CO2 conversion to CO by fluidized bed biomass gasification: Analysis of operational parameters
Florian Johann Müller, Josef Fuchs, Miguel Fanjul Cuesta, Ana Oblanca Gutiérrez, Simon Pratschner, Stefan Müller, Franz Winter
Abstract
Thermochemical conversion of CO 2 with 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 CO 2 conversion in such a system and combining them to demonstrate effective conversion. Wood char and CO 2 are 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 CO 2 flow 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 CO 2 conversion, 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 CO 2 conversions. The highest CO 2 conversion demonstrated in this paper is 86.1%. This experiment produces a gas with 82.75% CO, 10.01% H 2, and 5.90% CO 2 (nitrogen-free and dry). • CO 2 gasification is demonstrated to convert 86% of CO 2 in a fluidized bed reactor. • Temperature and contact time of CO 2 and biomass strongly influence conversion. • This paper includes 53 experiments and a semi-empirical model for CO 2 conversion. • CO 2 conversion is investigated at low biomass conversions (differential reactor).