Corrosion failures in plate heat exchangers arc discussed with reference to equipment design, service conditions and materials of construction. Included are case histories that illustrate service experience. Plate heat exchangers are chosen over shell-end-tube exchangers for applications requiring superior heat transfer efficiency and compactness, and lower weight. Efforts to maximize their inherent advantages drive plate heat exchanger design toward the usc of thin plate sections that require highly corrosion-resistant materials, and narrow flow passages that are conducive to fouling. Plate heat exchangers in general require extensive scaling along the edges of the plate. Consequently, crevice corrosion may occur under gaskets or adjacent to seal welds. Localized corrosion maybe either initiated or aggravated by the leaching of harmful ionic species into crevices from polymer gasket materials. Stress-corrsion failures are also encountered, particularly at cold formed corrugations incorporated into some designs to contain gaskets or to improve heat transfer coefficients.
Keywords: crevice corrosion, stress corrosion, SCC,
gasket, seal weld, amalgam, liquid metal cracking, liquid metal embrittlement, LME, mercury, hydride, pitting, heat flux, heat transfer, heat exchanger, fluorocarbon, polymer, cold box