Abstract: The effect of sulfur on catalyst activity and reaction route in bean oil hydrogenation was investigated. The activity of sulfided catalyst used in hydroprocessing vegetable oil will gradually decline due to the sulfur loss because of low content sulfur in feed. The experiments were carried out in a fixed bed reactor. The results indicate that continually adding sulfur agent (thiophene or H2S) can significantly slow down and partially restore the activity. Different sulfides have different role. However, the activity cannot be fully recovered as the degradation of active site is caused by loss of sulfur. The addition of moderate amount of thiophene as the sulfur resource is able to keep the catalyst activity; while the excess thiophene will has the opposite effect. On contrast, H2S enables to steadily promote hydroprocessing vegetable oil. In addition, both the thiophene and H2S can considerably lower hydrodeoxygenation/decarboxylation ratios.

Key words: sulfur, bean oil, hydrogenation, decarboxylation reaction, thiophene, hydrogen sulfide