Development of a complete simulation model for predicting the hydraulic and separation performance of distillation columns equipped with structured packings

This paper describes the work oriented toward the development of an advanced expert system capable of predicting the hydraulic and separation performance of corrugated sheet structured packings. The simulation programme consists of a number of modules covering different types of performance calculations. Traditional, overall approach relying on the assumption of plug flow of both phases is represented by a newly developed method, which unlike the known methods accounts explicitly for the effects imposed by micro and macro characteristics of packing geometry. A special feature of this method is that the effective areas are determined using the author's small scale liquid distribution method. This liquid flow distribution model represents the hart of a detailed calculation approach. The gas flow profile is assumed to be uniform and the established liquid distribution pattern enables the calculation of local L/V values which are used together with other relevant information's in a separate module to calculate the concentration changes along the bed and consequently the corresponding HETP value. A separate module is used to visualise the liquid flow pattern in the bed. Any kind of initial liquid distribution profile can be arranged, however, a separate module can be used to evaluate the performance of commercially available high performance liquid distributors. Generally the detailed model is designed to predict the mass transfer efficiency of a column operating in the preloading range, and is particularly suitable for the prediction of the effects of varying degrees of small scale liquid maldistribution. This in turn enables the determination of the optimum quality of initial liquid distribution for a given packing and creates a basis for optimisation of packing geometry. Present developments of the model and related software are discussed as well as the future refinements and improvements.