Infrafone - Sonic Soot Cleaning System for Power Plants

Infrafone has used sonic cleaning technology for more than 25 years. Continuous development has resulted in a preventive and effective soot cleaning system. The system harnesses the power of low-frequency, omni-directional, non-abrasive sound waves that spread to cause oscillations within the gas flow, preventing small particles from forming big soot flakes.

The sonic soot cleaning system is utilized to clean exhaust gas boilers, main boilers on turbine vessels, oil-fired boilers, thermal oil heaters, catalysts, exhaust gas uptakes and incinerators when it comes to marine applications, and economizers, air preheaters, electrostatic precipitators, catalysts and gas ducts when it comes to industrial and power plant applications. It provides the following cost-saving benefits:

• Elimination / reduction of steam soot blowers or water washing
• No erosion or corrosion
• Increased boiler efficiency and availability
• Lower pressure drop
• Reduced fan power
• Lower maintenance and operating cost than steam soot blowers
• Reaches cleaning surfaces that steam soot blowers cannot

Sonic soot cleaning system

The sonic cleaner operates on compressed air of 5bar - 8bar. The sonic cleaner normally operates for 2s-5s with a cycle time of 1min-5min. There are nine sizes of sonic cleaners. The diameter of the attachment socket ranges from 0.3m to 1.5m and the length ranges from 2.5m to 6m. Infrafone can always help to make an estimation of the size needed for a certain boiler and application.

Sonic cleaning system air consumption

The air consumption of the sonic cleaning system varies with sonic cleaner size and how frequently the unit is in operation. Smaller units consume approximately 20Nm³/h - 50Nm³/h, while the larger units consume approximately 40Nm³/h – 100Nm³/h.

Soot cleaning system for bio, garbage or black liquor-fired boilers

Infrafone’s soot cleaning system is applicable in the following boiler components:

• Economizers
• Air pre-heaters
• Catalyst reactors
• Ducts / goose necks
• Electrostatic precipitators

Soot cleaning system acoustic modelling

Infrafone makes detailed acoustic models for soot cleaning system applications based on the boiler characteristics. By acoustic modelling, the optimum sonic cleaner size, location and sound frequency is determined in order to focus the sound to the area where the highest cleaning effect is desired. An acoustic model can be verified by sound measurements.

Low-frequency sonic soot cleaners

Infrafone sonic cleaners operate at low frequencies of 15Hz – 30Hz, which are below or just above the hearing range of the human ear. By adding sound to a gas flow, the particles in the gas will start to oscillate and turbulence is increased, thus preventing soot from settling and building up.

Low-frequency sound has several advantages when it comes to soot removal, including the following:

• Provides greater displacement amplitude of the oscillating gas particles than high-frequency sound
• Low absorption
• Long wave length – covers the complete area to be cleaned, meaning only one sonic cleaner is generally required for economizer cleaning
• Spreads in all directions and reaches areas that may not be accessible by traditional steam soot blowers

Sonic soot cleaning system parts and maintenance

The sonic soot cleaning system spare-part consumption is low due to few components and a simple design – the spring and piston are the only moving parts. The maintenance procedure, which is recommended every three months, is easy and takes only one hour. In order to achieve long-term customer satisfaction, Infrafone offers both single visits and long-term service contracts.

Low-vibration sonic cleaners

There are very few installations of the sonic cleaning system that has encountered vibration problems as the heavy design of the sonic cleaner is usually enough to eliminate them. For installations demanding high acoustic power, the sonic cleaners are always equipped with vibration dampers, which successfully reduce mechanical vibrations by 80%-90%.

Infrafone guarantees that the daily noise exposure, defined in international standards ISO1999:1990, will not exceed 85dBA. This complies with the noise directive of the European Union, Directive 2003/10/EC.

Sonic cleaning system installation

The installation location of the sonic cleaning system is determined by considering results of the acoustic modelling and spatial possibilities. A hole is cut in the boiler wall and the attachment socket is welded to it, a process that takes no more than four hours. The attachment socket is blinded if remaining parts are to be mounted later on.