Types of Wet Air Scrubbers

An overview of types of wet air scrubbers

The primary function of any scrubber is to eliminate undesirable gases and particulates from industrial exhausts prior to their release into the atmosphere. The two main types of scrubbers are wet scrubbers and dry scrubbers. These scrubbers are capable of reducing emissions contributing to smog and acid rain by as much as 90%. Wet scrubbers are effective air pollution control devices for removing particles or gases from industrial exhaust streams. How does a wet scrubber work? The wet scrubber operates by introducing the dirty gas stream with a scrubbing liquid (typically water). Particulates or gases are collected in the scrubbing liquid. Wet scrubbers are the most appropriate air pollution control devices for collecting both particulates and gas in a single system. Compared to other air pollution control systems, scrubbers are quite multidisciplinary. They can remove solids, mists, and gases simultaneously while also providing cooling. These modern air pollution control devices are also capable of handling explosive and flammable gases safely.

An overview of types of wet air scrubbersWet air scrubbers are arranged in such a way that they force the polluted fumes to pass through a wet limestone slurry that traps sulfur particles. These types of scrubbers can be used to control particulate matter less than 10 micrometers as well as inorganic gases such as sulfur dioxide, chromic acid, hydrogen sulfide, ammonia, chlorides, and fluorides. Also, these wet air scrubbers may be used to control volatile organic compounds. The used solvent is subsequently disposed of in an environmentally approved way. Venturi scrubbers are a type of wet scrubber that pushes emission gases through a liquid solution at an increased velocity, which atomizes the scrubbing liquid more effectively to remove pollutants. Condensation scrubbing causes the pollutants to condense to be removed. Most coal-fired power plants with scrubbers use a wet scrubber system. Wet air scrubbers constitute a versatile and cost-effective air pollution control technology that can eliminate more than 99% of airborne particulate matter. Wet scrubbers that remove gaseous pollutants are referred to as absorbers. Good gas-to-liquid contact is essential to obtain high removal efficiencies in absorbers. Various wet scrubbers designs are used to remove gaseous pollutants, with one of the most popular subcategories of wet scrubber known as “packed bed scrubbers”, “packed tower scrubbers”, or “acid gas” (when they are used to control inorganic gases). There are several types of scrubbers:

  • Chemical scrubbers/Gas scrubbers. Effective gas scrubber removal efficiency is achieved by ensuring the appropriate contact time between the gas and the scrubbing liquid occurs. These systems incorporate a scrubbing vessel with a system fan, recycle pump, instrumentation and controls, mist eliminator, and exhaust stack. Packed bed scrubbers include random packing to facilitate gas-to-liquid contact.
  • Particulate scrubbers/Venturi scrubbers. These air pollution control devices can handle gas streams that contain moisture or are high temperature, the overall size of the equipment is typically smaller, and they have the potential to remove pollutant gas at the same time as the particulate.
  • Ammonia scrubbers. Aqueous ammonia solutions have a very high vapor pressure, which prevents plain water from being recycled in a wet, dry, or packed scrubber system. The water is discarded after each pass through the air scrubber.
  • Chlorine scrubbers. Chlorine is a frequent byproduct of many chemical reactions. Efficiency is critical for chlorine scrubbers. Wet chlorine scrubbers may utilize a multi-stage removal approach depending on the initial pollutant loading.
  • Particulate/Dust scrubbers. A liquid (typically water) is injected and entrain particulates from the waste gas stream collecting them in the sump for lockdown. The treated air stream is discharged through the exhaust stack.
  • Sulfuric acid scrubbers. Wet air scrubbers remove pollutants by injecting liquid into the gas stream. In the case of sulfuric acid scrubbers, efficiency is critical. Sulfuric acid gas is highly toxic.

Scroiler™ is a new type of wet air scrubber which has a number of advantages over conventional scrubbers, including being more compact, economical, and eco-friendly than other types of air scrubbers. We have already installed Scroiler™ at the asphalt concrete factory to suppress inert mineral dust. The air treatment consists of two stages there. First, there are bag filters operating at a temperature of 100°-120°C. Second, there is a Scroiler™ system. As a result, the air treatment quality is above 99.9%.

If you would like to purchase Scroiler™, please contact us at info@optromix.com