by comparing and subtracting it and performing appropriate calculations such as proportionality, integration, and differentiation.

- Next, the signal dividing means 40 divides the fluid pressure control signal into a stator vane automatic control signal 8v and a governor valve automatic control signal 8G.

The former signal stand v is output as a variable stator vane drive signal v via the stator vane drive signal selection means 50, and the stator vane drive signal selection means 25
to drive the variable stator vane 15. On the other hand, the latter signal 8G passes through the governor valve lock calculation means Q and is input to the governor drive signal selection means 9M. Either the stator blade automatic control signal av or the stator blade manual control signal 8w is selected by the stator blade automatic manual switching signal C applied from It is output to the stationary blade drive means 25 as a blade drive signal 8G.The governor valve drive signal selection means 90 selects the governor valve automatic control signal 8G.
In addition, signals such as the governor valve opening limit signal L and the rotation speed control signal fN are input, and the lowest signal among them is automatically selected and output as the governor signal G, and the governor valve 12 is activated. drive

Here, the method of signal division in the signal division means 40 will be described.

As shown in Fig. 3, when the fluid pressure control signal f is in the range from OS to Sfo, a signal is issued to hold the variable stator blade 15 at the specified lower limit position, and the pitch angle of the variable stator blade 15 is maintained at the specified angle. It will be done. Then, a command signal is outputted to the Liao valve 12 to operate the valve in a range from fully open to fully open. Also, foku f mi f
In the max range, a fully open command signal is issued to the speed governor valve 12, and the speed governor valve 12 is held at the fully open position. On the other hand, a command signal from the lower limit to the upper limit is output to the variable stator vane 15. As mentioned above, with respect to the furnace top pressure set value P set by the furnace top pressure setting device 5 of the blast furnace plant, the set value of the furnace top pressure control by the evening bin 13 is due to P irregularity - △P, and ΔP is set to a low value.

Thereby, when the turbine 13 is controlling the furnace top pressure, the pressure regulating valve 7 is automatically kept in a fully closed state, waiting for an increase in the furnace top pressure. Therefore, when the energy recovery turbine plant 11 is in a normal operating state (fo
<fS max), the governor valve 12 is held fully open and the furnace top pressure is controlled by the variable stator blades 15. However, blast furnace 2
The flow rate of exhaust gas discharged from the variable stator vane 1 has decreased abnormally.
If the furnace top pressure still decreases even if 5 reaches the lower limit (0
When ≦≦≦o), the opening degree of the regulating valve 12 is reduced to control the furnace top pressure. On the other hand, if the exhaust gas flow rate increases abnormally due to a phenomenon such as blow-through of the blast furnace 2, and the furnace top pressure still rises even after the variable static love 15 reaches its upper limit, the furnace top pressure setting value may be slightly higher. The pressure regulating valve 7, which is on standby, opens to control the furnace top pressure. In this way, the furnace top pressure control functions of the "fluid pressure control device using a pressure regulating valve" 8 in the blast furnace plant and the "fluid pressure control device using a turbine" 26 in the energy recovery turbine plant 11 cooperate with each other to control the exhaust of the blast furnace. It becomes possible to efficiently recover gas energy and at the same time operate the energy recovery turbine plant 11 in a sufficiently safe manner even in the event of an abnormality such as wind loss or blow-through in the blast furnace plant.

Next, feed forward compensation will be explained.

Blast furnace plant or energy recovery turbine plant 1
There are cases where an abnormality occurs in the turbine 13 and it is necessary to stop the turbine 13 urgently, or it may be necessary to reduce the output of the turbine 13 to an output equivalent to the no-load rated rotation speed. In these cases, it is necessary to rapidly open the pressure regulating valve 7 to release the sudden decrease in the gas flow rate passing through the turbine 13 to keep the furnace top pressure constant. A feed forward compensation signal is issued in order to rapidly open the pressure regulating valve 7 by a predetermined opening degree.
When the abnormal signal E is issued, the stator blade drive signal selection means 60
'The stator vane hold signal day is applied to the variable stator vane 15.
is held at the current angle.

On the other hand, the storage means 60 stores the regulating valve drive signal G (10) immediately before the abnormal signal E is issued. Therefore, in the feed forward signal calculation setting section 71, the drive signal G (10) from the storage means 60 and the governor valve drive signal nG (10) that changed after the issuance of the abnormal signal E are held. A signal such as a variable stator vane drive signal rv is input, and based on the flow characteristics of the governor valve 12 and the pressure regulating valve 7, the amount of change in the gas flow rate passing through the turbine 13 before and after the abnormal signal is issued is calculated. Further, an increase in the function of the pressure regulating valve 7 corresponding to the amount of change in the gas flow rate is calculated, and the opening degree of the pressure regulating valve 7 is set. Note that the feedforward signal transmitter 72 outputs the pressure regulating valve function setting signal a output from the feedforward signal calculation setting section 71 and the pressure regulating valve actual opening only when the abnormal signal E is issued. The closed signal continues to be outputted to the pressure regulating valve 7 until the signal b and the signal b match. Due to the above-described function of the feedforward signal calculation means 70, the pressure regulating valve 7 is opened as soon as possible before a sudden decrease in the gas flow rate passing through the turbine 13 affects the furnace top pressure of the blast furnace 2. This suppresses changes such as an excessive increase in the furnace top pressure PB, and avoids adversely affecting the operation of the blast furnace 2 in the event of an emergency shutdown due to an abnormality in the energy recovery turbine plant 11 or a large load change. Ru.
Next, locking of the speed regulating valve 12 will be explained.

During tapping work in blast furnace 2 or in the event of an abnormality, the furnace top pressure is lowered by simply reducing the air flow rate to the blast furnace without lowering the furnace top pressure set value, and the blast furnace is restarted from the moment work on the blast furnace side is completed. It is required to increase the air flow rate and restore furnace top pressure control. In order for the energy recovery turbine plant 11 to meet this demand during proper operation, the variable stator vanes 15 of the turbine 13 and the governor It is necessary to hold the valve 12 in that position and temporarily stop the furnace pressure control function by the turbine 13. Now, when the valve lock command signal L is issued from the outside, the stator vane hold signal is applied to the stator vane drive signal selection means 5, and the variable stator vane 15 is held at that angle.

On the other hand, the valve lock calculation means 80 switches the path interrupter 81 in response to the valve lock command signal L to cut off the circuit of the signal 8G for controlling the furnace top pressure by the governor valve 12, and the governor valve reversal signal selection means 90 The circuit 82, which is fed back from the output side to the input side, is brought into a conductive state.In this way, the furnace top pressure control function by the governor valve 12 is stopped, and at the same time,
The opening degree of the speed valve 12 is maintained. And the furnace top pressure P
At the time when B is restored, by releasing the valve lock command signal L, the valve 13 smoothly resumes the furnace top pressure control. As explained in detail above, the function of the "fluid pressure control device using a pressure regulating valve" in the blast furnace plant, the function of the "fluid pressure control device using a cylinder" in the energy recovery turbine plant, the feed forward compensation function, The valve lock function that holds the governor valve and variable stator vanes, and the coordination of each of the above functions, make it possible to operate the energy recovery turbine plant efficiently and safely without any negative impact on the operation of the blast furnace plant. Become.

In addition, although the above-mentioned embodiment was explained using a blast furnace gas energy recovery turbine plant as an example, a pressure regulating valve that is generally installed in a fluid flow path and has a function of maintaining the pressure of the fluid at a constant value on the upstream side; The present invention can be applied to all plants in which a turbine having a governor valve and variable stator blades is installed in parallel. [Effects of the Invention] First, in the first invention, the pressure regulating valve is fully closed and all the fluid flow can be guided to the turbine, and since the regulating valve is fully open, there is no throttling loss, and the upstream part of the turbine is The pressure of the fluid can be controlled by manipulating variable stator vanes.

Furthermore, when the amount of fluid flowing into the turbine increases, the variable stator blades reach their upper limit and lose the furnace pressure control function, but the "fluid pressure control device using the pressure regulating valve" waits at a slightly higher pressure setting. Since there is a turbine, fluid pressure control upstream of the turbine is entrusted to it. In this case, since the pressure regulating valve does not operate unless the fluid pressure upstream of the turbine increases slightly, it is possible to allow as much fluid as possible to flow into the turbine within a permissible range of fluid pressure upstream of the turbine. Therefore, it is possible to increase the energy generation rate of the turbine plant, adjust the gas flow rate guided to the turbine even in response to fluctuations in the amount of gas particles, and prevent abnormal pressure increases in the pressure source in response to sudden changes in the turbine. I can do it. The second invention has a feed forward compensation function, and even if a sudden change such as a trip or load interruption occurs, the pressure regulating valve can be opened before the pressure of the pressure source increases. Abnormal pressure rise in the pressure source is prevented.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the mechanical structure of the present invention, Fig. 2 is a control system diagram of a blast furnace gas energy recovery turbine plant which is an embodiment of the present invention, and Fig. 3 shows the control system for a blast furnace gas energy recovery turbine plant that is an embodiment of the present invention. A state diagram in which the signal is divided into a stationary blade automatic control signal and a governor valve automatic control signal, and FIG. 4 is a system diagram of a normal blast furnace gas energy recovery turbine plant. 7... Pressure regulating valve, 8... Fluid pressure control device using pressure regulating valve, 11... Energy recovery turbine plant, 12... Tuning valve, 13... Turbine , 15... variable stator vane, 25... stator vane driving means, 26
...Fluid pressure control device using a turbine, 30...
... Pressure control means, 31 ... Pressure deviation setting section, 3
2...Pressure adjustment section, 40...Signal dividing means, 5
0...Stator blade drive signal selection means, 51...Stator blade manual setting unit, 52...Signal selection unit, 60...
. . . storage means, 70 . . . feedforward signal calculation means, 71 . . . feedforward signal calculation setting section, 72 . . . feedforward signal transmission section,
90...Governing valve drive signal selection means, f...Fluid pressure control signal, Rv...Variable stator vane drive signal, R
...Governor valve reversal signal, E...Abnormal signal. Figure 1 Figure 3 Figure 2 Figure 4

Claims (1)

[Claims] 1. A pressure regulating valve installed in a fluid flow path, and a "pressure regulating valve" for driving the pressure regulating valve and maintaining the pressure of the liquid upstream of the pressure regulating valve at a set value. “Fluid pressure control device”
, a turbine having a speed governor valve and variable stator blades installed in parallel with the pressure regulating valve, and a turbine that drives the speed governor valve and the variable stator blades to control fluid pressure on their upstream side. In a turbine plant consisting of a "fluid pressure control device", the pressure of the fluid upstream of the pressure regulating valve is maintained at a pressure setting value that is slightly lower than the pressure setting value of the "fluid pressure control device using the pressure regulating valve". a pressure control means having a pressure deviation setting section and a pressure adjustment section; a signal dividing means for dividing the furnace top pressure control signal from the pressure control means; In order to output a blade drive signal, a stator blade drive signal selection means consisting of a stator blade manual setting section and a signal selection section, and a static drive that drives the variable stator blade of the turbine using the output signal of the stator blade drive signal selection means. and governor valve drive signal selection means for receiving the other divided signal and outputting a governor valve drive signal. 2. A pressure regulating valve installed in a fluid flow path, and a "fluid pressure control device using a pressure regulating valve" that drives the pressure regulating valve and maintains the pressure of the fluid upstream of the pressure regulating valve at a set value.
, a turbine having a speed governor valve and variable stator blades installed in parallel with the pressure regulating valve, and a turbine that drives the speed governor valve and the variable stator blades to control fluid pressure on their upstream side. In a turbine plant consisting of a "fluid pressure control device", the pressure of the fluid upstream of the pressure regulating valve is maintained at a pressure setting value slightly lower than the pressure setting value of the "fluid pressure control device using the pressure regulating valve". a pressure control means having a pressure deviation setting section and a pressure adjustment section; a signal dividing means for dividing a furnace top pressure control signal from the pressure control means; In order to output a blade drive signal, a stator blade drive signal selection means consisting of a stator blade manual setting section and a signal selection section, and a stator blade drive that drives the variable stator blade of the turbine using the output signal of the stator blade drive signal selection means. means, a governor valve drive signal selection means for receiving the other divided signal and outputting a governor valve drive signal, and a storage means for storing the immediately preceding governor valve drive signal when an abnormal signal is issued. , a feedforward signal calculation means comprising a feedforward signal calculation setting section and a feedforward signal transmission section for calculating an opening degree increment of the pressure regulating valve in response to the abnormal signal; A turbine plant control device comprising: