Development and Testing of an Anti-Scale/Corrosion Resistant Coating for DomesticHot Water Heat Exchangers

摘要

Shell-and-tube heat exchangers are used throughout the Army to supply domestichot water for large buildings. These units may fail to operate effectively due to the buildup of scale on the domestic waterside surfaces of their tube bundles, which serve to transfer heat from the heating medium to the water. The bundles may also corrode and fail prematurely. Both problems significantly increase maintenance and repair costs and inconvenience to building occupants. This report presents the results of an investigation into the use of baked-on phenolic coating to prevent scale deposit and corrosion in portable water heat exchangers. The report documents corrosion and scaling problems observed in portable water heat exchangers at Army installations and compares various methods for mitigating these problems, focusing on a laboratory and field testing of a baked-on phenolic coating system. A cost analysis showing the feasibility of the coating in various environments is presented. The coating proved to be effective in mitigating scaling and corrosion problems in portable water heat exchangers and in maintaining hot water temperatures at or above 140 F (59.4 C). The coating also proved to be highly cost effective in both corrosive and scaling environments by decreasing maintenance and repair and downtime costs.