JPS5864426A - Correction unit of calory of fuel - Google Patents

Abstract

PURPOSE:To optimize the operation of a boiler in response to the load irrespective of the calory of fuel by a method wherein fuel flow rate is corrected in proportion to the deviation between the oxygen density in exhaust gas and its set value and the opening of a fuel flow control valve is controlled in proportion to the deivation between said corrected fuel flow rate and its set flow rate. CONSTITUTION:During the operation of a boiler, the deviation between the oxygen density in exhaust gas detected by a detector 1 and the density set value given by a function generator 2 is obtained by a comparator 3 and the resultant output is sent through an integrator 4 to an adder 5 and an integrator 11. The combustion command of air flow rate set at a setter 17 is added to said output at the adder 5 in order to obtain the deviation between said resultant sum and the air flow rate detected by a detector 6 at a comparator 7 so as to control a damper driving unit in proportion to said deviation. On the other hand, the integrator 11 integrates the deviation between the output of the integrator 4 and the set value 10 and sends the result to a multiplier 13. The result, being corrected by the fuel flow rate detected by a detector 12, is compared with the combustion command of fuel flow rate set at the setter 17 at a comparator 14. The flow control valve 16 is finally controlled in proportion to the deviation obtained at the comparator 14.

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 is explained using Figure 1.
In the figure (rumor is a fuel flow rate detector, (A) is a multiplier, (C) is a manual signal generator that changes the coefficient depending on the type of fuel, (d)
is a comparison calculator, J) is a controller, and when the fuel changes, the flow rate signal Q1 detected by the fuel flow rate detector (α) is
The coefficient determined by the type of fuel set in the manual signal generator (C1) is multiplied by the multiplier (h), and the C
2 = K Qt is sent to the comparator (d) and calculated by the comparator (d) with the set fuel flow rate signal Q3, and the flow rate provided in the fuel supply pipe is determined according to the deviation of ΔQ = Q3 - Q2. As long as the control valve (el) is adjusted and the amount of steam generated is the same, even if the fuel changes, the calo IJ-
were made to be the same.

However, with such conventional devices, it is difficult to continuously set the coefficients when the calorie value changes from moment to moment or when the calorie value is not easily obtained.

In addition, if inappropriate settings are made, the output signals of the pressure control controller, steam temperature controller, exhaust gas 02 controller, etc. will be completely saturated (saturated), and the steam pressure, steam temperature, and exhaust gas 02 concentration will be Because the vehicle was not properly corrected, driving was often hindered.

The present invention was made for the purpose of automatically correcting steam pressure, steam temperature, and exhaust gas 02 concentration when the calorie of fuel fluctuates, thereby enabling smooth operation. A device, an integrator that corrects the detected fuel flow rate based on the deviation between the detected exhaust gas 02 concentration and the set exhaust gas 02 concentration, and a deviation between the fuel flow rate corrected by the integrator and the set fuel flow rate. The present invention is characterized in that it includes a comparator and a device that controls the opening degree of the fuel flow rate control valve based on the deviation signal of the comparator.

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

In the figure, (I) is the exhaust gas 02 concentration control circuit, (1) is the exhaust gas 02 concentration detector, and (2) is the signal sent from the setting device αD for the air flow rate and combustion command, which will be described later.
(2) is a function generator that generates a concentration output command, (3) is a detector (1) that generates a concentration output command;
) and a comparison calculator that compares and calculates the outputs sent from the function generator (2), (4) is an integrator connected to the comparison calculator (3), and (5) is an air flow rate according to the boiler load. and an adder that adds the output sent from the setter σB that sets the combustion command regarding the fuel flow rate and the output sent from the integrator (4).

Also, there is an air flow rate control circuit, in which (6) is an air flow rate detector, and (7) is a circuit that connects the output from the detector (6) and the adder (5).
), a comparator (8) is a controller whose output is sent from the comparator (7), and (9) is driven by the output sent from the controller (8). , a damper drive device that controls the damper opening in proportion to the magnitude of the output.

Furthermore, the surface is the fuel flow control circuit, and 00 is the integrator (4).
A setting device for setting the output of the integrator (4) and 1/2 of the range of the integrator (4), on is an integrator connected to the integrator (4), a
t is a fuel flow rate detector, a3 is a multiplier that multiplies the output from the detector aX5 and the integrator aυ, and ■ is a comparison calculator that compares the output from the multiplier a3 and the output from the setting device a71. , α9 is the output controller sent from the comparator I, and 161 is a flow rate control valve that is controlled in accordance with the magnitude of the output from the controller 09.

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

The exhaust gas 02 concentration corresponding to the load of the boiler is set in the function generator (2), and combustion commands for the air flow rate and the fuel flow rate are set in the setting device fiη. The exhaust gas O2 concentration discharged from the boiler is detected by the detector (1), the air flow rate is detected by the detector (6), and the fuel flow rate is detected by the detector az, and the output of the exhaust gas O2 concentration is detected by the comparison calculator ( 3), the output of the air flow rate is sent to the comparator (7), and the output of the fuel flow rate is sent to the comparator (04).

For example, if the load and fuel type do not change, the detection
Since the deviation between the output detected by the comparator (1) and sent to the comparator (3) and the output of the function generator (2) is zero, the output from the comparator (3) is zero. and an integrator (4
) is constant. Therefore, the exhaust gas 02 concentration control circuit (I) does not operate, and the air flow rate control circuit I and fuel flow rate control circuit Y are each independently controlled.

That is, the air flow control circuit (In, the detector (6)
The air flow rate detected by the controller (171) and the combustion command for the air flow rate set in the setting device (171) are compared and calculated in the comparator (7), and the deviation is sent to the damper drive device (9) via the controller (8). The output from the fuel flow rate detector α2 and the fuel from the setting device fiη are sent to the comparator Q41 via the multiplier Q3. The combustion command regarding the flow rate is compared and calculated by the comparator α, and the deviation is sent to the flow rate control valve αe via the controller a9, and the opening degree of the valve is controlled so that the deviation becomes zero.

Now, if the type of fuel changes, the calorific value 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, a deviation occurs between the output command for the exhaust gas 02 concentration set by the function generator (2) and the exhaust gas 02 concentration detected by the detector (]).

This deviation is compared and calculated by a comparison calculator (3), and its output is sent to an adder (5) and an integrator αB via an integrator (4).

10,000, the combustion command for the air flow rate set by the setting device (I71) is sent to the adder (5), and the adder (5) uses the integrator (4
) is added to the output sent from the detector (6), and the added value is input as a set value to the comparison calculator (8),
) is compared with the output of the air flow rate detected by the comparator (7), and the deviation is sent to the damper drive device (9) through the controller (8). The damper opening degree is controlled so that the deviation becomes zero.

Also, the deviation between the output of the integrator (4) and the value set by the setting device α is sent to the integrator Qll, and the output of the integrator αD is sent to the multiplier αJ, and the deviation between the output of the integrator (4) and the value set by the setting device α is sent to the multiplier αJ. The flow rate is multiplied by a coefficient, and this is sent as a detection signal corrected for the calorific value to the comparator I, where it is compared with the combustion command for the fuel flow rate set by the setting device +171, and the deviation is calculated. It passes through the controller α and is sent to the flow rate control valve αe, so that the deviation becomes zero. In other words, the opening degree of the valve is controlled so that even if the fuel changes, the calories correspond to the boiler load. Ru.

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, even if the fuel changes, it can automatically correct the steam pressure, steam temperature, exhaust gas 02%, etc. It is possible to perform operation optimally according to the load without any problems.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional example, and FIG. 2 is a detailed explanatory diagram of the present invention. In the figure, (1) is a detector for the exhaust gas 02 concentration, (2) is a function generator for setting the exhaust gas 02 concentration, (31 is a comparison calculator, (4) is an integrator, (5) is an adder, O3 is a fuel flow rate detector, α~ is a multiplier, O4 is a comparison calculator, (l[
9 is a flow rate control valve, and aη is a setting device for air flow rate and combustion command. Patent applicant Ishikawajima Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] 1) Device for detecting fuel flow rate and detected exhaust gas 02
an integrator that corrects the detected fuel flow rate based on the deviation between the concentration and the set exhaust gas 0□ concentration; a comparison calculator that calculates the deviation between the fuel flow rate corrected by the integrator and the set fuel flow rate; 1. A fuel calorie correction device comprising: a device for controlling the opening degree of a fuel flow rate control valve based on a deviation signal from a comparator.