Process optimization and mechanism analysis of dielectric barrier discharge synergistic purification of ethylene in mining diesel exhaust

To effectively remove hydrocarbon pollutants from mining diesel exhaust and optimize purification process parameters, a dielectric barrier discharge（DBD） non-thermal plasma reactor is constructed using ethylene as a representative simulant of hydrocarbons. Single-factor experiments combined with Box-Behnken response surface design are employed to systematically investigate the effects of discharge voltage, initial gas concentration, and inlet flow rate on purification efficiency. A quadratic regression model is established to optimize process parameters. Within the discharge voltage range of 0-35 kV, ethylene removal efficiency shows an initial increase followed by a decrease, reaching a maximum of 72% at 25 kV. Removal efficiency decreases significantly with increasing initial concentration （0-450 ppm）. Inlet flow rate exhibits a parabolic distribution within 1-6 L/min, with optimal performance at 3 L/min. The response surface analysis yields a quadratic regression model with R²=0.965. Factor importance ranking: inlet flow rate＞discharge voltage＞initial concentration. Optimal parameters: discharge voltage 19.54 kV, initial concentration 249.44 ppm, inlet flow rate 2.99 L/min, with predicted removal efficiency of 69.26% and experimental error of only 1.18%. NO_x addition enhanced ethylene removal by 10%-20%. The optimized parameters and synergistic purification mechanism provide theoretical foundation for engineering applications of DBD technology in mining diesel vehicle exhaust purification.