Abstract: A systematic experimental analysis and engineering practice study was conducted to address the critical operational challenges associated with long-term operation of large-scale coal-fired flue gas carbon capture units, encompassing water imbalance, amine solvent degradation, and amine emissions. Regarding water balance control, a water balance model for the absorption-regeneration system was established to investigate the effects of flue gas temperature rise across the absorption column on water consumption and CO₂ capture efficiency. A nonlinear positive correlation was observed between temperature rise and water consumption; specifically, at a temperature rise of 10 ℃, demineralized water consumption increased to 1.52 t/h, while capture efficiency decreased from 92.5% to 85.7% due to elevated outlet flue gas temperature. Optimal control maintaining the outlet flue gas temperature 0.5 ℃ above the inlet temperature achieved essentially stable water balance. For amine solvent performance control, the accumulation of heat-stable salts (HSS) was identified as the primary factor responsible for solvent degradation. Following prolonged operation, the mass concentration of HSS in the solvent increased to 4.16%, resulting in a decline of capture efficiency from 90.0% to 77.0% and daily CO₂ capture capacity from 210.0 to 158.4 t. Implementation of ion exchange resin purification technology reduced HSS mass concentration to 0.98%, restoring capture efficiency to 91.5% and daily CO₂ capture capacity to 210.0 t; notably, each 1.0% reduction in HSS mass concentration during the initial purification stage yielded a 3%−4% improvement in capture efficiency. Additionally, a composite antioxidant formulation was developed; accelerated oxidation experiments demonstrated that the synergistic combination of ethylenediaminetetraacetic acid(EDTA) and hydroquinone(HQ) at mass concentrations of 0.1% and 0.2%, respectively,reduced amine oxidative degradation rate from 21.51% to 11.42%, significantly outperforming individual antioxidants.Regarding amine emission control, operating parameters of the water wash section were optimized. A liquid-to-gas ratio of 3.0−3.5 L/m³ and amine concentration of 0.25%−0.50% were determined as optimal conditions, constraining amine emissions to approximately 10.3 mg/m³. The resulting wastewater could be recycled for the amine purification unit, achieving a balance between emission control and water conservation. Through the integrated strategies of flue gas temperature control, amine purification and formulation optimization, and water wash parameter adjustment, a systematic solution was provided to enhance long-term operational stability and economic viability of carbon capture units.