DEVELOPMENT OF A TECHNOLOGY FOR REDUCING OLEFIN AND BENZENE CONTENTS TO IMPROVE THE ENVIRONMENTAL CHARACTERISTICS OF GASOLINE

Abstract

The environmental quality of motor gasoline is increasingly determined not only by sulfur content, but also by the concentration and molecular structure of hydrocarbon groups that control evaporative reactivity, toxic emissions, oxidation stability and octane performance. Benzene is a regulated toxic aromatic compound, while excessive olefin content is associated with high chemical reactivity and fuel-stability concerns. The technological problem is complicated by the fact that olefins contribute substantially to the octane number of fluid catalytic cracking (FCC) gasoline, so indiscriminate hydrogenation can improve composition while simultaneously degrading product value. This paper develops a literature-based integrated technology for reducing olefins and benzene with limited octane loss. The proposed scheme combines FCC gasoline fractionation, selective olefin hydrogenation/hydrodesulfurization, separation of a benzene-rich C6 reformate cut, benzene–olefin alkylation over shape-selective acidic catalysts, optional benzene polishing, and controlled final blending. The approach uses olefin-rich and benzene-rich refinery streams as complementary reactants, thereby decreasing both target contaminants while converting them into higher-boiling alkyl aromatics or stable saturated products. Regulatory limits, process alternatives, expected performance, control variables and implementation risks are analyzed.