Surface Properties of Teflon Film in Saline Water Processes

摘要

Desalination evaporator scaling was considerably reduced by a thin polyfluorocarbon coating on boiler tubes. Coatings of 'McLube', made by McGee Chemical Company, less than 0.001-inch thick improved the heat transfer rate about 70% to 130% relative to the uncoated tubes. The initial small boiler was then modified in order to allow continuous feed of calcium sulfate solutions. The coating performance exhibited more improvement with (1) moderate feed rates of salt solution and (2) high temperature difference across the tube wall. The results from the small boiler were confirmed in a larger pilot scale boiler. The feasibility of using a low-adhesion coating to reduce scaling on evaporators has been established. Further study on durability of coatings and possible combination with seeding the feed solution is recommended. (WRSIC abstract)