Catalytic supercritical water gasification of eucalyptus wood chips in a batch reactor

Eucalyptus wood chips were reacted under supercritical water conditions to evaluate the effect of a NiFe2O4 catalyst, residence time and temperature parameters. Experiments were performed in a batch reactor at 400 degrees C, 450 degrees C and 500 degrees C using three different amounts of catalyst (0, 1.0, 2.0 g) and three different residence times (30, 45, 60 min). Results showed that eucalyptus wood chips reacted and produced CO2 as the dominant gas in all cases, followed by H-2 and CH4. However, the presence of NiFe2O4 catalyst led to a 60% increase in H-2 produced, while significantly reducing the solid residue and enhancing the percentage of methyl derivatives in the organic liquid products. The highest H-2 mol% was at 450 degrees C, 2 g of catalyst and 60 min of residence time. Analysis of the derived oils showed that they were mostly composed of ketones, aldehydes, methylbenzenes and alkylated phenols. Increasing the reaction temperature to 500 degrees C increased the molar composition of methane by 62% compared to its yield at 450 degrees C. In generally, this work showed that NiFe2O4 acted as an effective heterogeneous catalyst for improved production of H-2 and CH4 via supercritical water gasification process.