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[Display omitted] • Multi-stage circulation integrated SO 2 and CO 2 capture, coupled with NH 3 recovery. • Over 99.5% SO 2 and 70% CO 2 was captured with desorption duty of 2.48 GJ/t CO 2. • Adaptable strategies balanced efficiency and economy amid complex conditions. Amidst growing environmental concerns stemming from fossil fuel combustion, which releases a considerable amount of pollutants and greenhouse gas. In an effort to mitigate the costs of existing combustion flue gas desulfurization and CO 2 capture systems, a new multi-stage circulation (MSC) process for integrating capture of CO 2 and SO 2 using ammonia-based absorbents was proposed. Different functional zones were interconnected using ammonia (NH 3) and potassium carbonate (K 2 CO 3) blended solution as the absorbent, enabling efficient SO 2 capture in the 1st stage, CO 2 enrichment in the 2nd stage, CO 2 capture enhancement in the 3rd stage and recovery of escaped NH 3 in the 4th stage. Experimental results demonstrated the effectiveness of NH 3 /K 2 CO 3 solution in enhancing CO 2 capture efficiency. The overall CO 2 capture efficiency varied between 95.4 % and 84.1 % at inlet CO 2 concentrations ranging from 5 % to 30 %. Under typical combustion flue gas conditions of 622 ppm SO 2 and 15 vol% CO 2 , the process exhibited a SO 2 removal efficiency exceeding 99.5 %, with CO 2 capture efficiency surpassing 70 %. Furthermore, the CO 2 desorption duty was determined to be 2.48 GJ/t CO 2. 13C NMR results confirmed that simultaneous absorption of CO 2 and SO 2 led to the accumulation of SO 2 in the liquid phase, reducing the CO 2 loading in rich solvent. To address these challenges, coupled optimization strategies was proposed, ensuring high capture efficiency and low CO 2 desorption duty under the complex and variable conditions of flue gas parameters, SO 2 concentration, and CO 2 concentration. [ABSTRACT FROM AUTHOR]

• A normal behavior model of slurry circulating pump is established. • K-means algorithm is used to realize the operational condition recognition. • Memory matrix adaptive to varying operating condition are constructed. • The condition monitoring method can realize the early fault warning of the slurry circulating pump. The slurry circulating pump, a crucial component of wet flue gas desulfurization (WFGD) systems, often encounters faults such as impeller and bearing box damage due to limestone slurry's intense abrasion, corrosion, and cavitation. The various operating conditions, including frequent switching and rapid frequency variations of the slurry circulating pump will make the working environment worse undoubtedly. To ensure the process safety and operation efficiency of the WFGD system, this study proposed a condition monitoring (CM) method based on a novel multivariate state estimation technique (MSET), which can realize the fault early warning of the slurry circulating pump. To improve the accuracy of the conventional MSET, a memory matrix (MM) construction method based on K-means algorithm is proposed, which can provide a MM that varies with the operating condition of real-time observed vectors. In typical cases of predicting the pump's B-phase current under normal conditions, the root mean square error (RMSE) of our method is 0.25 A, much smaller than that of the conventional MSET method (2.08 A). On the other hand, the computation time of our method remains short (about 20 s) compared to other models (e.g., MEST aided with K-nearest neighbour model needs about 19,000 s) adaptive to varying conditions for over 3000 samples. Also, the proposed CM method can effectively provide early fault warning for impeller damage and bearing box damage of the slurry circulating pump, with 8 days and 1 day in advance, respectively. This can win enough time to inspection & maintenance before troubleshooting. [ABSTRACT FROM AUTHOR]