Unfortunately heat exchangers aren’t exempt from problems. Like any other product out there, they can attract a range of issues which can result in either; a poorly performing heat exchanger or a heat exchanger that just doesn’t work at all.
If regularly working with heat exchangers it would be a good idea to familiarise yourself with some of the most common problems, so you know what to expect if it should ever occur.
In this post we’ve taken a look at one of the most common problems found in heat exchangers and where possible we have thrown in a few simple solutions to help you fix the problem.
Heat Exchanger Fouling
Fouling is the buildup of debris and dirt on the surface area of a heat exchanger and is the most common problem encountered with heat exchangers. Fouling prevents heat from transferring, increases the pressure drop and can obstruct fluid flow. As such, regular maintenance to remove any dirt or debris is highly recommended and will benefit your heat exchanger in the long run.
There are numerous fouling types and each will depend on the fluid used and conditions of the heat exchanger. We’ve listed the more common fouling types below and the common ways to treat them.
Crystallization
Natural waters contain certain salts and these salts have a lower solubility in warm water than cold. This means than during the cooling process dissolved salts will crystallize on the surface.
A common way to avoid this happening is to reduce the temperature of the heat transfer surface.
Sedimentation
Another problem that can occur when using fresh water is sedimentation. Dirt, sand and rust can be commonly deposited in the tubes.
Increasing velocity will help to flush the particles off the surface.
Biological Organic Growth
Chemical reactions can cause biological organic growth material and when left to build up can cause a serious amount of damage.
When this type of fouling happens it would usually be removed by either a chemical treatment or mechanical brushing processes.
Chemical Fouling
This will happen when hydrocarbon deposits in a high temperature. It can be avoided by simply reducing the temperature between the fluid and the heat transfer surface.
Again, like biological organic growth fouling, if this type of fouling occurs, it must be removed by chemical treatment or mechanical descaling processes.
Other things to watch out for are corrosion and freezing fouling. Many people will understand that corrosion can destroy surface areas, it works exactly the same way in a heat exchanger. Freezing fouling happens when the heat transfer surface has been overcooled. This causes the solidification of some of the fluid stream components. Avoid costly damage and reduce the temperature gradient between the fluid and the heat transfer surface.
Be warned, if you fail to treat fouling you could be increasing your chance of attracting other major heat exchanger problems.
