Abstract
In this study, highly upgraded bio-oil was produced by microwave-metal interaction pyrolysis of water hyacinth biomass. A copper coil was used as a microwave receiver and heat generating antenna. The pyrolysis of biomass was carried out with and without using a cement catalyst. The fractional amounts of the as-produced bio-oil, biogas, and biochar were determined in terms of catalyst mass, reaction time, and the gauge of the copper coil antenna. In cement catalyzed pyrolysis, the water hyacinth was converted into 20% bio-oil and 31% combustible gases with overall conversion efficiency of 66%. In the case of uncatalyzed pyrolysis, the overall conversion efficiency remained below 60% with 10% bio-oil. The biomass to catalyst ratio of 5:1, 25 min of reaction time and 2.5 mm gauge of wire were predicted as optimum conditions for the pyrolysis process. The bio-oil was further analyzed through chromatography-mass spectrometry (GC-MS) while the gaseous products were analyzed through chemical testing and combustibility analysis. Significant difference in the chemical composition of the bio-oils, produced using catalytic and noncatalytic microwave-metal interaction pyrolysis, was noticed in these investigations. The oil product of the catalyzed and uncatalyzed pyrolysis contained 11.6% and 9.418% hydrocarbons, respectively. Similarly, oxygen content in the oil was measured about 14.73% and 16.66%, respectively. Also, unlike the thermal or thermo-catalytic pyrolysis, the bio-oil product of the microwave-metal interaction pyrolysis was found immiscible with water.