Dynamics of liquid-phase platform chemicals during the hydrothermal carbonization of lignocellulosic biomass

This paper studies the dynamics of process waters from hydrothermal carbonization of lignocellulosic biomasses, exploring the production of platform chemicals via the autohydrolysis of raw materials. Isothermal (200 °C) batch reactions went up to 2 h at a 7/1 liquid/solid ratio treating three wooden residuals, silver fir, beech, and olive. The distribution of liquid-phase chemicals depends on the biomass strongly. The peak concentrations of chemicals (furfural, 5-hydroxymethylfurfural, and lactic, formic, propionic, levulinic, and acetic acids) occur within 60 min of reaction. Biomass to chemicals conversion is up to 13 % (60 % of the total dissolved organic carbon). Simple equations describe system dynamics (R2 close to 0.99). UV and Vis optical density of the process waters monitors the reaction progress satisfactorily. The results foreshadow innovative process schemes for simultaneously converting biomass to energy and value products by recovering of furfurals during waste biomass hydrothermal carbonization.