Influence of reaction time and temperature on product formation and characteristics associated with the hydrothermal carbonization of cellulose

Studies have demonstrated that hydrothermal carbonization of biomass and waste streams results in the formation of beneficial materials/resources with minimal greenhouse gas production. Data necessary to understand how critical process conditions influence carbonization mechanisms, product formation, and associated environmental implications are currently lacking. The purpose of this work is to hydrothermally carbonize cellulose at different temperatures and to systematically sample over a 96-h period to determine how changes in reaction temperature influence product evolution. Understanding cellulose carbonization will provide insight to carbonization of cellulosic biomass and waste materials. Results from batch experiments indicate that the majority of cellulose conversion occurs between the first 0.5-4 h, and faster conversion occurs at higher temperatures. Data collected over time suggest cellulose solubilization occurs prior to conversion. The composition of solids recovered after 96 h is similar at all temperatures, consisting primarily of sp2 carbons (furanic and aromatic groups) and alkyl groups.