CO2conversion to CO by fluidized bed biomass gasification: Analysis of operational parameters

Thermochemical conversion of CO2with biomass to CO in fluidized bed gasifiers is promising for a sustainable carbon economy. Knowledge about this process is expanded by investigating experimental parameters influencing CO2conversion in such a system and combining them to demonstrate effective conversion. Wood char and CO2are fed to a lab-scale gasifier in 53 semi-continuous experiments. Six experimental parameters are varied: temperature, bed material type, initial bed-to-fuel ratio, initial fuel loading in the reactor, feed CO2flow rate, and fuel particle size. The results are compiled in a semi-empirical model based on reaction kinetics. High temperatures and high fuel-gas contact times are favorable for increasing CO2conversion, with the latter achieved through high initial fuel loadings in the reactor and low feed gas flow rates. Choosing olivine instead of silica sand as a bed material also results in higher CO2conversions. The highest CO2conversion demonstrated in this paper is 86.1%. This experiment produces a gas with 82.75% CO, 10.01% H2,and 5.90% CO2(nitrogen-free and dry).