FCC催化剂生产尾气洗涤废水的膜过滤试验

Field Study on Treatment of FCC Catalyst Production Wastewater by Hollow Fiber Membrane

针对FCC催化剂生产尾气洗涤废水具有悬浮物浓度高、酸性强的特点,采用沉淀—中空纤维膜过滤工艺,构建了产水能力为200 L/h的现场试验装置,采用聚四氟乙烯(PTFE)中空纤维膜,通过微滤技术去除FCC催化剂生产尾气洗涤废水中悬浮物,研究其处理效果及产水量的变化。该系统现场连续运行了1 865 h,在废水水质正常的情况下,出水浊度能降到10 NTU以下,且产水能力稳定;但是,废水水质出现了两次明显异常,导致沉淀过程失效,膜箱进水浊度达到了10 000 NTU,产水能力下降,出水水质变差,且出现膜堵塞,难以通过曝气与反洗的方式彻底恢复,有待开展化学清洗工艺的研究。

The wastewater from gas washing in FCC catalyst production is characterized by strong acid and high concentration of suspended solids. A field test system with water production capacity of 200 L/h was built using precipitation and hollow fiber membrane filtration. PTFE hollow fiber membrane was used to remove suspended solids from the wastewater. The treatment efficiency and the flux change were studied. The system was operated continuously for 1 865 hours. The operation results indicated that the turbidity of effluent was less than 10 NTU and the permeate flux was stable when the wastewater quality was normal. But there were two significant changes in wastewater quality during operation, and the pre- cipitation was ineffective. The turbidity of incoming water for membrane tank reached 10 000 NTU. The quality of permeate became worse and the permeate flux decreased dramatically because of membrane fouling. The permeate flux cannot be recovered fully by aeration or backwashing, so it is necessary to car- ry out study on chemical washing.