RF-ICP Thermal Plasma for Thermoplastic Waste Pyrolysis Process with High Conversion Yield and Tar Elimination

Abstract

This paper demonstrates an RF thermal plasma pyrolysis reaction apparatus that achieves 89 wt.% reaction conversion yield with no tar content. The demonstrated experimental apparatus consists of a 1100 W RFVII Inc. (104 Church St, Newfield, NJ 08344, United States) @ 13.56 MHz RF thermal plasma generator, a Navio matching network, intelligent feedback controller, and an 8-turn copper RF-ICP torch embedded in a 12 L thermochemical reactor. The intelligent feedback controller optimizes the thermal performance based on feedback signals from three online gas analyzers: CO, CO2 and NOx. The feedback controller output signal controls the RF thermal plasma torch current that provides real-time temperature control. The proposed reaction system achieves precise temperature profiles for both pyrolysis and gasification as well as increases end-product yield and eliminates undesired products such as tar and char. The identified hydrocarbon liquid mixture is 90 wt.% gasoline and 10 wt.%. diesel. The 8-turn RF-ICP thermal plasma torch has an average heating rate of +35 °C/min and a maximum operating temperature of 2000 °C and is able to sustain stable flame for more than 30 min. The reaction operating parameters are (550–990 °C τ = 30 min for pyrolysis and (1300 °C τ = 1 sec) for the gasification process. The identified hydrocarbon liquid products are 90 wt.% of a n-butyl-benzene (C6H5C4H9) and oluene (C7H8) mixture with less than 10 wt.% decane diesel fuel (C10 H22). Comsol simulation is used to assess the RF-ICP thermal plasma torch’s thermal performance.