Thermodynamic Study of Water-Steam Plasma Pyrolysis of Medical Waste for Recovery of CO and H2

This paper describes the equilibrium compositions of the typical medical waste under high temperature pyrolysis by a steam plasma torch using the NASA CEA2 program. Various components from selected typical medical waste were input to the program along with the treatment temperature from 1000 K ～ 4100 K. The program then performed the Gibbs free energy calculations and searched for the equilibrium composition with minimizing the total system Gibbs free energy. The calculation results indicate that, the equilibrium composition of a system C-H-O at C/O = 1 in the temperature range of 1400 K ～ 2000 K has demonstrated that gas composition are CO and H2 mainly, the other components (CO2, C2H4, C2H2, CH4 etc.) is less than 1%by volume and the degree of raw material transformation is about 100%. Comparison with air plasma, the steam plasma treatment will not produce nitrogen oxides, if the materials are free of nitrogen element.