Reaction Characteristics of Microwave Hydrogen Plasma

Hydrogen will be the main clean energy in the future, which will play a key role in the future’s green metallurgy. Taking low temperature plasma aided hydrogen direct reduction rection of iron ore as a background, a two-dimensional numerical model was established to study the reaction characteristics of microwave hydrogen plasma by combining reaction mechanisms from different literature and data from LXcat database. Compared with the experimental results in the literature, the rationality and reliability of the plasma model were verified. Based on that, the effects of the input power of the microwave and gas pressure of the plasma on the indicators such as electron density and concentration of excited hydrogen molecule (H₂s) in the plasma were investigated, which obtained key parameters for the iron ore reduction. The results show that, at a constant pressure of plasma medium and an increasing input power of the microwave, the electron density increases, while there exists a peak value with the H₂s concentration. When the pressure of the plasma medium increases, at a certain microwave power, the electron density decreases exponentially, and the H₂s concentration keeps monotonically increasing, whereas its molar fraction shows a peak with the variation. Furthermore, the reasons and characteristics for having peak in variation of the concentration and the fraction of H₂s, respectively, in the plasma reaction are discussed when the microwave power or the gas pressure reaches beyond a critical value. Such a study is expected to provide a theoretical reference for further research and application of hydrogen plasma iron oxide reduction in green iron making.