Effect of Reaction Pressure on Octane Number and Reformate and Hydrogen Yields in Catalytic Reforming

摘要

The effect of reaction pressure in catalytic reforming was studied in a pilot reactor with a commercial Pt—Re/Al_2O_3 reforming catalyst and a hydrotreated naphtha from a North Sea crude. Reformate and hydrogen yields, research octane numbers (RON), and reformate composition at reactor pressures in the range of 12-25 bar were measured as a function of temperature in the range of 95-105 RON. Reformate and hydrogen yields increased as the pressure was reduced. This effect was more pronounced at high severity and in the high-pressure range. For the lower reaction pressures the hydrogen yields increased with increasing severity, but for the higher pressures the hydrogen yields started to decline above certain severities. RON was linearly dependent on the concentration of aromatics in the reformate, although the selectivity toward aromatics depended on both pressure and temperature. Less hydrodealkylation of C_8 and heavier aromatics to benzene and toluene resulted in a shift toward xylenes and heavier aromatic components when pressure was lowered. Variations in the degree of paraffin isomerization did not influence RON significantly at those severities.