Pre-treatment of coniferous biomass via hydrothermal carbonization and torrefaction: mass and energy yields

Abstract

Fuel properties of woody biomass could be significantly improved with several pre-treatment technologies. This paper presents the results of experimental comparison of hydrothermal carbonization and torrefaction processes for coniferous wood chips. Hydrothermal carbonization was performed within the typical reaction temperatures 180 – 250 °C during six hours. In torrefaction tests, the biomass was kept in an inert atmosphere for 30 minutes at temperatures 240 - 300 °C. Mass and energy yields of pre-treated biomass were calculated for all experimental sets. Within the limits of selected operation parameters, HTC demonstrated more intensive decomposition of feedstock comparing to torrefaction, and with higher mass losses resulted in lower values of energy yields than in case of torrefaction.