Dealing Acoustically With Boiler Corrosion
Corrosion is one of the main causes of reduced reliability in steam generating systems and the industry in general pays a heavy price for this problem of boiler system corrosion.
The majority of corrosion problems occur in the hottest areas of the boiler- the water wall, screen, and superheater tubes as well as in economizers, de-aerators and feedwater heaters.
The most common causes of corrosion are dissolved gases (primarily oxygen and carbon dioxide), under-deposit attack, low pH, and attack of areas weakened by mechanical stress, leading to stress and fatigue cracking.
One way to reduce mechanical stress is to remove any existing steam soot blowers which were installed to try and remove boiler fouling and slagging and replace them with acoustic cleaners - aka 'sonic soot blowers'. This is an interesting page worth reading about the mechanisms of steam soot blower erosion.
Steam soot blowers employ high pressure superheated steam and air every 8 hours or so to try and dislodge sintered-on ash covering the tube banks.
Sonic soot blowers, on the other hand, use powerful but totally non-destructive sonic sound waves for a few seconds every few minutes. These sound waves reach every exposed surface, exciting the ash and thus debonding it into the gas stream.
Acoustic cleaning boiler application
Also worth noting is that sonic soot blowers operate at totally safe sound frequencies in the range of 350 Hz down to 60 Hz which are way above the mechanical resonating frequencies of steel. The result? Effective, ongoing particulate de-bonding with absolutely no risk of causing mechanical stress. Surely a Win-Win result!
- Tags: acoustic cleaning