Study On Characteristics Of DBD Plasma Assisted Coal Pool Fire Combustion With Plate To Plate Electrode Structure

DBD plasma assisted coal combustion is mainly used to reduce the bond energy required for combustion,improve the efficiency of combustion,expand the combustion limit and control the emission of pollutants through energetic active groups such as excited particles and free radicals generated by discharge.The research on the characteristics of plasma discharge and pool fire in the process of coal combustion under the atmosphere of coal combustion can provide theoretical basis for plasma-assisted coal combustion.In this thesis,a plate-to-plate electrode（DBD）combustion accelerator is built with an alumina（Al₂O₃）ceramic tube as the medium.Due to the unique discharge environment due to irregular bulk coal combustion,a plate-to-plate electrode DBD combustion device is developed with the ceramic tube as the discharge cavity and the coal itself as the blocking medium.The system matching of excitation source parameters,combustion device parameters and special working medium gas atmosphere is studied.The changes of power,temperature and mass in the combustion process of bulk coal are studied.The discharge characteristics of coal pool fire assisted by dielectric barrier discharge（DBD）plasma and its influence on combustion characteristics are studied.It provides theoretical basis for structure optimization and electrode design of DBD reactor.The experimental results show that the variation of voltage,current and power of DBD is closely related to the variation of external application parameters.The device can realize stable discharge when the external application voltage ranges from 32k V to40k V,and the intensity of discharge channel and discharge power are positively correlated with the peak value of external application voltage.Compared with coal without discharge combustion,DBD plasma can significantly improve the combustion efficiency of coal pool fire.When the amplitude of the applied pulse voltage increases gradually,the mass decay rate and temperature change rate of coal increase gradually,the maximum combustion temperature increases obviously,and the combustion limit is extended.Finally,the combustion state of coal in plate-electrode combustion device before and after plasma intervention is compared.The study of discharge characteristics and pool fire combustion characteristics of irregular coal combustion in this thesis can provide theoretical basis and reference for DBD plasma assisted coal combustion and DBD reactor parameter design and optimization.In this thesis,a one-dimensional DBD plasma simulation model of CO/NO/O₂mixture is established.The simulation model is calculated by finite element analysis method,and the discharge characteristics of CO/NO/O₂ mixture gas are analyzed.The results show that the density of CO and CO₂ in ionization space is higher in CO/NO/O₂mixed gas discharge.When the energy in the discharge space increases,the peak value of current pulses is increased first,and then the number of current pulses is increased.The reaction rate of N₂ at current peak and current extinction is affected by electron density and electron energy.Figure[33]table[11]reference[62]...