The Conventional NEQ Model

It will be helpful to begin with a brief review of the NEQ model of Krishnamurthy and Taylor [7] for conventional distillation and absorption operations. A schematic representation of the NEQ stage is shown in Fig. 9.2. This NEQ stage may represent a tray or a cross section of a packed column. 

The component molar balances for the vapor and liquid phases are 

j are the interfacial mass-transfer rates the product of the molar fluxes and the net interfacial area. The overall molar balances are obtained by summing Eqs. (9.8) and (9.9) over the total number (c) of components in the mixture. At the vapor-U-quid interface we have the continuity equations 

Ej are the interphase energy transfer rates, the product of the energy fluxes and the net interfacial area. We also have continuity of the energy transfer rates at the interface. 

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