The Importance of Internals

Nowadays, the ever-increasing efforts to achieve a process with optimal chemical engineering characteristics demand modern mass-transfer columns, i.e. high mass-transfer efficiency but a minimal energy requirement. These demands can only be met by the use of modern packed beds if the internals in the packed columns – liquid and gas distributors, hold-down and support structures, liquid collectors and redistributors – are designed according to modern principles. The gas and liquid distributors, which must be carefully designed and mounted with the greatest accuracy, are of prime importance in this respect. Detailed investigations into the uneven distribution of liquid in packed columns (maldistribution) have highlighted the influence on mass transfer efficiency of uniform distribution over the column cross-section. Properly designed support and holddown plates are also important if a reduction in throughput is to be avoided. Increased pressure drops may sometimes result from the use of an inadequate support plate.

Furthermore, there have been cases in which the tower packings have been damaged or even swept away due to the absence of a hold-down plate. The costs arising from the resultant malfunction in the downstream plant installations due to this damage are generally higher than the price of a hold-down plate. Our range of internals includes many types and sizes, manufactured in metal or plastic, and designed according to the state of the art of chemical engineering.

A modern column design demands a basic understanding of the fluid-dynamic flow relationships in mass transfer columns. Experiments in the pilot plants at Raschig have in the past produced important criteria for designing internals, criteria which are taken into account in every new design project today. We would be happy to advise you and are able to offer tailor-made solutions to your individual problems.