Comparison among different feeding behaviour in two-stage gasifier

The gasification plays an important role in solving the problems of waste-to-energy (WTE) processes. The most important drawback, common to the gasification processes used in WTE technology, consists of the need of cleaning facilities to obtain a clean syngas for powering generation. To eliminate this drawback and to obtain a sufficiently clean syngas, ready for a further use, a gasifier consisting of two stages in series was developed. Although the developed gasifier was tested in a lab-plant scale with various wastes, it was not taken into account how the performances change as a function of the injected waste.Aim of this paper is therefore to compare the effect of different feedings waste, i.e. RDF (Refuse Derived Fuel), ASR (Automotive Shredder Residue) and biomass such as olive oil husk, bagasse, and swithgrass on the gasifying performance of gasifier at two stages. This aim is accomplished by examining either already published or new data relevant the selected wastes.Two main items, namely residual carbon at stage one and syngas composition at stage two, are taken into account to perform this comparison by considering kinetic and thermodynamic of the process. According to the found kinetic law, carbon deposition at stage one is typical of the first hours of process and is characteristic of the short-time test normally performed in a bench scale reactor. As far as stage two concerns, the heat content of the outgoing syngas depends on the ultimate analysis of the used wastes in terms of carbon, hydrogen and oxygen. A thermodynamic analysis of the experimental data confirms the correctness of such a deduction.