Standardization of Mass Transfer Measurements: A Basis for the Description of Absorption Processes

Inaccurate mass transfer measurements may lead to an erroneous design of process equipment, since the accuracy of process modelling strongly depends on the quality of the model parameters. While procedures for measuring model parameters have been standardized for distillation, a standard for absorption has not been established yet. Thus the accuracy to predict the effective interfacial area and the mass transfer coefficients in the gas and liquid phase for several column internals varies significantly and the compatibility of data from different sources is limited. Therefore, a procedure to determine these mass transfer parameters is presented in this paper that includes guidelines for the choice of system, the experimental setup and procedure as well as the processing of experimental data. The procedure has been tested for classic and modern random packing types and results of absorption experiments are shown for a 25 mm Pall-Ring. A comparison of the experimental data with existing data and theoretical calculations from existing mass transfer correlations is presented. This comparison reveals not only discrepancies between the experimental and literature data but also the inconsistency of different sources and thus strongly supports the demand for a standardized procedure to determine mass transfer parameters for absorption systems.