Hydrothermal processes are suitable for converting highly-wet, biogenic residues into solid, liquid or gaseous carbon carriers. Large quantities of water in the biomass are a problem for 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 achieved in the process, which facilitates further use.
Especially for the disposal of sewage sludge and animal manure, which are the largest domestic source of phosphorus for agriculture, stricter legal provisions for recycling put an increasing pressure on this disposal. For such residues, 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 results in much simpler further use or allows for an efficient nutrient recovery. In this way, it helps to close nutrient cycles and to protect the environment.
But also lignocellulosic 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 fuels. If a biogenic residue is particularly rich in carbohydrates, it is also interesting to convert it into platform chemicals via HTP.
|In this project, HTP will be evaluated 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 various feedstocks under mild hydrothermal conditions. In addition, hydrothermal carbonisation is applied to utilize fermentation residues for an additional energy supply (hydrochar) or for nutrient recycling.|
Copyright: © Hartmut910 / pixelio.de / © Martin Dotzauer (DBFZ) / © nonameman / Fotolia.com (from the left.)