烟气脱硝除尘脱硫装置存在问题分析与改进

Analysis and Improvement of Problems in Flue Gas Denitrification,Desulfurization and Dust Removal Unit

催化裂化装置再生烟气含有NO_x、SO_x和催化剂粉尘,会引起环境污染,利用烟气脱硝除尘脱硫装置加以解决。装置存在的问题:脱硝过程中的注氨与氨逃逸直接影响到余热炉长周期运行,洗涤塔聚脲衬里不适用于该工艺的防腐,循环浆液分离效果受胀鼓滤芯安装、使用、控制诸因素影响,设计时对烟气脱硫系统汽水界面的腐蚀、磨蚀严重估计不足,工艺过于复杂,设备过于精细。这些问题的存在,影响了装置运行效率。针对脱硝,进行了注氨与脱硝效果、产生副反应的操作探索,摸清了氨在系统的作用边界,解决了有效脱硝与控制副反应。对于除尘脱硫综合塔内衬,找到了不合适的原因并选择了较好的衬里材料与工艺,避免了重复衬胶与脱落的恶性循环,确保了运行的连续性。废水处理系统主要从胀鼓滤袋精度筛选、酸碱度控制、絮凝剂的选择与浓度调适入手,提高了过滤器的过滤效果与使用周期;对于废水氧化系统设备设施、COD控制,提高设备材质、改进设施结构,选择易得风源、调整注风点、疏通废水后路等,稳定了外排废水质量。

The regenerated flue gas of FCC unit contains NOx,SOx and catalyst dust,which causes environmental pollution.A flue gas denitrification,desulfurization and dust removal unit was established to solve this problem.The problems in the flue gas denitrification,desulfurization and dust removal unit are as follows:the ammonia injection and ammonia escape during the denitrification directly affect the long-term operation of waste heat boiler,the polyurea lining of scrubber is not suitable for the anticorrosion of the process,the separation effect of recycle slurry is affected by the installation,operation and control of expansion drum filter core,the corrosion and abrasion of the steam-water interface in flue gas desulfurization system are seriously underestimated during the design,the process is too complicated,and the equipment is too fine.These problems have greatly affected the operation efficiency of the unit.For the denitrification,the ammonia injection, denitrification effect and side reaction was explored,the action boundary of ammonia in the system was found out,and the effective denitrification and the control of side reaction Were achieved.The reasons for the unsuitable lining of the desulfurization and dust removal tower was found and the better lining materials and technologies were selected,thus avoiding the vicious circle of repeated lining and shedding and ensuring the continuity of operation.The wastewater treatment system mainly focused on the selection of the accuracy of expansion drum flter bag,the control of acidity and alkalinity,the selection of flocculant and the adjustment of concentration,which improved the filtering efficiency and extended the operating cycle of the filter.The equipment and facilities of wastewater oxidation system and the control of COD are also discussed.to improve the equipment material and the structure of facilities.The quality of effluent can be effectively stabilized by choosing easy-to-get air source ,adjusting air injection point and dredging waste water.