Abstract: With high-density polyethylene (HDPE) and sawdust as the research objects, combined with thermodynamic analysis and experimental research, the influence rule of input power, HDPE mass ratio and steam-to-carbon ratio (S/C) on hydrogen production rate, gas product composition, and chlorine release behavior in the process of plasma gasification were investigated. Moreover, thermodynamic calculations was conducted based on the Gibbs minimum free energy principle. Simulation analysis revealed that increasing input power from 7.5 kW to 34.0 kW resulted in a maximum hydrogen proportion rate of 59% at 20 kW (corresponding temperature at 800 ℃). As HDPE mass ratio increased from 0 to 100%, the hydrogen production rate decreased from 65% to 56%. When S/C was 0, the proportion of hydrogen was the highest (80%), and with S/C increased from 0 to 3.0, the proportion of hydrogen showed a decreased trend. Chlorine products in the gas phase mainly comprised KCl(g) and (KCl)2(g). Experimental results confirmed the consistency between the effects of input power, HDPE mass ratio, and S/C on hydrogen production with thermodynamic analysis. When the input power was 22 kW, the proportion of HDPE raw material was 80% and S/C was 1.0, the optimal hydrogen production were 1.52 m3/kg, 1.51 m3/kg and 1.38 m3/kg， respectively. Gas-phase chlorine distribution reached the highest when the input power was at 22 kW, HDPE mass distribution of 20% and S/C of 1.4. Comparison of the experimental results validated the potential of thermodynamic simulation for qualitative and quantitative analysis of plasma gasification products. The feasibility of using thermodynamic calculation to simulate the co-gasification of biomass and HDPE plasma was explored, which could provide reference for the operation optimization and chlorine control of plasma gasification.

Key words: 　plasma gasification, sawdust, high-density polyethylene (HDPE), chlorine product analysis, thermodynamic equilibrium, hydrogen