Abstract: The benzene content of naphtha from DCC unit of Dongfang Petrochemical Corporation Ltd. was high. Being limited by the process flow, in order to reduce benzene content of naphtha, the operation of DCC unit was adjusted baseing on the understanding of mechanism of benzene formation. It is recognized that benzene comes from cracking reaction of side chains in aromatic hydrocarbon , hydrogen transfer reaction of cycloalkane and dehydrocyclization reaction of alkenes. The effects of raw material properties, operation conditions and properties of catalyst on benzene content in naphtha were analyzed. By adjusting the operation conditions，benzene content of naphtha was reduced from 1.60% to 1.40%.

Key words: DCC naphtha, benzene content, raw material property, reaction temperature