Theoretical and experimental studies on characterization and collection of particulate matter in single-wire, single-stage electrostatic precipitator with square cross-section.

Abstract

Electrostatic precipitation (ESP) is a technology widely used to remove particulate matter (PM) from industrial gas streams. To adopt the same for varying scales as well as for different clean air delivery applications as in indoor and outdoor air pollution, there exists a requirement for the development of comprehensive, readily adaptable, reasonably good, comparable, rigorous, step-by-step analytical theory and experimental validation of same for design of modular units of ESP. In this regard, the current study conducted theoretical and experimental studies to investigate corona characterization and PM collection efficiency in a modular unit of a single-wire, single-stage, wire-plate ESP with square cross-sectional geometry. The best agreement between the I-V characteristics of theory and the experiment was obtained while adjusting the inception electric field to 12.35 × 10⁵ Vm^-1 as well as the ion diffusion coefficient value to to 0.0647 × 10^-4 m²s^-1. Tuned theory predicted PM collection efficiency at three different flow rates of 30, 50, and 100 LPM and at various potentials 9, 11, and 13 kV, respectively. Comparing the predicted results from theory and experiment, it is understood that agreement between theory and experiment is acceptable in the case of varied flow rates and is good for potentials for varied size ranges from 13 nm to 800 nm. As accuracy and reliability of present model are verified in terms of collecting efficiency at different operating conditions of flow rate as well as potential, present model can facilitate the design and scale-up of ESPs for indoor PM control with high collection efficiency. The study also illustrated a sample calculation on the applicability of this filter-less technology for air cleaning in an indoor environment.Implications: Although corona modelling is a classical subject with much work already available, only a few studies focus on single-stage ESP where charging and collection happen simultaneously. In this regard, a comprehensive, readily adaptable, reasonably good, comparable, rigorous, step-by-step analytical theory that integrates particle charging and collection was developed. Different experiments were performed to validate the model. Comparing the predicted results from theory and experiment, it is understood that agreement between theory and experiment is acceptable in the case of varied flow rates and is good for potentials for varied size ranges from PM sizes 13 nm to 800 nm.