Fine particles can suspend in the air over a long period of time

which leads to fog and haze. As one of the main sources of fine particle emission

coal-fired units usually apply electrostatic precipitator(ESP) and wet flue gas desulfurization(WFGD) system to control particle emission. According to the coal and fly ash properties of a 600 MW coal-fired unit

the influence of flue gas conditioning(FGC) on the performance of ESP was experimentally studied

and the removal mechanism of fine particles was also analyzed. Moreover

the particle samples at inlet and outlet of the WFGD system were collected to measure the mass concentration of particles with different diameters. The results show that

the ash particle concentration at outlet of the ESP applying dual FGC was 18 mg/m~3

which was 55 mg/m~3 lower than that not using the FGC. The fly ash resistivity decreased to 1.23×1010 ?·cm after injecting 42.86 mg/m~3 SO3 at the ESP inlet

which was in the effective operating range. After the flue gas passed through the WFGD system

the particle concentration dropped from 18 mg/m~3 to 4.2 mg/m~3 and the particle removal efficiency was 76.67%. However

the fine particle concentration increased by 0.84 mg/m~3

which were mainly fine particles(generating during WFGD process

Ca SO4·2 H2 O) with diameter smaller than 1 μm.