More About Thermal Evaporators -
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Product Description -
A thermal evaporator is an industrial device to concentrate solutions, as well as recovery of distillate. In thermal evaporators the liquid product usually enters the evaporator at the head of the evaporator. The product is evenly distributed into the heating tubes. A thin film enters the heating tube and it flows downwards at boiling temperature and is partially evaporated. In most cases steam is used for heating the evaporator. The product and the vapor both flow downwards in a parallel flow. This gravity-induced downward movement is increasingly augmented by the co-current vapor flow. The separation of the concentrated product from its vapor is undergoing in the lower part of the heat exchanger and the separator.
However, thermal evaporators must be designed very carefully for each operating condition; sufficient wetting (product film thickness) of the heating surface by liquid is extremely important for trouble-free operation of the plant. If the heating surfaces are not wetted sufficiently, dry patches and incrustations will occur; at worst, the heating tubes will be completely clogged. In critical cases the wetting rate can be increased by extending or dividing the evaporator effects, keeping the advantages of single pass (no recirculation of product) operation.
