Hydrothermal processes are suitable for converting wet, biogenic material flows into solid, liquid or gaseous carbon carriers. Large quantities of water in the biomass are a problem to many conversion technologies and often require complex dewatering as a pre-treatment. This energy-intensive process step is not required for hydrothermal conversion, which results in energetic advantages. Biomasses with water contents of up to 95 % are suitable for HTP. A further advantage of hydrothermal treatment is the hygienisation of the material flow achieved in the process, which facilitates further utilisation.
Especially in the disposal of sewage sludge and animal manure, which are the largest domestic source of phosphorus for agriculture, there is an increasing pressure to dispose on the basis of stricter legal provisions for recycling. For such residual materials, conversion via hydrothermal carbonisation is particularly suitable. The resulting carbonaceous products have a higher calorific value and their hydrophobic (water-repellent) properties make mechanical dewatering much easier. This can make further use or nutrient recovery significantly simpler. In this way, it helps to close material cycles and protect the environment.
But also biomass, such as wood, grass or straw, or biogenic residues, such as brewers grains or fermentation residues, can be hydrothermally carbonised. If no carbonaceous product is desired, conversion via hydrothermal liquefaction or gasification is possible, resulting in liquid or gaseous products. These can be further processed into corresponding energy sources. If a biogenic residue is particularly rich in carbohydrates, it is also interesting to convert it into platform chemicals via HTP.
|HTP as part of a pilot plant for the production of liquefied natural gas (LNG) from biogenic residues. Funded by the federal ministry for transport and digital infrastructure the project pursues the increase of the total methane yield during fermentation through pre-treatment of feed material under mild hydrothermal conditions. In addition, hydrothermal carbonisation is applied to utilize fermentation residues as additional energy supply (hydrochar) or for nutrient recycling.|
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