Vane mist eliminators are physical separating devices that work on the principle of inertial impaction. Vanes, sometimes called chevrons, are parallel corrugated sheets held at a fixed distance apart to create a sinuous flow path for mist laden gas. As the mist laden gas flows through the vane, at every change in the direction the droplet tends to move in a straighter line than the bulk of gas. The captured droplets coalesce on the vane, forming larger drops which subsequently trickles down. Depending upon the operating conditions and physical properties of gas & liquid, typical droplet separation ranges from 10 µm to 40 µm.
Souders-Brown equation is still widely used to the determine the appropriate flow velocity for a given system. The Souders-Brown equation is as below:
Typical K values assuming an air-water system at ambient conditions are as below:
The above capacity factors are generalized numbers and derating factor should be applied based on operating and process conditions.
AMACS Plate-Pak™ Vanes are standard design without any pockets or hooks wherein the vane profile create the hydraulic pockets. AMACS’ standard design profile allows for low pressure drop and are predominantly used applications where fouling is a concern. Multiple plate spacings are available which allows to achieve better impaction characteristics for smaller droplets. AMACS Plate-Pak™ Vane can be utilized in both horizontal and vertical flow configurations.
The capacity of standard non-pocketed vanes can be increased by enhancing liquid drainage. Captured liquids are re-entrained when the velocity of the vapor exceeds the ideal/optimum velocity. To prevent liquid re-entrainment, the serpentine path offered by the vane is augmented with obstructions to allow for the pooling of liquid with protection from the passing vapor stream. AMACS pocketed vane blades are configured in such a way as to create pockets that allow droplets entrained in a gas stream to impinge and adhere, and then drain, without being re-entrained. This allows greater liquid capture with less in-pocket turbulence and shearing while reducing the pressure drop. Specific designs are available that can be utilized in both horizontal and vertical flow configuration.