Evaluation of thermodynamic efficiency of biowaste gasification

Concerns about global climate change and depletion of fossil fuels have increased interest in biomass and other renewable energy sources. Due to shortage of clean biomass much attention is recently devoted to various biowaste streams. This paper focuses on biowaste gasification, where the produced synthesis gas can be subsequently used to produce biofuels, including Fischer-Tropsch hydrocarbons, methanol and hydrogen. The thermodynamic efficiency of biowaste gasification is evaluated for various feedstocks using energy and exergy indicators. It is shown that exergetic efficiency is lower than corresponding energetic efficiencies. Modification of biomass gasification is proposed to improve process efficiency. Finally, the conversion efficiency of overall chains biomass-to-biofuel is discussed.