High Temperature Electrical Charger to Reduce Particulate Emissions from Small Biomass-Fired Boilers

Abstract

New particulate matter (PM) filtering technologies are needed to meet the emission regulations for small combustion appliances. In this work, we investigate the performance of a novel electrical particle filtration system, the single needle shielded corona charger (SCC), which offers an advantageous solution for PM control in boilers by enhancing particulate deposition within existing boiler sections. Experiments under different operating conditions of a wood-fired boiler were performed, wherein the SCC was installed upstream of either a condensing heat exchanger (CHX) or a cyclone. PM reduction was found to be strongly affected by the SCC temperature and the following collection surface area, and reached its highest reduction efficiency of >90% at the temperature range of 400–500 °C when operating in combination with a CHX. The SCC–cyclone combination was less efficient, providing a 27% PM reduction, as a result of the low surface area and residence time in the cyclone. These results indicate that the SCC can feasibly provide particle filtration when combined with a CHX, wet scrubber, or a cyclone to meet the new emission regulation requirements. The system is best suited for small-scale boilers but can be scaled up to larger boilers by increasing the number of corona chargers.

Keywords

• particulate emissions
• biomass combustion
• electrical charging