The catalytic hydrotreatment process is generally divided into two main reaction steps. In the 1st step, unsaturated fatty acids and triglycerides are converted into saturated fatty acids by catalytic hydrogenation. The saturated fatty acids are converted to straight chain alkanes by hydrodeoxygenation and decarboxylation, co-producing propane, water, CO and CO2. The early-developed catalysts that employed for this step were noble metals supported with zeolites or oxides, and later shifted to other transition metals (Ni, Mo, Co, Mo) or their supported bimetallic composites due to catalyst deactivation by poisoning, production of cracking species and process costs. In the 2nd step, the deoxygenated straight chain paraffins are selectively hydrocracked and isomerized yielding highly branched alkanes. The resulted organic product is a mixture of straight and branched CxH2x+2 that can be perfectly used as drop-in liquid fuel.
Within BioSFerA project the hydrotreatment of a new type of microbial oil, derived from a 2-step biological route using renewable H2 for the catalytic reactions is explored. The main challenge is to develop a proper reaction process using commercial catalysts where the desired bioliquids products (jet-like and bunker-like fuels) to be produced under certain operating conditions. Due to the novelty of this venture, the hydroprocessing step need to be tested and optimized at lab scale (TRL3). The production of large volumes of lipids (>400 kg of purified lipids) offers the opportunity to validate the process at pilot scale (TRL5).