EFFECT OF REACTION PRESSURE OIL OCTANE NUMBER AND REFORMATE AND HYDROGEN YIELDS IN CATALYTIC REFORMING

The effect of reaction pressure in catalytic reforming was studied in a pilot reactor with a commercial Pt-Re/Al2O3 reforming catalyst and a hydrotreated naphtha from a North Sea crude. Reformate and hydrogen y ields, research octane numbers (RON), and reformate composition at rea ctor pressures in the range of 12-25 bar were measured as a function o f temperature in the range of 95-105 RON. Reformate and hydrogen yield s increased as the pressure was reduced. This effect was more pronounc ed at high severity and in the high-pressure range. For the lower reac tion pressures the hydrogen yields increased with increasing severity, but for the higher pressures the hydrogen yields started to decline a bove certain severities. RON was linearly dependent on the concentrati on of aromatics in the reformate, although the selectivity toward arom atics depended on both pressure and temperature. Less hydrodealkylatio n of Cg and heavier aromatics to benzene and toluene resulted in a shi ft toward xylenes and heavier aromatic components when pressure was lo wered. Variations in the degree of paraffin isomerization did not infl uence RON significantly at those severities.