Effect of H 2S in recycle hydrogen on selective hydrodesulfurization of heavy FCC naphtha

Abstract

On a fix-bed hydrogenation pilot plant unit, the effect of H 2S in recycle hydrogen on the hydrodesulfurization (HDS) and olefin saturation (HYD) reactions during FCC heavy naphtha selective hydrogenation process over Co-Mo catalyst was studied. The results showed that the existence of H 2S could inhibit HDS reactions and promote HYD reactions, however, the selectivity of the catalyst decreased with the increase of H 2S content in recycle hydrogen. Results also showed that the effect of H 2S content in recycle hydrogen on HDS and HYD reactions was varied under various reaction severities: under relatively mild operation conditions to keep the total sulfur content of liquid product below 50 μg/g,the influence of H 2S was significant; under relatively severe operation conditions to keep the total sulfur content of liquid product below 10 μg/g,the influence of H 2S was less significant.