Paul W. Tamm

Aromatization of Hydrocarbons over Platinum Alkaline Earth Zeolites

A new platinum/zeolite catalyst is more active and selective for the aromatization of paraffins, especially hexanes and heptanes, than are the platinum/alumina naphtha reforming catalysts presently used in petroleum refining. The new catalyst, which contains highly dispersed platinum clusters in barium-exchanged potassium Zeolite L, is also effective for alkylcyclopentane aromatization. The preparation and characterization of the Pt/BaKL-zeolite catalyst are described. Its catalytic performance and the reactions it catalyzes are compared with those of other platinum reforming catalysts. Unlike the conventional reforming catalysts, which utilize acidic sites of the support as well as platinum sites, the Pt/BaKL catalyst is nonacidic and catalyzes aromatization using only the catalytic properties of the platinum clusters. The catalyst is extremely sensitive to poisoning by sulfur, but its stability for reforming of thoroughly desulfurized feed is illustrated by an uninterrupted one-year run with a refinery light naphtha.

Octane Enhancement By Selective Reforming of Light Paraffins

Abstract A new reforming process (AROMAXSM) is described for selectively converting C6-C7 paraffins to high octane aromatics. Since conventional processes are not very effective for these compounds and since lead additives are being phased out of gasoline, the AROMAX process fills an important industrial need. This process employs a catalyst comprising platinum on L-zeolite. Pure component studies are used to show that the high selectivity of the catalyst results from a different reaction network than conventional bifunctional reforming catalysts. Pilot-scale tests are used to show how unleaded gasoline or aromatic chemicals can be produced from refinery light naphthas with dramatically better yields than conventional reforming.

Catalytic Processes For Octane Enhancement By Increasing the Aromatics Content of Gasoline

Abstract Catalytic processes for enhancing the octane of gasoline by increasing its aromatic hydrocarbon content are reviewed. Major improvements have been made in the most important of these processes, the catalytic reforming of naphtha over bifunctional catalysts. However, liquid yield still declines severely in going to high octane, because of poor selectivity for light paraffin aromatization. New, monofunctional platinum aromatization catalysts produce much higher yields of high octane reformate from light paraffins. Reformate aromatics content and octane can also be increased by postreforming processes that remove low octane paraffins by shape-selective cracking over acidic zeolites. New processes can be used to increase both the supply of gasoline and its octane rating by converting very light hydrocarbons into aromatics-rich liquids.