JP2006274805A - Control system of furnace gas recovery turbine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control system of a furnace gas recovery turbine capable of instantaneously and optimally reducing the inflow of flue gas to the turbine when a load is cut off or the turbine is tripped without requiring a tremendously large equipment cost. <P>SOLUTION: In this control system of the furnace gas recovery turbine 1 having stators 2 and 3 and rotatingly driven by the flue gas of a blast furnace 51 to rotatingly drive a generator 81, at least one stage 3 of the second stage and after of the stators comprises angle variable mechanisms 34, 38, and 40 and is closed to its roughly flow passage full closure angle when the load of the turbine is cut off and/or the turbine is tripped. The first stage stator 2 comprises angle variable mechanisms 33, 37, and 39 and is desirably closed to a prescribed angle set to the opening side more than the flow passage full closure angle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control system for a furnace top pressure recovery turbine.

  Conventionally, in a furnace top pressure recovery turbine formed by providing a turbine plant in an exhaust gas path of a blast furnace plant, as shown in FIG. 8, exhaust gas exhausted from the blast furnace 100 is converted into a dust catcher 101, a wet dust collector 102, an inlet block. The turbine 105 is rotated by being guided to the turbine 105 through the stop valve 103 and the emergency shutoff valve 104. The turbine 105 rotates the generator 108 for use in power generation.

  In this furnace top pressure recovery turbine, in order to prevent overspeed of the turbine 105 when the load of the generator 108 is cut off or when a turbine trip occurs due to a failure or the like in the turbine 105, the turbine 105 It is necessary to reduce the exhaust gas flowing into the water instantaneously. As a method for instantaneously reducing the exhaust gas flowing into the turbine 105, the angle variable mechanism 107 is provided in the first stage stationary blade 106 of the turbine 105, and the first stage stationary blade 106 is instantaneously closed to the fully closed angle of the flow path, thereby causing the flow of the turbine 105. Some throttle the path, thereby reducing the exhaust gas flow into the turbine 105.

In addition, as shown in FIG. 9, there is a type in which a governing valve 112 is provided between the emergency shutoff valve 110 and the turbine 111, and the regulating valve 112 reduces the inflow of exhaust gas into the turbine 111. Such an exhaust gas inflow blocking system to the turbine 111 by the speed control valve 112 is also disclosed in various documents (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 60-32942 (FIG. 1)

  However, in the conventional control system for the furnace top pressure recovery turbine described above, the angle variable mechanism 107 is provided in the first stage stationary blade 106 of the former turbine 105, and the first stage stationary blade 106 is instantaneously closed to the fully closed channel angle. In the method of narrowing the flow path 105, both wet and dry furnace top pressure recovery turbines tend to partially adhere to the back surface 106a of the first stage stationary blade 106, as shown in FIG. The dust adhering to the back surface 106a cannot close the first stage stationary blade 106 to the fully closed angle of the flow path, and the exhaust gas flowing into the turbine 105 cannot be reduced to a predetermined flow rate. In addition, there is a problem that the first stage stationary blade 106 and the angle variable mechanism thereof are damaged when the first stage stationary blade 106 bites dust.

  The latter method of reducing the exhaust gas inflow to the turbine 111 by the speed control valve 112 has no particular problem in terms of reducing the exhaust gas inflow to the turbine 111, but it is very difficult to install the speed control valve. There is a problem that a large equipment cost is required.

  The present invention has been made to solve such problems, and a furnace capable of instantaneously and optimally reducing the inflow of exhaust gas to the turbine at the time of load interruption or turbine trip without requiring a large equipment cost. It is an object of the present invention to provide a control system for a top pressure recovery turbine.

  In order to solve the above-mentioned problems, the means adopted by the present invention is a control system for a furnace top pressure recovery turbine having a plurality of stages of stationary blades and rotatingly driven by exhaust gas from a blast furnace to rotate a generator. At least one stage after the second stage of the blades is to have an angle variable mechanism and close to a substantially full flow path closing angle when the turbine load is interrupted. Alternatively, in a control system for a furnace top pressure recovery turbine having a plurality of stages of stationary blades and rotatingly driven by exhaust gas from a blast furnace to rotate the generator, at least one stage after the second stage of the stationary blades is a variable angle mechanism. It is to close to a substantially full flow path closing angle at the time of turbine trip of the turbine.

  In both wet and dry furnace top pressure recovery turbines, no dust adheres to the second and subsequent stationary blades. For this reason, when at least one stage after the second stage is provided with the angle variable mechanism, the stationary blade can always be closed to the fully closed angle of the flow path. That is, when at least one stage after the second stage is closed to a fully closed angle of the flow path or an angle close to the full closed angle when the turbine load is interrupted or the turbine is tripped, the exhaust gas flowing into the turbine is instantaneously reduced. The turbine overspeed can be surely prevented. In addition, it is possible to eliminate the speed control valve that contributes to an increase in equipment costs.

  It is desirable that the first stage stationary blade of the turbine has a variable angle mechanism and closes to a predetermined angle that is set to the open side with respect to the flow path fully closed angle when the load is interrupted. Alternatively, it is desirable that the first stage stationary blade of the turbine has a variable angle mechanism and closes to a predetermined angle that is set on the open side with respect to the flow path fully closed angle when the turbine is tripped.

  When at least one of the second and subsequent vanes closes to a substantially fully closed angle when the load is interrupted or when the turbine trips, the first stage vane does not necessarily close to the fully closed angle when the load is interrupted or when the turbine is tripped. There is no need. Therefore, by preventing the first stage stationary blade from closing until the fully closed angle of the flow path at the time of load interruption or turbine trip, the first stage stationary blade is prevented from coming into contact with the dust adhered to the back surface. Damage to the variable angle mechanism can be prevented.

  It is desirable that the second and subsequent stator blades that close to the substantially full-flow-closing angle when the load is interrupted are controlled independently of the first-stage stator blades when the load is interrupted. Alternatively, it is desirable that the second and subsequent stage stationary blades that close to a substantially full-flow-closed angle when the turbine trips be controlled independently of the first stage stationary blades when the turbine trips.

  By separating the operation of closing the flow path from the second stage and beyond to the turbine fully closed angle or the angle close to the flow path full closed angle at the time of turbine trip, The operations of the second and subsequent stator vanes can be performed optimally.

  A stationary blade having a variable angle mechanism is controlled by a combination of a servo amplifier and a servo valve at the time of starting and stopping and during normal operation, while the operation at the time of load interruption is different from that of the servo amplifier and the servo valve. It is desirable to control by a combination of a servo amplifier and a servo valve or a combination of an electromagnetic valve and a logic valve. Alternatively, a stationary blade having a variable angle mechanism is controlled by a combination of a servo amplifier and a servo valve at the time of starting and stopping and during normal operation, while the operation at the time of turbine trip is different from that of the servo amplifier and the servo valve. It is desirable to control by a combination of another servo amplifier and a servo valve or a combination of a solenoid valve and a logic valve.

  By controlling the operation of a stationary blade with a variable angle mechanism when the load is interrupted or when the turbine is tripped by a control mechanism that is different from that when starting and stopping and during normal operation, the operation is interrupted when the load is interrupted or when the turbine is tripped. On the other hand, particularly when the load is interrupted, an operation for recovering to normal operation thereafter can be performed quickly.

  It is desirable that a stationary blade having a variable angle mechanism has a variable angle mechanism that is controlled independently of each other, and performs rotation speed control and / or load control and / or pressure control of the turbine. In this way, the stationary blade having the variable angle mechanism has the independent variable angle mechanism and performs the rotation speed control and / or load control and / or pressure control of the turbine. The angle variable control of the stage vane can be optimally performed.

  The control system for a top pressure recovery turbine of the present invention is a control system for a top pressure recovery turbine having a plurality of stages of stationary blades and driven to rotate by an exhaust gas of a blast furnace to rotate a generator. At least one stage after the stage has an angle variable mechanism and closes to a substantially full-flow-path closed angle when the turbine load is interrupted. Alternatively, in a control system for a furnace top pressure recovery turbine having a plurality of stages of stationary blades and rotatingly driven by exhaust gas from a blast furnace to rotate the generator, at least one stage after the second stage of the stationary blades is a variable angle mechanism. When the turbine trips, the turbine closes to a substantially full flow path closing angle.

  Therefore, there is an excellent effect that the exhaust gas inflow to the turbine can be instantaneously and optimally reduced at the time of load interruption or turbine trip without requiring a large equipment cost.

  The best mode for carrying out the control system for a furnace top pressure recovery turbine according to the present invention will be described in detail with reference to FIGS.

  As shown in FIG. 1, as a blast furnace plant, a blast furnace 51, a dust catcher 52, a wet dust collector 53, a bypass main valve 54 and a bypass control valve 55 arranged in parallel, and a gas holder 56 are arranged in this order. In the blast furnace plant, the furnace top pressure controller 63 and the furnace top pressure adjustment control for matching the furnace top pressure detected by the furnace top pressure detector 61 of the blast furnace 51 with the furnace top pressure set by the furnace top pressure setter 62. A device 64 and an electro-oil converter 65 are disposed.

  The exhaust gas from the blast furnace 51 is branched downstream of the wet dust collector 53, led to the turbine 1 through the inlet closing valve 57 and the emergency shutoff valve 58, and exhausted to the gas holder 56 through the outlet blocking valve 59. A gas pressure entering the turbine 1 is detected by a turbine pre-pressure detector 66, and a turbine pre-pressure controller 68 for matching the gas pressure with a gas pressure set by a turbine pre-pressure setter 67, and the turbine pre-pressure A bypass valve control device 70 that receives the signal from the controller 68 and operates the bypass main valve 54 and the bypass control valve 55 via the subtractor 69 is provided.

  The bypass valve control device 70 operates the bypass main valve 54 and the bypass control valve 55 via the electro-oil converters 71 and 72, and adjusts the gas pressure entering the turbine 1 to the set pressure. A generator 81 is connected to the turbine 1 via a shaft joint 80. The turbine 1 is a two-stage cascade turbine as an example of a turbine having a plurality of stages of stationary blades, and includes a first stage stationary blade 2 and a second stage stationary blade 3.

  As shown in FIGS. 1 and 2, a load limit setting device 21, a load setting device 22, a rotation speed setting device 23, and a stationary blade angle setting device 24 are connected to the electric governor 20. Note that FIG. 2 is extracted from FIG. 1 for ease of viewing only the angle variable mechanism of the second stage stationary blade 3 in particular. A control signal from the electric governor 20 is input to the servo amplifiers 31 and 32 that perform angle control of the first stage and the second stage stationary blades via the composite calculator 25. The control signals output from the servo amplifiers 31 and 32 are subjected to electro-oil conversion by the first stage and second stage stationary blade actuating servo valves 35 and 36, respectively, and then the first stage and second stage stationary blades actuating hydraulic actuators 39, 40 is activated. The hydraulic pressure of the hydraulic actuators 39 and 40 is generated by the pump unit 41, and the accumulator 42 replenishes the amount of oil when the load is interrupted and when the turbine trips.

  On the other hand, the load cutoff signal and the turbine trip signal of the turbine 1 are sent to the servo amplifiers 33 and 34 for angle control of the first stage and the second stage stationary blades, which are different from the servo amplifiers 31 and 32, without passing through the electric governor 20. Entered. The control signals output from the servo amplifiers 33 and 34 enter the first stage and second stage stationary blade actuating servo valves 37 and 38, which are different from the servo valves 35 and 36, respectively. The hydraulic actuators 39 and 40 for operating the first stage and the second stage stationary blades are operated. The hydraulic actuator 40 for operating the second stage stationary blade is provided with a limit switch 43 and a timer 44 for resetting the load cutoff signal by the operation of the limit switch 43.

  As shown in FIGS. 3 to 5, for example, an angle variable mechanism for changing the angle of the second stage stationary blade 3 is moved outside the inner casing 4 by the support roller 6 by a hydraulic actuator 40 for the second stage stationary blade (not shown). The supported rotating ring 5 is moved in the circumferential direction. When the rotating ring 5 moves in the circumferential direction, the stationary blade lever 8 is oscillated through the slidable joint 7 to rotate the second stage stationary blade 3 about the stationary blade shaft 9. The same applies to the angle variable mechanism of the first stage stationary blade 2.

  Next, the operation of the control system for the furnace top pressure recovery turbine will be described.

  As shown in FIG. 1, when the turbine 1 is started and stopped, the output signal from the electric governor 20 described above is combined with the composite calculator 25 and servo amplifiers 31 and 32 for controlling the angles of the first and second stage stationary blades. Are input to the servo valves 35 and 36 for operating the first stage and the second stage stationary blades, respectively. This signal is converted into electric oil by the servo valves 35 and 36, and the hydraulic actuators 39 and 40 of the first stage and second stage stationary blades are operated, respectively, and the angles of the first stage and second stage stationary blades 2 and 3 are started and stopped. To a predetermined angle. As a result, the gas flow rate passing through the turbine 1 changes, and the rotation speed control or load control of the turbine 1 is optimally performed.

  During normal operation, the servo valves 35 and 36 and hydraulic actuators 39 and 40 controlled by the servo valves 35 and 36 are similarly operated to change the angles of the first stage and second stage stationary blades 2 and 3 to the predetermined angles during normal operation. Thus, the flow rate of gas passing through the turbine 1 is changed. Thereby, load control or pressure control of the turbine 1 is performed. In this case, the first stage and second stage stationary blade actuating servo valves 37 and 38 for load shedding and turbine trip are respectively in the locked position, and the servo valves 37 and 38 do not adjust the oil amount.

  As described above, the first stage and second stage stationary blades 2 and 3 have variable angle mechanisms that are controlled independently of each other, and perform rotation speed control, load control, pressure control (furnace top pressure control), and the like. Is called. Thereby, the rotation speed control, load control, and pressure control of the turbine 1 can be optimally performed.

  Next, the control at the time of turbine trip when the load of the turbine 1 is interrupted and when a failure or the like occurs in the turbine 1 will be described.

  At the time of load interruption or turbine trip, the load interruption signal or the turbine trip signal is directly input to the first and second stage stationary blade servo amplifiers 33 and 34 without passing through the electric governor 20. The servo amplifiers 33 and 34 output control signals to the servo valves 37 and 38 for the first and second stage stationary blades, adjust the oil amount by electro-oil conversion, and operate the hydraulic actuators 39 and 40 independently. . As a result, the second stage stationary blade 3 is immediately closed to its fully closed angle. Thereby, the exhaust gas flowing into the turbine 1 is instantaneously reduced, and the overspeed of the turbine 1 is reliably prevented.

  Like the second stage stationary blade 3, the first stage stationary blade 2 immediately rotates to the closed side, but unlike the second stage stationary blade 3, it does not close to the flow channel fully closed angle and is set to the open side with respect to the flow channel fully closed angle. The rotation is stopped at the predetermined angle θ. This predetermined angle θ is appropriately set to such an angle that even if the first stage stationary blade 2 is closed to that angle, the first stage stationary blade 2 does not contact or bite dust attached to the back surface 2a.

  As described above, since the second stage stationary blade 3 closes to its fully closed angle when the load is interrupted or when the turbine trips, it is necessary to close the first stage stationary blade 2 to its fully closed angle as in the prior art. This is because it disappears. As a result, as shown in FIG. 6, even if dust adheres to the back surface 2a of the first stage stationary blade 2, the first stage stationary blade 2 does not contact or bite the dust, and the first stage stationary blade 2 and its angle variable mechanism Can be reliably prevented.

  On the other hand, the load cutoff signal and the turbine trip signal described above are also input to the electric governor 20 via another path. Based on this, the electric governor 20 outputs a rotational speed control signal, and the hydraulic actuators of the first and second stage stationary blades are connected via the servo amplifiers 31 and 32 and the servo valves 35 and 36 in the same manner as at the time of starting and stopping. 39 and 40 are operated to instruct the first stage and second stage stationary blades 2 and 3 to have the predetermined angle θ and the flow path fully closed angle, respectively.

  The control by the electric governor 20 is slower than the direct control by the servo amplifiers 33 and 34 described above, and is not suitable for emergency operation at the time of load interruption or turbine trip, but especially at the time of load interruption after the load interruption. This operation is necessary for appropriate angle control in preparation for the recovery of operation.

  When the load is interrupted, the limit switch 43 is operated by the movement of the hydraulic actuator 40 of the second stage stationary blade 3 to the fully closed angle position of the flow path, and the timer 44 is operated by the operation of the limit switch 43. When the timer 44 counts a predetermined time (generally about 0.5 seconds), the load cutoff signal is reset, and the servo valves 37, 1 and 2 of the first stage and second stage stationary blades 2, 3 via the servo amplifiers 33, 34 are reset. 38 is in the locked position.

  As a result, the emergency operation when the load is interrupted is terminated, and the normal control by the electric governor 20, the composite arithmetic unit 25, the servo amplifiers 31, 32, and the servo valves 35, 36 is resumed, and the rotational speed control by increasing / decreasing the amount of gas passing through the turbine 1 Is done. On the other hand, during the turbine trip, the turbine 1 is maintained as it is after the emergency stop. Therefore, the recovery operation by the limit switch 43 and the timer 44 described above is not performed.

  In the above-described furnace top pressure recovery turbine control system, the combination of the servo amplifiers 33 and 34 and the servo valves 37 and 38 allows the first stage and second stage stationary blades 2 and 3 at the time of load interruption or turbine trip. However, instead of this, as shown in FIG. 7, the hydraulic actuator 46 is operated at the time of load interruption or turbine trip by using a control valve 45 composed of a combination of an electromagnetic valve and a logic valve, It is also possible to close the second stage stationary blade 10 to its fully closed angle.

  Further, the operation of closing the first stage stationary blade to the predetermined angle θ set to the open side with respect to the fully closed angle of the flow path at the time of load interruption or turbine trip can be performed by a combination of the electromagnetic valve and the logic valve. The other description is the same as that of the control system for the furnace top pressure recovery turbine described above.

  Thus, according to the furnace top pressure recovery turbine control system, in the furnace top pressure recovery turbine having a plurality of stages of stationary blades 2 and 3, at least one stage after the second stage of the stationary blades, that is, in this case Since the second stage stationary blade 3 is provided with a variable angle mechanism, and the second stage stationary blade 3 is fully closed when the turbine load is interrupted or when the turbine trips, the exhaust gas flowing into the turbine 1 is instantaneously reduced and the turbine 1 is overloaded. Speed is reliably prevented.

  In addition, since the variable angle mechanisms of the first stage stationary blade 2 and the second stage stationary blade 3 are independently controlled, the operation of fully closing to a predetermined position when the turbine load is interrupted or when the turbine trips can be optimally performed. it can. Further, the variable-angle mechanism of the first stage stationary blade 2 and the second stage stationary blade 3 is a control mechanism different from that at the time of starting and stopping or during normal operation when the load is interrupted or when the turbine trips, for example, servo amplifiers 33 and 34. And servo valves 37 and 38, or a combination of solenoid valve and logic valve, the operation can be performed quickly when the load is interrupted or when the turbine trips. The servo amplifiers 31 and 32 and the servo valves 35 and 36 can quickly perform an operation for recovering the subsequent normal operation.

  The above-described control system for the furnace top pressure recovery turbine is merely an example, and various modifications can be made based on the gist of the present invention, and they are not excluded from the scope of the present invention.

  For example, when the load is interrupted or when the turbine trips, the first stage stationary blade 2 can be closed to the fully closed angle of the flow channel or an angle close thereto, similarly to the second stage stationary blade 3. Further, the angle variable mechanism of the first stage stationary blade 2 and the second stage stationary blade 3 angle variable mechanism may be controlled integrally instead of being independently controlled at the time of load interruption and turbine trip.

  The operation control at the time of load interruption or turbine trip of the turbine 1 may be performed not by a combination of a servo amplifier and a servo valve or a combination of an electromagnetic valve and a logic valve, but by another mechanism. Moreover, although the control system of the above-mentioned furnace top pressure recovery turbine was the turbine 1 having two stages of stationary blades 2 and 3, it can be similarly applied to a turbine having three or more stages of stationary blades. In addition, the stationary blade that closes to the fully closed angle of the flow path when the load is interrupted or when the turbine trips may be a stationary blade in any stage after the second stage. Further, the second and subsequent stationary blades that are closed when the load is interrupted or when the turbine trips are not necessarily closed to the fully closed angle of the flow path, but to an angle close to the fully closed flow path (substantially closed angle of the flow path). It may be closed.

It is a systematic diagram which shows the control system of the furnace top pressure recovery turbine of this invention. It is a systematic diagram which shows the angle variable mechanism of a 2nd stage stationary blade. It is a side view which shows the detail of the angle variable mechanism of a 2nd stage stationary blade. FIG. 10 is a schematic diagram showing the operation of the second stage stationary blade angle variable mechanism. FIG. 10 is a schematic diagram showing the operation of the second stage stationary blade angle variable mechanism. It is a trial figure which shows the action | operation of the control system of the furnace top pressure recovery turbine of this invention. It is a systematic diagram which shows the angle variable mechanism of another 2nd stage stationary blade. It is a systematic diagram which shows the control system of the conventional furnace top pressure recovery turbine. It is a systematic diagram which shows the control system of another conventional furnace top pressure recovery turbine. It is a trial figure which shows the action | operation of the control system of the conventional furnace top pressure recovery turbine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turbine 2 1st stage stationary blade 2a Back surface 3 2nd stage stationary blade 4 Inner casing 5 Rotating ring 6 Support roller 7 Sliding universal joint 8 Stator blade lever 9 Stator blade shaft 13 Second stage stationary blade 20 Electric governor 21 Load limit setting device 22 Load setting device 23 Rotational speed setter 24 Stator blade angle setter 25 Combined computing units 31, 32, 33, 34 Servo amplifiers 35, 36, 37, 38 Servo valves 39, 40 Hydraulic actuator 41 Pump unit 42 Accumulator 43 Limit switch 44 Timer 45 Control Valve 46 Hydraulic actuator 51 Blast furnace 52 Dust catcher 53 Wet dust collector 54 Bypass main valve 55 Bypass control valve 56 Gas holder 57 Inlet closing valve 58 Emergency shutoff valve 59 Outlet closing valve 61 Furnace top pressure detector 62 Furnace top pressure setter 63 Furnace Top Pressure Controller 64 Furnace Top Pressure Control Controller 65 Electro-Oil Converter 66 Turbi Pre-pressure detector 67 Turbine pre-pressure setter 68 Turbine pre-pressure controller 69 Subtractor 70 Bypass valve control devices 71 and 72 Electro-oil converter 80 Shaft coupling 81 Generator 100 Blast furnace 101 Dust catcher 102 Wet dust collector 103 Inlet block Stop valve 104 Emergency shut-off valve 105 Turbine 106 First stage stationary blade 106a Back face 107 Angle variable mechanism 108 Generator 110 Emergency shut-off valve 111 Turbine 112 Control valve

Claims (9)

  In the control system for a furnace top pressure recovery turbine (1) having a plurality of stages of stationary blades (2, 3, 13) and being rotationally driven by exhaust gas from a blast furnace (51) to rotationally drive a generator (81), At least one stage (3, 13) after the second stage of the blades has a variable angle mechanism (34, 38, 40, 45, 46) and closes to a substantially full flow path closing angle when the turbine load is interrupted. A control system for a furnace top pressure recovery turbine.   The first stage stationary blade (2) of the turbine (1) has a variable angle mechanism (33, 37, 39) and at a predetermined angle (θ) set to an open side with respect to the fully closed angle of the flow path when the load is interrupted. The furnace top pressure recovery turbine control system according to claim 1, wherein the control system is closed.   The second and subsequent stator vanes (3, 13) that close to a substantially full flow path closing angle when the load is interrupted are controlled independently of the first stage stator blade (2) when the load is interrupted. The control system for a furnace top pressure recovery turbine according to claim 2.   The stationary blades (2, 3, 13) having the variable angle mechanism are controlled by a combination of the servo amplifiers (31, 32) and the servo valves (35, 36) at the time of starting and stopping and normal operation. The operation at the time of the load shut-off is a combination of a servo amplifier (33, 34) and a servo valve (37, 38) different from the servo amplifier and the servo valve, or a solenoid valve (45) and a logic valve ( 45) The control system for the top pressure recovery turbine according to any one of claims 1 to 3, wherein the control system is controlled by a combination with (45).   In the control system for a furnace top pressure recovery turbine (1) having a plurality of stages of stationary blades (2, 3, 13) and being rotationally driven by exhaust gas from a blast furnace (51) to rotationally drive a generator (81), At least one stage (3, 13) after the second stage of the blades has an angle variable mechanism (34, 38, 40, 45, 46) and closes to a substantially full-flow-closing angle when the turbine is tripped. A control system for a furnace top pressure recovery turbine.   The first stage stationary blade (2) of the turbine (1) has a variable angle mechanism (33, 37, 39) and reaches a predetermined angle (θ) set to the open side with respect to the flow path fully closed angle during the turbine trip. 6. The furnace top pressure recovery turbine control system according to claim 5, wherein the control system is closed.   The second and subsequent stage stationary blades (3, 13) that close to a substantially full-flow-closing angle during the turbine trip are controlled independently of the first stage stationary blade (2) during the turbine trip. The furnace top pressure recovery turbine control system according to claim 6.   The stationary blades (2, 3, 13) having the variable angle mechanism are controlled by a combination of the servo amplifiers (31, 32) and the servo valves (35, 36) at the time of starting and stopping and normal operation. The operation at the time of the turbine trip is based on a combination of a servo amplifier (33, 34) and a servo valve (37, 38) different from the servo amplifier and the servo valve, or an electromagnetic valve (45) and a logic valve ( 45) The control system for a furnace top pressure recovery turbine according to any one of claims 5 to 7, wherein the control system is controlled by a combination with (45). The stationary blades (2, 3, 13) having a variable angle mechanism have the variable angle mechanisms (31, 32, 35, 36, 39, 40) controlled independently of each other, and the rotational speed of the turbine. The control system for a top pressure recovery turbine according to any one of claims 1 to 8, wherein control and / or load control and / or pressure control are performed.

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