Mass and heat transfer in heat integrated distillation column (HIDiC) with a rate-based model

Energy savings of distillation processes are inevitable demands for the sustainable world since the distillation processes are the biggest energy consumers in the chemical industries. An internally heat-integrated distillation columns (HIDiC) is one of the promising alternatives of the conventional distillation processes to reduce the energy consumptions in the chemical plants. The HIDiC, in which heat is directly translated from the rectifying section to the stripping section of the column, has much higher energy efficiency than conventional column. In previous work, an energy saving of 50 % is expected for the HIDiC form the simulation studies when it is applied to the separation of multicomponent hydrocarbons mixtures using tray tower columns with an equilibrium model. The proposed of the present work is to develop a method for rigorous prediction of separation performance of the HIDiC. A process simulator (gPROMS) for prediction of separation performance of the HIDiC with structured packing is developed by rate-based model using Maxwell-Stefan equations. Comparison of observed data from pilot-scale (benzene-toluene system) separation concentric HIDiC plant, in which consisted of about 20 m in height and 254 mm in diameter. Predicted simulation results such as concentration, temperature and flow rate of top and bottom in the rectifying section and stripping section show good agreement with observed data. The effect of mass transfer and heat transfer in the HIDiC is also discussed. Moreover, a simulator using this model is developed to multicomponent HIDiC with concentric and compact heat exchanger systems.