Choosing the Best Spray Nozzle
A properly designed Wet Scrubber removes a variety of air contaminants. Wet Packed Bed Scrubbers remove air contaminants and impurities by washing the airstream with a water liquid. Air contaminants are removed by the scrubbing liquid by impaction, reaction with a chemical solution or absorbed into the liquid. Air contaminants and the scrubbing liquid come into contact with other in the packed section of a wet scrubber filled with a high efficiency packing. Spray nozzles will spray small droplets and evenly introduce the scrubbing liquid above the packed bed section, which then flows down through the packing to the bottom of the scrubber sump. A mist eliminator section located above the spray nozzles removes liquid entrained in the cleaned exhaust airstream prior to entering the atmosphere.
Spray nozzles are selected at the lowest possible operating pressure to produce a uniform spray pattern with larger rather than smaller droplets. Any liquid particles that become airborne but do not wet the packing surface defeats the purpose of a scrubber. The function of the spray nozzle is to distribute liquid over the packing, not to test the operation of the mist eliminator. While the mist eliminator will capture the larger airborne droplets, agglomerate them and eventually drain back down to the packing, we do not want 80% of the liquid volume heading to the mist eliminator but instead onto the packing area. Selecting a spray nozzle with a larger particle size without creating a significant amount of smaller droplets than can become airborne and operating at lower operating pressure would be a better choice. In general, spiral spray nozzles should be avoided.
Features & Benefits
Several common spray nozzle types are candidates for use in a wet packed bed scrubber:
- Spiral spray also nozzles (TF and TFXP), also called pigtail nozzles producing a round spray pattern
- Full cone clog resistant nozzles (MP) giving medium to course droplet size
- Full cone whirl nozzles (SC and NC) with course atomization, available in round and square spray patterns
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