JPH0692807B2 - Moisture separation heating system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a moisture separation heating system of a power plant at startup, and a moisture separation heater system improved so as to improve economic efficiency and reliability. It is about.

[Conventional technology]

As the latest known technology closest to the present invention with respect to the moisture separation heater, there is Japanese Patent Publication No. 55-38563.

In the above-mentioned known technology, the exhaust gas of the high-pressure turbine is used as a heat source to heat the exhaust gas of the high-pressure turbine by the primary heater. However, in this known technology, the primary heater is warmed before starting the turbine. Machine (heat the equipment before operating it, and
It does not take into consideration a special configuration for reducing the thermal strain).

[Problems to be solved by the invention]

FIG. 2 is a schematic system diagram of a conventional moisture separation heating system.

As the heating steam for the primary heater 4 of the moisture separator / heater 3, the extracted steam of the high-pressure turbine 2 is supplied through the primary heating steam pipe 8.

The heating steam for the secondary heater 5 is the main steam 1 a generated from the steam generator 1 supplied through the secondary heating steam pipe 9.

The initial heating steam aeration for the above-mentioned primary heater 4 and secondary heater 5 is performed as follows. (See Figure 3). Before the turbine is installed in the secondary heater 5, main steam is supplied while the small capacity control valve 10 is slightly opened to warm up the secondary heater 5 and the pipe 11 for a sufficient time. be able to. After the turbine is installed, the opening of the small capacity control valve 10 gradually increases, and when it reaches a predetermined partial load operation, it is switched to the large capacity control valve 12.

The heating steam to the primary heater 4 is supplied by opening the valve 13 by the signal of "combination of turbine". Therefore, the primary heater 4 supplies heated steam under each turbine load condition without warming up. In this case, if the valve 13 is squeezed to warm up, there are two problems. The first point is that the valve 13 is a large-diameter valve and it is difficult to perform a throttle operation with a small flow rate, and the other point is that the load increase time of the turbine is significantly delayed, which greatly affects the plant start-up operation. Especially for a load following plant, extending the start-up time is a serious problem.

Next, the situation of temperature change for examining the thermal stress and thermal strain in the primary heater 4 and the secondary heater 5 will be described with reference to FIG.

FIG. 4 (B) is a chart in which temperature is plotted on the vertical axis and steam flow is plotted on the horizontal axis, and FIG. 4 (A) is an explanatory diagram of the measurement points of the temperature symbols shown in the chart.

The temperature difference ratio (ΔT _1N / ΔT _2N ) between the heated steam and the room temperature before warming up in each heater is about 0.85, and the temperature difference ratio between the heated steam and the heated steam (ΔT ₁ / ΔT ₂ ) is about 0.7. In case of
The temperature difference ratio between the secondary heater and the secondary heater is a value close to each other, and like the secondary heater 5, the primary heater 4 needs to be warmed up.

However, in the conventional technique, the warm-up of the primary heater 4 was not performed because the warm-up was impossible due to the system configuration as described above. For this reason, thermal stress and thermal strain are generated in each component of the moisture separation and heating system (especially at startup), which adversely affects the durability of the part.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a moisture separation heating system capable of sufficiently warming up a primary heater without extending the required startup time only at startup. And

[Means for solving problems]

In order to achieve the above object, the moisture separation heating system of the present invention comprises a steam source, a high pressure turbine driven by main steam supplied from the steam source through a main steam pipe, and the high pressure turbine. A primary heater that heats the exhaust gas of the high-pressure turbine by using the extracted steam of the turbine as a heat source, and a exhaust gas of the high-pressure turbine that heats part of the inlet steam of the high-pressure turbine as a heat source 2
In a moisture separation heating system including a secondary heater, a pipe and a valve for supplying heat source steam to the primary heater, the secondary heater, and a control device, the main steam pipe and the primary heater The pipe connected to the heat source steam supply pipe is connected to the pipe, and the valve connected to the pipe is opened / closed by receiving a turbine start operation control signal. It is characterized in that a control device for controlling is provided, and a part of the main steam can be supplied to the primary heater only at the time of starting.

[Action]

According to the above configuration, part of the main steam can be warmed up by flowing through the primary heater while controlling the flow rate with the valve. In addition, since this warm-up operation can be performed with a sufficient time margin before the turbine is combined, the effect of preventing thermal stress and thermal strain at the time of starting is remarkable.

〔Example〕

FIG. 1 shows a moisture separation heating system in one embodiment of the present invention. This embodiment is an improvement of the conventional example shown in FIG. 3 by applying the present invention. The difference from the conventional moisture separation heating system is that of the primary heater 4 of the moisture separation heater. A warm-up pipe 14 and a warm-up valve 15 which connect the primary heating steam pipe 8 and the secondary heating steam pipe 9 of the secondary heater 5 are provided, and the secondary heating device is connected to the secondary heating device before the turbine is installed. The heater was also done in order to complete warming up.

The primary heater 4 thus configured is warmed up as follows.

Before warming up the secondary heater 5 with the turbine, the small capacity control valve 10
By slightly opening and ventilating the main steam. on the other hand,
For warm-up of the primary heater, the small-diameter warm-up valve 15 provided by applying the present invention is opened by the interlock with the same signal as the open signal (main steam pressure specified pressure, etc.) of the small capacity control valve 10. By supplying main steam. Warm steam flow rate, pressure,
The temperature is monitored by respective instruments 16,17,18. The drain after warming up is collected in the condenser via the drain tank 19 and the drain valve 20.

When the above operation is performed, since the warm-up of the primary heater 4 is completed at the turbine adjoining time, the warm-up valve 15 is opened by the interlock in response to the "turbine adjoining" signal.

The valve 13 at the heating steam inlet of the primary heater 4 is a conventional example (third
(Fig.) And this embodiment (Fig. 1).

In the conventional example, this valve 13 was opened by the interlock based on the signal of "combining turbines", but in this embodiment, "warm-up valve 15 closed" even before "combining turbines".
It is configured so that the valve is opened by the interlock according to the AND condition with the signal. By providing the AND condition of this interlock, it is possible to prevent the backflow of the main steam for warm-up to the high-pressure turbine 2.

FIG. 5 is a chart showing the open / closed state of each valve described above.

FIG. 6 shows another embodiment of the present invention. The difference from the embodiment of FIG. 1 is that the warm-up valve 15 in the previous example is a regulating valve 21, main steam is supplied from the upstream side of the small capacity regulating valve 10, and the regulating valve 21 is controlled by a pressure control device 22. This is the configuration.

〔The invention's effect〕

According to the present invention, since the primary heater of the moisture separation heater can be sufficiently warmed up before the turbine is incorporated only at the time of start-up, (i) the problem of thermal stress of the primary heater can be solved, and cracks such as cracks Prevent accidents and improve reliability.

(Ii) Rapid heating steam can be supplied to the primary heater in the load operation stage, which is extremely effective for a quick start-stop plant in which shortening the start-up time is an essential condition only at start-up.

[Brief description of drawings]

FIG. 1 is a system diagram of one embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams of a conventional moisture separation heating system, and FIG. 4 is an explanatory diagram of temperature distribution which is the background of the present invention. FIG. 5 is an explanatory diagram of a valve opening / closing procedure and a turbine load in the embodiment of the present invention, and FIG. 6 is a system diagram in another embodiment of the present invention. 2 ... High-pressure turbine, 4 ... Primary heater, 5 ... Secondary heater,
8 ... Primary heating steam pipe, 9 ... Secondary heating steam pipe, 10 ... Small capacity adjusting valve, 11 ... Piping, 13 ... Valve, 14 ... Warming pipe, 15 ... Warming valve,
21 ... Regulator valve, 22 ... Pressure control device.

Claims (1)

[Claims] 1. A steam source, a high-pressure turbine driven by main steam supplied from the steam source through a main steam pipe, and bleeding steam of the high-pressure turbine as a heat source for heating exhaust gas of the high-pressure turbine. A primary heater, a secondary heater that heats exhaust gas of the high-pressure turbine by using a part of inlet steam of the high-pressure turbine as a heat source, and a pipe that supplies heat source steam to the primary heater and the secondary heater In a moisture separator heating system including a valve and a valve, a pipe line that connects the main steam pipe and the heat source steam supply pipe for the primary heater is provided, and a valve is connected to the pipe line. Further, the valve connected to the above-mentioned pipeline is equipped with a control device for performing opening / closing control signal for opening / closing the turbine when the turbine is started, and a part of main steam can be supplied to the primary heater only when the turbine is started. Moisture separation heating characterized by Integration.