Catalytic Supercritical Water Gasification of Refuse Derived Fuel for High Energy Content Fuel Gas

Abstract

Refuse derived fuel (RDF) was processed using hydrothermal gasification at high temperature to obtain a high energy content fuel gas. Supercritical water gasification of RDF was conducted at a temperature of 500 °C and 29 MPa pressure and also in the presence of a solid RuO2/γ-Al2O3 catalyst. The effect of residence time (0, 30 and 60 min) and different ruthenium loadings (5, 10, 20 wt% RuO2/γ-Al2O3) were investigated. Up to 93 % carbon gasification efficiency was achieved in the presence of 20 wt% RuO2/γ-Al2O3 catalyst. The fuel gas with the highest energy value of 22.5 MJ Nm−3 was produced with the 5 wt% RuO2/γ-Al2O3 catalyst after 30 min reaction time. The results were compared with the use of NaOH as a homogeneous catalyst. When NaOH was used, the maximum gross calorific value of the product gas was 32.4 MJ Nm−3 at 60 min reaction time as a result of CO2 fixation. High yields of H2 and CH4 were obtained in the presence of both the NaOH and RuO2/γ-Al2O3 catalysts.