TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The mineral portions are separated from the biomass, before the hydrothermal carbonization process. The coal particles of the coal slurry originated from the hydrothermal carbonization are moistened for dewatering with oil. The hydrothermal carbonization is carried out using a mixer. The method is accelerated using catalysts. In the method, the pollutants such as heavy metals are separated during the hydrothermal carbonization and recycling materials such as phosphorus are recycled, in which the solid components are migrated in liquid phase and subsequently deposited by separate dehydration process. In the method: the input materials are characterized before each batch, and the different input materials are selectively mixed before each batch; the input materials of each batch or mixture of many batch are analyzed according to material properties; the input materials of each batch or mixture of many batch are selectively mixed with another batch or mixtures of many batch depends on the observed properties, where the pH of the mixture is lowered and the solid content of the mixture is increased by at least one of mixed types of biomass; the input materials are different types of biomass; the input materials of the individual batch exhibit fluctuating properties, preferably condensing properties, and a mixing product is obtained by targeted mixture according to these properties; the input materials of the individual batch have no sufficient ability for other uses and a mixing product is obtained with sufficient ability for other uses by targeted mixture; and the process parameters are adjusted during each batch based on a mixing ratio and characteristics of input materials. In the method: a feeding device, preferably pump, which transports the biomass into high pressure unit against its constructive interpretation or other typical applications of feeding device, in which the output is choked to at least 50%, preferably by interval operation or slowing the conveying speed, is used; and after 2-6, preferably 3-5 hours, the coal slurry is separated with a fuel with a minimum of lignite quality. Preferred Components: The biomass is fermentation residues, marc, rapeseed press cake, food waste, green waste and/or algae. EXAMPLE - No suitable example given.