低氧、高CO2环境中SO2的催化氧化、快速捕获及固化机制

The SO2, released from high sulfur raw meal when preheating in the C2 or C3 Cyclone, was only reacted with the raw material for 1~2s and then exhausted into the atmosphere, resulting in high concentration of SO2 in the flue gas. The available wet FGD methods have high operating cost, serious corrosion of equipment, and yield secondary wastes. Whereas dry FGD methods present low efficiency due to slow reaction between SO2 and CaCO3, CaO, Ca(OH)2 particles, competition reaction of SO2 and CO2 with adsorbent, and poor thermal stability of sulfur-contained products. Therefore, process compatible desulfurization is expected though developing the desulfurization potential of the New Suspension Preheater line. According to SO2 release characteristics, catalyst, mineralizer and adsorbent are designed in this project, and then added into kiln with raw materials. The SO2 is oxidized into SO3 immediately and then absorbed by wet spray, the formed H2SO4 droplet reacted with CaCO3 to achieve FGD in C1 or C2 Cyclone within 2-3 second. The efficiency and rate can be improved dramatically since the desulfurization reaction is transformed from gas-solid (SO2-CaCO3) reaction to liquid-solid (H2SO4 droplet-CaCO3) reaction. The CaSO3 is oxidized to CaSO4, and then involved in solid phase reaction to produce calcium sulphoaluminates, which had higher thermal stability during clinkerlization, therefore higher amount of sulfur is solidified in clinker. This project has important scientific value and bright application prospects for cement industry in energy saving and emission reducing, sustainability and efficient utilization of high sulfur raw materials.

高硫原料在C2~C3旋风筒释放的SO2仅与生料接触1~2s即排出，导致烟气SO2浓度严重超标。现有湿法脱硫运行成本高、设备腐蚀严重、产生二次废渣；干法钙基脱硫速率慢、效率低（30~50%），无法解决低氧、高CO2（预热器）环境中脱硫反应速率慢、CO2竞争反应、固硫产物热稳定性差（分解率40~70%）等问题。因此，充分挖掘新型干法水泥生产各环节脱硫潜力，实现生产过程协同脱硫是发展方向和必然趋势。本申请基于SO2释放特点，设计催化剂、矿化剂和吸附剂并随生料加入，快速（1~2s）催化氧化SO2、雾化吸收SO3，生成的H2SO4液滴与CaCO3反应，将烟气脱硫由气固反应转化为液固反应，在C1~C2旋风筒内高效（>95%）脱硫。同时，将CaSO3催化氧化为CaSO4，并促进其反应生成热稳定性更高的硫铝酸钙，提高熟料固硫能力，是一项推动水泥工业节能减排、可持续发展和高硫原料利用的基础性研究工作。

预热器环境中钙基脱硫反应可逆且速率慢、固硫产物易分解，是提高水泥窑烟气脱硫效率的瓶颈。本项目系统研究了水泥窑系统中高硫原料SO2释放、捕获、富集与循环特征，提出了“SO2催化氧化-雾化増湿-生料脱硫-熟料固硫”新路线，揭示了预热器环境中SO2催化氧化、SO3雾化吸收、CaCO3脱硫反应动力学过程及影响机制，阐明了催化剂和矿化剂对烧成过程中固硫矿物热稳定性的影响，显著提高了熟料固硫能力。将催化剂、矿化剂及钙基吸附剂随生料加入，并在风管处增设雾化増湿设备，熟料固硫效率提升至75%以上，烟气脱硫效率达95%以上，实现了水泥生产过程自脱硫。.项目全面完成了研究任务，并拓展了烟气催化脱硫工业试验，形成了新型干法水泥窑烟气催化复合脱硫技术体系，为水泥工业烟气脱硫提供了新思路、新理论和技术支撑，并在360余条水泥生产线进行推广应用，取得了显著的经济和社会效益，获2018年度中国建筑材料联合会·中国硅酸盐学会科技进步一等奖。在Chemical Engineering Journal、Journal of Cleaner Production等国内外学术期刊发表论文4篇（SCI收录3篇），申请相关发明专利6件（授权4件），申请人获批国家自然科学基金优秀青年基金，培养博士研究生1人，硕士研究生4人。