Performance Analysis of a Biomass Supercritical Water Gasification Process under Energy Self-sufficient Condition

Abstract

Depletion of fossil fuel and environmental concerns stimulate the use of clean and renewable energy. Biomass is regarded as a potential energy source and can be efficiently converted to a useful synthesis gas via incomplete combustion in a gasification process. However, the thermal gasification causes a tar formation and requires high energy input when wet biomass is used. The objective of this study is to investigate the performance of an autothermal biomass gasification process in supercritical water. A flowsheet model of the gasification process is developed and validated with experimental data. Thermodynamic analysis is performed based on the minimization of total Gibbs free energy. Simulations are performed to study effects of key operational parameters on the supercritical water gasification process at an energy self-sufficient condition, which a total net heat energy can be zero. Hydrogen in the synthesis gas product and thermal efficiency of the gasification process are also considered and suitable operating conditions of the autothermal biomass gasification for hydrogen production are identified. © 2014 Elsevier B.V.