Investigation of the Relationship between Droplet and Fine Particle Emissions during the Limestone–Gypsum Wet Flue Gas Desulfurization Process

Slurry droplets containing fine particles are entrained out of the scrubber during the wet flue gas desulfurization process, resulting in adverse impacts on the environment and human health. The characteristics of droplets and fine particles generated and entrained out of the scrubber were analyzed with an experimental system. The effects of desulfurization operating parameters and slurry properties on the droplet and fine particle emissions were investigated. The numerical calculation analysis indicated that the sprayed droplet size was slightly decreased after contact with high-temperature gas. The experimental results showed that the sizes of droplets and fine particles entrained out of the scrubber were closely related to the sprayed droplets in the scrubber. The sizes of droplets after desulfurization were mainly less than 30 μm. Meanwhile, the corresponding fine particles were mainly in the sub-micrometer range. As a result of the increases in the superficial gas velocity, gas–liquid ratio, and desulfurization slurry concentration and the decrease in the gypsum size distribution in the desulfurization slurry, the count percentages of micrometer droplets and number concentrations of corresponding fine particles increased. Consequently, the optimization of operating parameters and desulfurization slurry is a feasible method to reduce the emission of droplets and fine particles.