Wet scrubbers: Wet gas filtering and scrubbing

There are several types of scrubbers, each adapted to specific needs:

• Packed Bed Scrubbers:
  In packed bed scrubbers the process is carried out by bringing the contaminated gas stream into contact with a scrubbing absorbent which reacts with the contaminants.
  The gas stream is fed into the base of the tower and rises upwards. There it passes through a bed of absorbent liquid-impregnated materials, where the chemical absorption reactions take place, and then the clean gases exit at the top.
  To optimise contaminant removal efficiency, the contact between the contaminated air and the absorbent liquid should be maximised. To achieve this, beds are used where specially designed filler materials are placed to fill the bed to a given depth. The combination of bed material, thickness, bed speed, chemical composition and amount of washing absorbent combine to achieve the desired results.

• Multi-purpose scrubbers (Emtrol MPS):
  The Emtrol MPS multi-purpose scrubber has a long and successful track record in many industrial applications. The scrubber is capable of effectively cooling gas streams, capturing particulates and absorbing gaseous contaminants in a single package.
  The inlet section, which can include a cooling section to handle gas temperatures up to 1100°C, uses a Venturi throat to capture particles with water droplets and send them to the separator. The separator, or bed, includes a packing section for gas absorption together with a drift eliminator to ensure a clean exhaust stack.
  How it works: When the gas temperature is above 200°C, fresh water is injected into a cooling section to bring the gas to a near-saturated state.  Wash water is then introduced and passed through a Venturi throat where it hits the particles and captures them. This sludge is disposed of in a separator section that includes a water recycling tank.  Once the gas particles have been removed, the gas enters a packed column where the gaseous contaminants are absorbed by a chemical reagent solution that has been sprayed onto the packed column by means of high-pressure spray nozzles. This scrubbing solution is recycled separately to minimise the use of chemicals.  The height and diameter of the packed column are determined according to the pollutants present and the required removal efficiencies.
  Finally, the gas passes through a mesh-type mist eliminator to ensure the removal of free water droplets before leaving the scrubbing tower.

• Venturi Scrubbers:
  Venturi scrubbers are widely used and are the best choice for dust collection when wet and/or sticky gas streams are present, as well as when gaseous contaminants may be present in the gas stream.
  How do they work?
  Contaminated gases enter the scrubber through a Venturi where the solids are impacted with water spray. The micro-droplets of water spray capture the particles by impact, interception and diffusion. Once the water has captured the dust, it is separated with a cyclone separator and discharged into a recycling tank. Part of the liquid accumulated in the tank is continuously purged to limit the concentration of solids in the water and to allow recirculation of water back to the Venturi sprayers. Additionally, the dust-free gases are discharged cleanly from the top of the unit.

All wet scrubbers are designed and manufactured by our strategic partner CECO ENVIRONMENTAL.