Experimental analysis on products distribution and characterization of medical waste pyrolysis with a focus on liquid...

The massive generation of medical waste (MW) poses a serious risk to the natural environment and human health. The pyrolysis technique is proposed as a potential treatment for MW to tackle the associated environmental issues and produce value-added products. In this work, medical waste pyrolysis has been conducted at various temperatures using a fixed bed reactor with a 20 °C·min^-1 heating rate and nitrogen was used as a career gas with a flow rate of 100 ml·min^-1. In addition, the effect of temperature on products yield and chemical composition of MW pyrolysis have been investigated. The maximum yield of 57.1% for liquid oil was observed from the mixed MW pyrolysis at 500 °C. The gas and char yield were found between 26.5-37.3% and 24.2-12.4%, respectively, for the pyrolysis temperature of 450 °C to 600 °C. According to GC analysis, the concentration of the main gaseous products such as CH₄, H₂, and C₂H₄ was increased with increasing temperature, while CO and CO₂ experienced a decreasing trend. The results of GC-MS analysis revealed that the main components of MW pyrolysis oil were aromatic hydrocarbons, cyclic hydrocarbons, aliphatic hydrocarbons, alcohol, carboxylic acids, and their derivatives. The aromatic and cyclic hydrocarbons content increased up to 38.2% at a pyrolysis temperature of 600 °C. As pyrolysis oil tends to have more long-chain hydrocarbons therefore carbon distributions from C₇ to C₃₅ were observed. The ultimate analysis of oil and char revealed that the increased temperature enhanced the carbon content up to 78.6% and 68.0%, respectively. Furthermore, the higher heat values of 41.8, 24.4, and 52.7 MJ·kg^-1 were reported for oil, char, and gas, respectively.