Gasification Behavior of Hydrothermal-Treated Municipal Waste

Abstract

To efficiently utilize inexpensive waste biomass, it has been proposed that municipal solid waste consisting of various raw materials is hydrothermally pretreated to uniformalize their properties and then pyrolytically gasified into syngas. The waste sample consisting of food waste, wood and paper wastes, rice straw and plastic was hydrothermally treated at 175 °Cand 1.0 MPa. The treated samples with a water content of 0, 30, 59 % (wet basis) were gasified using nitrogen gas containing water vapor and γ-Al2O3 particles as catalyst at 850 °C. The treated waste was successfully gasified. The results indicated that the gas yield increased with increasing the water content and reached 63% (carbon basis) with the water content of 59 %.Also, this study investigated the influences of hydrothermal treatment on subsequent gasification for Sugi sawdust as a representative of wood waste, and two plastic samples of polyethylene and polystyrene as a representative of plastic waste contained in municipal waste. The results indicated that Sugi sample became more difficult to be gasified after the hydrothermal treatment while the plastic samples were not chemically affected by the hydrothermal treatment.