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An integrated model was developed to investigate the effect of temperature on the particle re-entrainment in a high-temperature electrostatic precipitator (ESP). The numerical model considered the electric field, flow field, particle migration, and particle re-suspension due to the rupture of static equilibrium. The electric and flow field distributions at different temperatures were investigated. The minimum critical shear velocity needed to detach high-temperature deposited particles from the plate surface was calculated and discussed. On these basis, five types of ESPs with collection plates of different configurations were compared. The results show that high temperatures will exacerbate particle re-entrainment caused by airflow scouring and electrostatic lifting by enhancing the ionic wind and reducing particle resistivity. The hole-type plate may be a better plate form to reduce re-entrainment in the high-temperature ESPs, as it creates a low velocity, low electric field region in the near-plate region. [Display omitted] • A modified high-temperature ESP model involving particle re-entrainment was developed • The effect of temperature on the electric and flow field was investigated numerically. • The effect of temperature on the particle re-entrainment was evaluated. • The effectiveness of different types of collection electrodes in reducing particle re-entrainment was evaluated. [ABSTRACT FROM AUTHOR]

• A modified ESP model suitable for high temperature gas was established. • The effect of temperature on ESP performance was investigated numerically. • An optimized ESP with assistant electrodes was developed and compared with the conventional ESP. High-temperature electrostatic precipitators (ESPs) are a potentially effective technology for purifying high-temperature gases. In this study, a comprehensive numerical model was developed to investigate the electric field and particle migration characteristics of an ESP at temperatures ranging from 400 to 600 °C. Moreover, an optimized ESP with assistant electrodes for improved high-temperature particle capture was proposed. The electric field, flow field and particle capture characteristics of the two types of ESPs were compared to demonstrate the superiority of the optimized ESP. Results indicated that high temperatures had a negative impact on ESP performance. As the temperature increased, the operating voltage of the ESP decreased, leading to decreases in both the electric field strength and space charge density. The effective migration velocity of the particles also decreased with increasing temperature, and the inhibitory effect of high temperature on particle capture increased with increasing particle size. The optimized ESP with assistant electrodes exhibited more favorable electric field and flow field characteristics for particle capture compared to those of the conventional ESP. The optimized ESP exhibited higher electric field strength, which increased the electric field force on the particles and promoted particle capture. Meanwhile, the space charge density of the optimized ESP was lower, effectively inhibiting the occurrence of back corona. Moreover, the optimized ESP enhanced the ionic wind downstream of the discharge electrode, thereby promoting particle migration towards the collection electrode. Consequently, the ESP with assistant electrodes effectively improved the collection efficiency. [ABSTRACT FROM AUTHOR]

In this study, a numerical model of an electrostatic precipitator (ESP) suitable for high-temperature flue gas was established using COMSOL Multiphysics, and the effects of temperature and H 2 O concentration on the high-temperature ESP performance were studied. The results showed that, at the same voltage, increasing the temperature increased the negative ion density, thereby improving the particle charge and collection efficiency. However, increasing the temperature led to a decrease in the maximum operating voltage of the ESP, which reduced the negative ion density and electric field intensity at the maximum operating voltage and weakened the diffusion and field charges of the particles, leading to a further decrease in the maximum collection efficiency. Increasing the H 2 O concentration in the flue gas increased the negative ion density and, thus, enhanced the diffusion charge of the particles, which helped improve the collection efficiency. [Display omitted] • A modified ESP model suitable for high temperature gas was established. • The plasma model was used to simulate corona discharges in the ESP. • The effect of temperature on ESP performance was studied numerically. • The effect of H 2 O concentration in flue gas on ESP performance was studied. [ABSTRACT FROM AUTHOR]