Simulation and Optimization of the Stabilizer Tower Operation at Catalytic Reforming of Esfahan Oil Refining Company

Production of gasoline with low RVP specifications have made the operators of the catalytic reforming unit of Esfahan Oil refining company in Iran to apply new operating conditions. RVP is an abbreviation for Reid Vapor Pressure which is the vapor pressure of gasoline measured at 100°F. Removal of butanes from gasoline blendstocks has become more critical to meet product RVP requirements. In addition, Esfahan Oil Refining Company approximately has doubled its capacity. This feed increment implicated engineering study in each unit. The stabilizer of Catalytic Reforming Unit of the Company which sets the platformate RVP, also needs engineering revision. In this investigation the stabilizer is simulated using ASPEN HYSYS software, by changing the operating variables in their allowable ranges. As a result, some figures are produced which can be used to predict platformate RVP in different stabilizer conditions. By using these figures, the boilup ratio and the outlet temperature of re-boiler could be monitored to attain in suitable platformate RVP, while the stabilizer condition is optimized economically too. This study shows that by increasing the boil-up ratio and outlet temperature of re-boiler, the platformate RVP decreases but at the meantime, some increase in the C₅₊ content of the overhead product is observed too. The study also shows that for decreasing of the platformate RVP, the increase of the outlet temperature corresponds to a lower operating cost when compared to the increasing of the boilup ratio for the attaining of a specified RVP. Of course there might be some exceptions to this observations too. There might be situations at which monitoring of high boil-up ratio could result in more profit.