Modelling of Gasification of Refuse-derived fuel (RDF) based on laboratory experiments

In this work, a model of gasification process that enables all, material and energy balance, calculation of gas composition, gas heating value and reactor temperature is presented. The model parameters were estimated by laboratory experiments. A fraction of MSW generally separated from inorganic materials and biodegradable components, so called Refuse-derived fuel (RDF), was studied by material characterization methods and laboratory scale experiments. Composition of RDF was determined by the separation of a representative sample into its basic components (paper, foils, hard plastics, textiles), which were homogenized by grounding in a cryogenic mill. All components of RDF and also a representative mixed sample of RDF were studied by thermogravimetric (TGA) analysis, differential scanning calorimetry (DSC), elemental analysis and bomb calorimetry to determine the kinetics of thermal decomposition, proximate and elemental composition, heat of the reaction and higher heating value. The pyrolysis and gasification experiments were performed in a laboratory scale reactor. The amount of tar in raw produced gas was determined. Industrial scale gasification process were studied by mathematical modeling and computer simulation. All processes, gasification with air, gasification with oxygen and gasification with both oxygen and steam were investigated under different conditions. RDF conversion of 100% was achieved by gasification with air at the air to RDF mass ratio of 2.2. However, the gas heating value was only 4.6 MJ/Nm3, Gasification of RDF using oxygen enables producing a gas with the heating value of around 10 MJ/Nm 3 at the oxygen to RDF mass ratio of 0.5. By increasing the steam to RDF mass ratio, the content of H2 and CO2 increased, however the content of CO, reactor temperature and gas heating value decreased.