Essay On Fouling

Fouling

Fouling is an accumulation of undesirable material on the surface of solid . Fouling is not only the chronic problem of heat ex-changers but it is also one of the major problem that occur in whole industries. Because of that, the extra cost is required for the additional fuel consumption, cleaning action, maintenance, loss of production etc. There are several types of fouling that are caused by the different reasons. Biological fouling:

This fouling is caused because of the growth of different organism within the fluid which is mostly deposit out. This problem is normally overcome or remove by two ways.

Chemical treatment.

Mechanical processes. ( mostly brushing processes).

Chemical fouling:

When a layer of fouling is deposit on

It can be minimize by removing all the small spaces. For example, use welding instead of bolts and nuts. Use non-absorbent gasket like Teflon.

Steam or Water Hammer:-

Shock waves or Pressure spikes due to the sudden and rapid acceleration or deceleration of any liquid can cause damaging steam or water hammer to the heat exchanger. Pressure surges occur at a level in which the pressure exceeds 20,000psi which results in the complete rupture or collapse of the tubing of the heat exchanger.

Pressure surges can be as a result of an interruption in the cooling water flow or the stagnant water heated with the resulting generation of the steam. All of the process described would likely be a cause of the pressure surge , steam or water hammer. Hence, the flow of the cooling fluid should always start preliminary to adding the heat load.

The other main cause of the water hammer is the control valves that open or close suddenly to control the fluid flow. Modulating control valve is a preferable option to the “on-off “valve types. A vacuum breaker vents are important if the process involve a fluid that could easily condense on the walls of the shell or the tubes in the heat