Fine particle collection of an electrostatic precipitator in CO2-rich gas conditions for oxy-fuel combustion

The collection of particles in CO₂-enriched environments has long been important for the capture of CO₂ in order to clean gases via oxy-fuel combustion. We here report on the collection characteristics of fine and ultrafine particles using an electrostatic precipitator (ESP) in a CO₂-enriched atmosphere. In order to understand the characteristics of particle collection in CO₂-rich gas mixtures, the ionic properties of a CO₂-enriched atmosphere was also investigated. The electrical mobility of the ions in a CO₂-enriched atmosphere was found to be about 0.56 times that found in a conventional air atmosphere, due to the higher mass of CO₂ gas compared to that of air. The low electrical mobility of ions resulted in a low corona current under CO₂-enriched conditions. The collection efficiency of particles in a CO₂-rich atmosphere for a given power consumption was thus somewhat lower than that found in air, due to the low quantity of particle charging in CO₂-enriched air. At the same time, higher temperatures led to the higher electrical mobility of ions, which resulted in a greater collection efficiency for a given power. The presence of a negative corona also led to a greater collection efficiency of particles in an ESP than that achieved for a positive corona.