Heat exchanger cleaning to remove tube deposits, sedimentation, bio fouling and obstructions is a necessary process that has a tremendous impact on performance. Returning the surfaces to near bare metal starts a new lifecycle whereby the protective oxide coatings can rebuild to ensure a passive impact on fluid flow.
All heat exchanger cleaning services require that the cleaning process for shell and tube heat exchangers be performed while they are off line. The chosen process can be mechanical, chemical or through the use of high pressure water. The choice is dependent on the tube configuration, level and type of fouling as well as cost considerations.
When choosing the mechanical method for heat exchanger cleaning, the tool must match the deposit type in order to be effective. Light silt may best be removed using molded plastic cleaners while brushes can work equally well on microbial deposits in addition to silt. They can also be manipulated to maximize the effectiveness in cleaning tubes that have surfaces with fins, spirals or other surface enhancements as well as metal inserts or epoxy coatings. Metal cleaners are reserved for use with harder deposits and come in a variety of designs to fit the deposit and the tube diameter.
Chemical solutions for heat exchanger cleaning have been found to be effective on a wide variety of deposit types. The drawbacks include chemical disposal, environmental hazards, and the need for further mechanical cleaning in order to optimally complete the process.
Heat exchanger cleaning services are making highly effective use of the latest tools and technologies that utilize high-pressure water cleaning. In addition to effective removal of mineral deposits, scale, biological matter, and other debris, high pressure water systems facilitate a streamlined debris collection and removal process. This enables the removed deposits to be weighed in order to calculate general buildup levels over time so that a more regulated inspection and removal cycle can be established.
There are other cleaning systems and processes available such as combination air and water systems as well as compressed air systems that bring their own practices and effectiveness that are tube and deposit specific. What all of these methods must have in common is a highly trained heat exchanger cleaning service crew.
Not only should they be highly experienced in the use of the best tools and techniques, they most also have an almost encyclopedic understanding of corrosion, fouling agents and coatings. This ensures that the best methods and safety measures will be employed to work hand in hand with heat exchanger design understanding. The end result will be maximized equipment lifecycles and fluid flow along with minimized costs and operational risks.
John Merrick is the owner and president of The Merrick Group, Inc. He has over 25 years of experience with coordinating national and international sales efforts for nuclear and fossil fuel related maintenance projects. He has successfully completed projects in over 30 nuclear and fossil fuel sites.