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How to clean a Shell – and – Tube Heat Exchanger?

by jean•

As a seasoned supplier of Shell-and-Tube Heat Exchangers, I understand the critical importance of maintaining these essential pieces of equipment. A well-maintained heat exchanger not only ensures optimal performance but also extends its service life, saving you time and money in the long run. In this blog post, I’ll share my expertise on how to clean a Shell-and-Tube Heat Exchanger effectively. Shell-and-Tube Heat Exchanger

Understanding the Shell-and-Tube Heat Exchanger

Before we dive into the cleaning process, let’s briefly review the basic components of a Shell-and-Tube Heat Exchanger. It consists of a shell (a large cylindrical vessel) and a bundle of tubes inside the shell. One fluid flows through the tubes (tube side), while the other flows around the tubes in the shell (shell side). Heat is transferred between the two fluids through the tube walls.

Over time, various contaminants such as scale, sediment, rust, and biofilm can accumulate on the tube surfaces and inside the shell. These deposits act as insulators, reducing the heat transfer efficiency and increasing the pressure drop across the heat exchanger. Therefore, regular cleaning is necessary to maintain its performance.

Pre-Cleaning Preparations

  • Safety First: Always follow safety protocols when working with heat exchangers. Wear appropriate personal protective equipment (PPE), including safety glasses, gloves, and a face shield. Make sure the heat exchanger is shut down and isolated from the process to prevent any accidental release of fluids.
  • Gather Tools and Materials: You’ll need a variety of tools and materials for the cleaning process. These may include a pressure washer, cleaning brushes, chemical cleaners, hoses, and a collection container for the cleaning waste.
  • Inspect the Heat Exchanger: Before cleaning, conduct a thorough inspection of the heat exchanger to identify any signs of damage, leaks, or excessive fouling. This will help you determine the appropriate cleaning method and the extent of cleaning required.

Cleaning the Tube Side

The tube side is often more prone to fouling due to the flow of fluid through the tubes. Here’s a step-by-step guide on how to clean the tube side:

  1. Remove the Tube Sheet Covers: Carefully remove the tube sheet covers at both ends of the heat exchanger. This will give you access to the tube openings.
  2. Inspect the Tubes: Use a borescope or a flashlight to inspect the inside of the tubes. Look for any signs of blockage, scale, or corrosion. Note the condition of the tubes for future reference.
  3. Flush the Tubes: Start by flushing the tubes with water to remove any loose debris. You can use a high-pressure water jet or a hose to flush the tubes from one end to the other. Make sure to direct the water flow in the same direction as the normal fluid flow.
  4. Chemical Cleaning: If the tubes are heavily fouled, you may need to use a chemical cleaner to dissolve the scale and other deposits. Select a chemical cleaner that is compatible with the materials of the heat exchanger and the fluids it handles. Follow the manufacturer’s instructions for the proper dilution and application of the cleaner.
    • Soak the Tubes: Fill the tube side with the chemical cleaner and let it soak for the recommended time. This will allow the cleaner to penetrate and dissolve the deposits.
    • Agitate the Cleaner: Use a brush or a tube cleaning device to agitate the cleaner inside the tubes. This will help to dislodge the deposits and improve the cleaning效果.
    • Rinse the Tubes: After the soaking period, drain the chemical cleaner from the tube side and rinse the tubes thoroughly with water. Make sure to remove all traces of the cleaner.
  5. Mechanical Cleaning: For stubborn deposits that cannot be removed by chemical cleaning alone, you may need to use mechanical cleaning methods. This can include using tube cleaning brushes, drills, or high-pressure water jets.
    • Brush the Tubes: Insert a tube cleaning brush into each tube and rotate it to remove the deposits. Use a brush with the appropriate diameter to fit the tube size.
    • Drill the Tubes: If the deposits are very hard, you can use a drill with a tube cleaning attachment to break them up. Be careful not to damage the tube walls.
    • High-Pressure Water Jetting: Use a high-pressure water jet to clean the tubes from the inside. Adjust the pressure and flow rate of the water jet according to the tube material and the severity of the fouling.
  6. Reassemble the Tube Sheet Covers: Once the tubes are clean, reinstall the tube sheet covers and tighten them securely. Make sure to use new gaskets to prevent leaks.

Cleaning the Shell Side

The shell side of the heat exchanger can also accumulate fouling, although it is usually less severe than the tube side. Here’s how to clean the shell side:

  1. Remove the Shell Covers: Carefully remove the shell covers at both ends of the heat exchanger. This will give you access to the inside of the shell.
  2. Inspect the Shell: Use a flashlight to inspect the inside of the shell. Look for any signs of corrosion, scale, or debris. Note the condition of the shell for future reference.
  3. Flush the Shell: Start by flushing the shell with water to remove any loose debris. You can use a high-pressure water jet or a hose to flush the shell from one end to the other. Make sure to direct the water flow in the same direction as the normal fluid flow.
  4. Chemical Cleaning: If the shell is heavily fouled, you may need to use a chemical cleaner to dissolve the scale and other deposits. Select a chemical cleaner that is compatible with the materials of the heat exchanger and the fluids it handles. Follow the manufacturer’s instructions for the proper dilution and application of the cleaner.
    • Soak the Shell: Fill the shell side with the chemical cleaner and let it soak for the recommended time. This will allow the cleaner to penetrate and dissolve the deposits.
    • Agitate the Cleaner: Use a brush or a cleaning device to agitate the cleaner inside the shell. This will help to dislodge the deposits and improve the cleaning效果.
    • Rinse the Shell: After the soaking period, drain the chemical cleaner from the shell side and rinse the shell thoroughly with water. Make sure to remove all traces of the cleaner.
  5. Mechanical Cleaning: For stubborn deposits that cannot be removed by chemical cleaning alone, you may need to use mechanical cleaning methods. This can include using scrapers, brushes, or high-pressure water jets.
    • Scrape the Shell: Use a scraper to remove any large deposits from the inside of the shell. Be careful not to damage the shell walls.
    • Brush the Shell: Use a brush to clean the inside of the shell and remove any remaining deposits.
    • High-Pressure Water Jetting: Use a high-pressure water jet to clean the shell from the inside. Adjust the pressure and flow rate of the water jet according to the shell material and the severity of the fouling.
  6. Reassemble the Shell Covers: Once the shell is clean, reinstall the shell covers and tighten them securely. Make sure to use new gaskets to prevent leaks.

Post-Cleaning Checks

After cleaning the heat exchanger, it’s important to perform a series of checks to ensure that it is functioning properly. Here are some post-cleaning checks you should perform:

  • Inspect the Heat Exchanger: Conduct a visual inspection of the heat exchanger to make sure that all the components are clean and in good condition. Look for any signs of damage or leaks.
  • Check the Pressure Drop: Measure the pressure drop across the heat exchanger before and after cleaning. A significant reduction in the pressure drop indicates that the cleaning was successful.
  • Test the Heat Transfer Efficiency: Measure the heat transfer efficiency of the heat exchanger before and after cleaning. An increase in the heat transfer efficiency indicates that the cleaning was effective.
  • Flush the System: Flush the entire system with water to remove any remaining cleaning agents or debris. Make sure to drain all the water from the system.

Conclusion

Cleaning a Shell-and-Tube Heat Exchanger is a critical maintenance task that can help to ensure its optimal performance and extend its service life. By following the steps outlined in this blog post, you can effectively clean your heat exchanger and keep it running smoothly.

Finned Heat Exchanger If you’re in the market for a high-quality Shell-and-Tube Heat Exchanger or need assistance with maintenance and cleaning, I encourage you to reach out to me. I’m here to provide you with the best solutions for your heat transfer needs.

References

  • Incropera, F. P., & DeWitt, D. P. (2002). Fundamentals of heat and mass transfer. John Wiley & Sons.
  • Kern, D. Q. (1950). Process heat transfer. McGraw-Hill.
  • TEMA Standards. Tubular Exchanger Manufacturers Association.

Jiangsu Huanyang Equipment Technology Co., Ltd.
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