Characteristics of pyrolysis and combustion characteristics of solid waste under high concentration of CO₂ atmosphere

Abstract

Oxyfuel combustion is one of promising solid waste incineration methods as part of CCUS technology in response to the global warming issue. Since the main component of the exhaust gas is CO₂ by supplying pure oxygen with recirculated exhaust gas to the furnace instead of combustion air, the high concentrations of CO₂ can be directly recovered without separating N₂ gas, which is a great advantage for reducing total CO₂ emissions. In this study, thermogravimetric analysis and kinetics analysis of RDF pyrolysis and char combustion were conducted under CO₂ and N₂ atmosphere to investigate the effect of oxyfuel combustion on waste incineration in a vertical stoker-type furnace. As a result, no significant differences were observed in pyrolysis and combustion behavior depending on two different atmospheric gases. The results of kinetics analysis showed that the kinetics triplets tended to be somewhat larger when CO₂ gas was used for reaction, but the difference was not so great especially for char combustion. It was concluded that the decomposition rate of the sample was dominated by the O₂ gas rather than N₂ or CO₂ gas during combustion.