For packed distillation columns, maldistribution is by far the most important factor that has a negative influence on performance, especially efficiency. The amount of maldistribution related publications is enormous. For the maldistribution story the research work of the last 50 years is reviewed with a strong focus on structured packing and industrial relevance. The huge effort by packing manufacturers to develop even better products and to establish safe design rules is appreciated, as well as the important developments and support of Fractionation Research Institute (FRI) on this subject.
