Abstract: As the main flocculant of flue gas desulfurization wastewater treatment, polyaluminium chloride has the problems of large dosage and high cost in application.By observing the clarity of sewage and determining the concentration of pollutants in sewage, the flocculation effect of polyaluminium chloride, polyacrylamide with different molecular weight and their combination on flue gas desulfurization sewage from catalytic cracking unit is studied by spectrophotometry and chemical titration. The results show that the flocculation of polyaluminium chloride and polyacrylamide was superior to the flocculation of polyacrylamide alone, and the larger the relative molecular mass of polyacrylamide, the better the flocculation effect. At the same time, the effects of flocculant dosage, sewage pH value and stirring time on the flocculation effect were analyzed and optimized. The results showed that 30 mg/L polyaluminium chloride and 1.0 mg/L ultra⁃high molecular weight polyacrylamide were the best flocculation effect on catalytic cracking flue gas desulfurization wastewater at pH 7~8 and stirring time 4~6 minute. The research results also laid a solid foundation for the cost optimization of sewage treatment in the future.

Key words: Polyacrylamide, Polyaluminium chloride, Flue gas desulfurization wastewater, Molecular mass, Flocculation, Turbidity

摘要： 聚合氯化铝作为烟气脱硫污水处理的主要絮凝剂，在应用过程中存在用量大、成本高等问题。采用分光光度法和化学滴定法，通过观察污水的清澈度和测定污水中污染物的质量浓度，研究了聚合氯化铝、不同相对分子质量聚丙烯酰胺以及二者复配用于催化裂化装置烟气脱硫污水的絮凝效果。结果表明，聚合氯化铝和聚丙烯酰胺复配使用的絮凝效果优于二者单独使用的絮凝效果，且聚丙烯酰胺的相对分子质量越大，其絮凝效果越好。同时分析和优化了絮凝剂质量浓度、污水pH和搅拌时间等因素对絮凝效果的影响。结果表明，在pH为7~8、搅拌时间为4~6 min的条件下，30 mg/L聚合氯化铝和1.0 mg/L超高相对分子质量聚丙烯酰胺复配，对催化裂化烟气脱硫污水的絮凝效果最好，该研究结果也为日后污水处理的成本优化打下了坚实基础。

关键词: 聚丙烯酰胺, 聚合氯化铝, 烟气脱硫废水, 相对分子质量, 絮凝, 浊度