This study investigates the efficacy of coal dust removal using a wet-acid-ash experimental platform that incorporates flue-temperature coupling. The acidification–evaporation method was employed to quantify the dust eliminated from the flue gas and examine the particle-size distribution of submicron particles before and after the dust-removal process. These measurements were conducted under various conditions, including acidification, coupled humidification, cooling, and particle-concentration variations. Based on these experimental findings, we examined the aggregation and removal behaviors of submicron fine particulate matter. The temperature of the simulated hot dust-laden flue gas decreased from 120°C to 80°C, while the absolute humidity was adjusted to 8.90%, acidity to 4.183 ppm, and flyash particle concentration to 385.27 μg⸳m. Notably, there was a significant increase in the mean diameter of the volume distribution of submicron fine particles undergoing agglomeration, rising from to 20– 37μm to 51.355μm. After the dust-removal procedure, the effectiveness of the dust collector reached 99.63%, thereby successfully removing submicron fine particles. Furthermore, the mean diameter of the number distribution decreased from 1.769 to 0.869 μm. The experimental results demonstrate that when flue gas is evaporated through a high temperature and coupled with humidity and acid ash, the ability of fly ash particles to adsorb aerosol droplets is enhanced. This enhancement promotes mutual adhesion among the submicron fine particles, intensifying their agglomeration. Consequently, the agglomerated particles are effectively captured by the dust collector, facilitating the removal and reduction of submicron fine particles.