COMPARISON OF RIVER-WATER FOULING RATES FOR SPIRALLY INDENTED AND PLAIN TUBES

This article presents river-water fouling rates at 12 Tennessee Valley Authority (TVA) power plant condensers, nine of which were retubed wi th a commercially available enhanced tube. Four were located on the Cu mberland River, six on the Ohio, and two on the Clinch River The overa ll heat transfer coefficients were calculated from logged field data t aken over periods extending from 1 to 10 years. The fouling resistance s were next calculated with the separate resistance method and with a bundle correction factor to the condensing, single-tube Nusselt predic tion. The bundle correction factor was determined for each condenser u sing the data taken within 1000 hours after each cleaning. With the us e of this new bundle factor method, fouling rate data can be obtained even with variable operating conditions. The fouling rates with the en hanced tubes ranged from about the same as to about twice that of the plain tubes. However, the thermal performance with the enhanced tubes remained superior to that obtained with plain tubes for more than a ye ar without cleaning. Also after one year of operation, the enhanced-tu be fouling resistance values were less than the minimum value of the T EMA Standards for river water, and the plain-tube fouling resistance v alues were always less than one-half of this value. After shutdown and brush and/or acid cleaning, the thermal performance values for both t he plain and enhanced tubes were restored to essentially the new, clea n levels.