1. State Environmental Protection Center for Coal-Fired Air Pollution Control, Zhejiang University, Hangzhou 310027, China 2. Baima Lake Laboratory, Hangzhou 310056, China 3. Jiaxing Research Institute, Zhejiang University, Jiaxing 314031, China 4. Zhejiang Zheneng Technology Research Institute Limited Company, Hangzhou 311121, China
A model of the oxidation process in the wet flue gas desulfurization (WFGD) based on the mechanism of forced oxidation and natural oxidation process was established aiming at the problems of excessive oxidation air and high energy consumption of oxidation system under variable load and SO2 mass concentration operation existing in the application of limestone-gypsum WFGD technology. The influence of key parameters such as the O2 volume fraction in the flue gas, the diameter of bubbles or droplets and reaction enhancement factor on forced oxidation rate and natural oxidation rate was analyzed. A real-time operation optimization method of oxidation system based on the above-mentioned oxidation process model was proposed, and an industrial test was conducted on a 1 000 MW desulfurization unit. Results showed that the root-mean-square error (RMSE) of the variation of sulfur was less than 0.15 mol/m3. The natural oxidation rate fluctuated between 10% and 35% and the demand for oxidizing air fluctuated between 107 m3/min and 360 m3/min with the unit load fluctuating between 520 MW and 1 000 MW. The real-time operating optimization method of the oxidation subsystem can reduce the energy consumption by 23.7% compared with operating at rated power under the premise of enough oxidation rate of the WFGD system.
Hai-dong FAN,Zhu CHEN,Zhong-yang ZHAO,Cheng-si LIANG,Cheng-hang ZHENG,Xiang GAO. Operating optimization of oxidation subsystem of wet flue gas desulfurization system of 1 000 MW coal-fired unit. Journal of ZheJiang University (Engineering Science), 2023, 57(4): 675-682.
Fig.1Natural oxidation and forced oxidation in WFGD system
Fig.2Comparison of sulfite concentration changes between measured and predicted values
Fig.3Effects of important parameters on natural oxidation rate under different flue gas flow rate
Fig.4Effects of important parameters on forced oxidation rate under different bubble diameter
Fig.5Operating optimization method of oxidation system in WFGD system
Fig.6Unit load and natural oxidation rate
Fig.7Unit load and oxidizing air demand
运行策略
运行风机
fl,a/Hz
fh,a/Hz
Pa/kW
rw/%
按额定频率
1号
76.0
76.0
225.0
—
按额定频率
2号
85.0
85.0
225.0
—
按运行经验
1号
64.8
75.3
216.3
4.3
按运行经验
2号
75.0
84.5
215.9
4.0
按优化方法
1号
23.7
70.0
167.4
25.6
按优化方法
2号
37.4
79.5
176.0
21.8
Tab.1Analysis of energy consumption for different operating strategies of oxidation system
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