At approx. 300-350°C biomass can be converted into a high-viscosity-tar which has a higher heating value and a higher viscosity as well as a lower water content than liquefaction products from "dry" processes. The original process of the Shell company was called "Hydrothermal-Upgrading". The tar-like product contains a huge number of single substances, e.g. furfurale, erythrose, glycol aldehyde, phenols and milk acid. From these substances, finally, other basis chemicals and e.g. plastics are produceable. It concerns by-products of carbohydrates which can be produced with relatively high selectivity on account of the special properties of the water under these conditions – especially from glucose or fructose.
An important focus on research due to Hydrothermal Liquefaction is the production of algae. For Hydrothermal Liquefaction a continuous stirring reactor, the RUBIKON technical lab-scale plant is available.
- M. Watanabe, F. Bayer, and A. Kruse,
Oil formation from glucose with formic acid and cobalt catalyst in hot-compressed water,
Carbohydrate Research 341 (29-12-2006) 2891-2900.
- A. Kruse and A. Gawlik,
Biomass Conversion in Water at 330-410°C and 30-50 MPa. Identification of Key Compounds for Indicating Different Chemical Reaction Pathways, Ind. Eng. Chem. Res 42 (2003) 267-279.