From the standpoint of corrosion and deposition control, it would be ideal to have one fluid that could serve as both a heating and cooling medium. However, various heating and cooling mediums are often used, ranging from steam, water, glycol solutions and brines to a wide range of synthetic heat-transfer fluids. In a typical application, steam, cooling water and a chilled solution might all be used in the same jacket at different points in the reaction cycle. This is very efficient from a production standpoint, but potentially damaging in its effect on the jacket lining and vessel exterior.
The half-pipe jacket design is superior to conventional jackets in their ability to guard against contamination through the creation of multi-circuits. Because two or more completely separate circuits can be superimposed, incompatible heat transfer media can be used, speeding reaction time and avoiding risk of corrosion-accelerating cross-contamination. For example, you can run heating steam in one circuit and cooling brine or glycol/water in the other. With independent parallel circuits you can safely use combinations such as organic heat transfer media and cooling water, which could never be considered in a single circuit. You never need to worry about inadequate flushing or procedural error letting corrosion get a start, or about reconstitution of contaminated brines. An additional advantage: the split pipe coils form an efficient, environmentally favorable closed system, with low makeup requirements and less waste.