火电厂精处理再生废水气态膜法脱氨工艺中试研究

A pilot study on ammonia removal by gas membrane for waste water from condensate polishing regeneration system in power plant

开展了火电厂精处理再生废水气态膜法脱氨工艺中试研究,分析了精处理再生废水温度、pH值、脱氨膜出气口真空度、模组进液流量对氨氮脱除量的影响。升高废水温度,增加了膜分离过程的推动力和渗透通量,有助于提高氨氮脱除量。提升废水pH值,有助于水中氨氮平衡向增加氨气量的方向移动,增大膜组压差动力,但到达一定pH值后,对脱氨量的影响效果甚微,最佳pH值工况为11。提高真空度,有助于提高传质能力;但过高的真空度不利于氨的脱除,真空度在-0.046 MPa附近,系统整体脱氨量最高。低模组进液流量下,膜进液流量的提高对系统的整体脱氨量有较大幅度的提升;模组进液流量提高至一定程度后,流量增加对氨氮脱除量无明显影响。

A pilot study on the process of ammonia removal by gas membrane for waste water from condensate polishing regeneration system in power plant was carried out. The effects of temperature, pH, vacuum degree of outlet from deamination membrane, and inlet flow rate of membrane on the removal of ammonia nitrogen were analyzed. Increasing the temperature of waste water may increases the driving force and permeation flux of separation process, which is helpful to increase the removal amount of ammonia nitrogen. Raising the pH of waste water can help the balance of ammonia nitrogen in water moving towards the direction of increasing ammonia gas, so that the pressure difference of membrane is increased. However, after reaching a certain pH value, the effect on ammonia removal is very small. Thus the optimal pH value is set to 11. Increasing the vacuum degree is helpful to improve the mass transfer capacity, but too high vacuum degree is not conducive to ammonia removal. When the vacuum degree is around-0.046 MPa, the overall ammonia removal capacity of the system is the best. On the low inlet flow rate, the increase of membrane inlet flow rate can greatly improve the overall ammonia removal capacity of the system;after the flow rate is increased to a certain amount, the increase of flow rate has no obvious effect on the ammonia nitrogen removal amount. Also, the ion content of ammonia absorption solution is analyzed, the utilization of ammonia collected is proposed.