scope:

This guideline series VDI 3679 covers wet separation processes for air pollution control. Wet separators are employed for removing solid, liquid and gaseous pollutants from gas streams. Removal is accomplished by collecting the pollutants on a scrubbing liquid injected into the gas stream from which they are then separated together with the scrubbing liquid. The removal mechanisms involved in the capture of particles and gas molecules differ substantially.

Apart from particle and gas molecule transport and attachment to the scrubbing liquid, wet separators must also provide for subsequent removal of entrained liquid droplets from the gas stream. This process step is carried out in so-called mist eliminators, which are the subject of this guideline. In addition, this guideline describes mist eliminators for other applications involving the removal of liquid pollutants, e.g. in cooling towers, evaporation processes, air conditioning systems including mist eliminators for fine spray or aerosol collection. The latter type of liquid particle collector is employed for droplet sizes in the ultrafine range, i.e. micron range.

VDI 3679 Part 1 focuses on processes for the collection of solid or liquid air pollutants. Wet separators for the removal of gaseous air pollutants are dealt with in VDI 3679 Part 2.

Further guidelines of relevance to particle and/or droplet collection are:

• VDI 3676
• VDI 3677 Part 1
• VDI 3678 Part 1