Numerical analysis of plasma gasification of hazardous waste using Aspen Plus

Abstract

The COVID-19 pandemic raised the problem of dealing with the hazardous wastes generated. The World Health Organization (OMS) recommends the treatment of these wastes at high temperatures in order to neutralize their negative impact. For this reason, the main objective of this work is the development and analysis of a sustainable way to treat hazardous wastes generated by the COVID-19 pandemic. Thus, to achieve that goal, this paper presents an improved computational model that replicates a high-temperature thermal treatment system for COVID-19 wastes using plasma gasification in Aspen Plus V12.2. The distinctive aspect of the present plasma gasification model is the inclusion of an extra Gibbs reactor in order to enhance the calorific value of the syngas. The model validation results show an increase in the CO and CH4 molar fractions and a decrease of the H2 and CO2 molar fractions, which allows to increase the calorific value of the syngas from 4.97 to 5.19 MJ/m3. The most common types of hazardous waste generated during the pandemic were determined to be masks and syringes. COVID-19 waste from Turkey, discarded masks from Indonesia, Korea, and Lithuania, and Chinese syringes were used as feedstock into the computational model. The results suggest that the hazardous waste that allows for higher hydrogen molar fractions is Korean masks. On the other hand, the highest carbon monoxide molar fractions are obtained with medical waste from Turkey, while the highest molar fractions of methane are obtained with medical waste from Lithuania. A conclusion could be drawn that the lowest syngas calorific value is obtained with medical wastes from Turkey, while the highest syngas calorific value is obtained with medical wastes from Korea.