硫磺回收装置钠法烟气脱硫若干问题探析

在硫磺回收装置基础上增设以氢氧化钠(NaOH)为吸收剂的烟气碱洗单元,可满足GB 31570—2015《石油炼制工业污染物排放标准》大气污染物特别排放限值或更加苛刻的地方标准要求。调节循环碱液pH值对装置运行至关重要,pH值低有利于防止结垢物质生成,pH值高有利于吸收尾气中二氧化硫(SO_(2)),同时会过量吸收二氧化碳(CO_(2))。综合考虑碱洗塔脱硫效果和含盐废水曝气氧化效果,整个系统的pH值建议控制在7左右。提高尾气焚烧炉温度至750℃以上,可有效避免CO对SO_(2)检测结果的干扰,避免未燃尽的有机物进入含盐废水导致COD超标。针对硫磺回收装置开(停)工过程尾气流量低(约为正常值的1/3),SO_(2)质量浓度高(15-20 g/m^(3))等特点,需制订开(停)工尾气脱硫的操作方案,避免腐蚀、结垢(结晶)与堵塞等情况发生。

钠法烟气脱硫机理研究

采用离子平衡、电荷平衡、元素平衡原理研究钠法烟气脱硫机理,建立了相关数学模型。提出了吸收液脱硫容量、单位脱硫容量等概念,并依次分析了吸收液pH值、吸收液与烟气液气比、吸收液中碳酸盐容量、烟气中SO;浓度、吸收液中亚硫酸盐容量等对单位脱硫容量和脱硫效率的影响并对其影响机理进行了解释。根据研究结论提出了钠法脱硫技术进行进一步优化的方向。

Multi-pollutants simultaneous removal from flue gas

The multi-stages humidifier semi-dry flue gas cleaning technology, the CRS plasma flue gas cleaning technology and oxidative additive flue gas cleaning technology were investigated for multi-pollutants removal. The semi-dry flue gas cleaning technology using multi-stages humidifier and additive can improve oxidation and absorption, and it can achieve high multi-pollutants removal efficiency. The CRS discharge can produce many OH radicals that promote NO oxidation. Combining NaOH absorption can achieve high deSO2 and deNO, efficiencies. It is fit for the reconstruction of primary wet flue gas desulfurization （WFGD）. In addition, using NaClO2 as additive in the absorbent of WFGD can obtain very high removal efficiency of SO2 and NOx.