Maintaining your Air Cooled Heat Exchanger

smithco-fin-fan-cooler

Heat creation is a requirement in the majority of industrial processes. Heat allows materials to reform, such as thermoplastics; it creates steam to turn steam turbines; it melts ore to refine minerals into metals; it’s used in glass production, paper mill and petrochemical operations and refineries. Essentially it is found in all heavy industrial processes.

Once the material has been heated to the required temperature it then must be cooled back down to ambient temperatures. In the past heavy industrial processes were located on large bodies of waters, such as rivers, lakes and oceans for two primary reasons. One so that shipments of raw material and finished product could occur, and secondly so that the natural body of water could be used as a heat sink to take away the heat from whatever process was used in that plant.

Nowadays as people have become more environmentally conscious, industries are moving away from rejecting the heat into bodies of water and are now using devices such as cooling towers and air cooled heat exchangers sometimes referred to as “fin fans”.

“Fin Fans” are a trademarked name of the Hudson Products Corporation of Beasley, Texas. It is a registered trademark name similar to when people refer to facial tissue as “Kleenex”.

So we will talk about what many trades and operations people call “fin fans” but again to be correct air cooled heat exchangers.

So many heavy industrial processes rely on the efficient operation of their air cooled heat exchangers.
Generally there are a few things that need to be done to ensure safe and efficient operation of your air cooled heat exchanger equipment.

The rotating equipment portion, the fiberglass or aluminum wheel should be inspected on a regular basis for cracks and other indications of possible failure. So it is ideal to get a service man (such as people from Hudson if you have the fin fan brand) to inspect and replace and repair any parts that are showing indications of possible future failure.

Secondly cleaning of the coils is often an overlooked component to maintenance. When the coils are plugged often with organic material from neighboring trees, the airflow through the coils are obstructed and the heat rejection that is supposed to take place cannot occur. This has a ripple effect where the fluid traveling through the coils cannot release their heat. The fluid returns back to the process hotter than is desirable for the efficient operation of the process.
In the case of power generation it can mean reduced electricity output.

Inspection and cleaning up the coils is an important aspect of maintenance. It is crucial as well to do this properly. Calling a properly trained service man is prudent because improperly trained people have been known to use high-pressure water on the fin coils which causes the soft metal fins to bend over and create even more obstruction, or blockage, of the airflow.

Drive belts need to be inspected for wear and proper tension.

Gear boxes need to be checked for proper oil levels.

In addition to the routine maintenance one of the other things that can one can do to improve operation of air cooled heat exchangers is to upgrade the fan wheels.

Generally the fan wheels supplied in the past were selected to provide a reasonable amount efficiency at an affordable price. But with the rising cost of electricity it is often a quick payback energy saving project to retrofit existing wheels of low-to-medium efficiency to higher efficiency wheels. This will become even more important as electricity prices continue to rise.

These higher efficiency fan wheels can alternatively provide improved production throughput, because higher efficiency wheels allows an operations manager to decide whether to keep the energy savings, or to increase the airflow through the air cooled heat exchanger using the more efficient blades to “soak up” the energy savings. This will bring the energy consumption back to the pre-retrofitted consumption levels while delivering increased heat rejection. This can be used when a bottleneck in heat rejection is causing the process to be throughput limited.

The other remaining aspect is the condition of the tube bundles. As leaks occur, given time, vibration and wear, tube runs are plugged at the header to allow the unit to continue running. When too many tube runs are plugged permanently it is time to consider replacing the tube bundles.

Again the OEM manufacturers, such as Hudson or Smithco etc. are the ones to call to ensure a good fit up.

Following the above steps will mean that your air cooled heat exchangers will last a long time and the operations people will be able to control their processes tighter when correct heat rejection is available.

Smithco Heat ExchangersDependable, long-lasting, custom-made air-cooled heat exchangers by Smithco Engineering.

For a quote or for expert help regarding to your industrial operations, call toll free at 1-888-317-8959 ext.26 today.