Mist eliminators are designed to remove entrained liquid droplets from the gas streams such as oil mist during manufacturing or industrial process. Removal of contaminants will assist with recovery of valuable products, improve emissions, and protect downstream equipment. In this blog, we will discuss the basic similarities of vanes and mist eliminator mesh pads.
Both vane mist eliminators and mesh mist eliminators operate using the same principle of impaction to capture the droplets. As the droplets contact the filaments in a mesh pad or the surfaces of a vane, they will gather to form larger droplets and then drain with gravity. One of the primary differences between mesh pad mist eliminators and vanes is the ability to filter different size droplets. Vanes only work well for larger droplets and work well in high liquid loading situations as opposed to mesh pads that works for smaller droplets.
Vane mist eliminators are also known as chevrons. Typically, they consist of stainless steel, carbon steel, alloy steel, and sometimes plastic. They are constructed of various blades that are spaced to create difficult paths for the gas to follow. Vanes are used in columns, evaporators, and other vessels such as cooling towers, distillation towers. The blades can be smooth or hooked depending on the custom design. With each curve on the blade, the gas flow is forced to change direction, also known as “passes”. Vanes can be vertical or horizontal and are typically are round or rectangular.
Vanes can be custom made and offer high filtering and separating efficiency, long service life, they are resistant to fouling and offer low pressure drop. Unlike mesh mist eliminators, vane mist eliminators are not as efficient at collecting very fine droplets and are not effective for droplets smaller than 20mm in diameter, therefore, a mesh pad mist eliminator can be considered.
Mesh pads are made up of a collection of filaments. Much like vanes, mesh pads mist eliminators utilize inertial impaction to separate the gasses and can operate horizontally or vertically. As the gas rises within the mist at a certain speed, it will pass through the mist eliminator and collide with the different surfaces and strands of filaments through inertia. Fine droplets will collect to form larger droplets at which point, they separate from the gas, they will then fall with gravity from the pad. Typically, mesh pads are more economical than vanes.
