基于国产管式透气膜的养殖粪污沼液氨氮回收工艺装置构建及效能

为了探讨利用国产透气膜回收沼液氨氮的可行性及实际效果,以国产管式透气膜为关键组成部件构建沼液氨氮回收工艺模拟实验装置,开展沼液氨氮回收动态实验研究。结果表明:随着透气膜分离氨氮回收实验装置的运行,沼液氨氮浓度总体下降明显,提取液氨氮浓度呈先线性增加而后稳定在一定水平的变化规律;运行396 h后沼液氨氮去除率可达91.2%;根据氨氮回收速率的变化,装置运行过程可分为氨氮回收(0~252 h)和损失(252~420 h)两个阶段;氨氮回收阶段,提取液氨氮浓度小于10000 mg·L^-1,单位体积氨氮平均回收速率为1190 mg·L^-1·d^-1,氨氮损失阶段,提取液氨氮浓度平稳保持在11200~12180 mg·L^-1,单位体积氨氮平均回收速率仅为35 mg·L^-1·d^-1。若要令该工艺更为高效运行,可考虑增强沼液反应槽密封性,以降低沼液中气态NH₃的挥发损失,另外可将提取液pH是否超过7确定为是否应更换新提取液的指示参数。利用国产透气膜构建的沼液氨氮回收工艺过程可有效回收沼液氨氮,回收率接近80%。

Recovery of ammonia nitrogen from biogas slurry of digested livestock manure using indigenous tubular gaspermeable membrane

Dynamic experimental studies were conducted to explore the feasibility and practicality of recovering ammonia nitrogen from biogas slurry of livestock manure using an experimental device configured by an indigenous tubular gas-permeable membrane. The results showed that the ammonia nitrogen content in the biogas slurry decreased significantly, whereas the ammonia nitrogen content in the extract solution increased linearly and then stabilized at a high level. After 396 h of device operation, 91.2% of the ammonia nitrogen in the biogas slurry was removed. Based on the variations in the ammonia recovery velocity, the operating time of the device was divided into two stages, the ammonia recovery stage(0~252 h) and the ammonia loss stage(252~420 h). At the ammonia recovery stage, the ammonia nitrogen content of the extracted solution was <10 000 mg·L^-1 and the average ammonia nitrogen recovery velocity per unit volume was 1 190 mg·L^-1·d^-1. At the ammonia loss stage, the ammonia nitrogen content of the extracted solution remained stable ranging from 11 200 to 12 180 mg·L^-1, and the average ammonia nitrogen recovery velocity per unit volume was 35 mg·L^-1·d^-1. For efficient ammonia extraction, it is recommended to keep the biogas slurry reaction tank airtight to reduce the volatilization of gaseous NH₃. Additionally, when the pH of the extract exceeds 7, it can be used as an indicator for replacing the extract solution with a fresh solution. Ammonia nitrogen could be effectively recovered from biogas slurry using an indigenous tubular gas-permeable membrane with a recovery efficiency of about 80%.