摘要 |
<p>A cracked FCC naphtha is withdrawn through line (12) and passes to a mercaptan oxidation (sweetening) unit (13) in which the mercaptans are converted to higher boiling disulfide compounds. The effluent from the mercaptan oxidation unit is then passed to fractionator (14) in which it is split into a higher boiling fraction and a lower boiling fraction. The lower boiling fraction is collected and is free of mercaptans and retains high octane olefin content. The higher boiling fraction is hydrotreated (16) to remove sulfur and then sent to a shape-selective reactor to restore the octane loss.</p> |