Hydrothermal carbonization of anaerobically digested maize silage

► Hydrothermal carbonization of anaerobically digested maize silage yields hydrochars with distinct properties. ► Carbonization of digestate relies on decarboxylation. ► Despite high contents of lignin and cellulose carbonization occurs below 200 °C. ► Yield and surface area of the hydrochars are highest at 190 °C.