The main purpose of this technique is the production of liquid energy carriers, like pyrolysis oil or methanol. In most cases, this is achieved by combining some other thermo chemical treatment like gasification, pyrolysis or combustion.
Those three techniques together with torrefaction are in use currently or being developed for the future. Since this paper will focus more on torrefaction, other techniques are another future task to be studied. During the torrefaction process, the input biomass will lose about 30% of its mass, but only 10% of its energy. It is because of the moisture loss and de-gassing process of low energy volatile compounds, resulting in higher energy density of the biomass roughly 30% more energy per mass unit. Bioechemical torrefaction mechanisms are also changing biomasss’ structure, leading to new properties that make the handling of the final product will be much easier, especially for being transported.