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.