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The accumulation of uncollected fly ash from flue gas in post-combustion CO₂ capture processes is a significant concern in current coal-fired power plants due to its potential impact on the performance of CO₂ absorbent and absorption towers. In order to determine the effect of fly ash on the mass transfer performance of CO₂ absorption into monoethanolamine (MEA) and diethanolamine (DEA) aqueous solutions, experimental studies were carried out using a small-sized packed tower equipped with θ-ring random packing. These studies were conducted under various operating parameters, including solution temperature, liquid/gas ratio (L/G), packing height, and fly ash concentration. The results show that the effect of fly ash on the outlet CO₂ concentration was primarily observed during the initial stages of the experimental process. Moreover, the presence of fly ash leads to a reduction in the volumetric overall mass transfer coefficient (<i>K_Ga_v</i>) when using MEA and DEA solution, and increasing the fly ash concentration further exacerbates this negative impact. However, the effect of fly ash on the reduction in <i>K_Ga_v</i> is not significantly related to its chemical composition but rather depends on the operational parameters. With increasing solution temperature, liquid/gas ratio (L/G), and packing height, the <i>K_Ga_v</i> values for different solutions exhibit an upward trend. The negative effect of fly ash on <i>K_Ga_v</i> remains relatively stable for MEA as solution temperature and packing height increase. Compared to MEA, fly ash has a greater negative effect on DEA solution under the same experimental conditions. The analysis reveals that the detrimental effect of fly ash on <i>K_Ga_v</i> primarily stems from its ability to alter the distribution state of the absorption liquid within the packed tower.