Numerical study of biomass gasification combined with CO2 absorption in a bubbling fluidized bed

Biomass gasification combined with CO2 absorption-enhanced reforming (AER) in a bubbling fluidized bed (BFB) reactor is numerically studied via the multiphase particle-in-cell (MP-PIC) method featuring thermochemical and polydispersity sub-models. A novel bubble detection algorithm is proposed for efficiently characterizing bubble morphology. The effects of several crucial operating parameters on the microscale particle behaviors, mesoscale bubble dynamics, and macroscale reactor performance of the AER gasification process are analyzed. Compared with conventional gasification, AER gasification reduces the CO2 concentration by 33.58% but elevates the H-2 concentration by 32.13%. Higher operating temperature and steam-to-biomass (S/B) ratio promote H-2 generation but deteriorate gasification performance. A lower operating pressure improves gas-solid contact efficiency and gasification performance as the increased operating pressure inhibits bubble dynamics and particle kinematics. Compared with pure sand as bed material, the mixed bed material (CaO:sand = 1:1) significantly improves gasification performance by enhancing H-2 generation and CO2 removal.