Water Expert Andy Ball: Scaling and Fouling

Jan 08 2016 | 04:19 AM

Fouling refers to the accumulation of unwanted material on solid surfaces, most often in an aquatic environment. The fouling material can consists of either living organisms (biofouling) or be a non-living substance (inorganic or organic). Other terms used in the literature to describe fouling include: deposit formation, encrustation, scaling, scale formation, crudding, and deposition. The last four terms are less inclusive than fouling; therefore, they should be used with caution. Components subject to fouling
The following lists examples of components that may be subject of fouling and the direct effects of fouling:
heat exchanger surfaces – reduces thermal efficiency, increases temperature, creates corrosion, increases use of cooling water piping, flow channels – reduces flow, increases pressure drop, increases energy expenditure, may create flow oscillations ship hulls – increases fuel usage, reduces maximum speed turbines – reduces efficiency, increases probability of failure solar panels – decreases the electrical power generated reverse osmosis membranes – reduces efficiency of water purification, increases pressure drop, increases energy expenditure electrical heating elements – increases temperature of the element, increases corrosion, reduces lifespan nuclear fuel in pressurized water reactors – axial offset anomaly injection/spray nozzles (e.g., a nozzle spraying a fuel into a furnace) – incorrect amount injected, malformed jet, component inefficiency, component failure venturi tubes, orifice plates – inaccurate or incorrect measurement of flow rate pitot tubes in airplanes – inaccurate or incorrect indication of airplane speed teeth – promotes tooth disease, decreases aesthetics

Andy Ball
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