Modelling of Distillation Column that can Produce High Purity Aromatics from Catalytic Cracking or Reforming Unit using Aspen Hysys


The study involved modeling of a distillation column which can produce streams of high purity toluene and benzene from reformate of a catalytic cracking unit. Aspen Hysys was used to model and optimize a distillation column using Wilson as Fluid Package for physical properties of each component. For shot cut distillation column, employing available data yielded the lowest actual number of trays (31 trays). In the rigorous column (first distillation column), the following were obtained: optimal number of trays for the process (24), inlet feed stage (13 Ma), flow (top) rate (104 Kmol/hr), toluene in the bottom (0.0025 mole), e-benzene in distillate (0.009 mole), condenser duty (-6.157*10^6 KJ/h), reboiler duty (9.943*10^6 KJ/h), and external reflux ratio (0.806). In the second distillation column (short cut), optimum mole fraction of light key (n-heptane) in bottom (0.005 moles), optimum mole fraction of heavy key (toluene) in the distillate (0.005 moles), optimum number of trays (43) and reflux ratio (1.573), benzene flow rate (46Kmol/h), toluene (product) flow rate (25.76 or 26 Kmol/h), toluene purity (98.49%), condenser duty (-6432639.735), and reboiler duty (7285097.435). In the third Distillation Column (Short Cut), optimum mole fraction of light key (benzene) in bottom (0.020 moles), optimum mole fraction of heavy key (n-heptane) in the distillate (0.015 moles), optimum number of trays (37), reflux ratio (3.151), condenser duty (-5907570.031 KJ/hr), reboiler duty (6670143.257 KJ/hr), product rate (46.05 Kmol/hr), benzene purity (98.50%), and external reflux ratio (3.155). In this study, the distillation process was feasible and energy efficient. Therefore, Asphen Hysys can be used efficiently as a fast and easy tool to model and optimize a distillation column processes. Keywords: Hysys, Distillation, Trays, Condenser, Reboiler duty.


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