Operating Data of a Vertical Plane Surface,Falling Film Evaporator Using Slurry and High Concentration Feeds.

摘要

Demonstration tests with a 5,000gpd Laboratory Research Unit (LRU) substantiated the ability of a vertical,plane surface,falling film evaporator to take Roswell, N. Mex.,brackish well water to high concentrations without scaling. Two series of test conditions were run,each for a period of approximately 20days. Tests were run at about 11concentrations and at 25concentrations over a range of condensing temperatures. Heat transfer coefficients above 1,000Btu/hr-ft2-F (degree) were consistently achieved throughout the tests. Process conditions were identified and verified for scale-free operation. A conceptual design and economic study of a 2.5mgd plant (based on feed rate) showed that 90per cent of the Roswell brine could be converted to fresh water at a recovery rate of 24.7pounds of water per 1,000Btu. Ninety-six percent conversion may be achieved at an overall rate of 22.3pounds per 1,000Btu with increased capital costs. Cost of product water from the 2.5mgd plant is $2.08/1,000gallons for 96percent conversion.