JPH071200B2 - Combustion diagnostic device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a burner combustion diagnostic device used for a boiler or the like.

[Prior Art] The control technique by optical spectrum analysis is a classical technique in a chemical analysis room, and when it is extended to an online measurement of a plant-scale operation, a conventional general analysis technique is a sampling technique. Although it is based on off-line measurement, it is often necessary to continuously measure the actual plant. For example, a large number of burners installed in a boiler are constantly monitored, and in the event of an abnormality, unless immediate action is taken, an accident will result.

Therefore, in recent years, a device as shown in FIG. 4 has been considered as a device for diagnosing combustion. In this apparatus, the light of the flame b of the burner a is detected by the required detector c, and the detected light is guided to the spectroscope e via the optical fiber cable d, and the spectroscope e
The optical spectrum obtained for each predetermined wavelength is sent to the computer g through the A / D converter f, the spectral emissivity is obtained by the computer g, and the combustion state of the burner a is diagnosed from the result.

[Problems to be Solved by the Invention] However, in the above-described apparatus, the spectroscope e must be installed at a place away from the furnace wall, and therefore the optical fiber cable d needs to be laid from the detector c to the spectroscope e. Therefore, the cost is high, and the optical fiber cable d is vulnerable to external force so that it is easily damaged. Furthermore, the optical characteristic of the optical fiber cable d changes depending on the laying condition. Therefore, the gain calibration must be performed to maintain the measurement accuracy. Therefore, the maintainability is poor, and the spectroscope e performs scanning corresponding to various wavelengths. However, when scanning is performed for each wavelength, it is necessary to take a long measurement time for one point to perform scanning. There is a problem that it takes time to complete one cycle.

The present invention has been made in view of the above circumstances and has an object to solve the above-mentioned problems by eliminating the need for laying an optical fiber.

[Means for Solving the Problems] In order to achieve the above object, in the first means of the present invention, a plurality of lenses for converging the light of the flame of the burner and the light condensed by the plurality of lenses are used. A probe having a plurality of optical fibers provided corresponding to each lens for transmitting a plurality of lenses, and a plurality of lenses provided corresponding to each optical fiber and adapted to collect light from the optical fibers and corresponding to each lens And a plurality of filters adapted to extract light of different wavelengths from the light of wavelengths respectively extracted by other filters, and photoelectric conversion of light of different wavelengths extracted from each filter. A photometric device incorporating a plurality of photoelectric converters provided corresponding to each filter and assembled integrally with the probe, and a burner based on data from the photometric device. A computer for diagnosing the combustion state is provided, and in the second means of the present invention, one lens for collecting the light of the flame of the burner and an optical fiber provided for sending the light collected by the lens are provided. A built-in probe, a diffraction grating for splitting the light from the optical fiber into a plurality of different wavelengths of light, and a plurality of photoelectric converters for photoelectrically converting the light split by the diffraction grating for each wavelength, and A photometric device assembled integrally with the probe and a computer for diagnosing the combustion state of the burner based on the data from the photometric device are provided.

[Operation] In the first means, the light of the burner flame is condensed by a plurality of lenses and sent through the corresponding optical fibers, and the light from each optical fiber is transmitted to each optical fiber in the photometric device. It is sent to the filter through the corresponding lens, and in each filter, the light of the wavelength different from the light of the wavelength extracted by the other filter is extracted, and the photoelectric corresponding to each light of the different wavelength is obtained. The signals are sent to the converter, photoelectrically converted, and the photoelectrically converted signals are given to the computer as data to perform combustion diagnosis.

In the second means, the light of the burner flame is condensed by one lens, sent through the optical fiber and given to the diffraction grating of the photometric device, and is split into a plurality of lights of different wavelengths by the diffraction grating. The separated and dispersed light is photoelectrically converted by the corresponding photoelectric converters, and the photoelectrically converted signals are given to the computer as data to perform combustion diagnosis.

According to the present invention, since the probe and the photometric device are made compact and integrated in any of the first and second means,
It is not necessary to lay an optical fiber cable whose optical characteristics change.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention corresponding to claim 1. In the figure, 1 is a probe, 2 is a compact photometric device integrally attached to the rear of the probe 1, and 3 is a probe 1. A / D converter that can take in data according to the number of measured wavelengths and the number of wavelengths to be measured. Reference numeral 4 is a computer that can obtain temperature and spectral emissivity based on the data from A / D converter 3. .

The probe 1 is provided with an inner cylinder 5 and an outer cylinder 6, and a plurality of pieces (minimum 2 pieces) for collecting the light of the flame of the burner are provided at the tip of the outer cylinder 6.
Individual lenses 7 are provided, and an optical fiber 8 for sending the light condensed by the lenses 7 is provided behind each lens 7. Further, cooling air 9 for cooling the probe 1 can be supplied into the outer cylinder 6.

In the casing 10 of the photometric device 2, a lens 11 for collecting the light extracted from the rear end of the optical fiber 8 protruding into the casing 10 is arranged, and the lens 11 is provided behind the lens 11. A filter 12 for extracting only light of a predetermined wavelength selected from the light from the above is disposed, a photoelectric converter 13 and an amplifier 14 are sequentially disposed behind the filter 12 and amplified by the amplifier 14. An electric signal can be output from the photometric device 2 and given to the A / D converter 3 via the shielded electric wire 16.

The burner flame light collected by the lens 7 is taken in from the tip of the optical fiber 8 and sent through the inside of the optical fiber 8, is taken out from the rear end and is collected by the lens 11, and is selected by the filter 12 in advance. The light of the wavelength is extracted, and the light is converted into the photoelectric converter 13
Is converted into an electric signal proportional to the spectral radiant emittance, and the electric signal is amplified and output by the amplifier 14 and sent to the A / D converter 3. The wavelengths selected by the two sets of filters 12 of the photometric device 2 are different wavelengths. Also A / D converter 3
From this, data is given to the computer 4, the temperature and the spectral emissivity of the burner are obtained from the wavelength and the spectral radiant emittance, and the combustion state of the burner is diagnosed. When the diagnosis of one burner is completed, the data of the next burner is given from the A / D converter 3 to the computer 4, and the diagnosis of the burner is performed by the same procedure as described above.

Next, an example of a diagnosis method will be specifically described.

The spectral radiant emittance I _λ is represented by the Wien's equation, Becomes

Where ε; Spectral emissivity λ; Wavelength T; Temperatures C ₁ and C ₂ ; Constant Now, let λ ₁ and λ _{2 be} the wavelengths of light selected by the two filters 12 of the above-mentioned device, and the spectral radiant emittance. _Assuming I _λ1 and I _λ2 , the formula (i) is Becomes

By the way, in the above equations (ii) and (iii), the spectral emissivity ε _λ1 , ε
_{Since λ2} is the same for all wavelengths in gray near bodies, dividing equation (iii) by equation (ii) gives And transforming equation (iv), And, from equation (v) Is obtained.

Therefore, the measured wavelengths λ ₁ and λ ₂ and the measured wavelengths λ ₁ and λ
_If the spectral radiant emittances I _λ1 and I _λ2 for each ₂ are substituted into the equation (vi) to calculate, the temperature T is obtained, and if the temperature T is obtained, the spectral emissivity ε is obtained from the equation (ii) or (iii). _λ (= ε _λ2
= Ε _λ3 ) is obtained. For example, since the spectral emissivity ε _λ and the NOx or CO have a certain relationship as shown in FIG. 2, the burner combustion state can be diagnosed from the spectral emissivity ε _λ .

FIG. 3 shows another embodiment of the present invention corresponding to the second aspect of the present invention. The lens 7 and the optical fiber 8 are two sets in the above embodiment, but one set in this embodiment. Instead of the lens 11 and the filter 12, a diffraction grating 15 for performing high-level spectroscopy is provided. In the figure, the same reference numerals as those shown in FIG. 1 indicate the same components.

In the diffraction grating 15, the light is dispersed corresponding to the wavelengths λ ₁ and λ ₂ , and the separated light is sent to the photoelectric converter 13,
An electric signal proportional to the spectral radiant emittances I _λ1 and I _λ2 is output from 13, and the temperature and the spectral emissivity are calculated by the computer 4 in the same manner as described above, and the combustion state is diagnosed. In the diffraction grating, it suffices to carry out spectroscopy for at least two wavelengths.

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] In the combustion diagnostic device of the present invention, the probe and the photometric device are made compact and integrated, and the laying of an optical fiber cable whose optical characteristics change is not required, so that the cost is low and the measurement of gain comparison and the like is performed. Maintainability for accuracy is improved, data acquisition time is shortened, near real-time measurement is possible, and reliability is improved because there is no risk of accidental disconnection of optical fiber cable. Can play.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of the present invention, FIG. 2 is a graph showing the relationship between spectral emissivity and concentrations of NOx and CO, and FIG. 3 is an explanatory view of another embodiment of the present invention. FIG. 4 is an explanatory diagram of a conventional example. In the figure, 1 is a probe, 2 is a photometric device, 3 is an A / D converter, 4
Is a calculator, 7 is a lens, 8 is an optical fiber, 11 is a lens, 12 is a filter, 13 is a photoelectric converter, 14 is an amplifier, 15
Indicates a diffraction grating.

Claims (2)

[Claims] 1. A probe having a plurality of lenses for condensing the light of a burner flame and a plurality of optical fibers provided corresponding to each lens so as to send the light condensed by the plurality of lenses, and each of the above-mentioned probes. A plurality of lenses provided corresponding to the optical fibers and adapted to collect the light from the optical fibers, and light provided at the respective lenses and having a wavelength different from the wavelength of the light extracted by the other filters. Incorporating a plurality of photoelectric converters provided corresponding to each filter so as to photoelectrically convert light of different wavelengths extracted from each filter as well as a plurality of filters adapted to extract Combustion diagnostic device, which is provided with a photometric device that is assembled mechanically and a computer that diagnoses the combustion state of the burner based on the data from the photometric device. 2. A probe having a lens for collecting the light of a burner flame and an optical fiber provided to send the light condensed by the lens, and the light from the optical fiber having a plurality of different wavelengths. A diffracting grating for splitting light into a light and a plurality of photoelectric converters for photoelectrically converting the light split by the diffractive grating for each wavelength, and a photometric device assembled integrally with the probe, and the photometric device A combustion diagnosis device, which is equipped with a computer for diagnosing the combustion state of the burner based on the data from the.