Capital and energy intensive distillation columns, like those used for separation of close boiling mixtures, are becoming primary targets of energy conservation projects in refining, petrochemical and chemical industries. Continuous incremental improvement along the conventional line is an ongoing activity but not challenging enough. Driven by a global push for ultimate sustainability, some academic researchers strive for more, i.e. come with radical proposals implying that mass transfer process as encountered in distillation could be intensified by an order of magnitude or more. One in the line of such optimistic expectations is that related to the implementation of highly compact gas-liquid contactors utilizing nonselective porous membranes as replacement for structured packings in distillation applications, which, as demonstrated in this paper, looks to be technically unfounded. (c) 2010 Elsevier B.V. All rights reserved.