User Manual

TEMA J Shells are typically specified for phase change duties where significantly reduced shel l
side pressure drops are required. They are commonly used i n stacked sets with the single
nozzles used as the inlet and outlet. A special type of J-shell is used for flooded evaporation
of shell side fluids. A separate vapor disengagement vessel without tubes is installed above
the main J shell with the vapor outlet at the top of thi s vessel.
The TEMA K shell, also termed a "Kettl e Reboiler" is specified when the shell side stream will
undergo vaporization. The li quid level of a K shell design should just cover the tube bundle,
which fills the smaller diameter end of the shell. This liquid level is controlled by the liquid
flowing over a wier at the far end of the entrance nozzle. The expanded shel l area serves to
facilitate vapor disengagement for boiling liquid in the bottom of the shell. To insure against
excessive liquid carry-though with the vapor stream, a separate vessel as described above is
specified. Liquid carry-through can also be minimized by installing a mesh demister at the
vapor exit nozzle. U-bundles are typically used with K shell designs. K shells are expensiv e for
high pressure vaporization due to shell diameter and the required wall thickness.