Disproportionation of Light Paraffins

Various acidic catalysts were synthesized or obtained commercially to examine their activity for the catalytic disproportionation of saturated hydrocarbons under mild, energy-con serving conditions. The goal was to upgrade lower-value light hydrocarbon streams, especially isopentane, to higher-value refinery products in a simple process. The desired products can then be used for upgrading petroleum products into cleaner burning, more environmentally friendly fuels. These efforts were conducted in anticipation of more stringent future regulations, especially on Reid vapor pressure (RVP) and renewable fuels standards in U.S. fuels, which will significantly impact the flexibility that refiners have to blend gasoline. Significant quantities of light hydrocarbons, such as pentanes, may be forced out of the blending pool, causing current alternate markets for these streams to become oversupplied. Lost opportunity costs associated with the growing volume of orphaned streams, such as pentanes, pose a significant threat to a refiner's viability. Five different catalyst systems from zeolites to acidic ionic liquids were tested. All showed potential in converting light ends to value-added heavier products. Catalysts showed a typical trade off between high pentane conversion and selectivity to gasoline range products. A critical parameter for high conversion rates was space or contact time (liquid hour space velocity, LHSV) in order to allow for the unreactive paraffinic hydrocarbons to activate and react. Spent catalyst regeneration was also addressed in order to recover at least a portion of lost activity.