Numerical simulation of hot plasma mixed reactor

Arc thermal plasma has a promising application in high temperature chemical industry, as a high temperature heat source with high electric heating efficiency, controllable reaction atmosphere and zero emission after combined green electricity. Rapid mixing heating in milliseconds outside the arc torch can reduce negative effects while keeping the discharge stable. The present paper introduces a novel circumferential jet reactor that exhibits optimal mixing performance, after comparing the structural characteristics of circumferential jet, tangential jet, and sudden expansion, among others, and studies the influence of jet momentum ratio on mixing effect based on numerical simulation. The jet momentum ratio is defined as the ratio of the methane circumferential jet to the momentum of the hot plasma jet. The results show that the reactor combined with low power arc hot plasma jet can be used as a fast heater, which has the characteristics that the pyrolysis loss of cold materials increases first and then decreases after the momentum ratio increases. As a heater, the momentum ratio should be increased as much as possible. In the mean time, the reactor combined with high power arc thermal plasma can be used for methane pyrolysis to produce acetylene, which has the characteristics of highest acetylene selectivity and low carbon binding rate when the momentum ratio is about 1.55. The acetylene selectivity of arc hot plasma reactor can be greatly improved when combined with quenching. This work is of guiding significance to broaden the application of plasma heater, and is helpful to the combination of arc hot plasma and high temperature chemical industry.