Biomass Chemical Looping Gasification of pine wood using a synthetic Fe2O3/Al2O3 oxygen carrier in a continuous unit

Abstract

Biomass Chemical Looping Gasification is a novel technology allowing high quality syngas production at autothermal conditions without CO₂ emissions to the atmosphere and low tar generation. This work compiles gasification results corresponding to 38 h of continuous operation in a 1.5 kW_th unit using pine wood as fuel and a synthetic Fe-based oxygen carrier, Fe20Al. The main operating conditions such as temperature (T = 820-940 °C), steam-to-biomass ratio (S/B = 0.05-0.65), and oxygen-to-biomass ratio (λ = 0.2-0.6) were analyzed at steady state conditions using a novel method for controlling oxygen in the process. A syngas composed by 37% H₂, 21% CO, 34% CO₂ and 7% CH₄, and tars below 2 g/Nm³ could be obtained at autothermal conditions, leading to a syngas yield of 0.8 Nm³/kg dry biomass and a cold gas efficiency of 68%. The material maintained a high reactivity although some Fe lost was observed.

Keywords: Biofuels; Biomass; Chemical-looping gasification; Syngas; Tar.