Rapid Measurement Of Pulverized Coal By LIBS Under Magnetic Constraint

Coal is the most used primary energy in China.The detection of coal content can contribute to the safe,economical and efficient operation of power plants.LIBS technology cycle is short,measurement efficiency is high,and the scope of application is wide.In view of the shortcomings of low sensitivity in actual detection,the method of external magnetic constraint is adopted to improve,the specific content and research results are as follows:1)The magnetic confinement technology is introduced into the experiment of laser induced pulverized coal.The experimental platform of laser induction technology under magnetic constraint is set up.The core equipment and process of the experiment were introduced in detail.2)For exceptions and invalid data in the original data,Using the principle of normal distribution to filter the data,It improves the validity of spectral data.For the problem of spectral line overlap,The genetic algorithm with improved evolutionary strategy was used to decompose and fit.3)The influence of magnetic field on electron temperature,density and spectral intensity of laser-induced pulverized coal plasma was studied.Under the same laser output energy condition,When the magnetic field intensity increases gradually,the parameters of the plasma also increase gradually.The excitation efficiency of the particles and the sensitivity of the system are improved by adding magnetic field constraints.4)Aiming at the problem of slagging in power plant boilers,The partial least square method is used to analyze the content of minor elements Fe and Ca in pulverized coal.The results show that the element correlation coefficient increases under the magnetic field constraint,The average relative error of Fe decreased from 11.68% to5.52%,and the maximum relative error of Ca decreased from 13.5% to 5.4%.The method of partial least squares has high prediction accuracy in the magnetic field.Figure 19;Table 13;Reference 59...