Processing Sulfur-Containing Fuels

Sulfur is one of the noxious components that chemical engineering has helped to remove from burned fossil fuels. The catalytic converter cleaned up automotive exhaust, while other developments dealt with NOx and partially oxygenated hydrocarbons. Unleaded gasoline is another chemical engineering innovation that’s made life cleaner.


1954 — Sulfur in the form of hydrogen sulfide (H2S) is removed from heating oil and jet fuel by hydrofining — a catalytic fixed-bed hydrogenation process using hydrogen produced by catalytically reforming n-paraffins to high-octane aromatics. (Standard Oil Development)

1973 — Automotive catalytic converter is developed to clean up automobile exhaust emissions. Sulfur, a catalyst poison, must first be removed from the gasoline. (Engelhard; General Motors)

John J. Mooney co-invented (with Carl D. Keith) the three-way catalytic converter while working at Engelhard Industries (now BASF Corp.) The single catalytic bed in the three-way converter greatly reduced emissions of carbon monoxide, hydrocarbons and nitrogen oxides. First used on 1976 model-year cars, the converter’s O2 sensor feedback system also brought the computer to the automobile, resulting in a 10% to 12% improvement in fuel economy.

1978 — First unleaded premium gasoline is introduced. Gasoline would later be reformulated with less benzene and more oxygenated compounds (1989). (Mobil Oil)

1983 — Highly efficient selective removal of hydrogen sulfide and other acid gases is achieved using hindered amines (FLEXSORB SE). (Exxon Research and Engineering Co.)

1991 — Deep hydrodesulfurization of gasoline is achieved, making possible the simultaneous reductions of nitrogen and aromatic contents. (Mobil Oil)