Regulations to reduce the sulfur level in gasoline and automotive diesel to less than 50 ppm are in place or planned in many countries. A number of technologies have been developed to enable production of these fuels. For instance, SCANfiningTM I is a highly selective process for reducing sulfur in fluid catalytic cracked (FCC) naphtha with minimum olefin saturation/octane loss. Recently ExxonMobil announced the development of SCANfining II, a process that can selectively reduce even the sourest FCC naphthas to ppm sulfur levels with low octane loss. Both of these processes use RT–225, a catalyst jointly developed and commercialized by ExxonMobil and Akzo Nobel. These companies have also recently completed the development of NEBULA, a hydroprocessing catalyst with more than double the activity of any other commercial catalyst at medium-high pressures. NEBULA has recently been applied in several refinery distillate hydrotreaters and is performing as expected. Some countries are now considering reducing fuel sulfur even lower, to 10–15 ppm or less. Achieving this ultra-low sulfur level without large additional expenditures is a major challenge. Both ExxonMobil and Akzo Nobel are continuing to develop new catalyst and process technology options to help the refining industry meet these future needs.
Advanced designs of transportation vehicles to reduce air pollution have become increasingly dependent on the availability of low sulfur (S) fuels. Substantial reductions in gasoline and diesel sulfur levels have already begun to occur in some parts of North America, Europe, and Japan. This trend is expected to accelerate as additional regulations mandating 10–50 ppm S become effective between 2004–2008 in the U.S., Canada, Europe and elsewhere around the globe.
Meeting the new low sulfur fuel specifications presents a significant challenge to the petroleum refiner. In order to minimize the cost of producing these fuels, new technology advances are needed. For gasoline, the greatest challenge is to deeply desulfurize fluid catalytic cracked (FCC) naphtha (which contributes most of the sulfur in gasoline), while minimizing the loss of octane resulting from olefin hydrogenation during the desulfurization step. For diesel, the objective is to achieve the ultra-low sulfur specifications at the lowest possible cost. The application of improved catalyst technologies, along with effective molecule management in the refinery offer the greatest potential for achieving this objective.
ExxonMobil and Akzo Nobel are committed to developing cost-effective process and catalyst technology options for meeting current and future needs for mogas and diesel sulfur removal.
ExxonMobil has commercialized the SCANfining process for producing ultra-low sulfur gasoline with minimum loss of oc