IHS ESDU recently published its latest ‘User Guide’ to fouling in heat exchange systems, for systems with fresh water as the coolant. ESDU 07006 [1] is the third in a group, following the development of the Crude Oil Fouling User Guide [2] issued in 2000 and the Seawater Fouling User Guide [3] issued in 2004. ESDU 07006 was developed by IHS ESDU ov...
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Crystalline fouling . This includes the deposition of calcium carbonate, calcium sulphate and other salts that have a solubility that diminishes with increasing temperature, leading to crystallisation of deposits of the salts on the heat exchanger tubes. Corrosion fouling . Some metals are oxidised to produce insulating layers of oxides on the tubes. Biological fouling . A whole range of types of biological growths form on heat exchanger tubes in seawater. The organisms deposited range from bacteria and algae to mussels, barnacles etc. Particulate fouling . Seawater may contain many types of silt, mud, sand or other finely divided particles that may settle on the heat exchanger surfaces and insulate them, providing a fouling resistance. Of the above mechanisms, the ones presenting the most problems for seawater systems are corrosion fouling and biological fouling.