JPH0462306A - Feed water control method for drum type boiler when its pressure is raised - Google Patents

Abstract

PURPOSE:To make it possible raise pressure by a minimum required fuel by regulating the opening degrees of a feed water regulating valve and water drum blow valve in such a manner that the feed water temperature at the economizer outlet becomes lower than the saturated steam temperature obtained by operation from the boiler drum internal pressure. CONSTITUTION:Right after the start of pressure ascent of the internal pressure of a drum 1, the feed water flow rate is controlled by regulating the opening degree of a feed water regulating valve 3 by a signal of a drum water level regulator 10 so that a drum water level meter 16 shows the value set by a drum water level setting apparatus 9. Also, when an indicating value of a feed water thermometer at an economizer outlet 4 reaches a saturation temperature obtained by a pressure-saturation temperature converter 11 by a signal of a drum pressure gauge 5, the feed water flow rate is controlled automatically so that the indicating value of the feed water thermometer at the economizer outlet 4 does not exceed the saturation temperature, by regulating the opening degree of the feed water regulating valve 3 by passing through a high selector 13 by a signal of a feed water temperature regulator 12. By this method, the feed water flow rate can be kept at the minimum necessity, and the fuel required to raise pressure can be kept to the minimum.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for controlling the flow rate of feed water when increasing the pressure of a ram-type boiler, and more specifically, when increasing the pressure of a drum-type boiler equipped with an economizer, the feed water temperature at the exit of the economizer is controlled by the drum internal pressure. This paper is related to a method of controlling the feed water flow rate when pressurizing a tram-type boiler, which automatically adjusts the feed water aliquots to be lower than the saturated steam temperature determined from the saturated steam temperature, and minimizes the amount of fuel required for pressurization. The feed water flow rate of tram-type boilers equipped with an economizer is controlled so that the water level on the drum water level gauge is always constant.If promotion is carried out with this drum water level control maintained, the feed water flow will be too small, so the economizer The water temperature inside rises,
Ekotsuma evaporates inside Iza. Therefore, in order to prevent evaporation in the economizer, the feed water flow I III I
By switching I to manual and increasing the water supply flow rate, the temperature of the economizer outlet water supply is lowered, and the drum water level is regulated by the hydrosphere blow valve! i5 or opening the hydrosphere blow valve, it was necessary to increase the water supply flow rate and lower the temperature of the economizer outlet water supply.

Therefore, in order to increase the pressure using the minimum amount of fuel required, it is sufficient to reduce the water supply flow rate, but if the water supply flow rate is too low, it will evaporate within the economizer, so it is necessary to carry out severe water supply.

In summary, in the conventional method, the economizer ratio feed water temperature is manually adjusted, which tends to result in a large flow rate of water supply, leading to an increase in the amount of fuel used to increase the pressure.

Problems to be Solved by the Invention The present invention aims to solve the above-mentioned problems. Specifically, the water supply flow rate is automatically set so that the economizer outlet water supply temperature maintains an upper limit temperature that does not exceed the saturation temperature. Feedwater flow when pressurizing a drum-type boiler that can be pressurized using only a limited amount of fuel m! The purpose is to propose the 11 II+ 75 method.

Means for Solving the Problems and Their Effects Namely, the present invention provides, when controlling the feed water flow rate during pressurization of a drum-type boiler equipped with an economizer, the economizer outlet water feed water flow rate calculated from the boiler drum internal pressure. It is characterized by adjusting the opening degrees of the economizer's water supply flow rate control valve and water barrel blow valve so that the temperature is low.

Hereinafter, the configuration and operation of the means of the present invention will be explained with reference to the drawings.

In addition, FIG. 1 is an explanatory diagram showing the flow of the water supply control system of an example of mushroom loading used when putting the present invention into practice, and FIGS. 2(a), (bl, (C) and (( j) are graphs showing the relationship between time and each control factor according to the flow shown in FIG.

Code 1 is a drum (steam generator), 2 is an economizer, 3
is the water supply a amount control valve, 4 is the economizer outlet water supply temperature gauge,
5 is a drum pressure gauge, 6 is a hydrosphere blow valve, 7 is a super heater, 8 is a main steam blow well, 9 is a tram water level setting device, 10 is a drum water level controller, 11 is a pressure-saturation temperature converter, 12
13 is a water supply temperature controller, 13 is a high selector, 14 is a tram water level upper limit setter, 15 is a hydrosphere blow valve controller, 16 is a drum water level gauge, and 17 is a water barrel.

The operation will be explained below with reference to the explanatory diagram of the flow of the water supply control system for a drum boiler equipped with an economizer shown in FIG.

Immediately after the start of increasing the internal pressure of the drum 1, the drum water level controller 16 adjusts the water supply flow rate by changing the opening degree of the water supply flow rate control valve 3 using the OI7''l signal so that the drum water level gauge 16 reaches the value set by the drum water level setting device 9. As time passes after the start of pressure increase, each control factor changes as shown in Fig. 2 (a), (b), (C), and (d). Among them, the economizer outlet water supply The temperature rises as shown in Figure 2 (b) and approaches the saturation temperature determined by the pressure at that time.The indicated value of the economizer outlet feed water thermometer 4 is determined from the signal of the drum pressure gauge 5 by pressure-saturation temperature conversion. When the saturation temperature determined by the economizer outlet 11 is reached, the signal from the feed water temperature controller 12 passes through the high selector 13 and changes the opening degree of the feed water flow control valve 3, which automatically saturates the indicated value of the economizer outlet feed water thermometer 4. The water supply flow rate is controlled so as not to exceed the temperature.This water supply flow rate control is configured to be given priority over drum water level control by the high selector 13.

In addition, in order to make the indicated value of the economizer outlet feed water thermometer 4 below the saturation temperature, the opening degree of the feed water flow control valve 3 is forcibly adjusted [i5].
However, when the indicated value of the drum water level gauge 16 reaches the value set by the drum water level upper limit setter 14, the opening degree of the water barrel blow valve 6 is increased by the signal from the water barrel blow well controller 15. The tram water level is controlled so that it does not exceed the upper limit.

As explained above, since the temperature of the feed water at the exit without economizing is maintained at the upper limit of the saturated steam temperature, the feed water flow rate can be reduced to the required @low liter, and the fuel required for pressure increase can be kept to the minimum. becomes possible.

In addition, the feed water flow ω control m+ and drum water level control during pressure increase are completely automated, and the conventional method of manually controlling the feed water flow rate had the problem of pressure reduction when the feed water flow interval increased, but the present invention According to the method, there are no problems such as pressure drop, and the pressure increase can be completed within the scheduled time.

Example Hereinafter, an embodiment will be described according to the flow shown in FIG.

As shown in Figure 1, in order to keep the economizer outlet water supply temperature below the saturation temperature determined by the drum pressure,
A device for detecting the saturation temperature determined from the pressure of the drum 1 and a device for controlling the water supply at the exit of the economizer were used. Saturation: Temperature detection is indicated by 1 on tram pressure gauge 5
Calculation is performed using a pressure-saturation temperature converter 11 provided by the city, and the output of this pressure-saturation temperature converter 11 is set to a temperature lower than the saturation temperature, for example, 15° C. lower than the saturation temperature.

The saturation temperature can be detected by directly measuring the temperature inside the drum other than by using the drum pressure, but the method of determining it from the drum pressure is more accurate (automation is possible).

In addition, the method of controlling the economizer outlet water supply temperature is the first method.
This can be done by adjusting the feed water flow rate control valve 3 according to the flow of the embodiment shown in the figure. In this case, when the economizer outlet water supply temperature rises, the water barrel blow valve 6 is opened to increase the water supply flow rate 110 to prevent the drum water level from falling, and the economizer outlet water supply temperature can be lowered.

Note that even if the above operation is started when the temperature measured by the economizer outlet feed water thermometer 4 becomes higher than the temperature output from the pressure car-saturated phase temperature converter 11, the economizer outlet feed water thermometer 4 The temperature rises further, but then, starting from the bottom, it is measured by temperature measurement or pressure-saturation temperature converter 1.
The operation ends when the temperature becomes lower than the temperature output in step 1.

At this time, the pressure further decreases, so the economizer outlet water supply temperature becomes even lower, but then begins to rise.

As described above, the water supply flow rate is adjusted by keeping the economizer outlet water supply temperature below the saturated steam temperature, or the water barrel blow valve is adjusted according to the output of the water supply temperature alii1 moderator, so the water supply flow rate is adjusted to the minimum required amount. In addition, the amount of fuel required for boosting the pressure could be minimized.

Effects of the Invention As explained in detail above, the present invention has the following advantages: when controlling the water flow rate of a gas flashing of a drum-type boiler equipped with an economizer, The opening degree of the economizer's water supply flow rate control valve and hydrosphere blow valve is set to vA so that the temperature of the water supply water at the outlet of the Economizer is lowered.
It is characterized by knots.

According to the present invention, the following excellent features are achieved! 211 fruits are obtained.

(a) Since the economizer outlet temperature is maintained at the upper limit temperature below the saturated steam temperature, the feed water flow rate can be kept to the minimum required amount, and the fuel required for pressurization is now required to the minimum. .

(The feedwater flow pile control and drum standard control when increasing the BL pressure are completely automated, eliminating the need for the operator to perform operations when increasing the pressure, reducing the burden on the operator.

(C) Water supply flow during pressure increase - Since the control is performed automatically, the pressure will not drop due to the sudden increase in the amount of water supply a, and the pressure increase will be completed on time. became.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the flow of a water supply control system of an example of a device used when implementing the present invention, and FIGS. 2(a) and (b)
), (C) and (d) are graphs showing the relationship between time and each 1111 [1 factor] according to the flow of FIG. 1, respectively. Sign @1...Drum (steam generator)2...
・Economizer 3...Water supply flow rate control valve 4...Ecotsuma, Isa outlet water supply temperature gauge 5...
... Drum pressure gauge 6 ... Water control blow well 7 ... Super heater 8 ... Main steam blow valve 9 ... Tram water level setting device 10 ...Drum water level controller 11...Pressure-saturation temperature converter 12...
・Feed water temperature controller 3...High selector 4...Drum water level upper limit setter 5...Water barrel blow valve controller 6...Drum water level gauge 7 ...hydrosphere

Claims (1)

[Claims] 1) When controlling the feed water flow rate during pressurization of a drum-type boiler equipped with an economizer, the feed water flow rate control valve and water barrel of the economizer are adjusted so that the economizer outlet feed water temperature is lower than the saturated steam temperature calculated from the boiler drum internal pressure. A method for controlling the flow rate of feed water during pressurization of a drum-type boiler, characterized by adjusting the opening degree of a blow valve.