(71a) Research on Mass Transfer Columns "Old Hat or Still Relevant"

Schultes, M. - Presenter, RASCHIG GMBH

The past few years have witnessed a major decline in university-based research in the area of mass transfer columns although up until only about 10 years ago scientific research and communication at the international level were still highly intensive.

In the United Kingdom, for instance, P.V. Danckwerts developed mass transfer models for the calculation of mass transfer processes with a superimposed chemical reaction, and K.E. Porter worked intensively in the field of fluid dynamics and mass transfer efficiency of trayed and packed columns. In Japan, K. Onda developed equations for the calculation of mass transfer coefficients, and numerous other Japanese departments worked on describing chemical reactions in mass transfer columns. In the USA, T.H. Chilton and P.A. Colburn developed mass transfer theories based on driving forces, T.K. Sherwood developed calculation approaches for mass transfer coefficients using dimensionless numbers, E.V. Murphree elaborated degrees of plate efficiency, W.K. Lewis developed analogous relationships between heat and mass transfer in two-phase counterflow columns and J.R. Fair created equations for mass transfer coefficients for modern tower internals. In Germany, E. Kirschbaum worked on the fundamental calculation methods for the design of distillation columns, and A. Mersmann, R. Billet and J. Stichlmair worked, for instance, on mass transfer correlations for modern internals. These are only a few of the departments of that era to make a name for themselves in the field of mass transfer technology in two-phase mass transfer columns.

Meanwhile it has got quiet concerning university-based mass transfer research with trayed or packed towers. Many departments have been closed down or reassigned to other fields, e.g. the chair for mass transfer engineering of Z. Olujic at the Delft University of Technology in the Netherlands. Why is this? The long economic recession in the chemical and related industries in the last decade of 20th century led to a drastic reduction in the numbers of students in this field, and the financial constraints of the public sector reached the universities. Departments needing large amounts of funds for research were abandoned, possibly also in the belief that the research results from the 20th century would be sufficient to capture the future scope of trayed and packed column mass transfer engineering.

Recently in Germany a discussion restarted about the requirement of research in the field of mass transfer columns. It was concluded that the prediction of fluiddynamic and mass transfer efficiencies in trayed and packed columns are still too vague to minimise the investment cost and energy consumption of mass transfer towers. To reach this target a better experimental data base must to be available which is why new standards have to be defined to constitute testing procedures.

The paper gives an overview about the status of the predictability of mass transfer columns and will show topics to be considered for future research in this area. The question to be discussed is whether this research task is “Old Hat or Still Relevant”.