Baghouse Dust Collection System: Operation, Types, Bag Filters, Efficiency and Choosing

Author: Nikulin V, Head of Engineering

To ensure peak efficiency, the parts are regularly cleaned to eliminate the buildup of contaminants. Various cleaning techniques are used, such as vibration, reverse air and jet pulses, or mechanical strikes, which loosen the particles, causing them to drop into a hopper for collection. The collected pollutants is then removed for disposal or additional treatment. The equipment is widely used in industries such as cement production, metallurgy, chemicals, and more.

Baghouse collectors are categorized based on how they remove particulate matter from the cartridges. The selection of the appropriate type depends on operational conditions, including gas flow volume and the concentration of suspended solids. The main types are as follows:
1. Mechanical Cleaning
These use vibrating or shaking mechanisms to remove pollutants from the pockets. They are easy to operate but are more suitable for airstreams with low concentrations of contaminants.

2. Pulse Jet
These baghouses for dust extraction use compressed air pulses to dislodge particles from the surface of the units. They are highly efficient for handling high loads of particulate matter and are compact, making them ideal for installations with limited space.

3. Reverse Air
This mechanism cleans the elements by reversing the airflow through them. The method is best suited for larger bags and works well with low-pressure drop conditions, making it ideal for high-capacity configurations.

3. Particle Abrasiveness
For highly abrasive contaminants (such as cement powder, slag, and ash), aramid fabric pockets (Nomex, Kevlar) are favored due to their abrasion resistance. In moderately abrasive scenarios, such as coal residue filtration, polyester (PES) cartridges with polyurethane coatings are used. For extremely abrasive particles, like quartz sand, baghouse filters for dust collection with multi-layer fiberglass bags, coated with protective surfaces like PTFE or silicone, are effective.
4. Humidity and Tendency to Stick
Moist dust (such as from biomass combustion) requires fabrics with hydrophobic treatment, like PES with a silicone coating or PTFE. For wet and sticky dust, as found in coal boilers, PPS products, which are resistant to hydrolysis, are employed. In high humidity and temperature conditions, such as in the woodworking industry, materials with a Teflon membrane are commonly applied.
5. Type of Contaminants
For sticky or oily contaminants (e.g., in rubber manufacturing or metalworking), fiberglass elements with a fluorosilicone coating are ideal. In the food industry, where easy cleaning is essential, polyester fabrics with a non-stick coating are used. For toxic gases or fine particles, such as silica dust, a dust collection baghouse with PTFE membrane units or composite textile made from PPS and fiberglass is effective.

Here are some specific examples:
Example 1: Aramid fabric bags are employed in cement kilns, able to withstand temperatures up to 392°F (200°C) and resist the abrasive effects of dust.
Example 2: In chemical production, where acids and alkalis are present at temperatures up to 320°F (160°C), PPS with protective treatment is frequently applied.
Example 3: Coal power plants utilize fiberglass pockets with a PTFE membrane, resistant to high temperatures (up to 500°F) and chemical corrosion.

Selecting the correct bag material minimizes maintenance costs and extends equipment lifespan.

The efficiency of a dust collecting baghouse depends on several factors, including particle size, airstream velocity, the type of cartridge fabric, and system operating parameters such as temperature and humidity.

Particle size is a critical factor. Fine particles (less than 1 micron) are harder to capture and require higher pressure or specialized textile. For example, filters with PTFE or fiberglass membranes can capture particles as small as 0.3 microns with up to 99.9% efficiency.

Airflow velocity also directly affects filtration efficiency. Higher flow velocities reduce the contact time between the gas and the filter surface, leading to lower efficiency. The optimal value for most baghouse dust collection units is 1–2 m/s. Speeds above this reduce capture efficiency.

The material of the components was addressed in the previous section. It is essential because it allows the cleaning process to be tailored to specific pollutants and operating conditions. Temperature and humidity are considered at this stage to prevent particle buildup, clogging, and fabric damage.

Dust concentration in emissions is another important aspect. A higher level of contaminants requires a larger total filtration surface area, which means a larger collector baghouse and more powerful regeneration systems (like pulse-jet cleaning). Regular removal of buildup from the surface through the cleaning mechanism helps maintain maximum efficiency.