BENZENE CONVERSION IN AN IMPROVED GASOLINE UPGRADING PROCESS

摘要

Low sulfur gasoline is produced from an olefinic, cracked, sulfur-containing naphtha by treatment over an acidic catalyst, preferably an intermediate por e size zeolite such as ZSM-5 to crack low octane paraffins and olefins under mild conditions with limited aromatization of olefins and naphthenes. A benzene-rich co-feed is co-processed with the naphtha to reduce the benzene levels in teh co-feed by alkylation. This initial processing step is followe d by hydrodesulfurization over a hydrotreating catalyst such as CoMo on alumin a. In addition to reducing benzene levels in the combined feeds, the initial treatment over the acidic catalyst removes the olefins which would otherwise be saturated in the hydrodesulfurization, consuming hydrogen and lowering product octane, and converts them to compounds which make a positive contribution to octave. Overall liquid yield is high, typically at least 90 % or higher. Product aromatics are typically increased by no more than 25 wt.% relative to the combined feeds and may be lower than the feed.