Use of membrane collectors in electrostatic precipitators

Membrane collection surfaces, developed and patented by researchers at Ohio University, were used to replace steel plates in a dry electrostatic preci pitator (ESP). Such replacement facilitates tension-based rapping, which sh ears the adhered particle layer from the collector surface more effectively than hammer-based rapping. Tests were performed to measure the collection efficiency of the membranes and to quantify the potential improvements of t his novel cleaning technique with respect to re-entrainment. Results indica te that even semiconductor materials (e.g., carbon fibers) collect ash near ly as efficiently as steel plates, potentially indicating that collection s urface resistivity is primarily dictated by the accumulated ash layer and n ot by the underlying plate conductivity. In addition, virtually all sheared particles separated from the collecting membranes fell within the boundary layer of the membrane, indicating extremely low potential for re-entrainme nt.