JPH0468212A - Burner combustion control device - Google Patents

Abstract

PURPOSE:To enable a burner combustion control device to be applied to a wide range of combustion facility without having any relation with the kind of fuel or the kind of burner by a method wherein an optical sensor is connected to an amplifier, a capacitor, an amplifier, a flow regulator and an integrator are connected to one line of its output side, and an integrator and a multiplier are connected to the other line, and further a divider, a flow rate adjusting meter and a damper driving device are connected to an output side of these lines. CONSTITUTION:An optical sensor 13 at an extreme end of a furnace 1 monitors a state of a flame 3 being ignited. An amplifier 14 is connected to the optical sensor 13 so as to amplify an output signal of the optical sensor 13. An outside of the amplifier 14 is divided into two branches, wherein a capacitor 15, an amplifier 16, a flow regulator 17 and an integrator 18 are connected to one line, a vibrating power voltage value of a flame 3 is got and then inputted to a divider 19. An integrator 20 and a multiplier 21 are connected to the other line, an absolute optical amount voltage value is got and added to the divider 19. The divider 19 divides the vibration power voltage value from the integrator 18 with an absolute optical amount voltage value got from the multiplier 21. The divider 19 and a flow meter 7 are connected to an air flow meter adjusting meter 22 to receive both output signals, processes them to control a modutrol motor 10.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a combustion control device for a burner used in combustion equipment such as a boiler.

(Prior art) In a burner that burns liquid or gaseous fuel,
It is desirable to maintain the combustion state optimally during combustion.
Conventional techniques for this purpose include capturing the light intensity signal generated by the burner flame as an electrical signal using a semiconductor such as a phototransistor, photodiode, or solar cell, or using an electrode inserted into the flame instead of a light sensor. There is a method in which the ion current is captured using a rod, and combustion control is performed using the integrated value of the power spectrum obtained as a result of frequency analysis of the vibration waveform in the flame from the output fi. Of these, the method and device using the optical sensor are:
This has already been proposed (see Japanese Patent Application No. 63-306310, etc.).

The former of the conventional techniques described above, that is, a method in which the light generated from a flame is captured as an electrical signal and processed by an electric circuit, is a method in which the light signal generated by the flame is processed by a semiconductor such as a phototransistor or photodiode. This will be detected by an optical sensor, but until now there has been no particular rule regarding the location where the sensor should be installed, and it has been recognized that it is sufficient as long as the flame can be monitored. However, when actually controlling the temperature of the furnace by burning the burner, the installation position of the optical sensor is an extremely important element, and depending on its position, the accuracy of the electric circuit connected to the output side of the optical sensor can be affected. It has been found that no matter how high the temperature is increased, sufficient control characteristics may not be obtained.

Therefore, by setting the installation position of the optical sensor within a certain range and making full use of its functions, the electric circuit connected to it can be simplified and adjustments can be made easier. A burner combustion control device invented based on insight has already been proposed (Japanese Patent Application No. 1-312132).

The contents of this application include a burner that captures the flame emitted by a burner as an electrical signal by an optical sensor, electrically processes the signal captured by the optical sensor, and controls the amount of fuel and air supplied to the burner. In the combustion apparatus, the optical sensor is installed at a position where at least a part of the diffusion flame area of the flame falls within the light receiving range of the optical sensor.

With the above configuration, the light-receiving efficiency of the optical sensor will be significantly improved, and its output characteristics will also be stable, so the electrical circuit connected to the subsequent stage of the optical sensor can be simplified. . This device detects the vibration signal of synchrotron radiation caused by the fluctuations of a turbulent combustion flame with an optical sensor such as a photodiode, converts it into an electrical signal, and then converts the rectified and integrated vibration power between the air ratio and the air ratio. This method takes advantage of the proportional correlation shown in FIG. 3, and performs feedback control of the air ratio. However, the vibration power characteristics shown in FIG. 3 are for a long-flame burner, and are not the vibration characteristics for a short-flame burner in which fuel and combustion air are rapidly mixed at the ejection part of the burner nozzle.

As shown in Figure 4, the vibration power characteristic of a short flame burner has a chevron-shaped characteristic with respect to the air ratio, and since there are two air ratios for one vibration power, it is impossible to distinguish and combustion control is difficult. will not be possible. In addition, Figure 3 shows the combustion of a smoke tube boiler with evaporation ff15 T/H fired by heavy oil A.
24 (This is an example of measurement at 1476. The reason why the vibration power has a chevron-shaped characteristic as shown in Figure 4 is due to the turbulent combustion rate and equivalence ratio (reciprocal of the air ratio) according to Arnius reaction rate.
Figure 5 shows the case of a mixture of propane gas and air. Note that this FIG. 5 is quoted from Mechanical Engineering Handbook A6-79. This Fig. 5 and city gas-fired +2T/H furnace tube smoke tube boiler combustion 1i624i1. Comparing the vibration power characteristics in the case of /H (Fig. 6), it can be seen that the change patterns of the two are very similar. The vibration power is the sum of the vibration frequency components of the turbulent flow, and can be considered to represent the strength of the turbulent flow.

In general, the turbulent combustion velocity and the turbulent Reynolds number are in a proportional relationship, the air ratio in Figure 6 = the equivalence ratio in Figure 5, the power in Figure 6 = the turbulent combustion velocity in Figure 5, and vibration It is a general tendency for power to have a chevron-shaped characteristic with respect to air ratio. Third
It was confirmed that when the air ratio was further increased using a long-flame burner that obtained the vibration power characteristics shown in the figure, a chevron-shaped characteristic similar to that shown in FIG. 4 was obtained.

(Problems to be Solved by the Invention) The present invention has been made based on the knowledge explained above, and it is possible to improve the types of fuel such as gas and liquid, and the types of fuels such as long flame burners and short flame burners. The object of the present invention is to obtain a burner combustion control device that can be applied to a wide range of combustion equipment regardless of the type of burner.

(Means for Solving the Problems) The present invention provides a first method for solving the problems described above.
As shown in the figure, the flame 3 emitted by the burner 2 is detected by the optical sensor 1.
In a burner combustion apparatus that controls the amount of air supplied to the burner 2 by electrically processing the signal captured by the optical sensor 3 and controlling the amount of air supplied to the burner 2, the optical sensor 13 is connected to an amplifier 14. The output side of this amplifier 14 is branched into two paths, and a coupling capacitor 15, an amplifier 16, a rectifier 17, and an integrator 18 are sequentially connected to one path, and the other path is connected to An integrator 20 and a multiplier 21 are connected in sequence, and a divider 19 for dividing the output values of these two systems is connected to the output sides of these two systems. Air flow ffl controller 2
2 is connected, and a damper drive device (Modutrol motor 10) in the air supply system is connected to this air flow rate HB meter 22.

(Function) With the above configuration, the optical vibration of the flame is detected by the optical sensor and becomes an electrical signal, which is amplified and rectified.
Integration processing is performed to obtain a vibration power value. This vibration power value is then numerically calculated with the absolute light amount detected at the same time as this vibration power value to become a control parameter, and the combustion air supplied to the burner is controlled by this control parameter.

(Tora Embodiment) Next, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, 1 is a furnace, 2 is a burner attached to its base, and 3 is a flame generated by this burner 2. A fuel supply pipe 4 and a combustion air supply pipe 5 are connected to the burner 2 . The fuel supply pipe 4 is provided with a flow control valve 6 and a flow meter 7, and the combustion air supply pipe 5 is provided with a flow II control valve 8, which is a damper valve. Fuel supply pipe 4
Fuel is fed through a pump (not shown), and combustion air is fed from a blower 9 to the combustion air supply pipe 5. IO is a modutrol motor that adjusts the opening degree of the flow rate control valve 8.

Reference numeral 11 designates a temperature controller that receives an output signal from a thermometer 12 attached to the side wall of the furnace 1, compares it with a preset temperature value, and issues an output signal. This output signal is given to the flow control valve 6 to control the amount of fuel flowing through the fuel supply pipe 4. An optical sensor 13 made of a photodiode, a phototransistor, or the like is attached to a portion near the tip of the furnace 1 to monitor the state of the flame 3 during combustion. An amplifier 14 is connected to the sensor 13 in order to amplify the amplitude of the output signal of the optical sensor 13 to a predetermined level.

The output side of the amplifier 14 is branched into two, and one path has a coupling capacitor 15. An amplifier 16, a rectifier 17 and an integrator 18 are connected in sequence to obtain the oscillating power voltage value of the flame 3. This vibration power voltage value is connected to be input to a divider 19 at the next stage. An integrator 20 and a multiplier 21 are sequentially connected to another branched path on the output side of the amplifier 14 to obtain an absolute light amount voltage value.

This absolute light amount voltage value is added to the divider 19. As a result, the divider 19 divides the vibration power voltage value, which is the output signal from the integrator 18, by the absolute optical itt pressure value, which is the output signal from the multiplier 21.

An air flow rate controller 22 is connected to the output side of the divider 19. A divider 19 and the aforementioned flow meter 7 are connected to this air flow rate controller 22 so as to receive the Ryokawa force signal, process this, and control the Modutrol motor 10 based on the result. It looks like this.

The operation of this combustion control device having such a configuration will be explained. The flame signal detected by the optical sensor 13 and converted into an electrical signal is amplified to a predetermined level by the amplifier 14. This amplified signal flows into two paths. In one system, the DC component is first cut off by the coupling capacitor 15, only the AC component is input to the amplifier 16 and amplified, and after the amplification, is rectified by the rectifier 17. The rectified signal is subjected to integration processing by an integrator 18 to obtain a vibration power voltage value, which is input to a divider 19 . on the other hand,
In other systems, the DC vibration component amplified by the amplifier 14 is smoothed by the integrator 20 and multiplied by the multiplier 21 (in this embodiment, the output value of the integrator 20 is raised to the third power), and the divider 19 Output to. The divider 19 divides the vibration power voltage value input from the integrator 18 by the absolute light jl voltage value input from the multiplier 21 and outputs the result to the air flow rate controller 22.

Here, FIG. 2 shows the result of dividing the power value in FIG. 4 by the cube of the absolute light amount using this circuit. Conventional secondary characteristics are converted to primary characteristics, making it possible to use vibration power as a control parameter.

In addition, the amplification multiple of each amplifier 14 and 16, and the multiplier 2
The order of 1 is 1 as shown in Figure 2, depending on the furnace to be controlled.
Adjust to the extent possible. Air flow controller 22
Now, compare the vibration power table value, which has been set in advance to provide an appropriate air ratio for the flow rate signal input from the fuel flow meter 7, and the measured value input from the divider 19, and calculate the deviation. PID? jr calculation is performed, and the modutrol motor 31 is controlled based on the result. Thereby, the opening degree of the flow control valve 8 provided in the combustion air supply pipe 5 that guides the combustion air supplied to the burner 2 by the blower 9 is adjusted (feedback control).

Although analog circuits are used as signal processing circuits in the embodiments described above, the present invention is not limited to this. It is also possible to perform digital processing using a microcomputer or the like in the signal processing circuit.

(Effects of the Invention) As explained above, the present invention captures the flame emitted by the burner as an electrical signal using an optical sensor, and then electrically processes the signal captured by the sensor to control the amount of air supplied to the burner. In the burner combustion device to be controlled, the optical sensor is connected to an amplifier, the output side of this amplifier is branched into two paths, and one path is equipped with a coupling capacitor,
An amplifier, a rectifier, and an integrator are connected in sequence, an integrator and a multiplier are connected in sequence in the other system, and the output values of these two systems are divided on the output side of these two systems. A divider is connected, an air flow controller is connected to the output side of the divider, and a damper drive device in the air supply system is connected to the air flow controller. This has the effect of being applicable to a wide range of combustion equipment, regardless of the type of fuel such as liquid or the type of burner such as a long flame burner or a short flame burner.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, and FIGS.
The figure is a graph for explaining the present invention and the prior art. 1 - Furnace 2 - Burner 3 - Flame 4 - Fuel supply pipe 5 - Combustion air supply pipe 6.8 - Flow 1i control valve 7 - Flow meter 9 - Blower 10 - Modutrol motor 13 - Light Sensors 14, 16 - Amplifier 15 - Coupling capacitor 17 - Rectifier 18, 20 - Integrator 19 - Divider 21 - Multiplier 22 - Air flow rate controller "r!! figure power

Claims (1)

[Claims] (1) A burner combustion device in which a flame emitted by a burner is captured as an electrical signal by an optical sensor, and the signal captured by the optical sensor is electrically processed to control the amount of combustion air supplied to the burner, The optical sensor is connected to an amplifier, the output side of the amplifier is branched into two paths, a coupling capacitor, an amplifier, a rectifier, and an integrator are sequentially connected to one path, and the other path is connected to a coupling capacitor, an amplifier, a rectifier, and an integrator. connects an integrator and a multiplier in sequence, connects a divider to the output side of these two systems to divide the output values of these two systems, and connects an air flow rate adjustment device to the output side of the divider. 1. A combustion control device for a burner, characterized in that a damper drive device in an air supply system is connected to the air flow rate regulator.