Quality Improvement of Heavy Gas Oil with Hydroprocessing

Abstract

Quantity requirement for diesel fuel of low sulphur and aromatic content is increasing worldwide; meantime the quality of available crude oils has declined causing challenges in hydroprocessing of gas oils. Results of quality improvement of heavy gas oil are presented, it was carried out in one stage on NiMo/Al₂O₃ catalyst and in two stages on NiMo/Al₂O₃ and PtPd/USY-zeolit catalysts. In one stage hydroprocessing sulphur and polyaromatic contents of the products  met the requirements of the standard only if strict process parameters were applied which resulted in operation problems and product loss, moreover the advantageous process parameters of hydrodesulphurization and hydrodearomatization did not coincide. In two stages hydrotreating a partially hydrogenated product obtained on NiMo catalyst was further hydroprocessed on PtPd/USY at moderate process conditions. Results showed that the advantageous process parameters for reduction of sulphur and aromatics coincided. Quality parameters of products regarding to aromatics met not only the requirements of the standard but the stricter requirements of engine manufacturers also.