The half-pipe or split-coil jacket (referred to by DDPS as HemiCoil®) consists of a welded half pipe that wraps around the outside of the vessel, creating a circular path for the heat transfer fluid to pass through.
In a split-coil jacket, heating and cooling media flow through the pipe coils with high velocity and turbulence. Thus, film coefficients and heat transfer rates are higher than in conventional jackets. Vessel contents heat up and cool down, and the heat transfer circuit drains much faster-saving energy and reducing batch time. With the split-coil design, only the diameter of the pipe - not the unsupported height of the inner vessel - must contain the jacket pressure. This permits the safe use of much higher pressures within the coils than is possible in conventional jacketing: 450 psig at 500°F is the standard operating limit.
The coils on HemiCoil reactors are welded to the vessel prior to glassing; conventional jackets can be added to a vessel after. Also, it will cost you approximately 30% to 35% more than the same reactor with a conventional jacket. In many instances this premium can be more than offset by decreased operating costs, increased heat transfer rates and better processing efficiency. For more information about jacket selection for your reactor read our post on jacket options.