Experimental and numerical investigation of medical waste disposal via plasma gasification

Abstract

The COVID-19 pandemic has increased global awareness of proper medical waste disposal. Conventional methods like incineration and gasification are insufficient due to low energy efficiency and harmful emissions. Plasma gasification, however, offers significant advantages, including economical benefits, higher efficiency, lower emissions, and greater hydrogen production potential. Hence, plasma gasification can be an influential alternative to conventional methods with further developments. In this study, gasification characteristics of medical waste are investigated in a novel laboratory-scale updraft plasma gasifier. The gasifier utilizes a DC arc plasma torch with a maximum capacity of 5 kWh. Medical waste samples are prepared by mixing various consumables like face masks and cotton bandages, whereas waste capacity of the gasifier is estimated to be 7.0 kg/h for an equivalence ratio (ER) of 0.2. Simulations are conducted for ER values of 0.1, 0.2, 0.3, and 0.4 using ANSYS Fluent software, and the plasma jet is modeled as hot gas. Results demonstrate that integrating the throat configuration to the updraft plasma gasifier and increasing the ER value enhance H2 production and reduce CO content in the syngas. The minimum H2 content is found as 48.5% for ER = 0.1 with 24.1% CO, while the maximum H2 content is 54.7% for ER = 0.4 with 17.1% CO. The gasifier configuration achieves a carbon conversion rate (CCR) of 29.1% and a cold gas efficiency (CGE) of 28.5%.