干法钙基脱硫剂改性研究进展

Research progress on modification of dry calcium-based desulfurizers

目前,煤炭等传统化石能源的使用在全国仍占有较大比重,在日益严格的环保法规背景下,为实现工业尾气的超低排放,完成“碳达峰、碳中和”目标,提高工业生产中的脱硫脱硝效率已成为目前亟须解决的重要问题。长期应用于工业中的湿法/半干法脱硫技术现在很难经济有效地满足目前的排放标准,此外还存在维护费用高、技术工艺复杂、产物处理困难等问题。在众多脱硫脱硝方案中,干法钙基脱硫剂因其易回收、占用体积小、价格低廉、热量损耗少等优势而受到科研工作者的广泛关注。本文介绍了干法钙基脱硫剂的优势与劣势,并针对其存在的问题,通过大量文献调研,分类总结了脱硫剂的不同改性方法,分析了掺杂金属氧化物、蒸汽活化、掺入脱硝添加剂这三种常见改性策略的研究进展及机理。结果表明:在脱硫剂中单一掺杂或引入多种金属氧化物(如Fe_(2)O_(3)、MgO等)能够明显促进脱硫剂的脱硫反应;在脱硫剂制备或反应过程中使用蒸汽活化,可延长脱硫剂的使用寿命,从而提高脱硫剂的利用率;在脱硫剂中加入KMnO_(4)等增强脱硝的添加剂或在脱硫过程中引入O_(3)条件均可改善脱硫剂的脱硝性能,这说明在一定条件下脱硫过程能够促进脱硝反应的进行,同时还证实了脱硫脱硝一体化的可行性。上述三种方法采用优化反应条件、调控脱硫剂的结构或组分,实现降低脱硫反应的活化能,增加反应活性中心,增大脱硫剂的孔结构、比表面积,从而改善脱硫剂的脱除效果。干法钙基脱硫剂的改性策略建议结合使用,通过优化脱硫剂的比表面积等重要参数,合成出既能脱硫又能脱硝的高效脱硫剂。

At present,the use of traditional fossil energy such as coal still accounts for a large proportion in the country.In the context of increasingly strict environmental requirements,in order to achieve ultra-low emissions of industrial exhaust gas,complete the carbon peaking and carbon neutrality goals,and improve the efficiency of desulfurization and denitrification in industrial production,it has become an important issue that needs to be solved urgently.The wet/semi-dry desulfurization technology that has been used in industry for a long time is now difficult to meet current emission standards cost-effectively.In addition,there are also problems such as high maintenance costs,complex technical processes,and difficulty in handling reaction products.Among the many desulfurization and denitrification solutions,dry calcium-based desulfurization agents have received widespread attention from scientific researchers due to their advantages such as easy recovery,small occupied volume,low price,and low heat loss.The advantages and disadvantages of dry calcium-based desulfurizers are systematically introduced.Given its existing problems,through a large number of literature surveys,the different modification methods of desulfurizers are classified and analyzed.The research progress and mechanisms of three common modification strategies:doping metal oxides,steam activation,and incorporating denitration additives were analyzed.Single doping or introduction of multiple metal oxides(such as Fe_(2)O_(3),MgO,etc.)into the desulfurizer can significantly promote the desulfurization reaction of the desulfurizer;using steam activation during the preparation or reaction process of the desulfurizer can extend the service life of the desulfurizer and thereby improve the utilization rate of the desulfurizer;adding KMnO_(4)and other denitrification-enhancing additives to the desulfurizer or introducing O_(3)conditions during the desulfurization process can improve the denitrification performance of the desulfurizer.This shows that the desulfurization process can promote the denitrification reaction under certain conditions.At the same time,the feasibility of integrated desulfurization and denitrification was also confirmed.The above three methods optimize the reaction conditions and regulate the structure or components of the desulfurization agent to reduce the activation energy of the desulfurization reaction,increase the reaction active center,and increase the pore structure and specific sur-face area of the desulfurization agent,thereby improving the removal effect of the desulfurization agent.The modification strategies of dry calcium-based desulfurizers are recommended to be used in combination.By optimizing important parameters such as the specific surface area of the desulfurizer,a high-efficiency desulfurizer that can both desulfurize and denitrify can be synthesized.