ABSTRACT
Hydrothermal carbonization (HTC) is a 100-year-old technique in the synthesis of materials, with increasing interest originating from the formation of charcoal. The Bergius process, firstly developed by German chemist Friedrich Bergius in 1913, is a method of production of liquid hydrocarbons for use as synthetic fuel by hydrogenation of high-volatile bituminous coal at high temperature and pressure (Hu et al., 2010). He was also awarded the Nobel Prize in Chemistry in 1931 for his development of high-pressure chemistry (Bergius, 1996). The pyrolysis in the presence of subcritical liquid water is called hydrothermal carbonization (Tekin et al., 2014). The process generates both solid and liquid products. The solid fuel generated in HTC conversion is referred to as Hydrochar (HC) (biochar). HTC of lignocellulosic biomass has received extensive research over the last two decades for both the production of solid and liquid fuels (subcritical conditions), and for gasification (supercritical conditions).
