Thermokinetic synergistic evaluation of iron ores as oxygen carriers for TGA simulated pyrolysis, gasification, and chemical looping combustion of municipal solid wastes

The chemical looping process (CLP) is regarded as a promising approach for various carbon capture systems (CCS) including bioenergy generation from municipal solid waste (MSW) however, the diverse nature of MSW makes the operation complex. Low-cost iron ore sourced from mining industries is used as oxygen carriers (OC) to achieve environmentally friendly and highly efficient utilization of MSW through in-situ chemical looping processes. The effectiveness of OCs, ranging from 10 to 50 wt%, was studied using a thermogravimetric analysis (TGA) under various conditions. The temperature ranges for different reaction stages were observed under both inert and air environments. The temperature range was 130 °C–550 °C in an inert environment while 140 °C–530 °C in an air environment for stage II or the gas-solid reaction stage. For stage III or the solid-solid reaction stage, the temperature range was 670 °C–950 °C in an inert environment and 720 °C–950 °C in an air environment and MSW blends showed positive synergy in both environments. Thermo-kinetic parameters for seven reaction models were calculated when fitted to Arrhenius and Coats-Redfern methods while best-suited reaction models were observed to be one-dimensional diffusion (D1) and two-dimensional diffusion (D2) for the overall stage II and stage III respectively. Additionally, thermodynamic parameters were evaluated to understand the operating variables that influence the system's behavior in both fuel and air reactors. The energy recovery potential with mass burning technology can lead to a maximum electrical output of 1MWe, and 2.5MWe with CLP post-pretreatment of waste.