JPS606447B2 - Boiler control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION As shown in FIG. 1, part of the control system of a conventional once-through boiler is 011 a target power generation amount setting device, 02 an adder, 03 a deviation between the required power generation amount and the target power generation amount, 04 is a limiter that gives upper and lower limit values to deviation 03.

05 is the rate of change in the required power generation amount, 06 is the time integrator, 07
is the required power generation amount, 08 is the adder, 09 is the combustion amount command signal,
010 is a water supply amount command signal, and 011 is a code converter.

In order to improve the responsiveness of the power generation amount, the change rate 05 is added to the required power generation amount 07 in an adder 08, and the result is used as a command signal for the combustion amount and water supply amount.

However, in variable pressure boilers, the turbine governor valve is maintained near full open, so controllability of power generation becomes poor in the direction of increasing power generation, and steam pressure changes depending on power generation, which causes disturbance to steam temperature control. However, this control system has some inadequacies. The present invention was proposed in view of the above circumstances, and aims to provide a boiler control device that improves the controllability of power generation amount and steam temperature, and uses a constant that generates a constant determined by the sign of the rate of change in the required power generation amount. A generator, a function generator that generates a variable determined by the required power generation amount, a multiplier that multiplies the output of both generators by the rate of change in the required power generation amount, and a signal that adds the output of the multiplier to the required power generation amount. The present invention is characterized in that it is equipped with a control system consisting of an adder for obtaining the amount of water, and that the amount of combustion and the amount of water supplied are controlled using the output of the adder. One embodiment of the present invention will be explained with reference to FIG. 2. 1 is a target power generation amount setter, 2 is an adder, 3 is a deviation between the required power generation amount and the target power generation amount, 4 is a limiter, and 5 is a change in the required power generation amount. speed, 6 is a time integrator, 7 is the required power generation amount, 8 is a constant generator that generates a constant that differs depending on the sign of the change rate 5 of the required power generation amount, 9 is a multiplier, 1 value is determined by the value of the required power generation amount 7 A function generator that emits a value, 11 is a multiplier, 12
13 is a combustion amount command signal, 19 is a water supply amount command signal, and 22 is a code converter.

In such a control device, the rate of change of the required power generation amount 5
A constant generator 8 generates a constant according to the positive or negative sign of The output 20 is obtained by multiplying by the rate of change 5 of the required power generation amount.

This is added to the required power generation amount 7 in an adder 12 and used as a combustion amount command signal 13 and a water supply amount command signal 19. In the conventional control system, as shown in Fig. 1, the command signal for water supply and combustion amount is obtained by adding the required power generation amount and its rate of change as a correction signal, but in the present invention, the rate of change, which is the correction signal, is used as a command signal for water supply and combustion amount. The effect can be adjusted depending on the current required power generation amount and whether it is increasing or decreasing.

Another embodiment different from that shown in FIG. 2 will be described. As shown in FIG. 3, the control system shown in FIG. 2 is provided with two systems. That is, 14 is a constant generator like 8, 15 is a multiplier like 9, and 1
6 is a function generator like IQ, 17 is a multiplier like 11,
18 is an adder similar to 12, and its output becomes a command signal for water supply amount. In such a device, "the combustion amount 13 is controlled by one control system, and the water supply amount 19 is controlled by the other control system. Constant generators 8, 14
The constant value of and the function form of the function generators 10 and 16 are selected in accordance with the combustion characteristics of the boiler and water supply characteristics, and the combustion amount and water supply amount can be adjusted separately.

Therefore, for example, if the effect is strengthened when the rate of change in the required power generation amount is positive, it is possible to compensate for the decrease in controllability of the power generation amount when the load increases, and to reduce the ratio between the combustion amount and the water supply amount at low loads. By changing the temperature, it is possible to compensate for the decrease in controllability of the steam temperature due to the decrease in pressure. In practice, constant generators 8 and 14 and function generators 10 and 1 are used at the test run stage.
6 will be optimally set.

[Brief explanation of the drawing]

FIG. 1 is a control system diagram of a known boiler, and FIGS. 2 and 3 are control system diagrams showing embodiments of the present invention. 1... Target power generation setting device, 4... Limiter,
5... Change rate t of required power generation amount 6... Time integrator, 7... Demanded power generation amount, 8... Constant generator,
9... Multiplier, 10... Function generator, 11...
... Multiplier, 12 ... Adder, 13 ... 0 combustion amount command signal, 19 ... Water supply amount command signal. Figure 7 Leopard 2 Figure Mackerel 3 Figure

Claims (1)

[Claims] 1 A constant generator that generates a constant determined by the sign of the rate of change in the required power generation amount, a function generator that generates a variable determined by the required power generation amount, and a generator for multiplying the output of both generators by the rate of change in the required power generation amount. A boiler comprising a control system comprising a multiplier and an adder for obtaining a signal obtained by adding the output of the multiplier to the required power generation amount, and controlling the combustion amount and water supply amount using the output of the adder. control device.