The Basics of a Fiber Bed Filter
Fiber bed mist eliminators capture, collect, and remove liquid particle mists, sub-micron particles and harmful aerosols that cause pollution in the atmosphere. This pollution can take form as opacity, smoke, and blue haze. The pollution that is caused by mist is a product of operations of chemical and industrial processes such as, asphalt processing, acid mist control, Lube oil vents & reservoirs, metalworking (oil mist), precious metal recovery and many other applications.
The definition of mist is fine liquid droplets from submicron size to about 10 μm.
Fiber bed filters are used to remove the mist. Also known as candle filters, they assist with lowering atmospheric emissions. Fiber bed mist eliminators separate mist from a gas stream in the recovery process, which will improve emissions, protect downstream equipment, and maintain purity. These mist eliminators are highly adaptable and are custom designed for specific applications.
Candle filters are used to trap, collect and remove liquids and soluble particulate matter suspended in a gas stream. Liquid then drains from the filters and leaves the system through a drain located in the sump. The clean air will then exit to the atmosphere.
They are typically cylindrical elements where the “bed” is composed of fine fibers of media consisting of various grades and densities. The media is packed between two cylindrical screens. Various sheets of fiber bed media are supported by outer cages, inner cages and flanges constructed of carbon steel to corrosion resistant alloys and polymer materials. Sometimes the design will include a pre-filter. They can range from 1 ft to 20 plus ft in height, depending on the specific requirements.
Mist laden gas pass through the wall of the filters and gas that has been cleaned exits from the opposite side. As the particles try to pass through the fiber bed filters, they are trapped and held by the fibers. Methods of collection are known as inertial impaction, direct interception and diffusion. Larger particles are collected by inertial methods, where droplets will travel powered by inertia and then impact onto the media of the filter. When traveling at a lower momentum, the droplets will be intercepted by the filter media called interception. Brownian diffusion is when sub-micron particles that contain very little mass simply follow the airstream and as the air cools they randomly gather until they form larger droplets that will be impacted or intercepted.
Candle filters are economically efficient in comparison to other filtration options. Fiber bed mist eliminators have a long filter life and are custom designed. They can be repacked making them a very cost-effective solution. Fiber bed filters have a high removal performance efficiency rate, as high as 99.9 %.
Kimre has been a leader in mist elimination for more than 45 years. We design, engineer, manufacture and test each filter in house. Visit kimre.com for more information.