CN116482080A - LIBS technology-based coal quality analysis method - Google Patents

Abstract

The invention provides a coal quality analysis method based on LIBS technology, which comprises the following steps: after splitting the laser output by the laser, forming a first light beam and a second light beam; the first light beam is incident on the pulverized coal, the photoelectric detector array receives scattered light signals and sends the scattered light signals to the analysis unit, and the analysis unit outputs the particle size distribution of the pulverized coal; the second light beam is incident on the pulverized coal to generate a plasma signal, the plasma signal is sent to a spectrometer to obtain a spectrogram of the pulverized coal, the analysis unit processes the spectrogram and the particle size distribution by using an analysis model to obtain parameters of the pulverized coal, and the parameters comprise heating value. The invention has the advantages of accurate analysis and the like.

Description

Coal quality analysis method based on LIBS technology

technical field

The invention relates to LIBS technology, in particular to a coal quality analysis method based on LIBS technology.

Background technique

At present, in thermal power plants, most of the indicators such as the calorific value in coal used for thermal power generation are still taken on-site sampling, and then sent to the laboratory for chemical analysis. This method consumes a lot of time in the process of sampling and testing, which is not conducive to the online guidance of coal combustion. Among the on-line coal quality analysis instruments, the neutron activation method has high measurement accuracy, but its development is limited by the disadvantages of high cost, difficult maintenance, and radiation.

Laser Induced Breakdown Spectroscopy (LIBS) is an emerging rapid analysis technology, which is developing rapidly in online analysis technology due to its advantages of no need for sample preparation, fast analysis, and telemetry. Real-time detection of elements in online coal by LIBS can quickly calculate its calorific value and other indicators, which has real-time guiding significance for online combustion of power plants. In addition to the analysis of indicators such as calorific value in coal, the particle size of burning coal is also an important factor affecting its complete combustion. The existing instruments for measuring coal particle size include laser particle size analyzers, but most of them are offline instruments. The real-time detection and analysis of the particle size of coal combustion is also helpful for the ratio guidance of coal combustion, oxygen supply and water supply in power plants. Some online particle size analysis basically uses the image processing method, but the real-time working conditions on site have a great influence on the image processing of coal combustion. At the same time, it is considered that for LIBS spectroscopy, the particle size of the analyte is also one of the important factors affecting the intensity and stability of the signal.

Therefore, it is necessary to develop a new type of coal quality analyzer, which can not only detect the coal particle size online in real time, but also measure the combustion indicators such as the calorific value of coal, so that the power plant can grasp the real-time coal combustion situation and adjust the combustion situation online in real time.

Contents of the invention

In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides a coal quality analysis method based on LIBS technology.

The purpose of the present invention is achieved by the following technical solutions:

The coal quality analysis method based on LIBS technology, the described coal quality analysis method based on LIBS technology is:

The laser output by the laser is split to form a first beam and a second beam;

The first light beam is incident on the pulverized coal, the photodetector array receives the scattered light signal, and sends it to the analysis unit, and the analysis unit outputs the particle size distribution of the pulverized coal;

The second light beam is incident on the pulverized coal to generate a plasma signal, and the signal is sent to the spectrometer to obtain a spectrogram of the pulverized coal. The analysis unit uses an analysis model to process the spectrogram and particle size distribution to obtain parameters of the pulverized coal, which include calorific value.

Compared with prior art, the beneficial effect that the present invention has is:

1. By measuring the pulverized coal scattered light and laser-induced spectrum at the same time, the particle size distribution information of pulverized coal and the calorific value of pulverized coal are obtained;

2. The measured coal particle size distribution information has a certain influence on the laser-induced breakdown spectrum, and the information is used as a correction item for modeling information such as calorific value, and the result is more accurate and stable;

3. The coal samples of different particle sizes can be classified through the particle size distribution information, and the classification can be carried out before the quantitative analysis of calorific value and other information, so that the measurement results are more accurate.

Description of drawings

The disclosure of the present invention will become more comprehensible with reference to the accompanying drawings. Those skilled in the art can easily understand that these drawings are only used to illustrate the technical solution of the present invention, and are not intended to limit the protection scope of the present invention. In the picture:

Fig. 1 is a schematic flow chart of a coal quality analysis method based on LIBS technology according to an embodiment of the present invention.

Detailed ways

Figure 1 and the following description describe an alternative embodiment of the invention to teach those skilled in the art how to implement and reproduce the invention. In order to explain the technical solutions of the present invention, some conventional aspects have been simplified or omitted. It should be understood by those skilled in the art that modifications or substitutions from these embodiments will be within the scope of the present invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. As such, the invention is not limited to the alternative embodiments described below, but only by the claims and their equivalents.

Example 1:

Fig. 1 has schematically provided the flow chart of the coal quality analysis method based on LIBS technology of the embodiment of the present invention, as shown in Figure 1, described coal quality analysis method based on LIBS technology is:

The laser output by the laser is split to form a first beam and a second beam;

The first light beam is incident on the pulverized coal, the photodetector array receives the scattered light signal, and sends it to the analysis unit, and the analysis unit outputs the particle size distribution of the pulverized coal;

The second light beam is incident on the pulverized coal to generate a plasma signal, and the signal is sent to the spectrometer to obtain a spectrogram of the pulverized coal. The analysis unit uses an analysis model to process the spectrogram and particle size distribution to obtain parameters of the pulverized coal, which include calorific value.

In order to obtain accurate particle size distribution of pulverized coal, further, the first light beam is incident on the pulverized coal after beam expansion.

In order to obtain accurate pulverized coal particle size distribution, further, the method of obtaining the particle size distribution is:

The photodetector array outputs the position of the maximum light intensity of the scattered light, and the particle size distribution of the pulverized coal is obtained by using the corresponding relationship between the particle size and the position of the maximum light intensity of the scattered light.

In order to obtain accurate pulverized coal calorific value and other indicators, further, the way to establish the analysis model is:

Classify coal samples;

Obtain the spectrogram of the coal sample, collect the spectral lines of C, H and inorganic ash-forming elements in the coal sample, these spectral lines are used as the input variables of the model, establish the model between the spectral line and the calorific value, and obtain the coefficient matrix and error term of the model;

The particle size of the coal sample is used as a separate feature to calibrate the measurement error generated by the model, and a functional relationship is established between the modeling error of the coal sample and the size of the corresponding pulverized coal particle.

In order to establish an accurate analysis model, further, the classification method is:

Measure coal samples of different particle sizes, obtain different coal sample particle size data, make a particle size histogram, and classify according to the partial probability of particle size.

Example 2:

An application example of the coal quality analysis method based on LIBS technology according to Embodiment 1 of the present invention.

In this application example, as shown in Figure 1, the coal quality analysis method based on LIBS technology is:

build analytical models,

The laser output by the laser is split to form a reflected first beam and a transmitted second beam. The light intensity of the first beam accounts for 1%, and the light intensity of the second beam accounts for 99%;

The first light beam is incident on the coal powder, the photodetector array receives the scattered light signal, establishes the functional relationship between the particle size and the position of the strongest light intensity received by the photodetector array, takes the size of the coal powder particle size as the abscissa, and the position of the strongest light of the scattered light detected by the photodetector as the ordinate, establishes a calibration curve for particle size analysis, and stores it;

Measure coal samples of different particle sizes, obtain different coal sample particle size data, make a particle size histogram, and classify according to the partial probability of particle size;

Obtain the spectrogram of the coal sample, and collect the spectral lines of C, H and inorganic ash-forming elements (Si, Fe, Al, Ca, and Mg) in the coal sample. These spectral lines are used as input variables of the model, and the model between the spectral line and the calorific value is established to obtain the coefficient matrix and error terms of the model;

The coal sample particle size is used as a separate feature to calibrate the measurement error generated by the model, and a linear function relationship is established between the coal sample modeling error and the corresponding coal particle size.

formal analysis;

The laser output by the laser is split to form a reflected first beam and a transmitted second beam. The light intensity of the first beam accounts for 1%, and the light intensity of the second beam accounts for 99%;

The first beam expands and is incident on the upstream pulverized coal, the photodetector array receives the scattered light signal and sends it to the analysis unit, and the analysis unit uses the calibration curve to output the particle size distribution of the pulverized coal;

The second light beam is focused and incident on the pulverized coal in the downstream to generate a plasma signal, which is sent to a spectrometer to obtain a spectrogram of the pulverized coal, and the analysis unit processes the spectrogram by using an analysis model to obtain parameters of the pulverized coal, the parameters including calorific value;

The calorific value is substituted into the linear function relationship to obtain the corrected pulverized coal calorific value and other parameters.

Claims (6)

1. The LIBS technology-based coal quality analysis method is characterized by comprising the following steps of:

after splitting the laser output by the laser, forming a first light beam and a second light beam;

the first light beam is incident on the pulverized coal, the photoelectric detector array receives scattered light signals and sends the scattered light signals to the analysis unit, and the analysis unit outputs the particle size distribution of the pulverized coal;

the second light beam is incident on the pulverized coal to generate a plasma signal, the plasma signal is sent to a spectrometer to obtain a spectrogram of the pulverized coal, the analysis unit processes the spectrogram and the particle size distribution by using an analysis model to obtain parameters of the pulverized coal, and the parameters comprise heating value.

2. The LIBS technology based coal quality analysis method according to claim 1 wherein the first light beam is incident on pulverized coal after beam expansion.

3. The LIBS technology-based coal analysis method according to claim 1 wherein the particle size distribution is obtained by:

and the photoelectric detector array outputs the position of the maximum light intensity of scattered light, and the corresponding relation between the particle size and the position of the maximum light intensity of the scattered light is utilized to obtain the particle size distribution of the pulverized coal.

4. The LIBS technology-based coal quality analysis method according to claim 1 wherein the manner of establishing the analysis model is:

classifying the coal samples;

acquiring a spectrogram of a coal sample, collecting C, H and spectral lines of inorganic ash forming elements in the coal sample, taking the spectral lines as input variables of a model, and establishing the model between the spectral lines and the heating value to obtain a coefficient matrix and an error term of the model;

and (3) taking the particle size of the coal sample as an independent characteristic to calibrate the measurement error generated by the model, and establishing a functional relation between the modeling error of the coal sample and the corresponding size of the coal dust particles.

5. The LIBS technology based coal analysis method according to claim 4 wherein the inorganic element is Si, fe, al, ca or Mg.

6. The LIBS technology based coal analysis method according to claim 4 wherein the classification is:

and measuring coal samples with different particle sizes, obtaining particle size data of the different coal samples, making a particle size histogram, and classifying according to partial probability of the particle sizes.