A new testing facility to characterize ESD hazards in industrial baghouse filters

Abstract : Baghouse filters are common dust collection systems for pneumatic transport processes involving finely divided powder materials. However, safe use of these systems requires appropriate control of electrostatic charge and discharge phenomena. Numerous parameters may contribute to accidental inflammation due to uncontrolled ESDs. This is the reason why the experimental approach keeps the best way to investigate these complex hazards. The facility has been instrumented to measure appropriate electrostatic fields, and charge patterns within the filter cabinet according to operating conditions and to the type of filtering bags mounted. Preliminary results obtained in experiments illustrate how severe electrostatic charging and electrostatic accumulation can be in such a dynamic process involving finely divided powder material. It shows that worse electrostatic cases require high velocity and moderate powder concentration. Preliminary results also show that electrostatic potentials rise nearly instantaneously to their maximum and drop as soon as powder material runs out. The on-going testing program as well as future research opportunities offered by the new facility will permit to test other powders and bags in order to build a safety electrostatic concept for baghouse filters.