Thermogravimetric and kinetic study of thermal degradation of various types of municipal solid waste (MSW) under N₂, CO₂ and oxy-fuel conditions

Oxy-fuel combustion is one carbon capture and sequestration (CCS) technique that uses both O₂ and recirculated flue gas as an oxidiser. As a result, the produced gas is composed mainly of CO₂ and H₂O, which makes its sequestration more cost-effective. Changing the atmosphere from N₂ to CO₂ affects combustion behaviour. To study the impact of the atmosphere on the combustion process, the thermal degradation of representative types of municipal solid waste (MSW) under N₂, CO₂, and O₂/CO₂ atmospheres was analysed using a thermogravimetric (TG) instrument. Nonisothermal degradation experiments were conducted, and three heating rates were examined. Isoconversional methods were employed to determine kinetic data. Comparing N₂ and CO₂ atmospheres, it was found that below 600 °C, the shape of TG curves was not affected significantly. However, above 600 °C under CO₂ atmosphere, a second peak appeared, which indicated gasification reactions of the char with carbon dioxide. In the presence of oxygen, the second peak was shifted to lower temperatures, indicating that thermal decomposition with O₂ was more rapid. The reported kinetic parameters provide fundamental information on the conversion of solid waste. Thus, they are essential for designing chambers dedicated to the oxy-combustion of waste.