JPS6337291B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for correcting calorie fluctuations due to changes in fuel.

In plant fuel control, calorie fluctuations due to changes in fuel are large, so calorie correction is necessary for the plant to provide stable performance.

The conventional calorie correction method will be explained with reference to Fig. 1. In the figure, a indicates a fuel flow rate detector, b indicates a multiplier,
C is a manual signal generator that changes coefficients depending on the type of fuel, d is a comparator, f is a controller, and when the fuel changes, the flow rate command _Q1 detected by fuel flow rate detector a is a manual signal generator. The multiplier b multiplies the coefficient K determined by the type of fuel set in c, and sends it to the comparison operation d as Q ₂ =KQ ₁ , and the set fuel flow rate command Q ₃ and the comparison operation unit d
The controller f is calculated according to the deviation of ΔQ=Q ₃ −Q _2.
As long as the amount of steam generated remains the same, the amount of calories that can be obtained from the fuel changes even if the fuel changes. were made to be the same.

However, with such conventional devices, it is difficult to continuously set the coefficients when the calorie value fluctuates over time or when the calorie value cannot be easily obtained. If the calorie fluctuation range is large, or if inappropriate coefficient settings are continued for a long time, the output signals of the pressure control controller, steam temperature controller, exhaust gas O ₂ controller, etc. will swing out (saturate). The steam pressure, steam temperature,
Because the exhaust gas O ₂ concentration is not corrected properly,
It often interfered with driving.

The present invention was made for the purpose of automatically correcting steam pressure, steam temperature, and exhaust gas O ₂ concentration when the calorie of fuel fluctuates, thereby enabling smooth operation. Or, by comparing and calculating the steam pressure or steam temperature detected by the steam temperature detector and the steam pressure set value or steam temperature set value set by the steam pressure setting device or the steam temperature setting device, the deviation of the steam pressure or steam temperature is corrected. a first comparator for calculating a signal; an adder for adding a fuel flow rate command from a function generator that converts a boiler output command into a fuel flow rate command; and a deviation correction signal from the first comparator; A fuel flow control valve installed in a pipe line provided with the fuel flow rate detector, which compares and calculates a signal of the fuel flow rate detected by the flow rate detector and sent via the multiplier and the signal from the adder. a second comparison calculator that outputs a command signal to the function generator; a third steam calculator that compares and calculates the fuel flow rate command output from the function generator and the fuel flow rate signal output from the multiplier; The present invention is characterized in that it includes an integrator that integrates the deviation output from the arithmetic unit and provides the multiplier with a coefficient for calorie correction corresponding to the integrated value.

Embodiments of the present invention will be described below with reference to the drawings.

In Fig. 2, 1 is a steam pressure detector, 3 is a first comparator that compares and calculates the signal from the steam pressure setting device 2 and the signal from the steam pressure detector 1, and 4 is the signal from the comparator 3. 5 is a function generator that converts the boiler output command into a fuel command, 6 is an adder that adds the signal from the controller 4 and the signal from the function generator 5, and 7 is installed in the fuel supply system. 9 is a multiplier that multiplies the signal from the fuel flow rate detector 7 and the signal from the integrator 8; 10 is a second unit that compares and calculates the signal from the multiplier 9 and the signal from the adder 6; 11 is a controller that adjusts the signal from the comparison calculator 10, 12 is a fuel flow control valve whose opening degree can be adjusted according to the signal from the controller 11, and 13 is a function generator. This is a third comparator which compares the signal from multiplier 5 with the signal from multiplier 9 and sends the signal to integrator 8.

Next, the operation of the present invention will be explained.

First, to explain the case where the fuel does not change and there is no need to perform calorie correction, the steam pressure signal set by the steam pressure setting device 2 is sent to the comparator 3.
The pressure detected by the steam pressure detector 1 is compared with the pressure detected by the steam pressure detector 1, and the deviation correction signal is sent to the adder 6 via the controller 4.

On the other hand, the set boiler output command is converted into a fuel flow command by the function generator 5 and sent to the adder 6, where it is added to the deviation correction signal sent from the comparator 3 via the controller 4. and is sent to the comparator 10.

Also, the actual fuel flow rate being supplied is measured by the fuel flow rate detector 7 and sent to the multiplier 9, but if the fuel remains unchanged, the calorie correction signal (output of 8) is constant, so the multiplier is In case 9, the coefficient is 1.
In other words, the measured value is sent as is to the comparator 10, where it is compared with the signal from the adder 6 to determine the deviation, and the deviation correction signal is sent to the fuel flow control valve 12 as a fuel flow command. sent,
The valve opening degree of the fuel flow control valve 12 is controlled until the deviation from the comparator 10 becomes zero.

When the above-mentioned control is performed, the signal converted from the boiler output command to the fuel flow command by the function generator 5 and the signal from the fuel flow detector 7 are sent to the comparator 13.
However, since these signals are substantially equal, the output from the comparator 13 is zero. Also, although a deviation may occur temporarily from the comparator 13, by adjusting the integration time in the integrator 8 in advance, the output from the integrator 8 can be made zero, and therefore the output from the multiplier 9 can be reduced to zero. The coefficient of can be set to 1.

Now, when the type of fuel changes, the amount of combustion per unit flow rate of fuel changes, so it is not possible to obtain calories corresponding to the boiler load by simply controlling the fuel flow rate. Therefore, in this case, the following control is performed.

That is, when the type of fuel changes, in the case of a drum boiler, for example, a steady deviation in the steam pressure (in the case of a noble flow boiler, the steam temperature) due to a change in calories appears as the output of the comparator 3. The deviation correction signal which is the output of the controller 4 is added to the fuel command by the adder 6, and is sent to the comparator 10, controller 11,
A fuel flow control valve 12 changes the flow rate.
As a result, the calorie-based fuel flow rate command sent from the function generator 5 and the flow rate-based measured value from the fuel flow rate detector 7 differ, so a deviation is output from the comparator 13, and the deviation is integrated. The integrated value is sent to a multiplier 9 as a coefficient for modifying the fuel flow rate, multiplied by the fuel flow rate measurement value from the fuel flow rate detector 7, and sent to the comparator 10. This operation is performed until the calorie-based fuel flow command and the fuel flow rate after the calorie change are balanced without steady deviations due to calorie fluctuations in steam pressure (or steam temperature). In the new balanced state, the calorie-based fuel flow rate command from the adder 6 is compared again with the comparator 10, and the deviation is outputted as a flow rate control signal via the controller 11 and sent to the fuel flow rate control valve 12. The valve opening degree is controlled until the deviation becomes zero. During this control, the coefficient integrated by the integrator 8 changes moment by moment, and the output of the fuel flow rate detector 7 changes until the measured value of the fuel flow rate detector 7 matches the boiler output command from the function generator 5 on a calorie basis. When they match, the output value is held and normal operation resumes.

When performing calorie correction by detecting steam temperature instead of steam pressure, a steam temperature detector is used instead of the steam pressure detector, and a steam temperature setter is used instead of the steam pressure setter.

FIG. 3 shows another embodiment of the present invention. In the previous embodiment, liquid fuel is used for calorie correction, whereas in this embodiment, coal is used as the fuel for calorie correction. 14 in the figure is a coal flow rate detector;
Reference numeral 15 indicates an oil flow rate detector, and the same reference numerals as those shown in FIG. 2 indicate the same components.
The signals sent to the comparators 10 and 13 are the measured values of the coal flow rate and the oil flow rate.

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

Since the fuel calorie correction device of the present invention has the above-described configuration, it can automatically correct the steam pressure, etc. even if the fuel changes, and therefore can operate according to the load regardless of the fuel calorie. can be done optimally.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional example, FIG. 2 is an explanatory diagram of one embodiment of the present invention, and FIG. 3 is an explanatory diagram of another embodiment of the present invention. In the figure, 6 is an adder, 7 is a fuel flow rate detector, 8 is an integrator, 9 is a multiplier, 12 is a fuel flow control valve, 13
indicates a comparison operator.

Claims (1)

[Claims] 1 Compare and calculate the steam pressure or steam temperature detected by a steam pressure detector or steam temperature detector and the steam pressure set value or steam temperature set value set by a steam pressure setting device or steam temperature setting device to determine the steam pressure or steam temperature. Adding the fuel flow rate command from a first comparator calculating a steam temperature deviation correction signal, a function generator converting a boiler output command to a fuel flow rate command, and the deviation correction signal from the first comparator. A fuel flow rate signal detected by the fuel flow rate detector and sent via the multiplier is compared with the adder and the signal from the adder. a second comparator that outputs a command signal to the fuel flow control valve, and a third comparator that compares and computes the fuel flow command output from the function generator and the fuel flow signal output from the multiplier. 1. A fuel calorie correction device, characterized in that an integrator is provided which integrates a deviation output from the comparison calculation and provides a calorie correction coefficient corresponding to the integrated value to the multiplier.