Fractionation of Oil Mixture Into Jet and Diesel Fuel

Challenge

Petroleum-derived jet and diesel fuels originate from complex multicomponent hydrocarbon mixtures. Efficient separation of these fractions is energy-intensive, and suboptimal column design can significantly increase operating costs. The challenge was to model a jet–diesel fractionation process and identify operating conditions that minimize energy consumption while maintaining high-quality separation.

Solution

A rigorous simulation of the rectification process was developed using the ChemCad Universal Modeling Program (UMP). The TOWR distillation column module was selected. Thermodynamic behavior and phase equilibrium were modeled using the Grayson–Streed model for vapor–liquid equilibrium and the Lee–Kesler model for enthalpy calculations. The model included a distillation column, reflux condenser, and bottom-product cooler.

Process optimization focused on minimizing energy demand by adjusting three key parameters: number of trays, reflux ratio, and feed tray location. Sequential Quadratic Programming (SQP) was applied to determine optimal operating conditions.

Results

Simulation results showed that a 24-stage distillation column provided smooth temperature profiles without stagnant zones. Optimization identified an optimal reflux ratio of 0.6 and an optimal feed tray at stage 11. The bottom (reboiler) temperature was optimized to approximately 508 K.

Under optimized conditions, total energy consumption for the rectification process was calculated as 12,949 MJ/h. The resulting separation achieved clear fractionation: lighter aromatics and paraffins were concentrated in the jet fuel overhead product, while heavier hydrocarbons were concentrated in the diesel bottom product.