Synergistic Effects Towards Hydrochar Recovery During Hydrothermal Carbonization of Ferula Communis with Process Water Recirculation

Abstract

Recirculation of process water (PW) from hydrothermal carbonization (HTC) has revealed as an effective strategy for the residual aqueous phase valorization in order to make the process energetically more efficient while reducing its environmental footprint. The effects of temperature, solid load and consecutive conversion phases on PW recirculation were assessed by using Ferula Communis plant residues as feedstock in HTC experiments. Recirculation of solvent promoted strong synergistic interactions between biomass and PW aimed at increasing hydrochar mass recovery. Hydrochar yield increased by 4-12 wt% on a dry basis (d.b.) according to reaction conditions. Biomass degradation was catalyzed by the reactive intermediates dissolved in the PW. The energy balance results showed that the energy recovery almost doubled by recycling PW when compared to the experiments carried out using only deionized water as HTC solvent.