Heat exchangers are equipment that act as a medium of transfer between two or more fluids. They are used for both heating and cooling processes and are commonly used in various industries such as space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural gas processing and sewage treatment.
The heat exchangers undergo a large amount of strain throughout the years. Each time they heat up, the metal expands. In this article, we will investigate the possible heat exchanger defects that can occur.
Over time, the constant expansion and contraction weakens the metal in heat exchanger leading to tube corrosion. This is, naturally, a higher risk in older furnaces and/or furnaces that are not well maintained. Corrosion then deteriorates the metal even further, and this added stress on the heat exchangers leads to small cracks that would not just affect the production flow but also affect the health and safety of workers.
Finally, fouling is one of the most common issues in heat exchangers.
It occurs when solids, such as sand, algae, dirt or scale are deposited on conducting surfaces, thereby preventing heat exchanger from transferring heat from one medium to another. In extreme cases, fouling can be very expensive, especially when deposits cause blockage of internal tubes. In such cases, operators may be forced to take the unit out of service to be disassembled and cleaned.
Routine maintenance will help mitigate the risk of fouling. Ensuring that exchangers remain within designed operating ranges with regards to flow rate/velocity, differential pressure, and temperature is key to prevention as well.
In summary, these are common defects found in heat exchangers:
- Abrasion (caused by support plates rubbing against the tubes), thermal shock, sedimentation, fouling, etc.
Which is why regular inspection of heat exchangers is recommended, as it helps to ensure they are free from any such defects.