Conversion of medical waste into value-added products using a novel integrated system with tail gas treatment: Process design, optimization, and thermodynamic analysis.

The COVID-19 pandemic has generated substantial medical waste (MW), posing risks to society. Based on widespread MW incineration, this study proposes an integrated system with tail gas treatment to convert MW into value-added products with nearly zero emissions. Herein, steam generators and supercritical CO2 cycles were used to recover energy from MW to produce high-temperature/pressure steam and electricity. A simple power generation cycle achieved a net electricity efficiency of 22.4% through optimization. Thermodynamic analysis revealed that the most energy and exergy loss occurred in incineration. Furthermore, a pressurized reactive distillation column purified the resultant tail gas. The effects of inlet temperature, pressure, liquid/gas ratio, and recycle ratio on the removal and conversion efficiencies of NO2 and SO2 were evaluated. Nearly 100% of the SO2 and 75% of the NO2 generated by the incineration of MW have been converted into their acid forms. Based on the proposed tail gas treatment unit, high-purity CO2 (∼98% purity) was finally obtained.

Valorisation of hazardous medical waste using steam injected plasma gasifier: a parametric study on the modelling and multi-objective optimisation by integrating Aspen plus with RSM.

The COVID-19 Pandemic has a detrimental effect on the environment related to the exponential rise in medical waste (MW). Extraction of energy from the toxic MW with the latest gasification technology instead of conventional incineration is of utmost importance to promote sustainable development. This present study investigates the processing of MW for the generation of enriched hydrogen syngas using steam injected plasma gasifier. Modelling of Plasma gasifier was performed in Aspen Plus and Model validation was done with the experimental result and, a good agreement was attained. Sensitivity analysis was implemented on MW in which the influence of gasification temperature, equivalence ratio (ER), and Steam/Biomass (S/B) on the producer gas (PG) composition, gas yield, H2/CO ratio, cold gas efficiency (CGE), and the higher heating value (HHV) was calculated. Furthermore, Response surface methodology (RSM) has been incorporated for the multi-objective optimisation of the variable gasification parameters. R2 values obtained from ANOVA for H2, CGE, and HHV are 98.62%, 99.10%, and 98.9% respectively. Using the response optimiser, the optimum values of H2, CGE, and HHV were found to be 0.43 (mole frac), 89.95%, and 7.49 MJ/Nm3 for temperature at 1560.60°C, equivalence ratio 0.1, and S/B 0.99, respectively. The observed coefficient of desirability was about 0.97.