JP2006283563A - Control system of furnace top pressure recovery turbine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent development of clogging dust to a first stage stationary blade, by excluding influence in strength on a moving blade caused by a jet of the stationary blade, without requiring much facility cost. <P>SOLUTION: In this control system of a furnace top pressure recovery turbine 1 for rotatingly driving a generator 81 by being rotatingly driven by exhaust gas exhausted from a blast furnace 51, bypass control valves 54 and 55 capable of adjusting a flow rate of the exhaust gas passing through the inside, are arranged in parallel to the turbine in a gas passage 60 on the downstream side of the blase furnace, and rotating speed control and/or load control in starting and/or stopping of the turbine are performed by changing front pressure of the turbine by operation of the bypass control valves. The turbine has angle variable mechanisms 31, 32, 39 and 40 for changing a flow passage angle of the stationary blades 2 and 3, and the stationary blades are put in a state of opening more than a flow passage full closure angle in starting and/or stopping of the turbine. <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 that is used for power generation by installing a turbine in an exhaust gas passage of a blast furnace plant, the exhaust gas exhausted from the blast furnace 100 is converted into a dust catcher 101 and a wet dust collector 102 as shown in FIG. Then, the gas is guided to the turbine 105 through the inlet closing valve 103 and the emergency shutoff valve 104 to rotate the turbine 105. Then, the generator 107 is rotationally driven by the turbine 105 to be used for power generation.

  In the above-described furnace top pressure recovery turbine, when the turbine 105 is started and stopped, the stationary blade angle control is performed from the start to the initial set rotational speed (for example, 15% rotational speed). The rotation speed control is performed immediately before the set rotation speed (for example, 98% rotation speed) just before the start, and the load is applied immediately after reaching the 100% rotation speed and entering the power grid. Until then, load control is performed.

  In addition, pressure control is performed after entering normal operation. On the other hand, when the turbine 105 is stopped, the load control is performed from the set rotational speed immediately after the disconnection to the initial set rotational speed until the load is released from the normal operation and reaches the set rotational speed immediately after the disconnection (for example, 96.5% rotational speed). Rotational speed control is performed until this time, and stationary blade angle control is performed until it stops from the initial rotational speed.

  And at the time of starting of the turbine 105, the first stage stationary blade 106 provided with the angle variable mechanism is gradually opened from the fully closed angle of the flow path in a state where the pre-pressure of the turbine 105 is increased to the pressure at the normal operation. Lead gas to cascade. At this time, the bypass main valve 108, which is an on-off valve, is fully closed, while the bypass control valve 109 is gradually closed as shown in FIG. 5, and the pre-pressure of the turbine 105 is always the pressure during normal operation. Maintained.

  As shown in FIG. 6, a control valve 112 is provided between the emergency shut-off valve 110 and the turbine 111 to control the start and stop of the turbine 111. The control of the control valve 112, There is one that is performed by controlling the angle of the stationary blades 113 and 114 of the turbine 111 (see, for example, Patent Document 1).

  In the control system for the top pressure recovery turbine of this furnace, when the turbine 111 is started and stopped, the control valve opening control by the speed control valve 112 is performed from the initial setting speed from the start to the initial setting speed. Rotational speed control until the set rotational speed immediately before the start of uniform speed, load is applied immediately after reaching 100% rotational speed and entering the power grid, and until the load increases and normal operation is started Each is done.

  Further, pressure control is performed during normal operation. On the other hand, when the turbine 111 is stopped, load control is performed from the normal operation until the load is released and the set rotational speed immediately after disconnection, and the rotational speed control is performed from the set rotational speed immediately after disconnection to the initial set rotational speed. Until the engine speed is stopped from the initially set rotation speed, the control valve opening control by the control valve 112 is performed.

  When the turbine 111 is started, as shown in FIG. 7, the governor valve 112 is gradually opened in a state where the pre-pressure of the turbine 111 is increased to the pressure during normal operation, and the gas is guided to the blade row. . When the speed regulating valve 112 is almost fully opened, the stationary blades 113 and 114 having the variable angle mechanism are gradually opened from the initial setting angle of the flow path, and the normal operation is started. At this time, the bypass main valve 115 is fully closed while the bypass control valve 116 is gradually closed, so that the pre-pressure of the turbine 111 is always maintained at the pressure during normal operation.

In any of the above-described furnace top pressure recovery turbine control systems, the one that mainly controls the start and stop operations of the turbines 105 and 111 is the variable-angle mechanism of the first stage stationary blade 106 or the governing valve 112. The bypass control valves 109 and 116 are used to maintain the pre-pressure of the turbines 105 and 111 at the pressure during normal operation. The operations of the bypass control valves 109 and 116 are not controlled by an electric governor that controls the operation of the turbine, but are controlled by a bypass valve control device arranged separately from the electric governor.
Japanese Patent Laid-Open No. 60-32942 (FIG. 1)

  However, in the control system for the above-described conventional furnace top pressure recovery turbine, the control from the start of the former turbine to the initial rotation speed is performed by gradually opening the first stage stationary blade from the fully closed angle of the flow path. In the method, in the process of opening the first stage stationary blade from the fully closed angle of the flow path, the exhaust gas increased to the pressure during normal operation becomes a jet at the outlet of the first stage stationary blade, and this jet is blown to the rotor blade, There is a problem of affecting the strength of the first stage blade.

  In addition, there is a tendency for dust to adhere to the rear surface of the first stage stator blade, and this dust may cause problems such as the first stage stator blade being unable to be fully closed when the load is interrupted or when the turbine trips. There is a problem that dust adhesion to the first stage stationary blade is promoted by the jet generated by the first stage stationary blade. Further, even when the turbine is stopped, a jet flow is generated in the process of gradually closing the first stage stationary blades from the normal operation angle to the flow path fully closed angle, causing the same problem as the above two.

  On the other hand, the latter method, in which the control from the start of the turbine to the initial rotation speed is performed by gradually opening the governor valve and guiding the gas to the blade row, the gas pressure acting on the turbine by the governor valve. Therefore, the problem of the strength of the moving blade as described above or the problem of dust adhesion to the first stage stationary blade is unlikely to occur. However, there is a problem that a large equipment cost is required to install the governing valve.

  The present invention was made to solve such a problem, without requiring a large equipment cost, it is possible to eliminate the influence on the strength of the moving blade caused by the jet of the stationary blade, It is an object of the present invention to provide a control system for a furnace top pressure recovery turbine that can prevent dust adhesion to the first stage stationary blade due to the same cause.

  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 that is rotationally driven by exhaust gas exhausted from a blast furnace and rotationally drives a generator. A bypass control valve capable of adjusting the flow rate of the exhaust gas passing through the interior is arranged in parallel with the turbine, and the operation of this bypass control valve changes the pre-pressure of the turbine to control the rotational speed when the turbine is started and stopped And / or to perform load control.

  As described above, the control system for the top pressure recovery turbine of the present invention changes the turbine pre-pressure by the bypass control valve when the turbine is started or stopped, for example, gradually increasing or decreasing the turbine pre-pressure. Since the rotation speed control and load control are performed, the exhaust gas, which has been increased to the pressure during normal operation as in the prior art, gradually opens or closes the process of gradually opening the first stage stationary blade from its fully closed angle. It becomes a jet in the process, and this jet is prevented from being blown to the rotor blades. Moreover, the conventional speed control valve can also be eliminated.

  The turbine preferably includes an angle variable mechanism that changes the flow path angle of the stationary blade, and the stationary blade is desirably opened to a state where the flow path is fully closed when the turbine is started. Further, it is desirable that the turbine has an angle variable mechanism that changes the flow path angle of the stationary blade, and the stationary blade is opened more than the full flow path closed angle when the turbine is stopped. In this way, when the turbine is started or stopped, the stationary blade is opened more than its fully closed angle, and the flow passage area at the stationary blade outlet is widened to reliably prevent jets from being generated. Is done.

  The operation of the bypass control valve is preferably controlled by an electric governor signal. In the control system for a furnace top pressure recovery turbine according to the present invention, the bypass control valve mainly performs the rotation speed control and load control of the turbine when the turbine is started or stopped, so that the electric governor performs the control. Thus, turbine control at the time of starting and stopping of the turbine can be optimally performed.

  The control of the turbine is preferably performed by two bypass control valves arranged in parallel with the turbine. Thus, by controlling the turbine with the two bypass control valves arranged in parallel with the turbine, the rotational speed control and load control at the start and stop of the turbine are accurately and simply performed. There is an advantage that you can.

  The turbine has a variable angle mechanism that changes the flow path angle of the stationary blade, and the control by the bypass control valve at the start of the turbine is transferred to the control by changing the flow path angle of the stationary blade during the load control. Is desirable. The turbine also has an angle variable mechanism that changes the flow path angle of the stationary blade, and control by the bypass control valve when the turbine is stopped is shifted from control by changing the flow path angle of the stationary blade during load control. It is desirable. By doing so, the shift to the pressure control during the normal operation is smoothly performed, and only the pressure control by changing the flow path angle of the stationary blade is performed during the normal operation.

  It is desirable to increase the turbine pre-pressure from a pressure substantially equal to the turbine outlet pressure by the above-described operation of the bypass control valve when the turbine is started. Further, when the turbine is stopped, it is desirable to reduce the turbine pre-pressure to a pressure substantially equal to the turbine outlet pressure by the above operation of the bypass control valve. In this way, if the turbine is started from a state where there is no pressure difference in the front-rear pressure of the turbine, or if the turbine is stopped in a state where there is no pressure difference in the front-rear pressure of the turbine, the generation of the jet flow by the first stage stationary blade is further ensured. To be prevented.

  A control system for a furnace top pressure recovery turbine according to the present invention is a control system for a furnace top pressure recovery turbine that is rotationally driven by exhaust gas exhausted from a blast furnace and rotationally drives a generator. A bypass control valve capable of adjusting the flow rate of exhaust gas is arranged in parallel with the turbine, and the turbine pre-pressure is changed by the operation of the bypass control valve to control the rotational speed and / or load when the turbine is started and stopped. Therefore, as in the prior art, the exhaust gas, which has been increased to the pressure during normal operation, becomes a jet in the process of gradually opening or closing the first stage stationary blade from its fully closed angle, and this jet becomes a moving blade. It is prevented from being sprayed on. Moreover, the conventional speed control valve can also be eliminated.

  Therefore, the control system for the furnace top pressure recovery turbine of the present invention can eliminate the influence on the strength of the moving blade caused by the jet of the stationary blade without requiring a large equipment cost. As a result, it is possible to prevent the adhesion of dust to the first stage stationary blade.

  A best mode for carrying out a 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 first bypass control valve 54, a second bypass control valve 55, and a gas holder 56 are arranged in this order in the exhaust gas path 60. The The first bypass control valve 54 and the second bypass control valve 55 are respectively disposed in the exhaust gas passage 60 in parallel with the durbin 1. These two bypass control valves 54 and 55 are not mere on-off valves, but can adjust the flow rate of gas passing through the interior thereof. As a result, various adjustments can be made by adjusting the pre-pressure of the turbine 1 or adjusting the flow rate of gas passing through the turbine 1. Control can be performed.

  An exhaust gas passage 60 is branched upstream of the two bypass control valves 54 and 55, and a turbine gas passage 60 a that guides the exhaust gas exiting the wet dust collector 53 to the turbine 1 is disposed. An inlet closing valve 57 and an emergency shutoff valve 58 are arranged in this order in the turbine gas passage 60a. The gas that has exited the emergency shutoff valve 58 is guided to the turbine 1, passes through the turbine 1, and is exhausted to the gas holder 56 through the outlet closing valve 59. 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, and includes a first stage stationary blade 2 and a second stage stationary blade 3, and a first stage and a second stage moving blade (not shown).

  In the blast furnace plant, the furnace top pressure controller 63 and the furnace top pressure adjustment control for making the furnace top pressure detected by the furnace top pressure detector 61 of the blast furnace 51 coincide with the furnace top pressure set by the furnace top pressure setter 62. A device 64 and an electro-oil converter 65 are disposed.

  A load limit setting device 21, a load setting device 22, a rotation number setting device 23, and a bypass control valve opening setting device 24 are connected to the electric governor 20. Thereby, the rotation speed control, load control, and pressure control of the turbine 1 are performed. A control signal from the electric governor 20 is input to the first and second stationary blade angle control valves 31 and 32 for performing angle control of the first and second stage stationary blades independently of each other via the composite calculator 25. . The stator blade angle control valves 31 and 32 are, for example, one or a plurality of servo amplifiers and servo valves integrated, or a servo amplifier, a servo valve, an electromagnetic valve, and a logic valve integrated. . Note that the servo amplifier and the servo valve may be provided separately.

  The control signal from the electric governor 20 is electro-oil converted by the above-described stationary blade angle control valves 31 and 32, respectively, and then the hydraulic actuators 39 and 40 for operating the first stage and second stage stationary blades are operated. Thereby, the flow path angle of the 1st stage and 2nd stage stationary blades 2 and 3 of the turbine 1 is changed according to the pre-pressure etc. of the turbine at that time.

  While the load cutoff signal and the turbine trip signal of the turbine 1 are input to the electric governor 20, they are directly input to the first-stage and second-stage stationary blade angle control valves 31, 32, respectively, and the stationary blade angle control valves 31, 32 are input. Then, the hydraulic oils 39 and 40 for operating the first stage and 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.

  A gas pressure entering the turbine gas passage 60 a is detected by a turbine pre-pressure detector 66, and a turbine pre-pressure controller 68 is provided to match the gas pressure with the gas pressure set by the turbine pre-pressure setter 67. Is done. The control signal from the electric governor 20 is sent to the above-described first bypass control valve via the composite arithmetic unit 25, the first and second high level signal selectors 69 and 70, and the first and second electro-oil converters 71 and 72. 54 and the second bypass control valve 55, respectively. Thus, the operation of the first and second bypass control valves 54 and 55 is controlled by the signal of the electric governor 20.

  On the other hand, the output signal of the turbine pre-pressure controller 68 and the output signal of the electric governor 20 are input to the bypass control valve signal distributor 74 through the subtractor 73, and the control signal of the first bypass control valve 54 and the second bypass The control signal is distributed to the control signal of the control valve 55. This signal is input to the first and second high level signal selectors 69 and 70, respectively. This signal is selected by the first and second high level signal selectors 69 and 70 when the load is interrupted and the turbine is tripped, and the first and second electric oil converters 71 and 72 described above are used. Input to the bypass control valves 54 and 55, respectively.

  Next, the operation of the control system for the furnace top pressure recovery turbine will be described. First, the control at the time of starting the turbine 1 will be described. As shown in FIG. 2, before the turbine 1 is started, the inlet closing valve 57, the emergency shutoff valve 58, and the outlet closing valve 59 are opened. Thereby, the furnace top pressure detector 61, the furnace top pressure setter 62, the furnace top pressure controller 63, the furnace top pressure adjustment control device 64, and the electric oil converter 65 from the blast furnace 51 adjusted to a predetermined furnace top pressure. The exhaust gas flows separately into the turbine 1 in the turbine gas path 60 a and the bypass control valves 54, 55 in the exhaust gas path 60, merges again, and is guided to the gas holder 56.

  At this time, both the first bypass control valve 54 and the second bypass control valve 55 are fully opened by the respective control signals from the electric governor 20, and both the first stage and second stage stationary blades 2 and 3 of the turbine 1 are initially in the flow path. The angle is set. The channel initial setting angle is set to an angle corresponding to an opening of about 25 to 40% when the flow channel area when the blade row is fully opened is 100%. At this time, the pre-pressure of the turbine 1 is substantially equal to the outlet pressure of the turbine 1.

  The valve opening degree control by the first bypass control valve 54 is performed from the start to the initial set rotation speed (for example, 15% rotation speed) at the point A in the figure. The control signal output from the electric governor 20 is input to the first electro-oil converter 71 via the composite arithmetic unit 25 and the first high-level signal selector 69, where it is converted into electro-oil and is sent to the first bypass control valve 54. Entered. Thereby, the 1st bypass control valve 54 is closed gradually, and the front pressure of turbine 1 rises gradually.

  Between the initially set rotation speed (point A in the figure) and 100% rotation speed (point C in the figure), only the first bypass control valve 54 is gradually closed, and the pre-pressure of the turbine 1 further increases. At this time, the rotational speed control is performed from the initial set rotational speed (point A in the figure) to the rotational speed set immediately before the uniform speed start at the point B in the figure (for example, 98% rotational speed). From the point B (shown in the figure) to the 100% rotation speed (point C in the figure), uniform speed and insertion are performed. Immediately after the rotational speed of the turbine 1 reaches 100% and is inserted into the power grid, an initial load is applied, and then the turbine 1 shifts to load control.

  While the first bypass control valve 54 is fully closed during the load control of the turbine 1, the second bypass control valve 55 starts to close. As with the first bypass control valve 54, the second bypass control valve 55 is controlled by the control signal output from the electric governor 20 via the composite calculator 25 and the second high-level signal selector 70. This is performed by being input to the oil converter 72, where it is subjected to electro-oil conversion and input to the second bypass control valve 55.

  When the load further increases during the load control of the turbine 1, the control signal output from the electric governor 20 is input to the first stage and second stage stationary blade angle control valves 31 and 32 via the composite calculator 25, respectively. The electric oil is converted to actuate the hydraulic actuators 39 and 40 for operating the first and second stage stationary blades. Thereby, the flow path angle of the first stage and second stage stationary blades 2 and 3 is gradually changed in the opening direction. Thus, since control by changing the flow path angle of the stationary blades 2 and 3 is started during load control, the transition to pressure control in normal operation is performed smoothly.

  The second bypass control valve 55 is also fully closed when the first stage and the second stage stationary blades 2 and 3 reach a flow angle at which the total amount of exhaust gas exhausted from the blast furnace 51 reaches the turbine 1. Thereafter, pressure control is performed by changing the stationary blade flow path angle, and normal operation is performed. As described above, the two bypass control valves 54 and 55 arranged in parallel with the turbine 1 are sequentially opened from the fully opened state to the fully closed state when the turbine 1 is started, and all of them are normally operated. Is fully closed.

  As shown in FIG. 3, until the load control and the pressure control are performed by changing the stationary blade flow path angle, the valve opening degree control and the rotational speed control by the first bypass control valve 54 and the second bypass control valve 55 are performed. Then, the load control is performed, and the control shifts to the load control by changing the stationary blade flow path angle before the second bypass control valve 55 is fully closed. As shown in FIG. 2, during this time, the turbine pre-pressure increases from a pressure approximately equal to the outlet pressure of the turbine 1 to a pressure during normal operation until load control is started by changing the stationary blade flow path angle.

  When the turbine 1 is stopped, a control almost opposite to the control when the turbine 1 is started is performed. The control signal output from the electric governor 20 causes the first-stage and second-stage stationary blades 2 and 3 to gradually change the flow path angle in the closing direction. Thereby, the turbine 1 shifts from pressure control to load control. After the first-stage and second-stage stationary blades 2 and 3 are closed to the flow path initial setting angle, the load control by changing the angle of the stationary blades 2 and 3 shifts to the load control by the second bypass control valve 55. Thereafter, the second bypass control valve 55 is opened, and when the second bypass control valve 55 is fully opened, the first bypass control valve 54 starts to open.

  The load of the turbine 1 is returned to the initial load and disconnected. As a result, the set rotational speed (for example, 96.5% rotational speed) immediately after the disconnection of the illustrated E point is changed from the 100% rotational speed (point D in the figure) of the turbine 1 to shift from load control to rotational speed control. And when it becomes the initial setting rotation speed (for example, 15% rotation speed) of illustration F point, it transfers to valve opening degree control from rotation speed control, and the turbine 1 stops. While the second bypass control valve 55 and the first bypass control valve 54 are open, the turbine pre-pressure decreases from the pressure during normal operation to a pressure substantially equal to the outlet pressure of the turbine 1. As described above, the two bypass control valves 54 and 55 arranged in parallel with the turbine 1 are all fully closed during normal operation of the turbine 1, and are all fully closed when the turbine 1 is stopped. From the state, it turns from fully closed to fully open.

  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, a load interruption signal or a turbine trip signal is directly input to the first and second stationary blade angle control valves 31 and 32, respectively. Electro-oil conversion is performed in the first and second stationary blade angle control valves 31 and 32, and the hydraulic actuators 39 and 40 are operated independently.

  As a result, the first stage stationary blade 2 is closed to the channel initial setting angle, and the second stage stationary blade 3 is closed to the channel fully closed angle. For this reason, the exhaust gas flowing into the turbine 1 is instantaneously reduced, and the overspeed of the turbine 1 is prevented. As described above, the control by the first bypass control valve 54 and the second bypass control valve 55 is performed by changing the angles of the first stage and second stage stationary blades 2 and 3 when the load of the turbine 1 is interrupted and when the turbine trips. This is because the exhaust gas flowing into the turbine 1 cannot be reduced instantaneously.

  On the other hand, the pressure control after the load is interrupted or after the turbine trip is performed by the bypass control valves 54 and 55 based on the control signal via the bypass control valve signal distributor 74. Further, the rotational speed control after the load is interrupted, and the subsequent re-insertion and the load control are performed by adjusting the flow rate by changing the stationary blade flow path angle based on the control signal of the electric governor 20.

  According to the control system for the main furnace top pressure recovery turbine, two bypass control valves 54 and 55 are arranged in parallel with the turbine 1 in the exhaust gas passage 60 downstream of the blast furnace 51, and these bypass control valves are arranged in parallel. By 54 and 55, the pre-pressure of the durbin 1 is gradually increased or decreased, and the rotational speed control and load control when the turbine 1 is started and stopped are performed. Therefore, as in the prior art, the exhaust gas, which has been increased to the pressure during normal operation, becomes a jet in the process of gradually opening or closing the first stage stationary blade from its fully closed angle, and this jet flows into the moving blade. It is prevented from being sprayed on. Moreover, the conventional speed control valve is also unnecessary.

  For this reason, it is possible to eliminate the influence on the strength of the moving blade caused by the jet of the first stage stationary blade 2 without requiring a large equipment cost, and to prevent dust from adhering to the first stage stationary blade 2. it can. In addition, when the turbine is started or stopped, the stationary blades 2 and 3 are opened from the fully closed angle of the flow passage (flow passage initial setting angle), and the flow passage area at the stationary blade outlet is widened. Since the pre-pressure of 1 is increased, the generation of a jet is reliably prevented.

  Since the bypass control valves 54 and 55 are controlled by a signal from the electric governor 20, turbine control when the turbine 1 is started or stopped can be optimally performed. Further, since the rotational speed control and load control of the turbine 1 are performed by the two bypass control valves 54 and 55 arranged in parallel with the turbine 1, these controls when the turbine 1 is started and stopped are accurately performed. And with a simple configuration. Note that the number of bypass control valves provided in parallel with the turbine 1 is not limited to two, and may be one or three or more.

  In particular, when the turbine 1 is started, the pre-pressure of the turbine 1 is increased from a pressure substantially equal to the outlet pressure of the turbine 1 by the first and second bypass control valves 54 and 55, while when the turbine 1 is stopped, the front pressure of the turbine 1 is increased. The pressure is reduced to a pressure approximately equal to the outlet pressure of the turbine 1. In this way, the turbine 1 is started from a state where there is no pressure difference between the front and rear pressures of the turbine 1, and the turbine 1 is stopped while there is no pressure difference between the front and rear pressures of the turbine 1. This is surely prevented from occurring.

  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 turbine is started or when the turbine is stopped, the stationary blade does not necessarily have to be opened more than the fully closed angle of the flow path. However, in that case, it is desirable to gradually open the angle of the stationary blades as the turbine pre-pressure increases. Further, the control of the bypass control valve is not necessarily performed by the signal of the electric governor.

  It is not always necessary to shift the control of the turbine by the bypass control valve at the start of the turbine to the control by changing the flow angle of the stationary blade during the load control. The control of the turbine by the bypass control valve at the time of the turbine stop is the load control. There is no need to shift from control by changing the flow path angle of the stationary blade. In addition, it is necessary to increase the turbine pre-pressure from a pressure approximately equal to the turbine outlet pressure by the bypass control valve when the turbine is started, and to reduce the turbine pre-pressure to a pressure approximately equal to the turbine outlet pressure when the turbine is stopped. Nor.

It is a systematic diagram which shows the control system of the furnace top pressure recovery turbine of this invention. It is a graph which shows the relationship between the elapsed time of the control system of FIG. 1, and the operation | movement of a furnace top pressure recovery turbine. It is a graph which shows the relationship between the governor output of the control system of FIG. 1, and the opening degree of a bypass control valve. It is a systematic diagram which shows the control system of the conventional furnace top pressure recovery turbine. It is a graph which shows the relationship between the governor output of the control system of FIG. 4, and the opening degree of a bypass control valve. It is a systematic diagram which shows the control system of another conventional furnace top pressure recovery turbine. It is a graph which shows the relationship between the governor output of the control system of FIG. 6, and the opening degree of a bypass control valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turbine 2 1st stage stationary blade 3 2nd stage stationary blade 20 Electric governor 21 Load limit setting device 22 Load setting device 23 Rotation speed setting device 24 Bypass control valve opening degree setting device 25 Compound calculators 31 and 32 Stator blade angle control valves 39 and 40 Hydraulic actuator 43 Limit switch 44 Timer 51 Blast furnace 52 Dust catcher 53 Wet dust collector 54 First bypass control valve 55 Second bypass control valve 56 Gas holder 57 Inlet shut-off valve 58 Emergency shut-off valve 59 Outlet shut-off valve 60 Exhaust gas passage 60a Turbine Gas path 61 Furnace top pressure detector 62 Furnace top pressure setter 63 Furnace top pressure controller 64 Furnace top pressure adjustment controller 65 Electro-oil converter 66 Turbine pre-pressure detector 67 Turbine pre-pressure setter 68 Turbine pre-pressure regulator 69 1st high level signal selector 70 2nd high level signal selector 71 1st electric oil converter 72 2nd electric oil converter 73 Subtractor 74 Ipass control valve signal distributor 80 Shaft coupling 81 Generator 100 Blast furnace 101 Dust catcher 102 Wet dust collector 103 Inlet shut-off valve 104 Emergency shut-off valve 105 Turbine 106 First stage stationary blade 107 Generator 108 Bypass main valve 109 Bypass control valve 110 Critical Shut-off valve 111 Turbine 112 Control valve 113, 114 Stator blade 115 Bypass main valve 116 Bypass control valve

Claims (9)

  In the control system of the furnace top pressure recovery turbine (1) that is driven to rotate by the exhaust gas exhausted from the blast furnace (51) to drive the generator (81), the interior passes through the gas passage (60) downstream of the blast furnace. A bypass control valve (54, 55) capable of adjusting the flow rate of exhaust gas is disposed in parallel with the turbine, and the turbine pre-pressure is changed by the operation of the bypass control valve to start and / or stop the turbine. The furnace top pressure recovery turbine control system is characterized in that the rotation speed control and / or the load control are performed.   The turbine (1) has a variable angle mechanism (31, 32, 39, 40) for changing the flow path angle of the stationary blades (2, 3). The furnace top pressure recovery turbine control system according to claim 1, wherein the control system is set to be opened more than a closed angle.   The turbine (1) has a variable angle mechanism (31, 32, 39, 40) for changing the flow path angle of the stationary blades (2, 3). The control system for a furnace top pressure recovery turbine according to claim 1, wherein the control system is set to be opened more than a closed angle.   Control of the top pressure recovery turbine according to any one of claims 1 to 3, characterized in that the operation of the bypass control valve (54, 55) is controlled by a signal of an electric governor (20). system.   The said control of the said turbine (1) is performed by the two said bypass control valves (54, 55) arrange | positioned in parallel with the said turbine, The one of Claim 1 thru | or 4 characterized by the above-mentioned. Control system for turbine top pressure recovery turbine.   The turbine (1) has a variable angle mechanism (31, 32, 39, 40) for changing the flow path angle of the stationary blades (2, 3), and the bypass control valve (54, The control according to claim 55 is shifted to control by changing the flow path angle of the stationary blade during load control. Control system.   The turbine (1) has a variable angle mechanism (31, 32, 39, 40) for changing the flow path angle of the stationary blades (2, 3), and the bypass control valve (54, when the turbine is stopped). The control by 55) is shifted from the control by changing the flow path angle of the stationary blade during the load control, of the furnace top pressure recovery turbine according to any one of claims 1 to 6. Control system.   2. The start-up of the turbine (1) increases the pre-pressure of the turbine from a pressure substantially equal to the outlet pressure of the turbine by the operation of the bypass control valve (54, 55). The control system for a furnace top pressure recovery turbine according to any one of claims 7 to 9. The turbine according to any one of claims 1 to 8, wherein when the turbine (1) is stopped, the operation of the bypass control valve (54, 55) reduces the pre-pressure of the turbine to a pressure substantially equal to the outlet pressure of the turbine. The furnace top pressure recovery turbine control system according to any one of the above.

Images