Calcium sulphate scaling in falling film evaporators

✍ Scribed by T.D. Hodgson; M.N. Elliot; T.W.J. Jordan

• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 807 KB
• Volume: 14
• Category: Article
• ISSN: 0011-9164
• DOI: 10.1016/s0011-9164(00)80048-x

✦ Synopsis

The formation of calcium sulphate scale in Vertical Tube Evaporators (VTE) of the falling film type has been investigated in a single tube experiment using fluted tubes . It was found that the scaling threshold is dependent not only on the brine concentration and temperature, but also on the heat flux to the evaporating film . With normal sea water concentrations and a high heat flux, scale was observed at 244°F (115°C), whereas with a low heat flux scale-free operation was possible at 266°F (130°C) . The effect of heat flux is attributed to the presence of local areas of high concentration in the falling film which form as a result of uneven evaporation from the film . A simple model has been developed to explain the results.