JPS6151128B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a starting device for steam equipment in which a turbine is connected to a boiler via a main steam pipe, and a starting pipe having a starting valve is connected in parallel to the turbine.

When starting up this type of steam-powered equipment, the air generated in the boiler is first led to a starting pipe connected in parallel to the turbine. When a reheater is present, this type of start-up line connects the main steam line to the steam turbine to the reheater inlet. During phases when no steam is to be fed into the low pressure stage of the turbine, the steam leaving the reheater reaches the condenser via another pipe that can be closed. The condensate condensed in the condenser is sent to the water supply tank, passes through the preheater, and then passes through the boiler. In this type of steam-powered equipment, when the startup piping branches off from the main steam piping at a location close to the boiler, steam is not allowed to flow into the main steam piping until the high-pressure turbine is started. Therefore, if special measures are not taken to preheat the main steam line, delays may occur during cold start-up of the steam turbine installation. If the startup piping is branched from the main steam piping at a location close to the turbine, this means that the steam turbine plant has been shut down for more than a month during a cold start, and when restarted, the main steam piping must be connected from the initial stage of steam generation. Preheated. However, when the steam turbine plant is warmed up, that is, the operation of the steam turbine plant is temporarily stopped for a short period of time, for example, 8 to 24 hours, and then restarted, the steam generated in the boiler is initially
Since the temperature is lower than that of the main steam pipe, the main steam pipe is unnecessarily cooled and then heated again.

In other words, when starting a cold engine, the temperature of the main steam piping is almost equal to the environmental temperature of the steam turbine plant, for example, about 20°C, and on the other hand, the temperature of the boiler outlet steam at the beginning of startup is definitely the same as the temperature of the main steam piping. higher than the temperature of However, during warm-up and startup, if a steam turbine plant with a main steam temperature of 538° C. is shut down while in operation, the temperature of the turbine equipment, including the main steam piping, will begin to decrease due to natural cooling. However, if the temperature is stopped for a short time, the drop in temperature is small, and even if the temperature drops in the main steam piping, it still remains.
It maintains a temperature close to 500℃. Naturally, this temperature gradually decreases depending on the stopping time. On the other hand, the area around the boiler cools relatively quickly, and at the beginning of steam generation, the boiler outlet piping can only supply steam at a temperature lower than that of the main steam piping. Therefore, in the initial stage of warm-up, the main steam piping is cooled down.

The object of the present invention is to eliminate the above-mentioned disadvantages,
The idea is to avoid unnecessary thermal stress on the main steam piping to allow for desirable turbine start-up.

According to the invention, this purpose is achieved by two
Two start-up pipes are provided, one start-up pipe is located close to the boiler, and the other start-up pipe is branched from the main steam pipe at a position close to the turbine, and the start-up pipe is located after the start-up boiler exit of said one start-up pipe. It is controlled depending on the steam pressure in the main steam pipe, and the start valve of the other start pipe is controlled depending on the difference between the temperature of the main steam after the boiler outlet and the temperature of the main steam pipe before the turbine inlet. This is achieved by

The embodiments shown in the drawings will be described below. The steam power equipment in this example has water supply pumps 2 and 3 at the front and rear.
It consists of a water supply tank 1 connected to a preheater 4, a boiler 5 having a steam/water separator 6, a circulation pump 7, a superheater heat transfer surface 8, and a reheater 9. A main steam pipe 10 runs from the boiler to a high pressure turbine 1 to which a valve 1 is connected.
It leads to 1. Reheater 9 is connected between high pressure turbine 11 and low pressure turbine 13. A check valve 14 is connected between the high-pressure turbine 11 and the reheater 9, and another valve 15 is connected after the reheater 9. The high pressure turbine 11 and the low pressure turbine 13 are connected to the generator 16
and are arranged on one axis. A condenser 17 is connected after the low-pressure turbine 13, and the back air of the low-pressure turbine 13 is supplied thereto. A pipe 18 having a valve 19 is provided in parallel with the low pressure turbine 13, and the reheater 9 and the condenser 17 are communicated with each other.

In this power equipment, the starting valve 2
Two starting pipes 20 and 21 having numbers 2 and 23 are provided. The startup pipe 21 branches from the main steam pipe at a position close to the boiler outlet, while the startup pipe 2
0 is connected to the main steam line 10 immediately in front of the valve 12. The other ends of the startup pipes 20 and 21 are the reheater 9
It is connected to the entrance of Temperature measuring devices 24 and 25 are also provided for measuring the main steam temperature at the outlet of the superheat transfer surface 8 and at the inlet of the high-pressure turbine, that is, in front of the branch point between the valve 12 and the starting pipe 20. The output signals of both measuring crowns are led to a subtractor 28 , and the output signal of the subtractor 28 acts on the starting valve 22 of the starting pipe 20 via a control circuit 29 . Furthermore, a pressure measuring device 26 for measuring the main steam pressure in the main steam pipe 10 at the boiler outlet is provided, and its output signal acts on the starting valve 23 of the starting pipe 21 via a control circuit 27.

In the steam power equipment configured in this way,
During cold start, the start valves 22 and 23 are opened, the valves 12 and 15 in front of the high pressure turbine 11 and the low pressure turbine 13 are closed, and the valve 19 is completely closed.
or partially opened to allow steam to vent. When the temperature of the steam supplied from the boiler 5 rises and the steam temperature in the main steam pipe 10 reaches a superheated steam state higher than the saturated steam temperature, the valves 12 and 15 are gradually opened to allow steam to flow through the high pressure Turbine 11 and low pressure turbine 13 are driven.

On the other hand, in the case of warm-up startup, the valves 12 and 15 of the high-pressure turbine 11 and the low-pressure turbine 13 and the valve 1
9, the starting valve 22 is closed and the starting valve 23 is opened to allow steam to flow through, in the same state as in the case of cold starting. At this time, the steam supplied from the boiler 5 passes through the main steam pipe 10 and is connected to the starting valve 22 and the valve 12 of the high-pressure turbine 11, but the starting valve 22 and the valve 12 are closed and the steam is not flowing. Since there is no flow, heat transfer is extremely small, and the temperature of the main steam pipe 10 after the branch point of the startup pipe 21 hardly changes. Only when the temperature of the steam supplied from the boiler 5 reaches or exceeds the temperature of the main steam pipe 10 does the starting valve 22
When the steam temperature reaches a temperature suitable for driving the turbine, the valves 12 and 15 of the high-pressure turbine 11 and the low-pressure turbine 13 are opened and the turbines are driven.

That is, the starting valve 22 is controlled to open when the temperature difference between the temperature measuring devices 24 and 25 becomes positive. On the other hand, the starting valve 23 adjusts the pressure inside the main steam pipe 10, and the starting valve 22 is controlled to open and close based on the temperature difference between the two temperature measuring devices 24 and 25. By adjusting the opening degree of the starting valve 23, pressure changes in the main steam piping due to changes in the amount of steam are canceled out, and the optimum pressure condition for starting the turbine is achieved by adjusting the opening degree of the starting valve 23. It is something to do.

As explained above, by controlling the starting valve 22 in relation to temperature and the starting valve 23 in relation to pressure, the pressure and temperature in the main steam pipe 10 can be controlled at every stage of the starting process. , it is possible to maintain the desired state with only slight fluctuations, avoid generation of unnecessary thermal stress in the main steam piping, and enable smooth startup of the turbine.

[Brief explanation of the drawing]

The drawing is a schematic system diagram of a steam turbine installation based on the present invention. 1: Water tank, 2, 3: Water pump, 4: Preheater, 5: Boiler, 6: Steam separator, 7: Circulation pump, 8: Superheater heat transfer surface, 9: Reheater, 10: Main Air piping, 11: High pressure turbine, 12, 15, 1
9: Valve, 13: Low pressure turbine, 14: Check valve,
16: Generator, 17: Capacitor, 18: Piping,
20, 21: Starting pipe, 22, 23: Starting valve, 2
4, 25: Temperature measuring device, 26: Pressure measuring device, 2
7, 29: control circuit, 28: subtractor.

Claims (1)

[Claims] 1. In a starting device for steam power equipment in which a turbine is connected to a boiler via a main steam pipe, and a starting pipe with a starting valve is connected in parallel to the turbine, two starting pipes with starting valves are connected in parallel to the turbine. One of the startup piping branches off from the main steam piping at a position close to the boiler, and the other startup piping branches off from the main steam piping at a location near the turbine, and the startup valve of said one startup piping branches off from the main steam piping at a location near the boiler outlet. The starting valve of the other starting pipe is controlled depending on the difference between the temperature of the main steam after the boiler outlet and the temperature of the main steam pipe before the turbine inlet. A starting device for steam-powered equipment.