Effects of Biomass Types and Carbonization Conditions on the Chemical Characteristics of Hydrochars

Effects of biomass types (bark Mulch versus sugar beet pulp), and carbonization processing conditions (temperature, residence time; and phase of reaction medium) on the chemical characteristics of hydrochars were examined by elemental analysis, solid-state C-13 NMR, and chemical and biochemical oxygen demand measurements. Bark hydrochars were more aromatic than sugar beet hydrochars produced under the same processing conditions. The presence of lignin in bark led to a much lower biochemical oxygen demand (BOD) of bark than sugar beet and increasing trends of BOD after carbonization. Compared with those prepared, at 200 degrees C, 250 degrees C hydrochars were more aromatic and depleted of carbohydrates. Longer residence time (20 versus 3 h) at 250 degrees C resulted in the enrichment of nonprotonated aromatic carbons. Both bark and sugar beet pulp underwent deeper carbonization,,,during water hydrothermal carbonization than during steam hydrothermal carbonization (200 degrees C, 3 h) in terms of more abundant aromatic C but less carbohydrate C in water hydrochars.