Definition of Scrubber
“Scrubber are air pollution control device that use liquid to remove particulate matters or gases from an industrial exhaust or flue gas stream.this atomized liquid entrains particles and pollutant gases in order to effectively wash them out of the gas flow”.
In comparison to other air pollution control devices, scrubber are very multidisciplinary,with the ability to remove solids,mist,and gases simultaneously while also providing cooling.they are also capable of handling explosive and flammable gases safely.however, scrubber suffer from high levels of corrosion and produce slurry waste stream which are less convenient for recycling and disposal.
TYPES OF INDUSTRIAL SCRUBBER
- Wet industrial scrubber
- Dry industrial scrubber
WET INDUSTRIAL SCRUBBER:
One of the most basic of the various industrial scrubber is the wet industrial scrubber. in its most basic form, water is encapsulated in a metal or composite container. contaminated gas is passed through the water, and the water absorbs the contaminates.other liquids can be used to effectively remove varied contaminates. these liquids differ in the chemical composition and the overall charge.these liquid can be anything from highly positively or negatively charged to non-charged.because pollutants can differ in their charge,scrubber can be packed with a liquid that will bind most effectively to remove the contaminate from the gas.
The gas exiting the scrubber is thus cleaner. Development in wet scrubber have allowed for increased efficiency in pollutant removal.one of the major development has been to maximize the total surface of the liquid with which the polluted gas associates.more surface area means that more of the contaminates can be pulled out of the gas.another development in scrubber has been increasing the mixture of the gas with the scrubber fluid.these aspirator agitate the solution and increase the mixing of the polluted gas and the liquid.
The wet scrubber differs from the other different types of industrial scrubber because the liquid-gas association increase the moisture level of the gas that is being expelled from the scrubber.the increase moisture in the gas create a visible cloud existing the scrubber.
DRY INDUSTRIAL SCRUBBER:
Unlike wet industrial scrubber, dry scrubber do not utilize a liquid to absorb contaminants.because of this difference,steam is not produced by the reaction,and a wastewater system is not needed. A dry industrial scrubber is composed of a reaction center where dry reaction material that absorb contaminants is mixed with the polluted gas. also within the system is a material component that aids in the removal of the reaction product, which is the dry reaction bound to the pollutant. dry scrubber are used primarily to remove acid found within gases.
The dry reaction use to remove the acid from the gas is usually made of an alkaline slurry. this slurry is basic in nature and will neutralize the acid found in the gas. this reaction can be mixed with the acid gas in two ways.there are two different types of dry industrial scrubber.the first is called dry reaction injection during this process,the gas is mixed directly with the alkaline reaction.
The second method is the spray dryer absorbent method.in this method,the contaminate gas is processed through a mist of the sorbent. the sprayer allow for a good mixture and efficient removal of the pollutant from the gas.
Electrostatic precipitators function uniquely from the different types of industrial scrubbers by using charged energy to remove dust and other contaminates from a gas.it is important to match the polarity and type of charge to bind to and remove the pollutants from the gas.An example of the design of an electrostatics precipitator is a plate precipitator.
The plate is a sheet of metal that is charged with a specific type of charge.these plates are designed to run parallel with the piping so that the gas will pass through the plates and the plates will remove the dust or contaminate.
In addition to metal plate electrostatic precipitators,there are also wet electrostatic precipitators that help to remove high moisture gases.some of the bound pollutant is rotated away from the electrostatic precipitator to remove the contaminates and maintain an effective charged surface for pollutant removal.
Advantage and disadvantages of scrubber:
- Can handle flammable and explosive dusts with little risk.
- Provides gas absorption and dust collection in a single unit.
- Provides cooling of hot gases.
- High potential for corrosion problem.
- collected particulate contaminated and recyclable.
- Disposal of waste sludge can be very expensive.
- Requires makeup water to replace purged liquid and disposed sludge.
You can read:http://mechmaintenance.com/