Fabric Filters: Uses and Advantages
When it comes to cleaning industrial gases of particulate matter, filtration is one of the most efficient and versatile techniques ever discovered. The process primarily relies on filter fabrics, also known as baghouse filters, compact filters or sleeve filters, among many other names, is made of either felted or woven material.
Filter fabrics come in a unit that includes a gas inlet and outlet connections, a dust collection hopper, and a system that gets rid of the collected dust periodically. When gas passes through the fabric, dust can be trapped by way of different mechanisms, the most common of which are direct interception, diffusion and inertial impaction.
Fabric Filter Advantages
Fabric filters offer a lot of advantages, including:
> Up to 99.9+% collection efficiency and with more variations in particle size and inlet grain loadings Under certain limits, fabric collectors can maintain static pressure and efficiency for more particle concentrations and sizes compared to other alternatives.
> Collection efficiency is unaffected by the combustion fuel’s sulfur content, as in ESPs
> Works with wider particle size distribution
> No voltage requirements
> Filters flammable dust
> Capable of sub-micron smoke and fume removal with the help of special fibers or filter aids
> Come in a whole range of configurations, inlet/outlet locations and sizes
Types of Fabric Materials
The two main materials used to make fabric filters include tissue and felt. Tissue, a two-dimensional network that may be woven in different ways, can have varied levels of pliability and permeability. In addition, tissue properties are also dependent on the individual properties of the fibre or thread, the surface treatment and the coating. Tissue’s filter qualities are largely determined by the dust cake that gathers on the filter.
Felt is a three-dimensional network of fibers, making it more effective as a filter. With felt’s higher mechanical strength compared to tissue, high fabric loading can be done while a small filer installation is adequate.
Aromatic polyamide and glass fibre are two examples of basic materials used to make filter fabrics in gas applications, each having their own unique pros and cons in relation to chemical resistance, temperature, mechanical strength and cost.
Fabric filters come in handy for many different processes, and with the right filter material, limitations can be conquered. This method absorbs dioxins or gets rid of acid components when activated carbon or lime, respectively, is injected into the fume channel. Through catalytic fabric filters, dioxins can be removed as well.
Today, there are man industries where the use of fabric filters is prevalent, ranging from metal processing to cattle-feed.