High Quality Syngas Production with Supercritical Biomass Gasification Integrated with a Water–Gas Shift Reactor

Abstract

A thermodynamic assessment is conducted for a new configuration of a supercritical water gasification plant with a water–gas shift reactor. The proposed configuration offers the potential for the production of syngas at different H2:CO ratios for various applications such as the Fischer–Tropsch process or fuel cells, and it is a path for addressing the common challenges associated with conventional gasification plants such as nitrogen dilution and ash separation. The proposed concept consists of two reactors, R1 and R2, where the carbon containing fuel is gasified (in reactor R1) and in reactor R2, the quality of the syngas (H2:CO ratio) is substantially improved. Reactor R1 is a supercritical water gasifier and reactor R2 is a water–gas shift reactor. The proposed concept was modelled using the Gibbs minimization method with HSC chemistry software. Our results show that the supercritical water to fuel ratio (SCW/C) is a key parameter for determining the quality of syngas (molar ratio of H2:CO) and the carbon conversion reaches 100%, when the SWC/C ratio ranges between two and 2.5 at 500–1000 °C.