Wet air scrubbers: common reasons for using and problems

What is the lowest cost method of removing the particulate to an allowable emission level? Wet scrubbing usually provides high removal efficiencies as the dust particles are captured in the water droplets. When this happens, the particle size increases, thereby making it easier to remove the dust. A smaller dust particle would be surrounded by a larger water droplet. The combined dust particle and water droplet are then removed from the airstream together. Scrubbing systems are a diverse group of air pollution control devices that can be used to remove particles and/or gases from industrial exhaust streams. Traditionally, wet scrubbers have referred to air pollution control devices that used liquid to “scrub” unwanted pollutants from a gas stream. Nowadays scrubbers are also used to describe systems that inject a dry reagent or slurry into a dirty exhaust stream to “scrub out” acid gases. Scrubbers are one of the primary devices that control gaseous emissions, especially acid gases. Wet scrubbers can be classified by pressure drop as follows:

  • low-energy scrubbers have pressure drops of less than 12,7 cm of water
  • medium-energy scrubbers have pressure drops between 12,7 and 38,1 cm of water
  • high-energy scrubbers have pressure drops greater than 38,1 cm of water

Wet air scrubbers: common reasons for using and problemsScrubbers are commonly thought of as being too expensive. However, in fact, scrubbers themselves are very simple devices and are often the least expensive and most reliable device for removal of particulate from a gas stream. The long-term capital and operating costs for any separation device is a dependent evaluation. In the case of wet air scrubbers, the cost analysis is often dependent upon the availability of water and the infrastructure for waste treatment or disposal. There are several common process reasons for using scrubbers for particulate separation are:

  • wet scrubbers are simple to build and operate
  • wet air scrubbing is the most efficient way to cool high-temperature process gases for air treatment is by quenching with water
  • wet scrubbers may be more compact than other industrial tools
  • gaseous and particulate contaminants may be collected in the same device
  • wet scrubbers may be the safest way of hounding potentially explosive, pyrophoric, or combustible dust
  • wet air scrubbers can operate reliably on sticky or highly hygroscopic materials

All wet air scrubbers incorporate mist eliminators or entrainment separators to remove entrained droplets. The process of contacting the gas and liquid streams results in entrained droplets, which contain the contaminants or particulate matter. The most common mist eliminators are chevrons, mesh pads, and cyclones. Chevrons are simply zigzag baffles that cause the gas stream to turn it passes through the mist eliminator. Mesh pads are made from interlaced fibers that serve as the collection area. A cyclone is typically used for the small droplets generated in a venturi scrubber. The gas stream exiting the venturi enters the bottom of a vertical cylinder tangentially. The droplets are removed by centrifugal force as the gas stream spirals upward to the outlet.

Wet air scrubbers are susceptible to several operating problems. The most common of these include inadequate liquid flow, liquid re-entrainment, poor gas-liquid contact, corrosion, and plugged nozzles, beds, or mist eliminators.

Multi-vortex wet air scrubber is a new type of wet air scrubber that is devoid of many wet air scrubbers’ drawbacks while operating at the same efficiency. Multi-vortex wet air scrubber can replace any wet air scrubber as a whole, and in some cases, we can use old scrubber – primarily it’s body – as a basis for a Multi-vortex wet air scrubber system. Being a new type of wet scrubber, Multi-vortex wet air scrubber cleans air from gases, dust, vapors and other admixtures using water or other cleaning liquid. Multi-vortex wet air scrubber produces the cleaning mist differently from other scrubber systems, which results in running costs that are much lower than for a common wet scrubber.

If you would like to purchase Multi-vortex wet air scrubber, please contact us at info@optromix.com

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