Rotary kilns have been a boon to construction and industrialization around the world and are key to making some of the most common construction materials such as bricks and concrete. Unfortunately, this comes at a price. Many kilns are extremely ‘dirty,’ polluting the atmosphere with black smoke that contains thick particles as well as large amounts of CO2. This continues to be a significant source of pollution in many areas of the world.
Kiln manufacturers and those providing Kiln services have been constantly looking for ways to improve pollution capture systems and reduce the number of particles escaping into the atmosphere. There are two primary ways of doing this, generally called ‘dry dust removal’ and ‘wet dust removal.’
The Dry Dust Removal Process
Dry dust removal relies on cyclonic force and centrifugal force to capture as much particulate matter as possible. This is the older technology, having been used in some form for roughly a hundred years.
Modern designs utilize multi-tube cyclone collectors, all connected, running parallel to the main shell of the kiln. The escaping dust-filled airflow enters these collectors in sequence, with each one capturing more pollutants, before the mostly cleaned exhaust is allowed to escape.
Dry dust removal systems are also excellent for recapturing lost materials, as these particles can sometimes be recycled as fuel or used for other purposes.
The Wet Dust Removal Process
The newer method for capturing pollutants before they leave an industrial kiln is the ‘wet dust removal’ process. There are several ways of accomplishing this, such as gravity spray scrubbers and foam scrubbers, but the basic theory is the same in all cases: dampen the solid materials so they become sticky and too heavy to escape as part of the exhaust.
Wet dust removal systems are more energy-efficient than dry dust systems, which makes them preferable from an energy-usage standpoint. However, they are not always effective in all cases. Many particulate pollutants, such as SO2, are not very water-soluble, reducing their effectiveness in such cases.
Current research is largely focused on finding ways to improve the wet dust removal process and make it more generally applicable.
Having Difficulty Reducing Pollution? Call Kiln Tech!
For decades, the Kiln Technology Company Company has provided top-quality kiln services, supplies, inspections, repairs, and installations across America. If you are struggling to keep your rotary kiln running properly and within environmental regulations, contact us for Kiln equipment inspection.