Simulation of biomass gasification in a novel high-temperature directly irradiated hybrid solar/combustion reactor

Abstract

Solar thermochemical gasification of biomass promises a new path for synthetic fuels generation. However, it suffers from critical barriers related to solar energy variability caused by cloud passages and shut off at night. In the present work, we have investigated by simulation the concept of hybridized solar/autothermal gasification reactors. The goal was to demonstrate the operational feasibility of the hybrid process to stabilize the gasification temperature by injecting a controlled amount of oxygen and burning a portion of the feedstock for supplying the deficient process heat. The proposed CFD model was developed by taking into account the coupled momentum, heat and mass transfer and the chemical reactions (pyrolysis, heterogeneous char gasification and gas-phase reaction kinetics) along with the continuous particle injection. It was first validated against our experimental data during allothermal operation at 1200°C, 1300°C and 1400°C. Then, combustion reactions were integrated to the model to predict the hybridized reactor performance and synthesis gas composition. Moreover, first experimental results of the hybrid reactor operation were shared. The study has demonstrated the effectiveness and the feasibility of process hybridization for a directly irradiated solar gasifier.