During manufacturing and production operations, mist may form from mechanical, cooling, or reaction methods. In the case of cooling, a gas flow may develop mist droplets when the cooled gasses condense and form a vapor. The gaseous particles can create environmental hazards when emitted as stack plumes from vents, or process hazards when carried over to next unit operations.
To eliminate the mist from forming in the gas flow, mist elimination devices are put into place to improve air quality, or to remove droplets from being carried over to downstream unit.
Mist elimination is a method that helps to remove the mist from the gas flow to prevent the particles from being emitted with the exhausted gasses. To remove the mist, the gas is directed towards a barrier that has an opening to allow the gas to flow unimpeded.
As the mist reaches the barrier, it hits into the wall and forms into a liquid film. Depending on the size of the mist droplets, the liquid film will form and collect there until the droplets become large enough to run down the barrier wall to be drained away. Meanwhile, the gas continues to flow around the wall and to the outside.
Lechler mist eliminators are made as a baffle vane separator design. This curved design allows for primary separation and secondary separation of the mist particles from the gas flow. For the primary separation, droplets larger than the limit droplet diameter, such as bigger than three microns, become trapped as the liquid film. The secondary separation method captures mist particles that are smaller than the limit droplet size.
There are two designs to mist eliminators: horizontal separation vanes and vertical separation vanes. The horizontal separation vanes are typically used for when the gas flow moves horizontally. The vanes are placed vertically as gravity is used to move the collected liquid mist film downward. The shape of the baffle vane maximizes liquid film collection without reducing gas flow pressure.
Vertical separation vanes are used when the gas flow travels upward. The baffle vane is placed horizontally or at a horizontal angle that points slightly downward. The liquid film collected from the mist travels down in the opposite direction of the upward-moving gas. These types of vanes are suitable when dealing with larger droplet sizes that won't go back into the gas flowing past the collected particles.
Lechler mist eliminators may be used in any process or equipment where you want to separate generated mist from moving gas. The mist may contain particles such as oil, chemicals, or other unwanted particles. Some common applications for these devices may include knock-out drums, steam drying, process vessels, jet exhaust engines, compressor feeds, scrubbers, separators, distillation columns, and natural gas/flue gas cleaning.
When exhausted gas carries particles such as oils or chemicals, these particles simply do not evaporate or fade away once leaving processes. Instead, the droplets will collect and fall downward where they will adhere to the nearest object. These particles can worsen air quality when breathed in by factory workers or by the public when the gas is exhausted out of the facility.
Mist elimination improves air quality by acting as a filter to strain the particles from the mist. It cleans out the gas flow so that the particles do not enter the environment. To learn more about Lechler mist eliminators, contact us today.