Intensity of the Process Gas Emission from the Thermal Treatment of the 60-340 mm MSW Fraction under Steam

Gasification under steam excess of the residual from mechanical treatment of municipal solid waste (RMT-MSW, refuse derived fuel (RDF)-type) was investigated in a laboratory batch reactor, equipped with a section for high-temperature gas equilibration. Experiments were performed with recirculation of the condensate and residual tars/oils, for closing of the process loop. Gas emissions were registered at 300-500 degrees C (pyrolysis; maximum at 390 degrees C) and 650-800 degrees C (gasification; maximum at 740 degrees C). Peak areas, equivalent to the gas volume, were in a general proportion of 55:45. Mass of tars and oils collected together with condensing steam was only equal to 0.15% of the average weight loss of the RMT-MSW. Ninety-seven percent of organic compounds, mainly naphthalene, phenanthrene and derivatives, was separable by a simple filtration. Concentration of metals in aqueous condensate was equal to 135 mg/dm(3), 98.5% by mass was potassium and sodium ions. Concentration of NH4+ was equal to 2.49 g/dm(3) (mostly carbonate). According to the thermodynamic evaluation, volume of the process gas was equal to 2.11 m(3) (dry, 25 degrees C, 1 bar) per 1 kg of the dry waste. Standard enthalpy of the gas combustion was 24.6 MJ/kg of the dry waste; approximately 16% of this energy was due to endothermicity of the process.