Spare Air
Spare Air San Jose Ca Spare the air day? I live in San Jose, Ca. I just heard on the 11:00 news that tonight is a spare the air day which means I am not allowed to use my fireplace. First offende...
Spare Air
Air Cleaning by Crossflow Wet Scrubbers
Oleg Systems Co. is a designer of industrial airscrubbers for dust / fume collection and air cleaning. Wet type dust collectors / air scrubbers are available in numerous designs utilizing a number of principles and featuring wide variation in effectiveness, initial cost, operating and maintenance expense, space, arrangements and material of construction.
Wet type dust collectors are liquid (usually, but not necessarily, water) to capture and separate particulate matter (dust, mist, and fumes) from a gas stream. Some scrubbers operate by spraying the scrubbing liquid into the contaminated air. Others bubble air through the scrubbing liquid. In addition, many gybrid wet scrubbing designs exist.
Oleg Systems Crossflow Packed Bed Scrubbers are used in environmental control applications which require contaminant gas absorption with or without particle removal, as well as in odor control applications. The process involves a scrubbing liquid flowing vertically through the scrubber mixing chamber perpendicular to the contaminated air stream. The mixing chamber contains packing material which maximizes contact between the two streams, facilitating contaminant absorption of the scrubbing liquid before falling into the collector below.
For applications involving complex contaminants in gas stream Oleg Systems offers crossflow air scrubber configuration with multiple packing bed sections, each designed to capture a particular contaminant. The chemical dosing process of each bed is isolated by incorporating a separate mist eliminator and sump within each section. A multiple bed counter current gas scrubber requires a separate vessel for each bed section to avoid any carry over between sections. High density random packing, in conjunction with mesh pads and mist eleminators can be configured to further prevent mist carry over.
The company also offers crossflow scrubber design incorporating an ionizing section to more effectively eliminate sub-micron and non-polar particulates by charging arriving contaminant molecules before they enter the packed bed sections. The charged particles are attracted to the wetted packing media, greatly increasing absorption and removal.
Countercurrent packed bed air scrubbers involve a downward flowing liquid, either water or chemical solvent, impinging upon an upward flowing contaminated air stream. Contaminants are absorbed by the scrubbing liquid which collects in the sump. This type of wet scrubber is used to achieve gas absorption, with or without particle removal, using the principle of mass transfer. Packing material, as always, is used to maximize the wetted surface contact between the opposing streams.
Particle sizes, which can be controlled by a wet scrubber, range from 0.3 to 50 microns or a bit larger. Wet collectors may be used for the collection of most particulates from industrial process gas streams where economics allow for collection of the material in a wet state.
Because the liquid and gas streams in cross flow air scrubber do not directly impinge upon each other, this design is less suceptible to clogging, thus minimizing the required maintenance. Clossflow wet scrubbers also use less liquid compared to counter current scrubbers and require less pumping capacity. Consequently, clossflow air scrubber energy consumption costs are lower than for comparable counter current scrubber. Horizontal wet scrubbers are ideal for height restricted installations where height is limited, while counter current air scrubbers are suitable for applications where floor space is limited and height is not.
Advantage of wet collectors over dry type dust collectors include:
* Constant operating pressure;
* No secondary dust sources;
* Little spare parts requirements;
* Ability to collect both gases and particulates;
* Ability to handle high temperature and high humidity gas streams, as well as to reduce the possibility of fire or explosion;
* Reasonably small space requirements for air scrubbers;
* Possibility to continuously collect sticky and hygroscopic solids without becoming fouled.
All Canadian Air Systems air scrubbers use the following principles:
- high liquid-to-gas ration;
- intimate contact between the liquid and dust particles, which may be accomplished by formation of large numbers of small liquid droplets or by breaking up the gas flow into many small bubbles that are driven through a bath of scrubbing liquid, to increase the chances that contaminants will be wetted and collected;
- abrupt transition from dry to wet zones to avoid particle buildup where the dry gas enters the collector.
For additional information please refer to http://www.olegsystems.com/inquiry/Index.html.
Oleg Chetchel
Industrial Process Engineer
Oleg Systems Co.
http://www.olegsystems.com/damper/Index.html
http://www.olegsystems.com/scrubber/Index.html
About the Author
Oleg Chetchel
Ventilation Equipment Designer
Tenderall Fan Co.
http://tenderall.com