Energy and Exergy Analysis of the Crude Oil Fractionation Units


The petroleum refining industry is one of the largest users of distillationtechnology. The crude distillation unit is one of the most important refinery operationsfractionating preheated crude oil into respective product fractions like Heavy Naphtha,Kerosene, Aviation Fuel, Light Gas Oil, Heavy Gas Oil, Reduced Crude Oil, etc. Ituses heat supplied at higher temperature levels, and rejects almost equal amount ofheat in the condenser at lower temperature levels yielding a separation work ofmixtures. Therefore, it becomes important to study the energy and exergy of the crudeoil fractionation tower to analysis the energy efficiency.The present study deals with a thermodynamics analysis, energy and exergyefficiencies and the irreversibility rate for of the crude oil fractionation tower (AFT).The results shows that the total irreversibility losses are 90.7 MW, 95% arecontributed by the AFT, and 5% by the furnace, for a flow rate of 159.2 kg/s of crudeoil processed. The energy efficiencies are 0.597 for the AFT, 1.0 for the furnace as weare assuming adiabatic heat transfer in the process and 0.704 for the overall system.The exergy efficiencies are 0.5867 for the AFT, 0.974 for the furnace and 0.638 forthe overall system. From the values of the energy efficiencies, exergy efficiencies, andthe irreversibility rate in spite of the decline of the fractionation unit equipments, itshows that the operating conditions used (especially the temperature profile and thepressure profile of the AFT and the flow rates of the different streams) gives the bestresults.