Evaluation of the effect of the heat exchange tube profile on the energy and mass efficiency of the crystallizers

BACKGROUND: One of the important tasks of modern industry is the improvement of heat exchangers (since practically no industry can do without this equipment). One of the most common heat exchangers is “pipe-in-pipe” type devices, which allow the processes of heating, cooling, condensation and crystallization of various working products. Regardless of the process being carried out, the improvement of heat exchangers should primarily be aimed at increasing the heat exchange capacity. One of the ways to increase it is to increase the surface area of heat transfer.

AIMS: A capacitive crystallizer of the “pipe in a pipe” type with ice freezing on the inner surface of the heat exchange pipe is considered as an object of research. A solution for improving the crystallizer is proposed, which allows increasing the heat exchange surface area by changing the profile of the heat exchange pipe.

MATERIALS AND METHODS: As a method of evaluating proposals for improving crystallizers, specific indicators obtained using computer modeling characterizing resource conservation in the manufacture of crystallizers and energy saving during their operation are used.

RESULTS: The crystallizers were evaluated according to the energy and mass efficiency of a typical design, a design with heat transfer intensifiers in the form of round rods fixed on the outer surface of the heat exchange tube and a design with a cross section of the heat exchange tube in the form of an epitrochoid with 8 lobes.

CONCLUSIONS: It is noted that both the presence of intensifier rods and the change in the profile of the heat exchanger tube of the crystallizer contributes to a uniform distribution of the coolant velocity in its inter-tube space. The uniformity of the distribution, in turn, will have a positive effect on the intensity of the ice freezing process. Also, both presented technical solutions improve the considered specific indicators of the energy and mass efficiency of the crystallizers.