Production of Highly Upgraded Bio-oils through Two-Step Catalytic Pyrolysis of Water Hyacinth

Abstract

In this study, water hyacinth was converted into highly flammable bio-oil through a two-step catalytic pyrolysis approach. A three-pronged approach, based on biochemical pretreatment of the biomass, use of clinkered catalyst, and an additional pyrolysis step, was adopted to produce highly upgraded bio-oils. Fresh, putrefied, and microbe treated water hyacinth was pyrolyzed into oil, gas, and solid residue. The oil product of the first step of pyrolysis contained 9.42%, 36.72%, and 30.38% of combustible liquids by mass, respectively. The fractional distillation of the oil product of fresh, putrefied, and microbe treated samples resulted in 11.56%, 7.1%, and 31.67% of residue by mass, respectively. These residues were repyrolyzed, and the oil and gas products of the first and second step of the pyrolysis were further analyzed for their chemical composition. After two-stage pyrolysis, the amount of the highly upgraded oil was increased to 34.34%, 58.31%, and 43.21% by mass, respectively. The bio-oils, obtained from fresh, putrefied, and microbe treated-samples, were significantly different in terms of their chemical nature and the number of compounds.