Heat Exchanger Cleaning Equipment

Heat exchangers are at the heart of so many industrial processes that they are often forgotten and taken for granted. Heat exchangers have a long lifespan, so it is a gradual process of losing efficiency. Since this decline is such a long and slow process, it’s rarely even noticed that the heat exchanger is headed toward failure. Until something goes wrong. When something goes wrong with the heat exchanger, it goes really wrong, and it is urgent to remedy the situation immediately.

Heat exchangers often go so long without being properly cleaned and maintained that by the time there is a heat exchanger cleaning, the original specs and records have been lost or misplaced. This creates an additional problem, because without the original specs, no one knows what kind of performance the heat exchanger is supposed to have.

Once the heat exchanger finally is opened up for cleaning, it’s common to find that it has become so fouled that the heat exchanger cleaning takes significantly longer than it would have if it had been regularly maintained and cleaned. Ultimately, the lack of regular maintenance and cleaning results in a higher cost, longer cleaning duration, and greater loss of production.

This might sound like some sort of a rare, worst case scenario, but it’s entirely routine for the specialis cleaning companies. When cleaning is done, it’s often done without any real knowledge of what kind of performance benefit there will be, and how long this increased efficiency will last.

One of the most used heat exchanger configurations in industrial use is the straight of hairpin shell-and-tube-exchanger. This has bundles of hundreds or thousands of small-bore tubes. Even a moderate amount of scaling can take considerable cleaning and effort to return the heat exchanger back to optimal performance. If the outside of the bundle has heavy scaling, it’s exponentially more difficult to adequately clean the heat exchanger.

Advancements in design would be able to make heat exchanger cleaning faster, safer, and result in better waste containment. This would result in less time spent offline, and better performance.

Currently, heat exchangers are generally designed to have the capacity to operate even when they are significanly fouled. They are designed to operate with about 30% or 40% excess capacity. This is what industrial facilities want. They prioritize continued functionality over ease of maintenance and cleaning. Heat exchangers are designed and installed to use one of 3 methods of cleaning: mechanical, chemical, or pressure-jetting. This has been the standard for over 50 years.

Refineries, like other industries, use a 21 say shutdown process during which maintenance, including heat exchanger cleaning is done. This is the way it has been done for decades. Industry continues to use the same methods for heat exchanger cleaning that it has always used. The primary method is pressure washing with water.

It’s normal for a company to have their heat exchangers designed to continue running, even if not at optimal performance, instead of having them designed for efficiency, or ease of cleaning. This could require more frequent cleaning, but it would be easier, safer, and more cost effective, resulting in a more efficiently performing heat exchanger. BP (British Petroleum) was able to cut cleaning time of a shell and tube heat exchanger down to 3 hours by changing their heat exchanger cleaning method. Prior to that, cleaning would take 3 days.

If a company designs their heat exchangers for ease of cleaning and maintenance, the plant can remain at near full production capacity throughout the duration of the cleaning process. Banks of heat exchangers can be taken offline, while the rest remain on line. Heat exchangers designed to allow the header to be removed allows for heat exchanger cleaning with alternate methods to the usual high pressure water jet. This can cut heat exchanger cleaning time down to just a few hours, instead of a few days.

More frequent cleaning can also reduce the occurrence of heat exchanger fouling, and also minimizes the amount of time that the tubes are exposed to open air during cleaning. This results in a reduction of corrosion of the heat exchanger tubes.

Cleaner, smoother heat exchanger surfaces allow for more efficient heat transfer. When fouling does occur, it is easier and less time consuming to do the heat exchanger cleaning, and also allows for a wider variety of cleaning methods.

Generally, plants have heat exchanger cleaning intervals of 3 or 4 years. Unfortunately, spreading out the time period between cleanings winds up with a greater cost, not a lesser one. In the short term, it seems like a good idea to stay fully operational, but when the time for maintenance finally does come, down time, lost productivity, and cost is significantly higher than the shorter down times of a quicker maintenance schedule would be. Long maintenance schedules result in a much bigger job.

Big picture thinking, and better design can ultimately be a huge advantage in minimizing the cost of heat exchanger cleaning.