Hydrothermal liquefaction biocrude from agricultural wastes: Stability assessment and refinery integration

Abstract

This study investigated the storage stability and miscibility of biocrude derived from the hydrothermal liquefaction of wheat straw, before and after its upgrading via catalytic hydrotreatment, towards its refinery integration. The storage stability was assessed via a dedicated 6-month study under various conditions. Raw and hydrotreated biocrude were analyzed monthly to observe potential degradation in their properties during storage. They were also tested for miscibility with some potentially compatible petroleum intermediate refinery streams, while the stability of the interfacial tension and the dissolution characteristics were examined through various experimental tests. The findings demonstrate that biocrude exhibits almost no degradation when acidity, water content, and density are measured, even after six months of exposure to ambient conditions. However, only a small part of the biocrude was diluted with all tested petroleum fractions (light gas oil, light vacuum gas oil, and light cycle oil) and is considered incompatible. On the other hand, the hydrotreated biocrude exhibits no alteration in its properties over time suggesting its stability with time. Furthermore, hydrotreated biocrude shows complete solubility in all petroleum fractions without phase separation or turbidity. These results highlight the stability assessment of the biocrude derived from the hydrothermal liquefaction rendering it a valuable intermediate product towards its refinery integration.