Olefin hydrogenation process improvement and aromatics loss minimization in BTX production industry

Abstract

The olefin hydrogenation process is used to remove the olefin in reformate to prevent the catalyst and adsorbent damage in downstream processes. This research aims to change the reactor operation mode from a series to a single bed operation. The plant reliability is expected to be improved in the single bed operation by preventing catalyst deactivation in both reactors at the same time. The catalyst deactivations normally cause by the feed contaminants. Particularly, the sulfur compounds have a very high potential to permanently absorb on catalyst at high temperature, especially at the end of run conditions. In single bed operation, the reaction severity is decreased. The total olefin conversion is reduced from 95-99 wt% in the series to 85-92 wt% in single bed, while the effluent qualities still meet the downstream processes requirement. The other effect is the decreasing of aromatics loss. The amount of benzene loss is reduced from 0.25-0.5 mol% to 0.2-0.3 mol%. Toluene loss is reduced from 0.05-0.1 mol% to 0.03-0.07 mol%, which are increased the aromatics productivity and improve the benefit around 0.43 million US$ per year. The research is to study the variable control parameters, such as reactor inlet temperature, pressure, H2:HC ratio and LHSV. Higher temperatures cause more hydrogenation of olefin and aromatics while other parameters are not significantly effect. As result, running at the lowest temperature which still makes the product quality acceptable is the operating goal. Furthermore, the H2:HC ratio controller is improved by apply the advance process control. The in situ catalyst regeneration is studied also.