The main causes of a heat exchanger failure

21-02-2020

Changing thermal load

Varying thermal loads can result in a very local plastic deformation, creating the risk of damage. The insertions of the tubes into the pipe plates are particularly sensitive to this and can lead to leaks.

Steam or water hammer

In industry, steam is often used, both directly and indirectly. In practice we encounter many situations in which the condensate drain of these heat exchangers does not function properly. These problems occur in particular in part-load operation of the heat exchangers. A properly functioning steam trap is essential.

We prefer to place the heat exchanger in such a way that the steam can condense vertically or gravitally. If this is not possible, try placing the horizontal steam tubes under a slight slope. In this way, the condensate can still run by gravity.

In practice, heat exchangers are also often over-dimensioned to ensure that sufficient capacity is available. However, this over-dimensioning ensures that the steam pressure in the heat exchanger is lower under normal operating conditions and that problems with condensate discharge can occur. The advice is therefore not to over-dimension steam heat exchangers too much.

Chlorides and stainless steel

Stainless steel heat exchangers are widely used in refrigeration technology. It is a misconception that stainless steel cannot rust or corrode.

Chlorides often occur in the cooling water. Check the concentration of chlorides and determine the correct material choice. Temperature also plays a major role in the resistance of stainless steel to certain chloride levels.

Other forms of corrosion

By corrosion we mean the undesired disappearance of material or the change of the structure of the material, under the influence of chemical or electrochemical processes. Selecting the right material depends on various factors. In addition to the pH and the chloride content, a broad spectrum must be examined to see whether other factors may be present that could negatively influence the life of the heat exchanger.

Old age (general fatigue)

Metal fatigue or simply fatigue is a complex topic. The collapse of a structure due to fatigue often seems to happen randomly. In practice, however, fatigue can be predicted relatively accurately, provided that a number of design rules and assumptions are observed.

Mechanical vibrations

Mechanical vibrations can cause damage to heat exchangers. Usually they are not the direct cause, but with prolonged or intense exposure they can give rise to the damage.