JPH07190352A - Method for detecting ignition - Google Patents

Abstract

PURPOSE:To enable a precision ignition/extinguishing of a main burner and an ignition burner to be discriminated by a method wherein a frequency component corresponding to each of an air flow sound or a combustion sound and the discriminated value are compared for their values. CONSTITUTION:An operation of a main burner (including ignition and fire loss) is discriminated in reference to a comparison data between a low frequency component corresponding to an air flow sound passed through a filter 4 or a high frequency component corresponding to a combustion sound passed through a filter 3 and a discriminated value (a threshold value) set by a discriminated value setting circuit 11. Ignition/extinguishing of burners (the main burner and the ignition burner) which is discriminated as operation are discriminated in reference to the comparison data between a vibration amplitude ratio between a low frequency component corresponding to the air flow sound passed through the filter 4 and a high frequency component corresponding to the combustion sound passed through the filter 4 as well as the discriminated value (threshold value) V set by a discriminated value setting circuit 13. With such an arrangement as above, an ignition/extinguishing of the main burner and the ignition burner can be precisely discriminated irrespective of the type of the furnace.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition detection method for individually detecting ignition / extinction of a main burner and an ignition burner in an industrial furnace or the like.

[0002]

2. Description of the Related Art In an industrial furnace or the like, an ignition burner (a pilot burner) is provided as a pair for each main burner. The main burner has a larger combustion capacity than the ignition burner, and depending on the furnace, it is necessary to reliably detect the ignition of the main burner because the fire is frequently repeated depending on the load depending on the load. On the other hand, the ignition burner has a good flammability due to its flame holding performance and is less likely to cause misfire. Therefore, in a small-scale industrial furnace, ignition detection of the ignition burner is often not performed.

However, in a power generation boiler and a large-scale industrial furnace, the ignition burner has a large amount of combustion, and if a misfire should occur, a serious accident could occur, so ignition detection is exclusively performed for the ignition burner. In many cases, safety measures are implemented with means.

This type of ignition detection means includes an optical type and an acoustic type (for example, disclosed in Japanese Utility Model Publication No. 4-49482). The optical type has a main burner and an ignition burner. However, it is difficult for one sensor to monitor, and each burner has its own sensor.

The above-mentioned acoustic type uses the difference in the combustion sound frequencies of the main burner and the ignition burner to identify the ignition and extinction of both burners, and has the advantage that a single sensor is sufficient. .

[0006]

However, due to recent exhaust gas regulations and the like, not only the main burner but also the ignition burner tends to shift from rapid combustion with good combustibility to slow combustion with low NOx and SOx emissions. However, there is a case where there is no large frequency difference when the main burner and the ignition burner burn or extinguish, and there is a problem that the reliability of the state determination of the main burner and the ignition burner decreases.

The present invention has been made in order to solve this problem, and it is highly reliable and economical that the ignition / extinction of the main burner and the ignition burner can be accurately determined regardless of the furnace type. It is an object of the present invention to provide an ignition detection method capable of significantly improving the safety of furnace operation.

[0008]

In order to achieve the above object, the present invention provides a means for igniting and extinguishing a pair of a main burner and an ignition burner, which uses a common small pressure vibration generated by the burner. In the case of using the electric signal as an electric signal and making a judgment for each burner using the electric signal and a judgment value set in advance, the frequency component average value and the first judgment value in a predetermined band corresponding to the combustion sound included in the electric signal. And a ratio of the average amplitude of the frequency component of the predetermined band included in the electric signal to the average amplitude of the frequency component of the predetermined band corresponding to the airflow sound or the average amplitude of the electric signal, and The burner is judged for each burner based on the combination of four comparison data consisting of the magnitude comparison result with the judgment value.

According to a second aspect of the present invention, the ignition / extinction of the paired main burner and ignition burner is taken out as an electric signal by using a small pressure vibration generated by the burner by using a common means, and the electric signal and a predetermined judgment value are set. In the case of making a determination for each burner by utilizing, the comparison result of the magnitude of the vibration energy calculated from the frequency component of the predetermined band corresponding to the combustion sound included in the electric signal and the first judgment value, the electric signal includes the above Comparison of the ratio between the vibration energy calculated from the frequency component of the predetermined band and the vibration energy obtained from the frequency component of the predetermined band corresponding to the air flow sound or the total vibration energy obtained from the electric signal and the second judgment value. The burner was judged for each burner based on the combination of the four comparison data obtained from the results.

According to a third aspect of the present invention, the calculation is performed from the magnitude comparison result of the frequency component average value of the predetermined band corresponding to the combustion sound included in the electric signal and the first determination value, and the frequency component of the predetermined band included in the electric signal. From the comparison result of the ratio between the vibration energy and the vibration energy obtained from the frequency component of the predetermined band corresponding to the combustion sound included in the electric signal or the total vibration energy obtained from the electric signal, and the second judgment value. The burner is judged for each burner based on the combination of the four comparison data.

According to a fourth aspect of the present invention, the magnitude comparison result of the vibration energy calculated from the frequency component of the predetermined band corresponding to the combustion sound included in the electric signal and the first determination value, and the frequency of the predetermined band included in the electric signal. From the combination of four comparison data consisting of the magnitude comparison result of the ratio of the average amplitude of the component and the average amplitude of the frequency component of the predetermined band corresponding to the air flow sound or the average amplitude of the electric signal, and the second judgment value. The configuration is such that each burner is judged.

[0012]

The present invention compares the magnitude of the frequency component corresponding to the airflow sound or the frequency component corresponding to the combustion sound with the judgment value, or the vibration energy corresponding to the airflow sound or the vibration energy corresponding to the combustion sound and the judgment value. Based on the magnitude comparison data, it is determined whether the main burner is operating (including ignition and misfire) (whether the ignition burner is operating), and the frequency components corresponding to the air flow noise and the combustion noise are handled. Ignition / burning of the burner determined to be the above-mentioned operation is performed by comparing the magnitude of the vibration amplitude ratio with the frequency component and the judgment value, or the magnitude of the ratio of the vibration energy corresponding to the air flow sound and the vibration energy corresponding to the combustion sound and the judgment value. Determine fire extinguishing.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 is a microphone, and as shown in FIG. 2, the end of the probe 2 outside the furnace, which is exposed to the vicinity of the tips of the main burner 42 and the ignition burner 43 through the furnace wall 41 of the furnace 40. It is provided in.

Reference numeral 3 is a first band pass filter, and 4 is a second band pass filter. The first band pass filter 3 is a filter having a high frequency component (for example, 200 Hz to 1 kHz) as a pass band, and the output of the band pass filter 3 is smoothed by the smoothing circuit 5. The output of the smoothing circuit 5 is A. The second band pass filter 4 is a filter having a low frequency component (for example, 20 Hz to 200 Hz) as a pass band, and the output of the band pass filter 2 is smoothed by the smoothing circuit 6. The output of the smoothing circuit 6 is B.
Reference numeral 7 is a first vibration energy calculation circuit (square calculation circuit) for calculating A ² . A second vibration energy calculation circuit (square calculation circuit) 8 calculates B ² . Reference numeral 9 denotes a ratio calculation circuit, which calculates a ratio E ₁ = A ² / B ² of the calculation values A ² and B ² of the vibration energy calculation circuits 7 and 8. 10
Is a first determination circuit (energy determination circuit),
The output A ² of the vibration energy calculation circuit 7 is compared with the determination value U (threshold value), and when A ² > U, it is determined that the main burner 42 is operating (ignition or misfire), and the “H” level is reached. Is output, and when A ² <U, it is determined that the main burner 42 is stopped, and an “L” level signal is output. 11
Is a judgment value setting circuit for setting the judgment value U. 1
2 is a second determination circuit (energy ratio determination circuit),
The output E ₁ of the ratio calculation circuit 9 is compared with a determination value (threshold value) V, and when E ₁ > V, it is determined that “ignition” has occurred,
An "H" level signal is output, and when E ₁ <V, it is determined that "fire extinguishing" is performed, and an "L" level signal is output. Reference numeral 13 is a judgment value setting circuit for setting the judgment value V.

Reference numeral 14 is a burner state judging section, which is provided with four gate circuits 15 to 18 and inverting circuits 19 and 20. The gate circuit 15 is a main burner ignition detection gate circuit, and includes the output of the first determination circuit 10 and the second determination circuit 1.
2 is introduced and both outputs are at the “H” level, the main burner 42 ignition detection output is generated. The gate circuit 16 is a main burner misfire detection gate circuit,
A signal obtained by inverting the output of the determination circuit 10 and the output of the second determination circuit 12 is introduced, and the main burner 42 misfire detection output is generated when the former is at the “H” level and the latter is at the “L” level. To do.

The gate circuit 17 is an ignition burner ignition detection gate circuit, and the output of the second determination circuit 12 and the output of the first determination circuit 10 are guided to the former, which is at the "H" level, and the latter. Is at "L" level, the ignition burner 43
Generates ignition detection output. The gate circuit 18 is an ignition burner misfire detection gate circuit, and a signal obtained by inverting the output of the first determination circuit 10 and a signal obtained by inverting the output of the second determination circuit 12 are introduced, and both outputs are "L". All burners fire extinguishing (complete extinguishing) detection output is generated when the level is set.

The present inventors obtained the results shown in FIG. 6 when they analyzed the sound generated in the boiler in a boiler or the like in which the flow velocity of the combustion air was high and which was easily affected by the air flow noise. This FIG. 6 shows representatively the analysis result of the generated sound at a certain combustion amount.

(A) At the time of misfire, the signal level of the low frequency component (for example, 20 Hz to 200 Hz), which is considered to be an air flow noise, becomes larger than that at the time of combustion.

(B) The level of a high frequency component (for example, 200 Hz to 1 kHz), which is considered to be caused by the combustion noise, at the time of misfire is the same or smaller than that at the time of combustion.

It shows that

From the above, the present inventors have found that the ratio of the level (vibration amplitude) of the signal output from the microphone 1, that is, However, as shown in FIG. 7, at the time of misfire, the denominator B of the expression (1) becomes large, so it is small, and at the time of combustion, the denominator B of the expression (1) becomes small and it becomes large. After repeating the experiment, it was found that the vibration amplitude ratio Y ₁ hardly changed even when the combustion amount was changed.

Based on the above consideration, the inventors of the present invention tried the same consideration with respect to the vibration energy, not the vibration amplitude, with respect to the furnace having the main burner and the ignition burner, and obtained the results shown in FIG. It was As is clear from FIG. 8, since the low frequency component at the time of misfire is considerably larger than the high frequency component, (1) When the main burner 42 and the ignition burner 43 are both extinguished, the air flow sound S Vibration energy of possible low-frequency components (20 Hz to 200 Hz) is considered to be high-frequency components (200 Hz to 1 k) considered to be caused by combustion noise.
Hz) of vibration energy.

(2) From the state of (1) above, the ignition burner 4
When 3 ignites, the vibration energy of the low frequency component becomes smaller than the vibration energy of the high frequency component.

(3) When the ignited main burner 42 misfires, the vibration energy of the low frequency component becomes larger than the vibration energy of the high frequency component. At this time, the vibration energy of the low frequency component and the vibration energy of the high frequency component. Both are at considerably higher levels than in the case of complete extinction in (1) above.

(4) When the main burner 42 is ignited,
The vibration energy of the low frequency component becomes smaller than the vibration energy of the high frequency component. At this time, both the vibration energy of the low frequency component and the vibration energy of the high frequency component are in the case of complete extinction in (1) and in the case of (2). The level is considerably higher than that of.

FIG. 9 shows the following energy ratio E ₁ between the vibration energy of the low frequency component and the vibration energy of the high frequency component in the states (1) to (4).

[0028] (5) When the main burner 42 and the ignition burner 43 are both misfiring, the energy ratio E ₁ is small.

(6) When only the ignition burner 43 is ignited, the energy ratio E ₁ is considerably large.

(7) When the ignited main burner 42 misfires, the energy ratio E ₁ becomes sufficiently small.

(8) When the main burner 42 is ignited,
The energy ratio E ₁ is quite large.

Therefore, as shown in FIG. 8, (1),
A determination value U for identifying the state of (2) and the states of (3) and (4) is set, and as shown in FIG. 9, (5),
If the judgment value V for distinguishing the state of (7) from the states of (6) and (8) is set, as shown in the table below, "combustion of the main burner", "misfire of the main burner", " It is possible to clearly distinguish "combustion of the ignition burner" and "complete extinction".

[0033] In the embodiment of FIG. 1, in the first determination circuit 10, the states (1) and (2) and the states (3) and (4), that is,
Combustion or misfire of the main burner 42 / combustion or misfire of the ignition burner 43 is discriminated, and in the second determination circuit 12, the states (5) and (7) and the states (6) and (8), that is,
Ignition / extinction of the main burner 42 or the ignition burner 43 is identified.

In the present embodiment, when the main burner 42 alone burns, the energy of the high frequency component is sufficiently large to be discriminated compared to when only the ignition burner 43 burns.
When only 2 is misfired, the main burner 42 and the ignition burner 43 are discriminated by utilizing the fact that the energy of the low frequency component is large enough to be discriminated compared to when the ignition burner 43 is misfired.
Utilizing the fact that the energy ratio at the time of combustion of the main burner 42 / at the time of combustion of the ignition burner 43 is sufficiently large to be discriminable compared with the energy ratio at the time of combustion of the main burner 42 / at the time of misfire of the ignition burner 43. Since the "ignition" and "misfire" of the discriminated burner are discriminated, it is possible to clearly discriminate the four cases of ignition / misfiring of the main burner 42 and ignition / misfiring of the ignition burner 43.

Moreover, this judgment is made by the pair of main burners 4
2 and the ignition burner can be performed by using a common sensor (the microphone 1 in the above embodiment).

As described above, according to the present embodiment, the main burner 42 is ignited / misfired, and the ignition burner 43 is ignited / misfired.
Since it is possible to clearly distinguish between the two cases, operate the furnace while sequentially confirming the sequence of ignition burner combustion command → ignition burner combustion check → main burner combustion command → main burner combustion check. As a matter of course, it is possible to confirm the interlock even in the sequence at the time of fire extinguishing, and the safety is greatly improved.

In the circuit of FIG. 1, the signal amplitude A ² of the high frequency component / the signal amplitude B ² of the low frequency component is obtained. Instead of the energy ratio E ₁ , the high frequency component of the entire combustion sound is calculated. The ratio of the signal amplitude A ² , that is, Can be used. A circuit in the case of utilizing the vibration amplitude ratio E ₂ is shown in FIG.

In the circuits of FIGS. 1 and 3, the energies A ² and B are
^{Although 2} and the energy ratio E are used, it is apparent from the above description that the vibration amplitudes A and C and the amplitude ratio Y ₁ may be used as shown in FIG. In the figure, 21 is a judgment value setting circuit for setting the judgment value X, and 22 is a judgment value setting circuit for setting the judgment value Z.

Further, as shown in FIG. 5, vibration amplitudes A and C
And the amplitude ratio Y ₂ can also be used.

[0040] In the above description, the main burner and the ignition burner are discriminated from the combination of the amplitude and the amplitude ratio, and the combination of the vibration energy and the vibration energy ratio, but the combination of the amplitude and the vibration energy ratio, The same determination can be made from the combination of the vibration energy and the amplitude ratio.

[0041]

As described above, the present invention compares the magnitude of the frequency component corresponding to the air flow sound or the frequency component corresponding to the combustion sound with the determination value, or the vibration energy corresponding to the air flow sound or the vibration corresponding to the combustion sound. Based on the magnitude comparison data between the energy and the judgment value, it is determined whether the main burner is operating (including ignition and misfire) (whether the ignition burner is operating), and the frequency component corresponding to the air flow sound. And the comparison between the vibration amplitude ratio of the frequency component corresponding to the combustion sound and the judgment value, or the ratio of the vibration energy corresponding to the air flow sound and the vibration energy corresponding to the combustion sound, and the judgment value, the above operation is performed. Since the determined burner ignition / misfire is determined, the main burner's ignition, misfire, ignition burner's ignition, and misfire should be clearly identified regardless of furnace type and using common means. Can contribute significantly to the improved safety of the furnace operation.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a layout view of a main burner and an ignition burner of the above embodiment.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing a third embodiment of the present invention.

FIG. 5 is a block diagram showing a fourth embodiment of the present invention.

FIG. 6 is a diagram showing frequency component signal levels at the time of misfire / ignition.

FIG. 7 is a diagram showing a signal amplitude ratio at the time of misfire / ignition.

FIG. 8 is a diagram showing vibration energy amplitude at the time of misfire / ignition.

FIG. 9 is a diagram showing a vibration energy amplitude ratio upon misfire / ignition.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microphone 2 Probe 3, 4 Band pass filter 5, 6 8 Smoothing circuit 6, 8 Vibration energy calculation circuit 9 Ratio calculation circuit 10, 12 Judgment circuit 11 13 Judgment value setting circuit 14 Burner state judgment part 15-18 Gate circuit 19, 20 Inversion circuit 42 Main burner 43 Ignition burner

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shigeo Nakamura Inventor Shigeo Nakamura Ubei Kawara, Hijinohe City, Aomori Pref. 1-1, Tohoku Electric Power Co., Inc. Hachinohe Thermal Power Plant (72) Satoru Taniguchi 1-chome Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture 5-5 Incorporated company Kobe Steel, Ltd. Kobe Research Institute (72) Inventor Tatsuo Kono 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo Inside Kobe Steel Co., Ltd.

Claims (4)

[Claims] Claims: 1. Ignition of a pair of main burner and ignition burner
When extinguishing a fire is taken out as an electric signal by using a common means for minute pressure oscillations generated by the burner, and the judgment is made for each burner by using the electric signal and a judgment value set in advance, the combustion sound included in the electric signal is detected. The magnitude comparison result of the frequency component average value of the corresponding predetermined band and the first determination value,
And a ratio of the average amplitude of the frequency component of the predetermined band included in the electric signal to the average amplitude of the frequency component of the predetermined band corresponding to the air flow sound or the average amplitude of the electric signal, and the second
An ignition detection method characterized by making a judgment for each burner from a combination of four comparison data consisting of the magnitude comparison result with the judgment value of. 2. Ignition of a pair of main burner and ignition burner
When fire extinguishing is taken out as an electric signal by using a small pressure vibration generated by the burner using a common means, and the judgment is made by the electric signal and a preset judgment value, when the judgment is made for each burner, a predetermined band included in the electric signal The magnitude comparison result of the vibration energy calculated from the frequency component of the first and the first determination value, the vibration energy calculated from the frequency component of the predetermined band corresponding to the combustion sound included in the electric signal, and the predetermined band corresponding to the air flow sound Is determined for each burner based on a combination of four comparison data consisting of the magnitude comparison result of the vibration energy obtained from the frequency component of or the total vibration energy obtained from the electric signal and the second decision value. Ignition detection method. 3. Ignition of a pair of main burner and ignition burner
When extinguishing a fire is taken out as an electric signal by using a common means for minute pressure oscillations generated by the burner, and the judgment is made for each burner by using the electric signal and a judgment value set in advance, the combustion sound included in the electric signal is detected. The magnitude comparison result of the frequency component average value of the corresponding predetermined band and the first determination value,
And vibration energy calculated from the frequency component of the predetermined band included in the electric signal, and vibration energy calculated from the frequency component of the predetermined band corresponding to the air flow sound included in the electric signal or total vibration energy calculated from the electric signal. The ignition detection method is characterized in that determination is made for each burner based on a combination of four comparison data consisting of the magnitude comparison result of the ratio of the above and the second determination value. 4. Ignition of a pair of main burner and ignition burner
When extinguishing a fire is taken out as an electric signal by using a common means for minute pressure oscillations generated by the burner, and the judgment is made for each burner by using the electric signal and a judgment value set in advance, the combustion sound included in the electric signal is detected. The magnitude comparison result of the vibration energy calculated from the frequency component of the corresponding predetermined band and the first determination value, the average amplitude of the frequency component of the predetermined band included in the electric signal, and the frequency of the predetermined band corresponding to the air flow sound An ignition detection method characterized in that each burner is judged from the combination of four comparison data consisting of the magnitude comparison result of the average amplitude of the component or the ratio of the average amplitude of the electric signal and the second determination value.