Chemical modification of biomass residues during hydrothermal carbonization - What makes the difference, temperature or feedstock?

► Hydrothermal carbonization temperature is the main control of hydrochar chemistry. ► Feedstock did not influence hydrochar composition except for N content and recovery. ► Environmental risk of hydrochar is low with respect to PAH and dioxin contents. ► Hydrochar may be less stable than pyrochar but show higher C and N yields.