Urban energy mining from municipal solid waste (MSW) via the enhanced thermo–chemical process by carbon dioxide (CO2) as a reaction medium

The enhanced gasification of municipal solid waste (MSW) using carbon dioxide (CO2) as the gasification medium was investigated to achieve environmentally benign and energy efficient ways for the disposal of MSW. Two main steps of thermal decomposition of MSW were observed. The first thermal degradation step occurs at temperature between 280 and 350 °C and consists of the decomposition of the biomass component into light C1–3-hydrocarbons. The second thermal degradation step occurs between 380 and 450 °C and is mainly attributed to polymer components, such as plastics and rubber, in MSW. To extend this understanding to a more practical level, MSW samples were tested in a drop tube reactor (DTR) at a temperature range from 500 to 1000 °C under various atmospheres with CO2 concentrations of 0–30%. The release of major chemical species from the DTR has been determined using a micro-GC. For example, CO (∼30%), H2 (∼25%) and CH4 (∼10%) were generated.

► Thermo–chemical process of municipal solid waste (MSW).
► Enhanced gasification of MSW by using CO2 as a reaction medium.
► Substantial reduction of condensable hydrocarbons (tar) in CO2 atmosphere.
► Substantial increase of Syngas under the presence of CO2.
► Modification of gasification products under the presence of CO2.