Experimental study on strengthening the electrostatic precipitation removal of PM_2.5 and SO₃ by desulfurization wastewater evaporation

In order to study the influence of desulfurization wastewater evaporation (DWE) on the ESP and the desulfurization performance, an experimental setup with DWE and the coal-fired thermal system was established. The removal of PM_2.5 and SO₃ from coal combustion with DWE and the evolution of fine particle size and PM_2.5 and SO₃ concentration at ESP outlet were investigated. Also, the mechanism of PM_2.5 and SO₃ removal was analyzed. The results show that DWE can increase the average size of particles from 0.1 μm to 1.1 μm. Compared SEM image before DWE with that after DWE, the particles reuniting and floc formation between particles are clearly observed. The ESP efficiency is increased by 5%; the removal efficiency of PM_2.5 in number concentration is increased by 25% at the ESP outlet; and the removal efficiency of SO₃ by ESP is 60%-80%. The SO₃ concentration in flue gas has an effect on PM_2.5 and SO₃ removal by ESP. However, the DWE has no effect on the desulfurization efficiency and the pH value of the desulfurization slurry.