🔹 Design: Since many asphalt plants are portable, dust collection systems must also be rugged and easy to transport. The compactness of the design and ease of maintenance are all key considerations.

🔹 Filter Media: Asphalt production involves high temperatures. The baghouse installed on the dryer end of the system must be able to handle continuous operating temperatures up to 375°F (190°C) — and sometimes even higher during spikes.

For this reason, aramid filter media (commonly known by the trade name Nomex®) is the go-to choice. It’s a heat-resistant material that performs well under the high-temperature, high-dust conditions of asphalt operations.

To improve performance in space-constrained systems, pleated filter elements made with aramid media are gaining popularity. These offer increased surface area in the same or smaller footprint, which helps overcome the limitations of older, compact baghouse designs. However, pleated filters come with some temperature limitations and should be used where appropriate.

If you choose membrane-coated bags to cut down emissions, be warned—hydrocarbon contamination from the mix or burner can blind those bags fast.

Knockout boxes or cyclones reduce dust loading on the bags and help stabilize pressure drop, which makes the whole system easier to maintain and run.

🔹 Dust Cake and Precleaners: A good cyclone can pull out 80–90% of large aggregate dust before it ever hits the bags. This helps build a healthy dust cake and cuts wear on the filters. We also sometimes install knockout boxes or cyclones when space or volume demands. These reduce dust loading on the bags and help stabilize pressure drop, which makes the whole system easier to maintain and run.

🔹 Fan Sizing and Air-to-Cloth Ratio: Too many asphalt plants are still running baghouses with poor air-to-cloth ratios—sometimes 5:1 or more—which leads to overloaded filters and early failure. Can velocity and fan performance need to be dialed in carefully to avoid high differential pressure (DP) and re-entrainment. We recommend staying between 3.5–4.5:1 for most applications.

🔹 Cleaning System: It’s almost always pulse-jet cleaning in the asphalt world. Most systems run at 60–70 psi, which is usually enough. Cranking it up to 90–100 psi often just shreds bags faster without actually solving the problem.

Your cleaning should be on-demand with a magnehelic or photohelic set to trigger between 3–5 inches W.C. Don’t space out cleaning pulses too far apart—if you wait too long between row cleanings, air takes the easiest path and some bags end up doing all the work.

Conveyor belts are used to move a large amount of material between different parts of the asphalt plant

🔹 Discharge System: Reusing the dust you collect (as we talked about in the previous articles) makes the whole operation more profitable. To handle the bulk material collected, you need one of the following options:

• ✧ Rotary Airlocks, especially for coarse or abrasive dust. 
• ✧ Slide gates are cheap and simple, but they’re prone to leaking and jamming.
• ✧ Conveying Systems: Screw conveyors are standard, but some plants are now implementing conveyor belts or even pneumatic systems for faster, cleaner transfers.