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Abstract: HCl in coal-fired flue gas has adverse impact on the environment, equipment, and the flue gas desulfurization (FGD) system. The existence of HCl also increases the difficulty of the treatment of desulfurization waste water. semi-dry dechlorination technology is put forward to attach chlorine to fly ash by spraying in alkaline solution. Simultaneously, desulphurization waste water is used as the solvent of alkali, and this could help realize the target of near-zero emission of desulfurization waste water. CHEMKIN is used to build a chemical kinetics model, which is based on the measured components of flue gas in a coal-fired power plant. NaOH is set as the alkali absorbent in the model. Both the competitive relationship of SO₂ and HCl and the effects of different factors on HCl reaction efficiency are analyzed. SO₂ with high concentration would compete for more NaOH, but when na/Cl (ratio in mole) is 1, the reaction efficiency of HCl achieves 22.28%, and it is positively correlated with na/Cl. When na/Cl surpasses 5, the reaction efficiency of HCl increases to beyond 70%. As na/Cl continues to increase, there is a slower growth of HCl reaction efficiency and it finally achieves 100% when na/Cl reaches 12. With a fixed value of na/Cl, a change of 1000 mg/m³ in SO₂ concentration would change the reaction efficiency of HCl about 13%. The effect of flue temperature on HCl reaction efficiency is not significant. Acid gases in flue gas react with NaOH completely in 0.1 s and come to equilibrium after about 1 s.

燃煤烟气半干法脱氯的化学动力学模拟

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