JPS62276326A - Diagnosis of combustion - Google Patents

Abstract

PURPOSE:To diagnose the burning condition of a burner correctly by a method wherein the relative values of an arbitrary number of specified wavelengths among the emission spectrums of two areas of a flame are utilized. CONSTITUTION:The light of a flame 3 of a burner 2, which is condensed by lenses 4a, 4b, is sent into spectroscopes 6a, 6b from the tip end of optical fibers 5a, 5b through optical fiber cables 7a, 7b, and the light with preselected wavelength is converted into an electric signal, proportional to the strength of the light, to output after amplifying while the electric signal is input to an A/D converter 8 and is sent into a computer 9 after scanning sequentially whereby the behavior of the production, elimination or the like of some specified chemical kinds or the like may be grasped by a formula I through optical analysis in two neighboring areas A, B. With respect to the generation of soot or fine solid particles showing the characteristics of continuous emission, it may be decided whether the generation thereof is progressing or decreasing by analyzing the mutual relations thereof in the same manner and whereby combustion may be decided whether it is good or not.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention provides a method for diagnosing the combustion state of a burner using emission spectra detected in two adjacent regions of a flame. It is about the method used.

[Prior art] Control techniques using optical spectrum analysis are classic techniques for chemical analysis, and when extending this to on-line measurements of plant-scale operations, the conventional general analytical techniques are Although this is done through sampling and off-line measurements, continuous measurements are often required in actual plants. For example, each of the many burners installed in a boiler is constantly monitored, and if an abnormality occurs, failure to take immediate action can lead to an accident.

For this reason, in recent years, as a means of diagnosing combustion conditions, the third
The method shown in the figure is being considered. In this means, light in one area of the flame of burner a is detected by a required detector C, the detected light is guided to a spectrometer O via an optical fiber cable d, and the spectrometer e detects the light at a predetermined wavelength. The optical spectrum obtained in each case is sent to the calculation unit q via the A/D converter f, and the combustion state is diagnosed by the calculation unit taq, for example, based on the formation and extinction behavior of a specific substance at a predetermined wavelength.

[Problems to be solved by the invention] However, in general, the combustion reaction progresses in the direction of the outflow of the flame, and accompanying temperature changes and the production and extinction reactions of substances accompanying the reaction occur, and the combustion state (especially low Even though the production and extinction behavior of certain substances differs depending on the type of combustion (NOx combustion and other slow combustion), the combustion state can be diagnosed by looking at the emission spectrum of one region of the flame and spectroscopically analyzing it. Therefore, there is a problem that accurate diagnosis cannot be performed when the ignition point of the flame changes depending on combustion conditions.

In view of the above-mentioned circumstances, the present invention has been made with the object of accurately diagnosing the combustion state of a burner by spectroscopically analyzing the emission spectra of two adjacent regions of the flame.

[Means for Solving the Problems] The present invention provides a combustion diagnosis method that evaluates the combustion state using the emission spectrum from the flame.
The combustion state is diagnosed based on the correlation value of any number of specific wavelengths among the emission spectra in the two regions.

[Function] The flame emission spectrum is detected in two regions, and the combustion state is diagnosed based on the correlation value of any number of specific wavelengths determined from the two emission spectra.

[Example] Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention, in which 1a and Ib are lenses 4a and 4b for condensing the light of the flame 3 of the burner 2.
The probe is equipped with optical fibers 5a and 5b that transmit the light condensed by the lenses 4a and 4b, and the probe 1a
, Ib makes it possible to detect the emission spectra of two adjacent regions A and B near the burner section of the flame 3 and downstream thereof.

6a and 6b are spectrometers that separate the light sent from the probes la and 1b via optical fiber cables 7a and 7b, each of which is equipped with a diffraction grating, a photoelectric converter, and an amplifier, and has a plurality of spectrometers selected in advance. It is designed to extract light corresponding to the wavelength of the light, convert it into an electrical signal of the intensity of the light, amplify it, and output it.

8 is an A/D converter that receives and sequentially scans the electrical signals transmitted from the spectrometers 6a and 6b through the electric wire cable; 9 is a computer that performs predetermined calculations based on the electrical signals from the A/D converter 8; 10 is a display device that displays the results calculated by the computer 9.

The light from the flame 3 of the burner 2 focused by the lenses 4a, 4b is taken in from the tips of the optical fibers 5a, 5b, sent into the optical fibers 5a, 5b, passes through the optical fiber cables 7a, 7b, and is sent to the spectrometer 6a, Sent to 6b,
The spectrometers 6a and 6b convert light with a pre-selected wavelength into an electrical signal proportional to the intensity of the light, amplify it and output it, and the electrical signal is taken into an A/D converter 8 and sequentially scanned. and sent to the computer 9, where the area A
, B or the change in temperature due to heat generation is calculated and displayed on the display device 10. As a result, area A
, B, the behavior such as the production and disappearance of certain chemical species, etc. is grasped, and the progress of combustion or the quality of combustion is determined.

Next, a method of grasping the behavior such as generation and extinction of specific chemical species will be explained. This is expressed by comparing the generation status of specific chemical species in regions A and B of the flame 3.

Here, T: period The occurrence situation of the specified character type β at time t when two adjacent areas A are generated according to the above (D formula).

The behavior of certain chemical species, such as generation and disappearance, can be grasped by optical analysis in B.

The above (+) formula is It can be rewritten as

Here, N: Number of scanning Aτ: Scanning period: Constant From the above equation (n), it is possible to grasp the behavior such as the production and disappearance of specific chemical species α and β at an arbitrary time delay τ.

That is, the generation and annihilation of radicals such as OH and CHSC2 differ depending on the reaction, and for example, the cross-correlation of CH emission intensities in regions A and B is R6H! Then, the directionality of the CH reaction between regions A and B can be seen from FIG.

Regarding the generation of soot, which is a fine solid particle that exhibits the characteristic of continuous light emission, by similarly performing a cross-correlation, it can be determined from Figure 2 whether the generation is progressing further or is decreasing, and it is possible to determine whether the generation is progressing further or decreasing. You can judge whether it is good or bad.

Furthermore, areas A, B1. The temperatures TA and TB at : are determined by solving for the gray body from Wien's equation.

Here, C1, C,; Pre-selected wavelengths λ81, λ82 of the specific chemical species in region A; Pre-selected wavelengths IλA1 of the specific chemical species in region B; Spectral radiant emittance of A2 IλB1, Iλ82; wavelength λ81, λ8 in region B
A spectral radiant emittance of 2, for example T > T, indicates that the exothermic reaction is promoted near the burner, resulting in very good combustion.
On the other hand, if TA is T8, it means that combustion will be slow depending on the degree.

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.

[Effects of the Invention] According to the combustion diagnosis device of the present invention, since the combustion state of the burner is diagnosed using the emission spectra detected in two adjacent flame regions, the combustion state of the burner can be diagnosed. It has an excellent effect of being able to accurately diagnose.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the present invention, FIG. 2 is a graph showing the relationship between the direction of flame flow and Q degree or temperature, and FIG. 3 is an explanatory diagram of a conventional example. In the figure, 1a and 1b are probes, 2 is a burner, 3 is a flame, and 4
a, 4b are lenses, 5a, 5b are optical fibers, 8
7a, 7b are optical fiber cables, 8 is an A/D converter, 9 is a computer, and 1o is a display device.

Claims (1)

[Claims] 1) In a combustion diagnosis method that evaluates the combustion state using the emission spectrum from a flame, the combustion state is diagnosed based on the correlation value of an arbitrary number of specific wavelengths among the emission spectra of two regions of the detected flame. A combustion diagnosis method characterized by the following.