Upgrading FCC gasoline through adsorption separation of normal hydrocarbons

The octane number and the olefin content are two crucial indices for FCC gasoline. FCC gasoline was upgraded by a separation process that was superior to chemical processes including hydrogenation. The adsorption separation of normal paraffins and normal olefins in FCC gasoline was performed in a fixed-bed adsorber packed with 5A zeolites. The content of low octane normal paraffins decreased from 5 wt% to less than 0.1 wt% by the shape-selective separation of zeolites, leading to an increase in research octane number from 88.9 to 92.3. The olefin content decreased from 35.23 wt% to 29.02 wt% due to the removal of normal olefins. The adsorbabilities observed from the breakthrough curves of normal paraffins and normal olefins were consistent with the adsorption energies. The desorption oil, which was rich in normal hydrocarbons, showed excellent cracking performance for producing ethylene in a steam cracker.