Products: Air Pollution Control, Dust Removal
Industry: Cement & Lime
Location: Cape Girardeau, USA

The fabric filter on the kiln & raw mill at Buzzi Unicem USA’s Cape Girardeau plant was past its useful life and Boldrocchi was awarded a turnkey flange-to-flange contract to replace it, along with the filter’s ID fan, emergency / fresh air damper and dust transport system for commissioning in spring 2018. Boldrocchi designed a baghouse that reduces dust emissions to a mere 0.01 lbs per ton of clinker (2 mg/Nm3), well under all regulations.

Fabric Filter

Engineers customized a pulse-jet – high dust model that includes a dust pre-separation section to reduce the amount of dust reaching the 8-meter (26’) long bags.

Among the design considerations to ensure such stringent emissions levels are reached, especially in high dust environments:

  • The bag fixation system should have a double sealing ring at the top to ensure no dust leakage (Boldrocchi uses an in-house developed snap-ring concept);
  • The bag cleaning system should be high efficiency to optimize the compressed air pressure & consumption mitigating the mechanical stress on the bags (Boldrocchi prioritizes online versions);
  • Cleaning accessories should be designed to increase the induced airflow in long bags, such as the ones in this project. This ensures proper cleaning throughout the entire bag length and avoids dust cakes.


Boldrocchi not only engineered and manufactured the fabric filter package, but also installed and commissioned it in 2018.

To learn more about this project, read our article “Optimizing American Performance,” World Cement, May 2018.