National Heat Exchange (NHE)
National Heat Exchange (NHE) is a newly patented technology for cleaning the shell-side of heat exchangers and coolers, restoring their peak efficiency to a level previously unattainable with the traditional approaches, such as high pressure washing or a bubble vat process. This new procedure utilizes a totally enclosed self-contained cleaning unit: The Mobile Cooler Cleaner or MCC.
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- Service provider
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- Market Focus:
- Nationally (across the country)
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The cleaning is accomplished through high volume flow (up to 1,500 gallons per minute) of the properly matched cleaning solution, heated to its proper heating temperature. Spray bars are mounted and matched to the bundle size, allowing full length bundle cleaning as the bundle rotates in the MCC. The cleaning solution circulates through a closed Kidney Loop Process where all solids are captured in the MCC's filter system. This process flushes particulate, biological films, calcium deposits, and carbon build-up while the cleaning solution is continually being filtered and recycled.
Tube ID cleaning or lancing can also be done in the MCC. The MCC accommodates bundles up to 5' diameter and 33' in length. The MCC can be set up at your location or your exchangers may be sent to our facility. NHE also has a newly built H2 Cleaner, especially designed for generator cooler cleaning, hydrogen, exciter, and other rectangular, open-sided coolers.
Dollars and Sense of Cleaning
Why Shell Side Cleaning?
Lube oil performs many functions in turbine-generation, all of which are not only necessary for optimal production for the moment, but optimum equipment reliability for the future. Both production and reliability are essential elements of increased profits.
For lube oil to do it's job it must be kept clean and at the proper temperature. Lube oil coolers are an essential element in this process.
The primary purpose of lube oil coolers is to cool turbine oil. This is accomplished as the heated oil travels a serpentine path through the shell side of the bundle, while cooling water flows through the tube side. Heat is transferred from the oil to the water, keeping the oil temperature within its ideal operating range.
As the oil travels this serpentine path through the cooler the heat transfer itself helps to cause foreign materials in the oil to drop out and adhere to the outside of the tubes. This is a two edged sword. First, the build up on the shell side of the tubes becomes an insulator reducing the ability of heat to be transferred. Then, as the build up of contaminates continues, sections of the bundle will become plugged, restricting the flow and further reducing heat exchange. Eventually, some of this material will move through the bundle and cause premature wear on the bearings and other parts.
How does turbine oil become contaminated? The oil storage tanks themselves are very often located in such a place as to collect all kinds of dust and debris. They may also contain debris going all the way back to plant construction such as dust, chips and weld splatter. Leaky tubes on the coolers themselves may cause water to get into the oil. The continuous wear of machine parts, gears, couplings or the bearings themselves provide contaminates. And just the cooking and chemical action in the hot spots of the unit will cause sludge and varnish to build up on the tubes. A thin coat can cause a 10% to 15% loss in heat transfer.
Neither equipment failure nor decreased production is acceptable. The only solution is a proper preventative shell and tube side cleaning program. A thorough shell side cleaning at least every 3 to 5 years, coupled with intermittent tube side cleaning as needed, will not only increase the time between major outages, but will allow you to maintain the turbine at maximum load.
There are only three alternatives in regard to shell side cleaning. First is high pressure washing which is only about 40% effective, produces thousands of gallons of liquid waste, and actually serves to pack contaminates more tightly into the center of the bundle. Next is bubble vat cleaning. In this method the bundle is placed into a vat of chemicals and air is circulated through the tank in an attempt to break up and dissolve some of the contaminates. The bundle is then removed and pressure washed. This still produces large amounts of liquid waste and is at best only about 70% effective.
The only real solution is our patented state of the art MCC process, which utilizes a totally enclosed container. The tube nests are placed inside where they are rotated as they are sprayed full length with 1500 gallons a minute of a cleaner that is compatible to your turbine oil. This cleaning agent is heated to between 160° & 180°. All solids are captured in a closed kidney loop filter system, so only clean solution is flushed over and through your cooler at all times. With this process we are able to wash your bundle clean all the way to the center restoring 92% to 98% of new efficiency.
Why National Heat Exchange?
Quite honestly with high pressure techniques it's like taking your dirty clothes, laying them on the floor and spraying them off with a hose. It just doesn't work and makes a huge mess. A bubble vat is like putting your clothes in a washing machine, but not turning it on, pretty much all that happens is they get wet. But at NHE, with our patented process we actually turn the washing machine on. The result is your heat exchanger restored to as near to new as possible.