Production of aromatic drop-in jet and diesel fuel from vegetable oils

Vegetable oils are excellent feedstock for production of diesel and jet fuels. However, catalysts and processes published in the literature do not produce drop-in fuels. One of the major problems is the selectivity and stability of the catalysts. It is vital that the hydrotreating is tested after at least 200 h on stream to measure the steady-state performance of the catalyst rather than its initial activity. The presence of aromatics is a critical issue. This study addresses specifically the issue of aromatics related to the composition of the vegetable oils. A novel Pt/Al₂O₃/SAPO-11 is used. Testing six different oils indicates that a certain level of poly-unsaturation of the fatty acids is required to produce relatively high aromatics content. This was further supported in specific tests of the vegetable oils, the fatty acids and the C16 hydrocarbons dissolved in decane. Therefore, soybean, sunflower and camelina oils produce fuels containing about 15 wt% aromatics while the content of aromatics in the product of palm or castor oils hydrotreating is 2 wt%. Three stage processes were proposed to produce jet fuels that meet the standards. 42-48 wt% yield of the jet fuel is reported. This is a basis for commercial production of drop-in diesel and jet fuel.