Production of renewable diesel by hydrotreatment of soybean oil: Effect of reaction parameters

•Hydrotreatment of oil in batch and continuous reactors, to produce green diesel.•Finding the optimum operating conditions for using the Ni and CoMoSx catalysts.•Comparisons of reaction and product, between batch and continuous systems.•The Ni catalyst showed higher activity in decarboxylation/decarbonylation.•The CoMoSx catalyst showed higher activity in hydrodeoxygenation. The effects of varying reaction parameters on the hydrotreatment of soybean oil using Ni and CoMoSx catalysts were investigated. The reactions were carried out in both batch and continuous reactors, at reaction temperatures of 300–440°C, and hydrogen pressures of 2.5–15.0MPa. The effects on hydrotreating conversion, gasoline/jet/diesel selectivity, and the degree of oxygen removal were investigated, to find optimum hydrotreatment conditions using both types of catalysts. Analyses of liquid composition, using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC–TOFMS) and GC-flame ionization detection (FID), revealed that decarboxylation, decarbonylation, and hydrodeoxygenation reactions occurred competitively, and that each reaction pathway had different optimal conditions, as expected from the thermodynamic characteristics. The differences in the hydrotreatment reaction, liquid product compositions, and dominant reaction pathways between the batch and continuous reactions are also discussed.