Recent Innovations in Turbulent Mixing with Static Elements

Static Mixer consists of a number of stationary mixing elements inserted along the direction of flow in a pipe. Each mixing element allows to divide the flow and to recombine it in a geometric sequence. A lot of static mixers are now available, e.g. Sulzer SMV and SMI, Chemineer KM, the Kenics HEV. These products differ quite considerably and the construction have effects on the manufacturing costs and also on the costs for the inbuilt the mixers in a plant. These well known motionless mixers allow to obtain good performances but usually the mixing length necessary for obtaining the homogeneity is longer than 5-10 pipe diameters. Another important constrain is the maximum permissible pressure loss in the operation. In the recent years, new products composed of a minimum number of elements, have been launched. These new products have a short inbuilt device length, they require a short mixing path and they have low pressure drops. This review analyzes the behaviour of these new innovative static mixers.