Electric Power Technology and Environmental Protection

【目的】随着电厂废水“零排放”政策的推进和燃煤烟气氯化氢(HCl)排放的逐步控制，提升燃煤烟气脱氯效率已成为亟需 解决的重要课题。为了进一步明确HCl控制的有效方法，通过各类技术对比分析识别其优缺点是当前的研究重点。【方法】本文 通过梳理相关文献，围绕燃烧前、燃烧中和燃烧后3类脱氯路径展开系统综述，对各类技术的基本原理及优缺点进行全面归纳 与比较。【结果】研究表明，燃烧前脱氯多依赖物理洗选等手段，其中洗煤法的脱氯效率为27%~56%，该方法可有效脱除无机 氯，但对煤中有机氯的脱除效果有限，且成本高，难以满足燃煤电厂烟气脱氯的需求；燃烧中脱氯依赖于高温条件下添加反应 剂，但由于SO2 等酸性气体竞争反应强烈，难以实现HCl的选择性脱除；相比之下，燃烧后脱氯技术更具应用潜力，尤其可与现 有烟气净化系统耦合，实现高效协同治理。其中，湿法脱氯技术成熟，但存在废水排放的问题。干法/半干法技术具有无废水 产生、对锅炉效率影响小等特点，但相关技术受限于烟气组分干扰、在线监测手段不完善、粉煤灰品质下降等因素。目前国内 干法/半干法脱氯效率大多在70%以下，低于美国环境保护署利用Na2 CO3 ∙NaHCO3 ∙2H2O干法喷射技术取得的90%脱氯效率。 【结论】总体而言，燃烧后干法/半干法脱氯技术在满足环保政策需求、实现高效脱氯及推动工业化应用方面具有广阔发展前 景，值得进一步深入研究和优化。

 [Objective] With the increasingly stringent "zero discharge" policy for power plant wastewater and emission limits on hydrogen chloride (HCl) from coal-fired flue gas, improving the dechlorination efficiency of coal combustion flue gas has become an urgent issue to address. In order to further reveal the effective method of HCl control, it is the current research focus to compare and analyze various technologies and identify their advantages and disadvantages. [Methods] This paper systematically reviews the literature on three categories of dechlorination pathways—pre-combustion, in-combustion, and post-combustion—comprehensively summarising and comparing the fundamental principles, advantages, and disadvantages of each technology. [Results] Research indicates that coal washing achieves a dechlorination efficiency of approximately 27%-56%, effectively removing inorganic chlorine but with limited effectiveness in eliminating organic chlorine in coal. Furthermore, it is costly and cannot meet the dechlorination needs of coal-fired power plants. In-combustion dechlorination depends on the addition of reactants under high-temperature conditions, but strong competitive reactions with acidic gases such as SO₂ hinder the selective removal of HCl. In contrast, post-combustion dechlorination technologies show greater application potential, especially due to their compatibility with existing flue gas purification systems, enabling efficient and synergistic pollutant control. Among them, wet dechlorination is a mature technology but leads to wastewater discharge issues. Dry/semi-dry methods feature advantages such as no wastewater generation and minimal impact on boiler efficiency. However, these technologies are constrained by factors including flue gas composition effects, incomplete online detection methods, and degradation of fly ash quality. Currently, domestic dry/semi-dry dechlorination efficiencies are mostly below 70%, lower than the 90% efficiency achieved by the U. S. Environmental Protection Agency using Na₂CO₃ ·NaHCO₃ ·2H₂O dry injection. [Conclusion] Overall, post-combustion dry/semi-dry dechlorination technologies hold great potential in meeting environmental regulations, achieving high dechlorination efficiency, and promoting industrial application. They merit further in-depth research and optimization.