BENZENE PRODUCTION BY SOLVENT EXTRACTION AND HYDRODEALKYLATION

摘要

A process for converting a naphtha feedstock to a pure benzene including the steps of: reforming the naphtha; removing a major fraction of C4 - C5 and heavy reformate components to obtain a reformate containing a major portion of C6 - C8 aromatic hydrocarbons and an associated saturated portion; extracting the aromatic hydrocarbons from the reformate countercurrently in a simplified process with a selective hydrophilic solvent, such as sulfolane, having high solubility for aromatic hydrocarbons and low solubility for paraffin hydrocarbons to obtain an extract stream rich in C6 - C8 aromatic hydrocarbons and a raffinate stream rich in paraffinic hydrocarbon. and recovering the selective solvent from the extract stream to obtain an aromatic component comprising a major C6 - C8 aromatic hydrocarbons and about 3 to 18 wt. paraffinic hydrocarbon impurity. The paraffinic impurity is removed and alkyl benzenes are converted by hydrodealkylating the aromatic component to recover substantially pure benzene. A feature of the simplified extraction, process provides for low energy consumption because no stream rich in paraffin is recycled to the solvents extraction unit, thus eliminating the need for stripping the paraffinic impurity from the aromatic component prior to dealkylation.