Revolutionizing Heat Exchanger Maintenance: The Benefits of Automatic Tube Cleaning Systems (ATCS)

Online Automatic Shell and Tube Heat exchanger Tube Cleaning Systems (ATCS)

Automatic cleaning of heat exchangers and condensers tubes by means of sponge balls is well known since the early sixties, with expanding application from steam power plants to process industry to industrial cooling and air conditioning systems. Main benefits in cost savings are generally considered as: elimination of maintenance down-time and need for chemical and more efficient operation of process and plant.

In this Blog will discuss the performance and benefits of an Automatic Tube Cleaning System (ATCS) implementations. The balls injection and trapping methods, their unique operation benefits are revealed and resulting operation and maintenance cost savings.

 

The most common solution to fouling is periodic off- line cleaning of the heat exchanger, either by mechanical or chemical methods, which has several drawbacks:

•  Requires process shutdown or process direction to parallel heat exchangers for cleaning.
•  Fouling accumulates between treatments gradually increases performance degradation.
• Harmful to the environment: the residues and cleaning chemicals require special disposal.

The costs of fouling and its off-line cleaning approach can be divided to following points:

Lesser productivity: due to escalated efficiency degradation and to loss of production during planned or unplanned shutdowns. These are considered to be the main cost of fouling.

Higher maintenance costs: for removing fouling deposits and for chemicals or other operating costs of antifouling devices. Typically, 6-8% of the maintenance costs of a process plant can be attributed to heat exchangers fouling.

More energy consumption: in many processes’ extra electricity, fuel or process steam is needed to    overcome the effects of fouling. Between 1% and 5% of the energy consumed by the industrial sector is used to overcome fouling.

More heat transfer area: the design excess surface area for fouling varies between 10% - 200%, with an average around 25%. Such excess area may correspond to additional capital cost of 20%. This also includes costs of stronger foundations for heavier or redundant heat exchangers, provisions for extra space and increased transportation and installation costs.

Evidently, off-line cleaning cannot be considered an       adequate solution for the fouling problem, hence there is a better alternative of on-line cleaning.

 

Automatic Tube Cleaning System (ATCS) is a very effective solution to mitigate fouling problem in Shell and Tube Heat Exchangers. It has wide applications in HVAC chillers, Power Plants, Process Condensers and Industrial refrigeration. It helps to save upto 20% energy in HVAC chillers and helps reducing carbon footprint.

In today's competitive world, maintaining higher efficiency is the key to success .

 

The old way to clean your heat exchanger involved long shutdowns, harmful chemicals, and ongoing operating expenses.

The automated system consists of an injection pump, collection pump, ball trap, ball collector, control valves and a controller.

                                                                     Figure A

During injection cycle, the injection pump takes water from the cooling water inlet pipe and boosts the pressure in the ball collector where the cleaning sponge balls are housed and the sponge balls are injected into the condenser almost simultaneously at the condenser tube sheet.   The automated pump, which forces water through the pipes and into the collector, where the system periodically injects all of the balls into the inlet pipe at the same time.

 

The balls start out in a collector that's connected to your heat exchanger or condenser through the system's main line. A window in the collector allows you to easily monitor the condition and number of balls.  

Then, normal system water flow carries the balls through the inlet pipe and into the main line. The balls go from the main line to the heat exchanger, where they are randomly distributed across the condenser tubes.  They are effectively spread at the inlet of the condenser tubes.

The balls flow through the tubes at normal system flow velocity, and as the water pushes the balls through the pipes, they clean off residue, deposits, and buildup before it has a chance to take hold.

 

The sponge balls pass through the tubes and carry the fouling inside the tubes with them.

After cleaning, the sponge balls come out of the condenser tubes. They are trapped in the ball trap and they wait for the collection back into the ball collector. Now, the collection cycle is initiated by the programmed logic controller. The collection pump starts and the balls from the ball trap are collected back to the ball collector where the balls are thoroughly rinsed and are staged and prepared to be ready for the next injection cycle. The entire process is a batch operation and the cleaning takes place 3 to 4 times an hour automatically.

 

The injection and collection pump hardly run for 2 to 3 minutes in each cycle. This fully automatic system works on continuous basis without any shutdown for cleaning. Zero ball Loss System ensures 100% cleaning of tubes and needs replacement of cleaning balls only once in 5 to 6 months. Single system can manage couple of chillers effectively, making it very cost effective and gives faster payback and return on investment.

It can save up to 15-20% energy in HVAC& R chillers and in case of power plants can increases the power output by 2 to 6%. It will increase cooling capacity of chillers and life of condenser tubes avoiding costly shutdown and downtime, use of harmful chemicals and completely avoids offline cleaning.

The Automated Tube Cleaning System is installed on heat exchangers and keeps them clean without intervention. The system (Fig. A) periodically injects into the tubes sponge balls that are slightly larger in diameter than the tubes themselves. The natural pressure head pushes the balls through the tube that is thus rubbed clean. The balls are trapped on the outlet of the heat exchanger, where they are prepared for the next cleaning cycle. By providing on-line cleaning, the ATCS should be in fact considered as a cost-effective fouling mitigation method.  

Some of advantages of ATCS over other cleaning products (sponge balls, brushes and tube inserts) are excellent thorough cleaning, balls are periodically injected at a single shot carried by the fluid and reaching all tubes, both central and peripheral, Simple design, delivering high reliability, rapid installation, low maintenance, and high viability to cost sensitive markets, Wide range of sizes: suitable for a wide variety of heat exchangers, from small condensers in air conditioning, to large industrial applications, Better ball trapping mechanism, Better control of the cleaning process and cleaning periods are customizable to maintain a high level of performance, and minimize balls wear.

 

CQM has installed more than 2,000 ATCS around the world, delivering value to several markets as Central air conditioning systems and industrial refrigeration- up to 25% savings in energy costs,  as well as typically 600 tons of greenhouse gases per 1000 tons of refrigeration per year., Electric Power Plants: up to 4% increase in annual power generation and Industrial processes: significant increase in productivity and reduction of operation and maintenance costs.

 

In Conclusion

The main cost of fouling is due to decrease in productivity by double digit percentage of total cost. Energy efficiency methods aim to both avoid Green House Gas GHG and increase both the potential and actual productivity of existing infrastructures (more kWh from existing power plants). Inefficient fouling mitigation thus not only is costly, it also pollutes and necessitates more energy production, more power plants, etc. The usage of these energy and resources can be significantly reduced using effective fouling mitigation measures. Therefore, online cleaning of heat exchangers should become a high priority in the effort to promote private, national and global energy efficiency interests.

 It saves energy, reduces maintenance, extends the life of your capital equipment, and optimizes heat transfer performance, saving you thousands of dollars every year. 

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