If Air Cannons Work, Why Are Plants Still Water Washing?
Riser ducts have historically been subject to buildup. Most cement plants combat the buildup
with air cannons and high pressure water washing. Many plant managers would report that
their air cannons are operating well. But if they are working effectively, why is there a need for
high pressure water washing?
Sadly, the cement industry has accepted an incredibly low standard for air cannon cleaning. It is
time to demand more! Plant managers should expect air cannons to remove buildup and to
drastically reduce manual cleaning. Only then should they report that their air cannon
installation is operating well.
The Need to Eliminate High Pressure Water Washing
Primarily, it is a safety risk. Injuries include burns, carpal tunnel, hurt backs, and even death. Plants that employ regular high pressure water washing place their employees at risk to maintain good operations. High pressure water washing is expensive due to the cost of false air. Dracyon has been told that the false air associated with a 1” diameter pipe produces an increased fuel cost of $50/hour. An 8’ by 8’ inspection door, often opened for high-pressure water washing, allows 64 times more false air into the Tower.Based on the increased fuel cost of the 1” diameter pipe, the average access door would produce an added cost of $3,200 per hour. If you use high pressure water wash four hours per day, the added cost is $12,800 per day. Based on a 300-day year of operation, false air equals a cost is $3,840,000 per year.
When an air cannon installation is powerful and successful, false air costs are significantly
minimized. Additional savings include:
- Extended life of the refractory in the riser duct
- Elimination of the combustion air swings. These are often caused by buildup and force high-pressure water washing
The ROI for an air cannon system that eliminates high pressure water washing is extremely quick. Not months or years, but, in many cases, a matter of days.
The Way to Eliminate High Pressure Water Washing
If High pressure water washing is unsafe and inefficient, why has it not been eliminated by air cannons already? Most air cannons lack the required power. They are simply unable to clean deep into the application, so supplemental cleaning is necessary. A standard air cannon installation in a riser duct will include the following features:
The guiding principle behind this strategy is that peak force is the most important factor for effective cleaning. An example of this type of installation is shown in the picture below:
Above: Typical air cannon installation.
Decades of industry suggest this type of installation will never eliminate high pressure water washing. The cement industry does not need more of the same air cannon. It needs a new air cannon. The Dracyon Big Dog Air Cannon is specifically designed to meet the needs of today’s industry. Several design features ensure it will have sufficient power to clean deeply into the application.
First, it employs a larger reservoir tank. Volume is key to better cleaning. The standard 70L tank does not have enough power. Dracyon typically recommends a 300L reservoir tank, which has
4.3 times more clean energy than 70L.
Second, it employs a more effective cleaning cycle. The impulse time required to discharge 300L of air is far greater than it is to discharge 70L. The longer cleaning cycle per discharge enables
the cleaning action to penetrate much deeper into the application. Think of a leaf blower. Do you move the leaves with momentary blast or continuous blowing? The same principle applies.
Above: Dracyon’s recommended installation.
Third, it employs a more effective nozzle. One of the reasons air cannons do not penetrate deep into the application is the nozzle. The standard fan jet nozzle produces a wide, thin blast of air.
This only cleans buildup within 3 feet of the air cannon and allows accumulation in the middle of the riser duct. The CFD modeling below shows the deficiency:
Above: CFD testing clearly shows that fan jet nozzles are insufficient.
The is, however, a better way. Third-party CFD testing indicates that increasing the nozzle size from 4’’ to 6’’ produces 4x more peak force and far better air flow.
The result is a nozzle which is able to clean deep into the application, where most of the buildup occurs.
Above: Deeper penetration is crucial to eliminating high pressure water washing.
The design features described above are quite simple. More air is discharged for a longer duration through a larger nozzle. It makes perfect sense why that produces more effective cleaning. It is today’s air cannon which will solve today’s challenges.
Protecting the Air Cannons
The final step to eliminating high pressure water washing is simple: protect your air cannons. The technology will only contribute if it is working properly. The best way to ensure the
reliability of air cannons is to take the following steps:
Protector Valve™ (Anti-Leak Valve Technology)
- Stays sealed 99% of the time, blocking false air entry
- Prevents heat, dust, and corrosive gas from infiltrating internal parts
- Shields the piston and seals from premature wear
When these two simple objectives are met, air cannons prove to be extremely reliable. It doe not matter how good the technology is when it is not working. Dracyon employs years of experience to ensure each cannon is installed with long-term reliability in mind.
Summary
The cement industry has accepted a low standard of air cannon cleaning for far too long. As a result, most riser ducts are replete with buildup and require regular high pressure water washing. That is an unsafe and inefficient solution. The air cannon technology to significantly reduce or eliminate high pressure water washing exists. The Big Blue Air Cannon has more cleaning energy than the standard air cannon. It has a more effective cleaning cycle. And it
discharges through a more efficient nozzle. It is a simple concept but it will produce a immediate ROI. When that technology is protected through proven installation techniques, it will eliminate high pressure water washing for the long term. The technology to eliminate common buildup problems is there. It is time to demand more of your air cannon