Recent methods for aerosol removal in ammonia-based flue gas desulfurization

Aerosol removal is a relatively systematic process. Firstly, it is necessary to prevent the formation of aerosols by maintaining a low pH value, thereby avoiding direct contact between ammonia gas and sulfur dioxide that could lead to the formation of aerosols. At the same time, an adequate liquid-to-gas ratio must be maintained to ensure effective desulfurization. If the desulfurization effect is poor, it will inevitably result in a large amount of aerosols. At present, most desulfurization plants use multi-stage demisting systems (in most cases, the demisting height is greater than the absorption height); they generally involve washing processes (at one or two stages, or even multiple stages) to remove gas-liquid entrainment, and then other types of demisters are used in combination to eliminate aerosols – the approach is more or less the same across all such systems. At present, aerosol control in ultra-low emission projects is quite good; dust levels in specific areas can be kept at 5 mg/m3, and this dust consists mainly of soluble salts (aerosols), which indicates an effective removal of aerosols.