JPS58170805A - Starting method of plant with boiler and turbine - Google Patents

Abstract

PURPOSE:To permit the rapid starting of a plant by a method wherein a superheater spraying device, adjusting a steam temperature at the outlet of the final superheater to a specified value upon putting the turbine into the parallel operation in the plant for a period until the parallel operation after passing steam through the turbine, is provided in the plant. CONSTITUTION:A plant of a boiler and a turbine is provided with a final superheater 10, a turbine 11 and a reheater 12. An adder 15 calculates a difference between the final superheater outlet steam temperature Tact and the specified value Tset of the final superheater outlet steam temperature upon putting the turbine into the parallel operation and inputs it into a proportional plus integral controller 17 through a changeover switch 16. The final superheater outlet steam temperature is controlled by the superheater spraying device so that it becomes the specified value of the final superheater outlet steam temperature upon putting the turbine into the parallel operation. Thus, the rising of a turbine inlet steam temperature may be suppressed and the matching of the turbines may be facilitated while the amount of spray becomes a much amount of evaporation and the rapid starting of the plant after putting the turbine into the parallel operation may be permitted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature control method at the time of startup in a plant consisting of a drum boiler having a turbine bypass, a variable pressure monotube boiler, and a steam turbine.

Conventionally, the turbine inlet steam temperature at startup of a boiler/turbine plant with a turbine bypass is controlled only by fuel, so the amount of fuel input is suppressed by the specified temperature of the turbine inlet steam during ventilation and parallel entry. (Fuel input can be given manually or based on a preset pattern).

In the conventional method, the amount of fuel input during parallel entry is suppressed by the matching temperature with the turbine metal during parallel entry, so the increase in the fuel injection lid from ventilation to parallel entry is small, or the amount of fuel input is suppressed. may even decrease. Therefore,
＃The fuel input is also limited, and it is impossible to have a large amount of evaporation. As a result, rapid startup of plants is required.

With rapid startup, the time to increase from normal to full load is very short, but during this time the electric drive water pump (MBFP)
) to turbine-driven water pump (TBFP) (
The load change rate can be suppressed to about 5%/min due to the need to save time for operations such as additional drive of the TBFP (carried out at about 50% load) and restrictions such as temperature control. Therefore, from the initial load after parallel input, MBFP/TBFP
The load increase until switching is much higher than before (
Then I won't have a monkey.

However, in order to obtain the necessary amount of turbine steam using the conventional method, even if the fuel is increased after parallel injection, it is difficult to secure the necessary amount of evaporation due to the delay in heat absorption in the boiler. In addition, a sudden change in fuel causes a sudden rise in the metal temperature of each part of the boiler, which is undesirable because it releases thermal stress, making it impossible to perform a rapid start-up.

The present invention has been made in view of the above circumstances.In order to ensure the amount of evaporation necessary for rapid startup at the time of parallel entry, sufficient fuel is gradually introduced between ventilation and parallel entry, and the accompanying turbine inlet steam is The purpose is to suppress temperature rise and enable rapid startup of the plant.

According to the present invention, in a startup temperature control method for a plant including a drum boiler, a variable pressure monotube boiler, and a steam turbine having a turbine bypass, turbine ventilation is In addition to injecting a large amount of fuel between the piers, this operation also prevents overmatching of the steam and turbine metals during parallel piping.5. The superheater spray device provides for adjusting the final superheater outlet steam temperature to a specified value of the final superheater outlet steam temperature during parallel entry.

In other words, in order to ensure the amount of evaporation necessary for rapid startup of the plant at the time of parallel entry, if a large amount of fuel is injected between ventilation and parallel entry, the turbine artificial steam temperature will rise, so there will be an overflow of steam and metal at the time of parallel entry. Matching occurs, but by suppressing this temperature rise using the superheater sgerley device, matching becomes easier, and it also takes advantage of the fact that the amount of evaporation increases with the addition of fuel input and that the amount of spray becomes the amount of evaporation. A method for a boiler-turbine plant is provided that enables rapid start-up of the plant after commissioning by obtaining a large amount of evaporation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below as illustrated in the accompanying drawings.

FIG. 1 shows the configuration of a superheater spray control device in a boiler turbine plant implementing the method of the present invention. In FIG. 1, reference numeral 1O indicates a final superheater, 11 a turbine, and 12 a reheater. Further, reference numeral 13 is a final superheater outlet source, a temperature detector for detecting the air temperature Tact,
14 is the specified value Tse of the final superheater outlet steam temperature during parallel entry
15 is an adder, 16 is a changeover switch, and 17 is a proportional-integral controller.

The method of the present invention uses such a control device to manipulate the superheater spray amount to control the turpin inlet temperature after the turbine is vented until the turbine is turned on.

The adder 15 receives the final superheater outlet steam temperature Tact and the specified value T4et of the final superheater outlet steam temperature at the time of parallel input, takes the deviation of these, and inputs it to the proportional-integral controller 17 via the changeover switch 16. . This proportional-integral controller 17 determines the amount of superheater spray operation. Changeover switch 1
Reference numeral 6 denotes an ON-OFF changeover switch, which is controlled to be OFF by the adder 15 while the deviation between Tact and Tset is negative, and is kept ON thereafter once the deviation becomes positive. That is, this changeover switch is used to prevent a negative deviation from being stored in the proportional-integral controller 17 while the temperature is being increased between ventilation and parallelization (during Tact<Tset).

FIG. 2(a) shows the amount of fuel input at startup. If a large amount of fuel is injected as shown in the figure, without considering the matching at the time of parallel entry, as shown in the figure, the conventional superheater spray will not be used. In this method, the turbine inlet steam temperature is determined as shown in Figure 2 (
As shown in b), the temperature rises and matching cannot be performed when paralleled, but if a superheater Sergei is used, the temperature can be controlled by spraying as shown in Fig. 2 (scent) and matching can be done easily.

At this time, the amount of spray is shown in Figure 2(d), and the amount of evaporation is shown in Figure 2(d).
e).

In Fig. 2 (b) and (C), the symbol TS is the specified final superheater outlet steam temperature during parallel entry, TR is the specified final superheater outlet steam temperature during ventilation, and TS' is the specified turbine inlet steam temperature during parallel entry. The temperature TR' indicates the specified turbine inlet steam temperature during ventilation.

In the case of the example shown in FIG. 2, the amount of evaporation increases due to the increase in the amount of fuel input, and since the amount of spray is all the amount of evaporation, a sufficient amount of evaporation can be ensured by combining the two. This makes it possible to increase the load increase rate from the initial load after parallel entry, making it easier to start up quickly, and by using the spray's dependence on steam temperature, it is possible to match the steam temperature and turbine metal temperature at the time of parallel entry. becomes easier.

Although the present invention has been described in detail with reference to a preferred embodiment thereof, the present invention is not limited to this specific embodiment (although many changes and modifications can be made without departing from the spirit of the invention).

For example, in the present invention, superheater spray was used to obtain the large amount of evaporation necessary to increase the rate of load increase from the initial load of a plant consisting of a boiler and a steam turbine with a turbine bypass and a drum. Even in general boiler/turbine plants, it is an effective method to use superheater spray after the turbine steam enters the turbine until it enters the turbine, in order to easily match the temperatures of the steam and turbine metal during parallel entry. The invented method can be easily applied for this purpose.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a control device for implementing the method of the present invention, and FIG. 2 is a graph showing various examples of states at the time of startup of a point turbine plant. 10... Final superheater, 11... Turbine, 12... Reheater, 13... Temperature detector, 14... Setting device, 15... Adder, 16... Changeover switch, 17... Proportional-integral control vessel. 'IJZ diagram [e] Salmon tea bowl Ginryu

Claims (1)

[Claims] In a boiler 0 turbine plant, turbine ventilation M,
II. A method for starting a boiler/turbine plant that includes adjusting the final superheater outlet steam temperature or the final superheater outlet steam temperature at the time of heating by a superheater spray device to the current value for up to two people.