An experimental investigation of electrostatic precipitation in a wire–cylinder configuration at high temperatures

Abstract

High-temperature electrostatic precipitation is a potentially convenient method for hot gas clean-up. This paper reports the characteristics of electrostatic precipitation in a wire–cylinder configuration for a temperature range of 350°C to 700°C. Three parameters, i.e., particle collection efficiency, energy consumption index and the outlet mass concentration of particles, are investigated to evaluate the comprehensive performance of an electrostatic precipitator at high temperatures and to propose a method to choose an optimum combination of the operation parameters for different conditions. The collection efficiency can be greater than 0.996 when the gas temperature is 350–700°C and the inlet mass concentration of particles is 200–3600mg/Nm3. When the voltage applied to the two electrodes is high enough (greater than 15,900V in this work), the collection efficiency is hardly influenced by the inlet mass concentrations of particles in the testing range. For example, at 620°C when the applied voltage is 15,925V, the fluctuations of the collection efficiency are within ~0.2% even if the inlet mass concentration increases ~10 times. For a given inlet mass concentration of particles, the collection efficiency increases rapidly as the applied voltage increases from the first stage to the second stage, while the collection efficiency increases slowly as the applied voltage increases from the second stage to the third stage. The relationship between the energy consumption index, the applied voltage and the inlet mass concentration of particles is given by φ=CUp2(Up−Uc)/min. As the temperature increases from 350°C to 700°C, the value of C increases from 1.0×10−5 to 3.2×10−5 and the value of Uc decreases from 20,860 to 12,503. The electric energy consumed by an electrostatic precipitator increases rapidly with the increase in the temperature.