M.Ing. / Deposition of scale on heating surfaces is a major problem in industry as well as households. The scale that forms on the heating surfaces acts as an insulator and results in decreased heat transfer effectiveness . These are two main approaches to prevent or reduce scaling. Although these approaches are claimed to be efficient, there is a need to evaluate or verify their efficacy. This calls for a method which should preferably enable quantitative and rapid evaluation of these techniques in the laboratory. A reliable, rapid and quantitative measurement method which was comprised of stripping the scale from heat exchanger pipes with a 10% acetic acid solution and measuring the Ca concentration in the acid after stripping, was developed. A total of 11 tests, 7 to test the reproducibility, 2 to test a physical water treatment device and 2 to test the effect of zinc, were conducted. The reproducibility amongst different pipes, and amongst different experiments could not be achieved. Attempts to explain the inconsistency through statistical analysis of the data showed that, the inconsistency in the results could partly attributed to chemical differences, particularly changes in calcium concentration and TDS. Metal contamination, particularly zinc could also be responsible for a part of the inconsistency.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:9577 |
| Date | 05 September 2012 |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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