Explosion-proof industrial baghouse for dust collection systems

The design process started with visiting the customer’s production facility and determining the essential requirements (the customer could not provide it before the project start). Relying on our expertise in air filtration and purification, we estimated the 32 000 cubic meters per hour air uptake would provide a safe dust collection. 

As a result, a modular Ex-proof design for the 32,000 m3/h (delivered by a radial fan), enclosing packed tubular bag filters (an equivalent to an old F9-class specification), automatically cleaned by pulse-jet technology. The pulse-jet cleaning purges the dust off the fabric bag filters ensuring the filter stays permeable to airflow. 

The baghouse’s Ex-proof protection required following strict techniques and guidelines, as sugar powder is a highly explosive IIIB environment (as per European ATEX compliance for hazardous location protection methods and markings).

As part of the engineering concept development, EnCata’s engineers conducted airflow CFD computer simulations for:

• the pulse-jet cleaning system/process and
• baghouse air filtration performance.

As part of the Ex-proof engineering, all the electrical wires and unit electronics were non-sparking and adopted specific components. A special antistatic coating was cast to the metal surfaces of the unit. 

The electronics comprised a custom PLC commanding the filter’s self-cleaning process. The cleaning process’s PLC logic relied on differential pressure sensors, which reported if filters were contaminated and required cleansing with a jet pulse. A variable frequency drive (VFD) and the pressure sensors work in a feedback loop with the two fans’ filters. The adjustable frequency drive enables power-saving and ensures reliable baghouse performance. 

The bunker design incorporated the rotary valve to facilitate the discharge of the accumulated dust to the beanbags.

Special attention to materials and coatings, modules, and parts conjunctions was paid to guarantee protection from sugar dust explosion. The engineering design incorporated several features:

• Ability to replace tubular bag filters without stopping the unit operation (utilization of dampers at the air inlet).
• The quick-detachable cover allows quick replacement of filter elements. It does not require the dismantling of pneumatic lines.
• Pneumatic hammers were added to the lower part of the bunker. Hammers facilitated the separation of dust stuck to the lower part of the bunker wall, preventing sugar caking;
• PLC software integrated with the plant’s SCADA system.
• An Ex-proof venting membrane (explosion venting panel) design ensured additional safety of the baghouse. The membrane is an extra security measure to ease the flame’s burst pressure from the baghouse if an explosion happens.

The baghouse was produced and assembled in-house, and multiple tests were performed before shipping the unit in modules to the customer. The filter system was installed and commissioned at the factory.