(204d) Effects of Impurities in Two-Step Vs. One-Step Hydroprocessing of Algae Oils
Microbial lipids are a promising precursor to renewable diesel fuels, but catalytic hydroprocessing of the crude lipid extracts is an under-studied operation. In particular, impurities in the crude extracts can lead to catalyst deactivation. Hydroprocessing of these lipids to green diesel fuel typically comprises deoxygenation (DO) and hydroisomerization (HI) chemistry, and can be conducted in a two-step or one-step configuration. We have shown that in a two-step configuration using Pd/C for DO and Pt/SAPO-11 for HI, a fuel with acceptable cold weather and boiling range properties can be produced without lipid cleanup steps but under severe conditions. In contrast, a Pt/SAPO-11 catalyst is deactivated in one-step DO/HI. However, multiple oil bleaching approaches can remove nitrogen-containing impurities that may be causing the deactivation.