Abstract
Hydrotreating of naphtha (HDS) is one of the important units in crude oil refineries in which compounds such as sulfur, nitrogen, oxygen and metal are removed. A commonly used HDS catalyst is molybdenum–nickel on alumina support. sulfur and nitrogen compounds have been removed with hydrogenation in which hydrogen sulfide and ammonia are produced and then removed by a flash drum. In this paper, naphtha hydrotreating unit of a target refinery in Iran was studied. Design capacity of unit was 12000 BPSD, but because of increasing gasoline demand, the unit capacity was turned on 15000 BPSD. It made many difficulties such as increasing pressure drop of air coolers and corrosion, and decreasing of recycle compressor discharge pressure. To reduce mentioned difficulties, a supplementary flash drum was added to the primary designed separation process. To show the effect of that, the revamped process was simulated by Aspen Plus software. Results confirmed that not only the mentioned problems was removed, but also a considerable energy saving was achieved