Heat Exchanger Maintenance Essentials You Need to Know
Heat exchangers are essential components in many industrial systems, providing a safe, efficient way to transfer heat from one process to another. Proper maintenance is necessary to ensure that heat exchangers are functioning optimally and producing the desired results. Let’s review what should be included in heat exchanger maintenance and the risks of poor maintenance.
Risks of Poor Heat Exchanger Maintenance
If a heat exchanger is not properly maintained, it can cause a variety of problems, including decreased performance and efficiency, decreased reliability, and increased risk of fire or explosion. It is also important to note that heat exchangers (like all process equipment) can become a safety hazard if not properly maintained.
Replacing Equipment
If a heat exchanger is not maintained properly, it may need to be replaced. Replacing a heat exchanger is a costly and time-consuming process, so it is important to perform regular maintenance to ensure the heat exchanger is working properly and efficiently.
Larger Maintenance Costs in the Long Term
If a heat exchanger is not maintained properly, it may require more extensive maintenance and repairs, which can be expensive when unplanned. It is important to perform regular maintenance to ensure that the heat exchanger is operating efficiently, safely, and reliably.
Shutdowns Causing Production Loss
If a heat exchanger is not properly maintained, it may need to be shut down for repairs or maintenance, resulting in a loss of production. Performing regular maintenance on a heat exchanger can help avoid costly unplanned shutdowns and production losses.
Cleaning Heat Exchangers
Removing Sediment
Sediment can accumulate in a heat exchanger over time, causing decreased efficiency and performance. Sediment typically builds up in “dead zones”, places in the heat exchanger where fluid velocities drop (eg, at baffles opposite to opening). It is important to regularly inspect and clean the heat exchanger to remove any sediment that may have built up.
Remove Any Biological Growth
Biological growth (a type of fouling), such as algae or bacteria, can accumulate in heat exchanger services that utilize river water. This can cause severe performance degradation and encourage corrosion. It is important to regularly inspect and clean the heat exchanger to remove any biological growth that may have built up.
Scaling and Incrustation
Scaling and incrustation can also accumulate in a heat exchanger over time. These can cause decreased efficiency such as reduced heat transfer and higher pressure drops. It is important to regularly inspect and clean the heat exchanger to remove any scaling or incrustation that may have built up.
How to Clean a Shell and Tube Heat Exchanger
One way to clean a shell and tube heat exchanger is to use a chemical cleaning solution. This solution should be applied to the heat exchanger and allowed to soak for a few hours. After the soak time is complete, the heat exchanger should be rinsed with water to remove any residue from the chemical cleaning solution. Cleaning can also be performed using mechanical and ultrasonic methods.
Maintenance and Inspection of Shell and Tube Heat Exchanger
Once the heat exchanger is clean, it should be thoroughly inspected to ensure that the pressure envelope and flanged joints are in good working condition. Exchangers with removable bundles (AEU, BEU, AES, BES, etc) will need their bundle removed for a thorough inspection. Fixed-bundle exchangers like AEL, BEM, and NEN will typically have their channel covers (or bonnets) removed to access and inspect the tubesheet faces and tubes (inside surfaces only).
Typically the pressure boundary surfaces are visually inspected for pitting and other visible damage. Ultrasonic NDT (non-destructive testing) may be performed to measure the thickness of components relative to like-new condition. Local corrosion and pitting damage can be repaired with grinding and welding repairs. Areas affected with greater damage may require welded patches or complete component replacement.
Tubes may be inspected and measured for thickness and cracks. Welded tubesheet joints may have LPI (liquid penetrant inspection) examination performed to identify cracks. Defective tubes are typically fly-cut and plugged.
Flanges will be checked for flatness and portable machining may be required to refresh the surface finish. Fresh gaskets will be installed and everything will need to be properly bolted-up and tensioned (or torqued) to calculated values.
Altex is Ready to Handle All Your Heat Exchanger Maintenance Needs
At Altex, we understand the importance of regular heat exchanger maintenance and we are committed to providing the highest quality service. Our trained technicians are experts in heat exchanger maintenance and can help ensure your heat exchanger is working properly and safely. Contact us today to learn more about our heat exchanger maintenance services.
