The 6th International Conference on Biomass Energy (ICBE2018)

549 / 2018-09-26 15:12:19

Properties and Stability of Microalgae Biocrude oil via Hydrothermal Liquefaction at different Storage Conditions

Liquid Biofuel > C. Liquid Biofuel

Hydrothermal liquefaction (HTL) was a promising technology to convert wet biowaste into biocrude oil. The stability is a critical aspect for downstream oil refining, however, the stability of biocrude oil via HTL was seldom documented. In this study we investigated the thermal and oxidation stability of biocrude oil from microalgae at four different storage conditions: 15oC and 35oC with and without N2 protected over 12 weeks. The slight change of oil weight revealed that the biocrude oil is not easy to volatilized. Significant changes of oil viscosity were observed when the storage temperature was shifted from 35oC to 15oC at open conditions. Interestingly, the addition of N2 protection led to similar viscosity at two storage temperatures. A layer of oil “Oxidation shell” up to the bottle was formed, and the rigidity was increased with the store temperature and air atmosphere. TGA analysis shows that the “Oxidation shell” of every biocrude oil was aging more severely than the oil inside. The total acid number of biocrude oil decreased (22.6~24%) when stored with N2 protection and increased (9.1~10.1%) without N2 protection. Although element contents and higher heating value of biocrude oil did not change obviously, its chemical compositions greatly changed. Specifically, some oxygenated compounds occurred during the storage, indicating that the O2 in air especially in higher temperature may negatively impact the stability of biocrude oil.