Automatic Adjustment and Optimization of Desulphurization Slurry Supply for 335 MW Unit

Generally, single PID loop was adopted in desulfurization and slurry supply control strategy in power plant. There is no feedforward, and the influence of the boiler load and SO 2 concentration change on the slurry adjustment is not considered. When the original slurry supply is automatically put into operation, the SO 2 concentration in the desulfurization outlet fluctuates greatly due to the mismatch between the set pH value and the operating conditions. The instantaneous NOx often exceeds 35 mg/m3, resulting in less automatic injection time, and the operating personnel mainly adjust the slurry supply by manual means. In this paper, based on the original control strategy, the feedforward and corresponding blocking logic are added, so that the slurry supply can be automatically adjusted in the whole process including CEMS purging and pH meter rinsing, which not only improves the automation level of the auxiliary machine, but also reduces the labor intensity of the operating personnel.