Supercritical water gasification of phenol as a model for plant biomass

Abstract

As the demand for energy grows, sustainable energy sources like plant biomass become increasingly important. Plant biomass consists of three main components: cellulose, hemicellulose and lignin. Phenol is a model compound for the phenolic structures comprising the lignin in biomass. Also the macromolecular chemical structure of biomass contains many phenolic monomers. In this study, gasification of phenol as a model substance for plant biomass waste was carried out in supercritical water at a temperature range 400 to 600 °C and for the pressures 20.0, 27.5, 35.0 and 42.5 MPa. Experiments were performed in the absence and presence of alkali catalyst potassium carbonate (K2CO3) for a reaction time of 1 h. Both the gas and liquid phases were analyzed by using chromatographic techniques, which identified and quantified the reaction intermediates and products, including H2, CH4, CO2, CO and C2–C4 hydrocarbons, in the gas phase and different compounds (carboxylic acids, furfurals, aldehydes and ketones) in the liquid phase. Higher temperatures and using catalyst K2CO3 promoted gasification and resulted in a product gas rich in CH4 and H2.