(170a) Hydrotreatment of wood derived biocrudes – Investigation of possibilities and challenges related to refinery integration

A biocrude derived from wood, produced through the process of hydrothermal liquefaction at Aalborg university, was subjected to hydrotreatment in a once-through pilot unit. This unit consisted of two reactors: the first reactor was used for stabilization of the biocrude, while the second reactor was used for hydrodeoxygenation. Upon reaching a steady state, typically after a period of 2-3 days, a mass balance was conducted.

To investigate the effect of temperature on the hydrodeoxygenation, the temperature in the second reactor was varied during the experiment. A significant catalyst deactivation was observed during the experiment, which was primarily ascribed to the presence of impurities in the biocrude. The hydrotreated biocrude, which had an oxygen content of 4.2 wt%, was found to be miscible with fossil crude.

In a separate co-processing experiment conducted using the same pilot unit, the first reactor was loaded with a hydrotreating catalyst, and the second reactor was loaded with a hydrocracking catalyst. The products collected from this process were then fractionated and subjected to thorough analysis. Initially, the selectivity and activity of the catalysts were tested using vacuum gas oil (VGO) as feed. Subsequently, 10% of the VGO was replaced with the hydrotreated biocrude, and the effect of varying the temperature in the hydrocracking reactor was investigated.

The results of this investigation showed that in order to maintain the same conversion, the temperature in the hydrocracking reactor had to be increased by approximately 5°C. Furthermore, co-processing of the hydrotreated biocrude resulted in an increase in the aromatic content and a decrease in the hydrogen content in most fractions. Nevertheless, it was possible to produce kerosene that met the specifications for jet fuel as described in D7566.