Collection of Deposited Carbon Utilizing Porous Carbon Materials in the Pyrolysis of Sawdust

Abstract

It is desired to fix carbon as stable solid for the conversion of carbonaceous resources to reduce the emission of CO₂. In this study, it is proposed to obtain fuel gas and solid carbon through the pyrolysis of biomass by use of porous carbon to collect deposited carbon generated by the secondary decomposition of volatile matter. Activated carbon promotes the generation of gaseous products during the pyrolysis of sawdust in the batch reactor, although it minimally influences the decomposition behavior of volatile matter. H conversion ratio, which is the ratio of hydrogen generated as H₂ and CH₄ to that in the sawdust, increases monotonically with the increase of temperature, and reaches 32% at 800 °C. It was found that almost carbon can be collected above 500 °C since the secondary decomposition of tar fraction preferentially occurs on the surface of activated carbon. The difference in micropore structure is not observed between activated carbons before and after carbon deposition, indicating that it does not occur in the micropores. Similar effect was obtained when pyrolyzed char of sawdust was used instead of the activated carbon although the amount of carbon deposited on the pyrolyzed char surface is reduced compared with activated carbon.