Heat Exchanger Fouling

Fouling is defined as the formation of undesired deposits on heat transfer surfaces, which increase the resistance to fluid flow, resulting in higher pressure drop and reduced heat transfer. The growth of deposits causes the thermohydraulic performance of heat exchanger to degrade over time. Fouling affects the energy consumption and therefore increases the amount of extra material or fuel required to generate the required amount of heat transfer.

The fouling layers of the surfaces are known generally to increase with time as the heat exchanger is operated. Since the fouling layers normally have lower thermal conductivity than the fluids or the conducting wall, they increase the overall thermal resistance.

There is an increase of the surface roughness, thus increasing frictional resistance to flow, and fouling blocks flow passages. Pressure drop, due to these effects, across the heat exchanger increases.

Fouling may create a localized environment where corrosion is promoted.

Fouling reduces the thermal effectiveness of heat exchangers, which in turn affects the subsequent processes or will increase the thermal load in the system.

An additional goal is prevention of contamination of a process fluid and product.