Natural Circulation – Tubular Evaporation, Steam-Based
Industry: Fruit and Vegetables (NAICS 3114) Dairy (NAICS 3115)
Process Brief: Water is removed from a product by adding an external heater to a batch pan evaporator.
Energy source: Steam/natural gas
Natural circulation evaporators use a short tube bundle within a batch pan, or more commonly, an external shell and tube heater that is separate from the main vessel. The product is heated by steam in the external shell and natural convection causes the product to rise in the tubes and circulate through the main vessel. This configuration eliminates one of the major problems of batch pans; low HTC. Natural circulation evaporators generally are not used exclusively to produce a product. Instead, they are used as a reboiler at the base of a distillation column.