| The cost of fuel takes significant importance in the power plant. Usually, the traditional method of coal quality analys is off-line. Therefore, the traditional measurements spent too much long time and analyze so slowly. So the results can't represent the coal quality in time. The traditional technologies couldn't meet the requirement of modern power plant due to the unavailable real-time data of coal quality. It is extremely urgent to find a new technology, which can analyze the coal quality on-line and quickly compared with the limitations of the off-line technologies. Element analysis is one of the most concerning in the assessment of coal quality. Firstly, the existing and potential technologies used for element analysis have been identified and assessed in this thesis. Meanwhile, the impact of coal on boiler of power plant was analyzed in detail,and then, put forward to the necessity of developing a new technology , know as Laser-induced Breakdown Spectroscopy(LIBS), which could analyze coal on-line. This thesis has carried on important researches from the several following respects mainly: The mechanism and character of laser plasma were introduced in detail. Meanwhile, the production theory and effect from continuous background of the plasma spectrum was analyzed, finally, the LIBS experiment system was described detail. Traditional spectrum quantitative analysis needs to utilize the standard sample experiment to get the calibration curve before the quantitative result is done. In order to make the quantitative analysis liberate from traditional quantitative method and realize the freedom calibration, this thesis put forward to a calibration-free model of LIBS. In order to improve the precision of quantitative analysis fatherly, a self-absorption model has been mentioned, which correct and complete the calibration-free model. According to the LIBS experiment of standard copper target and atmospheric pressure, the calibration-free model has been certified, the result shows the model was feasible. The anthracite coal, bituminite coal and lignite coal had been analysed in this paper, other researcher had studied the lignite coal only. The physical and chemical characters of coal effecting on the laser plasma have been studied in detail. With the high drgree of coalification, the plasma temperature is higher, and coal sample is easily to generate double ionization. The plasma intensity of chip sample is more higher than powder sample. In addition, the experimental results show that the plasma temperature and the analysis precision are higher with the smalle partical size. The effect of delay time on the calibration curves has been discussed too, the results indicate that the delay times are different for each element, the optimal times depend on the experiment. The experiments of laser-induced breakdown spectroscopy on a series of fly ash samples and the quantitative analysis of carbon contents have been carried out. The result shows that carbon content of fly ash measured by LIBS and method of Weight-Combustion are coincident well. It's authenticated that LIBS can be used to measure carbon content of fly ash as a new method. A quantitative elements (C, H, O, N, S, Ca, Al, Si and Fe) analysis of coal samples were carried out with LIBS. Because of the self-absorbtion of laser plasma, the calibration curves of those elements shows that the curves has a trend of bend down when the concentration of the analyzed elements are higher. In addition, the quantitative measurement results shows that LIBS is a effective technology for quantitative analysis, and the relative error for each elements are almost less 5%. Finally, general summary and conclusion of the thesis as well as further development direction about research of LIBS in coal combustion are presented, and the context of on-going work is determined.
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