沼液膜蒸馏资源化利用中NH3、CO2和H2O(g)的传质定向调控机制

沼液氨氮的资源化回收与利用对于降低环境风险与促进农业循环经济具有重要意义。但现有沼液氨氮回收过程中化学品与能源消耗量大，进而导致氨氮回收成本和碳足迹偏高。本项目拟采用膜蒸馏技术从沼液中分离获得氮肥，大幅降低温室气体排放与沼液处理成本。通过开展膜蒸馏选择性分离CO2与NH3实验，研究CO2与NH3的传质定向调控机制，开展全生命周期评估，并构建低碳足迹与低成本的沼液氨氮回收路径。开展膜蒸馏回收氨氮长期实验，表征膜表面污染物特性并推演其形成规律，计算不同程度膜污染对NH3与H2O(g)的传质阻力，解析污染层对NH3与H2O(g)的传质影响机理，建立膜蒸馏低能耗回收沼液氨氮的长效模式。对膜蒸馏回收沼液氨氮进行综合评估并阐释沼液CO2、NH3与H2O(g)的传质定向调控机制，期望为沼液氨氮回收与综合利用提供一种新思路和新方法。

The recycling and utilization of ammonia nitrogen in biogas slurry is of great significance for reducing environmental risks and promoting agricultural circular economy. However, the large chemical and energy consumptions result in high cost and carbon footprint during biogas slurry ammonia recovery process. This project intends to use membrane distillation technology to recover nitrogen fertilizer from biogas slurry. It is anticipating reducing the greenhouse gas emissions and cost during biogas slurry treatment process. Membrane distillation experiment for selective separation of CO2 and NH3 will be carried out to study the mass transfer and directional regulation mechanism. Then the low carbon footprint and low-cost ammonia nitrogen recovery pathway will be constructed by combining the experimental results and life cycle assessment. According to the long-term membrane distillation experiment, fouling characteristic on the membrane surface will be tested to analysis its formation rules. By calculating NH3 and H2O(g) mass transfer resistance results from different degrees of membrane fouling, the mass transfer mechanism of NH3 and H2O(g) in the fouling membrane will be explained. Then a long-term model of biogas slurry ammonia recovery process characterized by low energy consumption will be established. Finally, membrane distillation used for ammonia recovery from biogas slurry will be comprehensively evaluated, and the directional regulation mechanism of NH3, CO2 and H2O(g) mass transfer from biogas slurry will be analyzed. It is expected to provide a new idea and method for ammonia recovery and comprehensive utilization of biogas slurry.