JPH0567765B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION From the viewpoint of recent energy conservation, an appropriate design of the steam system of an industrial turbine is desired. The present invention relates to a control device for an extraction mixed pressure turbine that satisfies such requirements.

In an extraction turbine, the steam demand of the extraction system is not always constant throughout the year. The extraction system is also connected not only to the extraction air from the turbine, but also to other steam sources, such as waste heat boilers, or to the extraction or exhaust air of other turbines, so that it can respond to changes in the steam demand of the factory. It is generally configured.

With this configuration, for example, when the demand for extracted air in the summer is low, excess steam in the system is mixed into the turbine pickup and recovered as electricity, and when the demand for steam is high in the winter, the demand is increased by extracting air from the turbine. can correspond to The present invention is a so-called extraction/mixed pressure turbine in which the extraction system from the turbine becomes a mixed system due to changes in steam demand, and also has an extraction system in another pressure stage. To provide a control device in which an automatic output controller (APC) for making electricity constant is added to an electricity purchasing system and can be independently controlled.

The present invention will be described in detail below based on embodiments shown in the accompanying drawings.

FIG. 1 shows a turbine control system according to an embodiment of the present invention.

In this example, 10, 12 and 14 indicate the high pressure section, intermediate pressure section and low pressure section of the turbine, respectively. A main steam path 18 connected to the boiler 16 is connected to a stop valve SV _H and a high pressure regulating valve CV _H. Further, a stop valve SV _I and an intermediate pressure regulating valve CV _I are connected to a steam path 20 extending from a steam outlet of the high pressure section 10 to a steam inlet of the intermediate pressure section 12. _I and CV In the upstream part of _I , there is a bleed air passage 22 leading to the factory plant.
is connected. Furthermore, a low pressure regulating valve CV _L is connected to the steam path 24 leading from the steam outlet of the pressure section 12 to the steam inlet of the low pressure section 14, and on the upstream side of the valve there is a control valve for the extraction and mixing of air leading to the plant. A line 26 is connected to which is normally connected a boiler 28 for supplying process steam to the plant.

In the figure, 30 is a hydraulic speed control device,
In this device, the hydraulic pressure in each cylinder is connected to hydraulically operated servo motors 32, 34, and 36 of a high pressure regulating valve CV _H , an intermediate pressure regulating valve CV _I , and a low pressure regulating valve CV _L , and the hydraulic pressure drives the servo motor. operates,
The positions of the first, second, and third valve control devices 38, 40, and 42 that open and close the associated control valves, and the sleeves 44, 46, and 48 of each valve control device are set to predetermined positions. A rotation speed setting device 50 sets the rotation speed of the turbine by setting the oil pressure in the cylinder, and the rotation speed is set by receiving oil pressure corresponding to the rotation speed of a governor impeller 52 connected to the rotating shaft of the turbine. If the spring pressure is other than the value, the first, second and third valve control devices 38, 40, 42 act against the set spring pressure set by the setting device 50.
The bellows device 54 controls the output of the turbine by changing the position of the sleeves 44, 46, 48 of the turbine.

This control device is well known in the art and therefore a detailed description thereof will be omitted.

In the present invention, the first and second valve control devices 3
Motors 56 and 58 for controlling the spring pressure and therefore the oil pressure in the cylinders 8 and 40 are connected to the bleed passage 22, respectively.
and first and second pressure sensing devices 60, 62 connected to the bleed/admixture passage 26,
For example, if the bleed pressure in the bleed air passage 22 becomes higher than a predetermined value, the motor 56 receives a corresponding electric signal, which weakens the spring pressure, lowers the oil pressure in the cylinder, and operates the servo motor 32. to reduce the opening degree of the high pressure regulating valve CV _H , thereby reducing the
2 The extraction pressure is lowered to a predetermined value.

A motor 64 that controls the spring pressure in the cylinder of the third valve control device 42 is connected to an automatic output control device APC described below. That is, the automatic output control device APC is for keeping the electricity purchase power constant, and is connected to the external power system 66, senses the amount of electricity purchase power, and when the consumption rate becomes above or below a predetermined value, A corresponding signal is sent to the motor 64, which changes the spring pressure in the cylinder of the third valve control device 48 to change the oil pressure in the same cylinder, thereby actuating the servo motor 36 of the low pressure regulator CV _L. By changing the opening degree of the valve CV _L and changing the output of the turbine low pressure section, the amount of power purchased can be kept constant. As shown in the figure, the external power system is connected to the output system of the turbine generator 68 to supply power.

The above control system is in a normal control state, but when it becomes impossible to control the turbine output by operating the low pressure regulator CV _L to keep the amount of power purchased constant, that is, when the low pressure regulator CV _L becomes fully open or fully closed, the control system described below will replace the low pressure regulator CV _L with the intermediate pressure regulator CV _I , and if the intermediate pressure regulator CV _I becomes fully closed or fully open, is a high pressure regulator instead of a medium pressure regulator
CV _H allows you to perform the same operation.

That is, in the figure, 70 and 72 are switching devices, and the first switching device 70 is electrically connected to the electricity purchase power setting device 76 and the fully open/fully closed limit switch 78 of the low pressure regulating valve CV _L through an AND circuit 74. In addition, the second switching device 72 is connected to an AND circuit 82.
Power purchase through power setting device 76 and medium pressure regulating valve
It is electrically connected to the fully open/closed limit switch 84 of CV _I. Further, the first switching device 70
and second switches 88, 89, and second switching device 72 is mechanically connected to third and fourth switches 82, 84.
Now, if the low pressure regulating valve CV _L is fully opened or fully closed while the automatic output control device APC is sensing that the amount of electricity purchased has become above or below the set value, the AND circuit 74 will have a low pressure Signals are received from the control valve full open/full close limit switch 78 and the power purchase setting device 76, and the AND circuit 74 operates the switching device 70 to switch between the first and second switches. That is, the second valve control device 40 was previously connected to the second pressure sensing device 62 via the first switch 88 and was under the control of the sensing device. Automatic output control device via 2 switch 90
It is connected to the APC and controlled by the controller APC to increase or decrease the output of the turbine intermediate pressure section by controlling the intermediate pressure regulator CV _I. Similarly, the switching device 72 disconnects the first valve control device 38 from the first pressure sensing device 60 and connects it to the automatic output control device APC by the above switching.
Under the APC control signal, the high pressure regulating valve CV _H is controlled to increase or decrease the output of the turbine high pressure section.

The configuration and operation of the turbine control device according to the embodiment shown in FIG. 1 are as described above.

Now, when considering the economic efficiency of the above-mentioned extraction/mixed pressure turbine, power purchase power control, extraction path 2
When considering the control priorities of the pressure control of No. 2 and the pressure control of the air extraction/mixing passage 26, the priorities are as listed above. As mentioned above, in the embodiment shown in FIG. 1, control of the electricity purchase is given priority first, and in order to give priority to the electricity purchase, the control of the extraction/mixing passage 26 is stopped, and then the control of the extraction air passage 22 is stopped. Control is now stopped, which is consistent with the above priorities. Therefore, efficient turbine control is performed in the turbine, and the intended purpose can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a control device according to an embodiment of the present invention. 10... High pressure section; 12... Intermediate pressure section; 14... Low pressure section; 22... Air extraction path; 26... Air extraction/mixing path;
38... First valve control device; 40... Second valve control device; 42... Third valve control device; 60... First pressure sensing device; 62... Second pressure sensing device; 7
0...First switching device; 72...Second switching device; APC...Automatic output control device; CV _H ...High pressure regulating valve; CV _I ...Intermediate pressure regulating valve; CV _L ...Low pressure regulating valve .

Claims (1)

[Claims] 1. A high pressure regulating valve provided at the steam inlet of the high pressure section of the turbine; An intermediate pressure regulating valve provided at the steam inlet of the intermediate pressure section of the turbine; A high pressure regulating valve provided at the steam inlet of the intermediate pressure section of the turbine; a low pressure regulating valve provided at the steam inlet section; a first pressure sensing device connected to the bleed air passage from the high pressure section; a second pressure sensing device connected to the bleed air mixture passage from the intermediate pressure section or the low pressure section; an apparatus and a boiler for supplying process steam; a first valve control device that controls the opening degree of the high pressure regulating valve; a second valve control device that controls the opening degree of the intermediate pressure regulating valve; and an opening degree of the low pressure regulating valve. a third valve control device for controlling; an automatic output control device connected to the power purchasing system to keep the amount of power purchased constant; a first signal transmission system for transmitting a signal to a first valve control device, whereby the first valve control device opens and closes a high pressure regulating valve in response to the signal to maintain the pressure within a certain range; ; A signal generated by the second pressure sensing device corresponding to the pressure sensed by the device is transmitted to the second valve control device, whereby the second valve control device operates the valve opening/closing of the intermediate pressure regulating valve in response to the signal. a second signal transmission system for controlling the pressure and keeping the pressure within a certain range; The signal is transmitted to the third valve control device, thereby causing the third valve control device to open and close the low pressure regulating valve in accordance with the signal, thereby controlling the output of the turbine low pressure section. a third signal transmission system for maintaining the amount of electrical power within a certain range; and an automatic output control device that disconnects the second signal transmission system in response to the low pressure regulating valve becoming fully open or fully closed; is connected to a second valve control device to cause the second valve control device to open and close the intermediate pressure regulating valve in response to the above-mentioned signal issued by the automatic output control device, thereby controlling the output of the turbine intermediate pressure section. a first switching device for maintaining the amount of electricity purchased within a certain range by controlling; after the switching, a first signal in response to the intermediate pressure regulating valve being fully opened or fully closed; The transmission system is disconnected, the automatic output control device is connected to the first valve control device, and the first valve control device is operated to open and close the high pressure regulating valve in response to the above-mentioned signal issued by the automatic output control device. a second switching device for maintaining the amount of power purchased within a certain range by controlling the output of the turbine high pressure section;