High quality oil is produced from catalytic hydrotreating of HTL biocrude, which can be further converted into biofuel.

To prepare the solubilized asphaltene in water (SAW), the feedstock of hydroprocessing experiments, oxidation reactions were conducted in a 550 mL batch reactor in the presence of NaOH in aqueous phase. At 240 °C and 2 h residence time the asphaltenes conversion reached 80% with 50% yield to SAW. The characterization of solubilized asphaltene in water (SAW) revealed that it contains a wide range of carboxylic acids with various alkyl tails. The presence of carboxylate and carboxylic functional groups in the SAW structure was also confirmed with FTIR analyses. The catalytic hydroprocessing of SAW was studied in a 100 mL batch reactor with presulfided NiMo/γ-Al 2 O 3 catalyst. The hydroprocessing results at 320 °C and 3 h residence time for SAW prepared at different severities shows that higher oxidation temperature produces the lighter liquid hydrocarbons, which suggests the oxy-cracking of asphaltene through wet oxidation. Increasing the concentration of solubilized asphaltene in water increased solids formation in hydroprocessing from 12.5% for nonconcentrated SAW to 26% for 10 times concentrated solution. The hydrogen deficiency was evidenced in hydroprocessing of high concentrated SAW, where increasing the initial hydrogen pressure from 600 psig to 1000 psig suppressed the solid formation from 26% to 9.5%. Liquid products from hydroprocessing mainly consisted of two cyclohexyl fused hydrocarbons with higher selectivity to naphthenic and lower selectivity to aromatic compounds. Detecting CO 2 as a major component in the gas phase in parallel with the results of GC/MS before and after hydroprocessing confirms that oxygen removal is dominated by decarboxylation.

The solubilized asphaltene in water (SAW) was prepared by low-temperature oxidation in aqueous phase and used as a feedstock of hydroprocessing reaction. Hydroprocessing experiments were carried out in a 100 mL batch reactor within the temperature range of 280–320 °C in the presence of presulfided NiMo/γ-Al2O3 catalyst. A lumped kinetic model with four components including water-soluble fractions, water-insoluble fractions, liquid hydrocarbons, and gas products was proposed, which accurately predicted the experimental results. The activation energy of global reaction was calculated to be 83 kJ/mol. At 320 °C, the liquid hydrocarbons yield increased around 8% by prolonging the residence time from 1 to 6 h. For 3 h residence time, by increasing the reaction temperature from 280 to 320 °C, the liquid yield was increased 5% and the conversion was enhanced by 8%. Increasing the reaction temperature affected the quality of products; that is, liquid hydrocarbons with lower boiling point distribution were obtained at higher reaction temperatures. At 320 °C, phenol derivative products disappeared, indicating the progress of deoxygenation at higher reaction temperatures. Fourier transform infrared analyses confirmed that disappearance of carboxylate functional groups through decarboxylation or protonation was the main reason for the production of water-insoluble fractions after the hydroprocessing. An extended Henry’s law with γ–ϕ approach was implemented to predict the thermodynamics status of the system at reaction conditions. The occurrence of reaction in the liquid phase was confirmed, where at 320 °C more than 80 wt % of water remained in the liquid phase and the liquid level in the reactor increased 25%.

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