摘要 |
This invention relates to a method of producing a processed biofuel, for instance in the form of pellets/briquettes with a high energy content, based upon a raw material in the form of hydrous fibre sludge, sludge from purifying plants and/or fibre-based material like for instance wood raw material. According to the invention the method is characterized by the combination of the following steps: the fibre- and/or sludge material is mixed with bio-oil and is heated in such a way that the water in the material is driven away so that this one is dried; the mentioned mixture is de-oiled in a pressing device, whereafter the de-oiled material is formed to pellets/briquettes; the formed, pressed products are homogenized, i.e. are given a supplementary, thermal treatment at a temperature of 50-200 DEG C, a chemical reaction being started up, by which the products are crystallized, i.e. are hardened to a material with qualities being like those of carbon. |