Sustainable Development Solutions for the Medical Waste Problem Using Thermal Plasmas

Abstract

Waste-to-energy (WTE) conversion is a vital process in the Middle East, especially in the Kingdom of Saudi Arabia (KSA), which is considered sustainable development for the environmental strategic project. Previous publications dealt with the environmentally friendly plasma treatment of wastes such as municipal waste, scrap tire waste, plastic waste, and grey water, using thermal plasmas produced by the cornerstone part of plasma reactors, namely the air plasma torch. In the present paper, with a view to energy recovery from medical waste, the thermodynamic properties of air plasma torches with a flow rate of air ranging from 10 mg/s to 30 mg/s and plasma jet temperatures ranging from 1500 °C to 5000 °C were investigated; these include power loss, enthalpy, plasma flux, and torch efficiency variation with plasma input power and air flow rate. The measured electrothermal efficiency of the plasma torch is in the range of 42% to 80% and increases with the increasing input power and gas flow rate. In Makkah, the number of beds in the hospitals is 10,500; the average annual weight of the medical waste in the hospitals is 2835 × 103 t, with an extracted amount of pyrolysis oil equivalent to 2268 × 103 t and an equivalent energy of 90 × 109 M J. In the proposed plasma treatment project, the amount of diesel oil after the distillation process will reach up to 1928 × 103 t, with an estimated sale profit of the electricity reaching up to 21 × 106 MW·h. The sale profit of pyrolysis oil in 2022 reaches up to USD 34.44 million, and the sale profit of electricity extracted by using the diesel oil in 2022 reaches up to USD 1020 million for households and USD 1445 million for factories.