Theoretical and experimental investigation of a pulsed ESP

The superiority of hybrid pulsed-power/direct-voltage precipitators over conventional designs is now well accepted. In order to maximise the collection efficiency of these devices, a better knowledge of the free-ion charge density and the variation of the inter-electrode electric field is needed. This paper presents the results of an experimental investigation and a theoretical simulation of negative corona discharge in air, under the application of pulsed energisation to a bench-scale coaxial electrode configuration. The construction of the experimental apparatus developed for the present study is described. Corona space charge injection and collection are quantitatively investigated under controlled operating conditions of applied voltage magnitude and frequency. The experimental results obtained are used to verify a new corona model that provides quantitative information regarding corona space charge magnitude and collection time, and can account for the effect of electrode dimensions. The model also quantifies the interdependence of corona discharge parameters including the magnitude of direct and impulse voltage components, impulse frequency and space charge and electric field distributions. This yields the magnitude of important parameters such as the frequency of applied voltage for maximum collection, and the minimum direct voltage level required to prevent corona ions from flowing back to the corona wire.