Entrained-flow gasification characteristics of plastic waste pyrolysis oil

Abstract

Plastic waste (PW) pyrolysis is a promising method in chemical recycling technology; however, PW pyrolysis oil cannot be used directly because of its high contaminant content. Entrained-flow gasification (EFG) is a suitable method for removing contaminants from pyrolysis oil and enhancing the conversion compared with fixed bed or fluidized bed gasification. We examined the basic characteristics of PW pyrolysis oil through EFG with the variation of O2/fuel ratios from 0.6 to 1.4 and steam/fuel ratio from 0.4 to 0.7 at 600–900°C in a lab-scale reactor. The H2 composition and Cold Gas Efficiency (CGE) showed the highest when the O2/fuel ratio was 0.8. The Carbon Conversion Efficiency (CCE) showed the highest values when the ratio was 1.4. C2-C3 gases tended to decrease at higher temperatures because of the thermal cracking of hydrocarbons. In the experiments with the variation of steam/fuel ratio, CO2 concentration decreased with increasing temperature from 600 to 800°C because of the reverse water-gas-shift reaction. The residence time was calculated to review the reaction conditions and was found to be 4.2–7.3 seconds. The experimental data from a lab-scale EFG can serve as fundamental data for the scale-up of integrated pyrolysis and gasification systems.