Abstract:

In order to avoid thermal instability in the catalytic bed during Fischer-Tropsch synthesis, the light synthetic oil and feed gas were co-fed into the reactor. The effect of light synthetic oil on the performance of cobalt-based catalyst was investigated in a fixed-bed reactor by changing space velocity and light oil compositions. The light synthetic oils are found to have a positive effect on decreasing the selectivity of CO2. Increase of liquid space velocity leads to an increase of methane selectivity and a decrease of C5+ selectivity. The content of olefin decreases significantly. The local hot spots in the bed are no longer present. The temperature distribution of the catalytic bed is improved. As the light oil fed into the bed becomes heavier, the selectivity of methane and C5+ are both decreased, while the temperature distribution of the catalyst bed is further improved. It is concluded that the addition of light synthetic oil can not only improve the temperature gradient and catalyst performance, but also can adjust the F-T product distributions by changing the composition of the light synthetic oils.

Key words: Fisher-Tropsch synthesis, fixed-bed, light synthetic oil, recycle, temperature distribution, product distribution