Mitigation of scaling in heat exchangers by physical water treatment using zinc and tourmaline

• Published in: Applied thermal engineering 2011-08, Vol.31 (11), p.2025-2031
• Main Authors: Tijing, Leonard D., Yu, Mi-Hwa, Kim, Chae-Hwa, Amarjargal, Altangerel, Lee, Young Chan, Lee, Dong-Hwan, Kim, Dong-Won, Kim, Cheol Sang
• Format: Article
• Language: English
• Subjects: Applied sciences; catalytic material; Crystal structure; Deposition; Devices using thermal energy; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fouling; Fouling resistance; Heat exchangers; Heat exchangers (included heat transformers, condensers, cooling towers); Heat transfer; Physical water treatment; Scaling; Theoretical studies. Data and constants. Metering; Tourmaline; Water treatment; Zinc
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2011.03.011

This paper presents a study on the mitigation of calcium carbonate scaling in a double-pipe heat exchanger by physical water treatment (PWT) using zinc and tourmaline as catalytic materials. Artificially-hardened water at 300 mgL −1 was utilized as the fluid medium to form fouling deposits. The cooling water (i.e., hard water) velocity was varied from 0.3 to 0.8 ms −1. The inlet temperatures were maintained at 86 ± 1° C and 22 ± 1° C for hot- and cold-water sides, respectively. The results show that in PWT-treatment case, the fouling resistances are 13–50% lower than those in no-treatment case. The SEM image of the deposit shows a blunt shape crystal structure in case of PWT-treatment, while a pointed crystal structure in case of no-treatment. The calcium content of deposits formed in the cases of PWT-treatment is lower by 17–22% than those of the no-treatment, which corresponds to a thinner fouling in case of PWT-treatment. ► Physical water treatment (PWT) is a non-chemical method for scaling mitigation. ► We present the use of catalytic materials as PWT to mitigate scaling in heat exchangers. ► PWT using tourmaline and zinc decreased the fouling resistance by 13–50%. ► There was lower calcium content for deposits after PWT-treatment. ► PWT-treatment case showed thinner fouling deposits when checked visually.