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Based on limestone wet desulfurization spray scrubber technology, this paper explicitly introduces the ionization process of water in slurry, deduces controlled range of slurry PH value and equation of slurry PH value in slurry droplet by analyzing the main origin of H + and OH -, and other factors that influence ionization balance of water in slurry, provides theories for simulation of slurry PH value and optimization in practical operation. Besides, it concludes the reasonable range of slurry PH value by analyzing various factors such as increasing SO 2 removal efficiency, decreasing operation cost, dissolution of CaCO 3 , oxidation of SO 3 2-and HSO 3 -, and relationship of slurry PH values between slurry surface and the undersurface, provides reference for optimization of slurry PH value in practice. Finally, an optimization experiment of slurry PH value is designed for #11FGD in Taiyuan co-generation power plant, and the slurry PH value is optimized effectively. Keywords-wet desulfurization; slurry PH value; ionization balance; ion product of water; forced oxidation I.INTRODUCTION In limestone wet desulfurization technology, SO 2 removal efficiency is mainly influenced by a wide range of variables, such as inlet SO 2 concentration, flue gas flow rate, slurry PH value, recirculation slurry flow rate, calcium-sulfur ratio, ratio of liquid to gas and so on. Slurry PH value is the most important and complicated variable among them, which not only reflects the acid degree of slurry, but also directly influences absorption of SO 2 , dissolution of CaCO 3 , CaSO 3 ·1/2H 2 O and CaSO 4 ·2H 2 O and so on. On the one hand, high slurry PH value can make a good advantage of absorption of SO 2 , on the other hand, a higher slurry PH value will cause thick deposition on surface of spray scrubber and equipments. While low slurry PH value not only makes a disadvantage of absorption of SO 2 but also causes decline of SO 2 removal efficiency and limestone's utility [1] .The reasonable range of slurry PH value has not been given theoretically. Some copy internal or external experiences, some summarize from practical operation, the others study by experimenting. However, the reasonable range of slurry PH value will vary with different desulfurization systems, different operation modes, and different control targets. So far, no reasonable and theoretical methods are practically applied in optimization of slurry PH value. This paper deduces theories on the ionization process of water in slurry based on chemical reaction dynamics, and optimization method of slurry PH value that meets different

In view of the improvement of NOX emission control requirements for coal-fired units, traditional PID controllers have been unable to effectively control large delay, large inertia, nonlinear, time-varying SNCR denitration systems, and most advanced control algorithms are often object-based models. Therefore, a model of SNCR denitration system based on adaptive weight particle swarm optimization algorithm is established. A 2×200MW heating steam turbine generator set equipped with a 2×705t/h circulating fluidized bed boiler was used as the test unit, and the selective non-catalytic reduction technology denitration system was analysed. The particle swarm optimization algorithm with adaptive weights was used to model the relationship between the urea flow rate and the NOX concentration at the chimney outlet of the SNCR denitration system under working conditions of 140 MW, 170 MW and 200 MW, respectively, to provide a process for the automatic control of the SNCR denitration systemmodel. Apply the actual data from the field to verify the model. The results show that the error between the output of the model and the actual operational data is within the allowable range, which verifies the validity of the model. This result opens up a new path for the particle swarm optimization algorithm to model the SNCR denitration process, and promotes the application of intelligent algorithms in other industrial processes.

First proposed the Shanxi Coal Power Plant PhaseⅡPingshuo 2×300MW CFB direct air cooled system winter frostproof protection of frost question, introduced its direct air cooled system of the power plant control system, elaborated the automatically controlled scheme of frostproof in the direct air cooled system, analyzing the existing existence question and carring on to optimization the existing programs, meanwhile, the engineering operation for further elaboration and analysis, optimized the direct air cooled system's frostproof protection control scheme. Keywords-the direct air cooled system; winter protect; automatic control; circulation fluid bed;2011 International Conference on Computer Distributed Control and Intelligent Environmental Monitoring 978-0-7695-4350-5/11 $26.00