Properties of biochar obtained by hydrothermal carbonization and torrefaction of peat

Hydrothermal carbonization and torrefaction are modern low-temperature methods to improve characteristics of peat and other types of biomass as a fuel. The influence of the pretreatment methods at different temperatures on physical-chemical and energy properties of the resulting biochar is studied. Characteristics of the initial peat and biochar were determined such as elemental composition, ash, moisture, heating values, specific surface, mineral composition; and thermal gravimetric analysis was carried out as well. It has been established that biochar obtained by hydrothermal carbonization has a larger specific surface in contrast with the initial peat and a higher exothermic effect during decomposition and has a more dispersed structure whereas less ash than in samples obtained by torrefaction. Torrefied biochar had a larger energy and mass yield, but less heating values in contrast with carbonized samples.