In hydrothermal liquefaction processes, long carbon chain molecules in biomass are thermally cracked and oxygen is removed in the form of HO (dehydration) and CO (decarboxylation). These reactions result in the production of high H/C ratio bio-oil. Simplified descriptions of dehydration and decarboxylation reactions can be found in the literature (e.g. Asghari and Yoshida (2006) and Snåre et al. (2007).