A novel monitoring framework for slurry deterioration detection in the wet flue gas desulfurization system

Healthy gypsum slurry is the foundation of continuous and stable operation during wet flue gas desulfurization process, but there is relatively little research on it. In the paper, a compound parameter is proposed to remove the influences from gas volume and inlet sulfur dioxide concentration to limestone slurry flow. The compound parameter, desulfurization efficiency and pH value are then taken as parameters for gypsum slurry quality monitoring. Moreover, a new framework combining condensed nearest neighbor algorithm and multivariate state estimation technique is then proposed. The proposed procedure is then applied in a self-defined function, and are compared with the actual function values with satisfying metrics (all less than 1.00 x 10-03). After the efficiency certification on the framework, a wet flue gas desulfurization system in 660 MW unit has been taken for gypsum slurry quality monitoring and quantization. The deviation degree begins to be smaller from the 380th sample corresponding with the replacement time in the system, and drops to 0.1507 at the 555th sample indicating slurry regains normal quality after replacement. Therefore, results by the proposed framework can be taken for gypsum slurry quality quantization and deterioration detection in the field.