Electrostatic precipitation as a method to control the emissions of particulate matter from small-scale combustion units

Abstract

The aim of this study was to investigate the use of an electrostatic precipitator (ESP) for controlling the emissions of particulate matter (PM) from small-scale heating units, specifically boilers that combust solid fuel with a heating power output of <300 kW. The equilibrium between the required precipitation efficiency and the structural parameters of the ESP in combination with the applied voltage were determined. This study presents a method of optimising the applied voltage alongside the specific ESP structural parameters while retaining the required precipitation efficiency. The ESP was designed, optimised, and integrated into a 15-kW boiler without expanding its volume. The theoretically predicted voltages and resulting ESP efficiency (20 kV and 85% respectively) were verified by measuring the reduction in the particle number concentration. The measurements were based on different principles and simultaneously sampled. The PM concentrations were reduced below 40 mg/m(3) (0 degrees C, 101.3 kPa; at reference O-2 =10 %(vol)(.)) by nominal and reducing the heat power, which allowed the boiler to meet the requirements of the EU's Ecodesign Directive. The presented optimisation method can be used in the practical engineering of any type of ESP.