How do baghouse filters remove particulate matter from power-plant emissions?

Baghouse filters are highly efficient devices used in air pollution control to remove particulate matter from power-plant emissions.12

The process functions as follows:
* Filtration: Dust-laden air is blown upward into an enclosure containing an array of long, narrow fabric bags. As the air passes through the fabric, particulates are trapped inside the bags, allowing clean air to exit at the top.1
* Dust Cake Formation: In most systems, the fabric acts as a substrate for a layer of accumulated dust known as a "dust cake." This layer is essential, as it performs the majority of the particle capture. Filters coated with membranes, such as polytetrafluoroethylene, can operate at high efficiency without relying on this cake.1
* Cleaning: To maintain airflow, bags are periodically cleaned by mechanical shaking, reversing airflow, or using short bursts of air. The dislodged dust falls into a hopper for disposal.1

Because these filters create resistance to airflow, they require significant energy for fan systems and often necessitate cooling the exhaust gases before filtration.1