Influence factors and mechanism of typical slurry ions and operating conditions on SO3 scrubbing characteristics in simulated desulfurized flue gas of coal-fired power plants

Abstract

The unconventional pollutant SO3 in coal-fired flue gas is closely related to the formation of condensable particulate matter, which seriously harms human health and aggravates environmental pollution. In this study, the isopropanol method was used to absorb SO3 in the simulated desulfurized flue gas, and the concentration of SO42− was detected by the thorium-barium titration method. Combined with the experimental results, the SO3 scrubbing model was used to analyze the influence mechanism of typical slurry ions on the scrubbing and removal characteristics of SO3 in the simulated desulfurized flue gas, and the effects of flue gas conditions and slurry temperature on the desulfurization slurry scrubbing SO3 were also explored. The results showed that the SO3 scrubbing efficiency of deionized water was the lowest overall, the scrubbing effects of Ca2+ and Mg2+ solution were close to that of deionized water, the hydrolysis of Fe3+ and Al3+ to form Fe(OH)3 and Al(OH)3 promoted the scrubbing of SO3, the adsorption of fluorine-aluminum complexes can promote the scrubbing of SO3 in a short time, the ionization and hydrolysis of NH4+ can improve the scrubbing of SO3, various alkaline substances corresponding to multivalent manganese ions can also promote the scrubbing of SO3 and achieve the similar lasting scrubbing effect of NH4+ and Al3+, the increase of NH3 and NO concentration can promote the scrubbing of SO3 with limestone slurry, while the increase of SO2 concentration and the slurry temperature can inhibit the scrubbing of SO3.