Fouling Of Heat Exchanger/ Water Fouling. Fouling Factor and Disadvantages of Fouling

What is water fouling of heat exchanger?

A medium (or water) flow through a heat exchanger not always finely purified. It may contain certain amount of impurities such as minerals and organic and inorganic foreign materials. The impurities eventually deposit inside of the water tube and heat exchanging equipment. This is known as fouling. The fouling not exclusive to heat exchanger it also happened in many other components. Such as solar panel, turbines, nozzle, venturi tubes, spark plug electrode in vehicle, etc. Here we are discussing the fouling in heat exchanger.

Fouling is defined as deposition and accumulation unwanted material such as salts, scale, suspended solid article on the surface of heat exchanging equipment. Fouling significantly affect the thermal and mechanical performance of heat exchanger. The deposit on the wall restricts the water flow, and increase the pressure drop across heat exchanger. Fouling insulates the tube and reduces the heat capacity of materials. The fouling also accelerates the corrosion.

Disadvantages/ negative impact of fouling.

1. Fouling restricts the fluid flow.
2. It causes the pressure drop across the heat exchanger.
3. The deposit on the wall resists the heat exchanging and reduces the thermal conductivity.
4. It accelerates the corrosion of the tube surface.
5. Frequent Shutdown and increase maintenance cost.
6. Production loss due to low efficiency.

What is fouling factor or dirt factor?

Fouling factor is defined as the reciprocal heat transfer coefficient for the material of scale. It represents the theoretical resistance to heat transfer due to build-up layer of fouling material. Since the thickness of fouling mater generally not known until shutdown work, the fouling factor should take into account for the calculation of overall heat transfer coefficient.