This information has been compiled to directly address the needs of those who have the responsibility for the operation,
safety and maintenance, as well as the economics associated with commercial and industrial boilers.
So, for simplicity sake, let’s start off with a quick review of the very basics. What is a boiler? A boiler is an
encased vessel that provides a means for combustion heat to be transferred into water until it becomes heated water
or steam. The hot water or steam is then usable for transferring the heat to a process. When water is boiled into
steam its volume increases about 1,600 times, producing a force that
is almost as explosive as gun powder. This is a very good and efficient means for transferring heat for a process,
but it can also be extremely dangerous.
Boilers represent the “heart” of many institutions including:
Airports, condominiums, dry cleaners, production factories, food companies, general industry, hospitals, hotels,
housing authorities, medical centers, office buildings, power utilities, schools, shopping malls, and any other locations
where hot water or steam is an essential part of the operation.
Scale is the accumulation of minerals such as calcium and magnesium on the water side of boiler heating surfaces. When
boiler water turns to steam, residual minerals are left in the boiler. These minerals then settle out of the boiler water
and form scale on the boiler heating surfaces. If the water delivered to the boiler contains even small amounts of
scale-forming materials, the internal heating surfaces of the boilers can soon become coated with scale, leading to
overheating, increased fuel consumption and subsequent tube failures. Even light or spotty scale deposition can be the
foundation for hot spots, cracking, and distortion. For this reason, regularly cleaning the interior of steam
generator systems is imperative.
Boiler maintenance is crucial to the continued efficient operation of your facility. One component to your boilers
preventive maintenance program should be an annual cleaning to remove mineral scales that have accumulated within the
boiler. These deposits are great insulators that inhibit heat exchange and cause the boiler to lose heat transfer, thus
For instance, scale that is only 1mm thick will cause the boiler to use 27% more fuel! A common unknown fact is that
boiler tube failures account for the majority of a power plant’s forced outages. This, all because the boiler may be
suffering from inadequate heat transfer.
Water scale deposited in steam boilers is usually harder and denser than deposits found in hot water boilers. This is due
primarily to the temperatures involved. But even the smallest amount of boiler scale deposits hampers good over-all
heating efficiency. These mineral deposits may occur from poor blow down and/or poor water treatment practices.
Mineral deposits come from:
1) Operating hours
2) Feed water hardness
3) Boiler treatment methods
4) Feed-water control fluctuations
5) Blow down techniques and procedures
Fuel Cost Increase Due to Boiler Scale
ScaleAwaySFATM in conjunction with ScaleAway’s System Descaling CartTM is the perfect tool for dissolving these
deposits that rob efficiency and dramatically increase your fuel consumption.
An annual cleaning with ScaleAwaySFATM will dissolve the calcium, magnesium, rust, and other deposits into
solution without harming the metallurgy or components within your boiler.
ScaleAwaySFATM is the universal product of choice for boiler scale removal.
Besides avoiding boiler failures, with ScaleAwaySFATM you regain original design steam output, efficiency, and reliability!
With ScaleAwayTM descaling solutions, cleaning the waterside on a regular basis will improve the boiler’s technical and
economic performance. As long as you have spent the time and money on tracking tube failures, boiler inspections, and
general boiler conditions, now is the time to purchase ScaleAway’s System Descaling CartTM to maintain the water
side of your boiler in peak operating condition.
Inspections & Frequency
Boiler manufacturers, industrial cleaning companies, and industry organizations have published standards that recommend
the frequency for boiler cleanings. Most standards use the deposit weight density from a tube sample to decide when a
boiler should be chemically cleaned. You should confirm that a consistent method is used when comparing results over time.
Heat-transfer surfaces in boilers must remain clean to maintain the system's energy efficiency. Regular inspections
and scheduled descaling, coupled with a water-treatment program, are critical steps in keeping units operating safely
Some boilers can take a great deal of abuse and inattention and still function at competent levels. They may even
have hinged doors to easily expose the tubes for inspection and cleaning. Regardless of the type and design of your
boiler, the deposits should be monitored by visual inspection, tube sampling, or other methods.
Various Other Applications for ScaleAwaySFATM
The following are some names or terminology of boilers and other associated water-operated equipment that can also be
cleaned with ScaleAwaySFATM:
Economizers, fire tube boilers, fuel gas vaporizers, furnace and flue tubes, furnace tubes, performance gas heaters,
pressure reducing systems, reheaters, scotch marine boilers, sectional boilers, superheaters, thermal fluid heaters,
water bath heaters, water tube boilers, water heat recovery coils, hot water donkeys and other similar applications.
Factors to Consider before Boiler Cleaning
- Type and design of boiler; low temperature hot water, high temperature hot water, low pressure steam or high pressure steam?
- Size of boiler can be obtained from the name plate or other documentation.
- What is boiler used for? Heating or process (heat exchanger)?
- Age of boiler?
- The characteristics of the deposits and deposit analysis.
- Thickness of deposit; thickest area, thinnest area, average?
- Date last cleaned, if ever?
- Has any boiler feed-water treatment been used?
- Boiler history?
- What is the boiler’s water capacity?
- Compatibility of the cleaning solvent with the metallurgy of the system.
- Ease of the cleaning application.
- Method of spent solvent disposal.
- Cost of cleaning method.
- Any tubes or sections leaking now? If so, they should be fixed before cleaning.
Basic Boiler Cleaning Procedures
- Shut down boiler.
- Blow down with pressure still on.
- Close steam valve.
- Drain and flush unit.
- Add ScaleAway'sTM Descaling Solution, and then top off with water.
- Circulate from drain piping and back into top of boiler through the opening where the pressure relief valve was removed. Top of boiler or circulating drum should be vented to atmosphere to allow gases to escape.
- Circulate at least 4 hours. Longer circulating time for larger boilers, but no more than 8 hours.
- Open steam valve.
- Drain, flush, re-fill and start up.
Improve the operational efficiency of steam boilers, industrial boilers and process systems by using
ScaleAway’s System Descaling CartTM and ScaleAwaySFATM to alleviate the problems associated with such
installations; namely scale formation, corrosion, boiler water carryover and sludge deposition.
When water is turned into steam in a boiler, the minerals previously dissolved in the water are
left behind and deposit a scale on the hot boiler surfaces. This scale, mostly calcium and
magnesium, is an excellent insulator and slows the transfer of heat to the water. When boiler
surfaces are covered with scale, heat normally absorbed by the water goes up the stack instead,
and the tube metal temperature rises to the point of failure.
Boiler failure occurs when scale is allowed to accumulate. Steel retains its strength up
to 3700 Celsius, and it starts to weaken above that point. At 5300 Celsius
it has a hard time supporting its own weight. How does steel survive in a boiler when the flame
temperature is 16500 Celsius? It survives because the water absorbs the heat from
the metal fast enough so the temperature of the metal does not reach the danger point. Start
adding insulation such as scale between the metal and water, and the metal temperature
increases. With enough scale, the metal will overheat causing blisters, bags, and eventually a
ruptured pressure part.
The management of waterscale, limescale and rust from the waterside of your equipment and
associated piping with scale dispersant and sludge conditioner is of paramount importance for
the efficiency of your water boilers and furnaces.
Contact us TODAY to purchase these descaling products or to take advantage of our scheduled
preventative maintenance services!
Alternatively, speak to one of our service technicians about acquiring
a ScaleAway’s System Descaling CartTM for your maintenance team to do your own descaling in-house!