基于超声雾化再生和半渗透膜技术的热泵驱动型溶液除湿系统研究

Dehumidifier and regenerator are the two core components of liquid desiccant system. The packed-column dehumidifier has the trouble of liquid carryover in the processed air, and hence, it is very necessary to develop semi-permeable membrane dehumidifier. But the semi-permeable membrane has high resistance of mass transfer, which results in low working efficiency of dehumidifier. Two measures can be taken to improve the working efficiency of the membrane-type solution dehumidifier: one is to develop semi-permeable membrane materials with high permeability of water vapor, and the other is to improve the working conditions of the membrane-type solution dehumidifier, such as increasing inlet concentration of solution through improving the working performance of solution regenerator. Ultrasonic atomization will produce a gas-liquid reaction area of many times larger than that of a packed column, and it is expected to develop a solution regenerator with super-high performance which provides the stronger solution for the membrane-type solution dehumidifier. Based on this, this project proposes a heat-pump driven solution dehumidification system with the ultrasonic atomizing regenerator and the semi-permeable membrane dehumidifier, and meanwhile, it makes a theoretical study on the issues related to the new type solution dehumidification system including the collision mechanism and the heat-and-mass transfer characteristics of atomization droplets, thermodynamics of ultrasonic atomizing regenerator, semi-permeable fiber membrane materials, mass transfer mechanism of semi-permeable fiber membranes, thermodynamics of membrane-based dehumidifier, matching optimization and dynamic coupling characteristics between dehumidification system and heat pump system. The research contents in this project will lay a theoretic foundation for developing the safe and efficient solution desiccant system and have high scientific theoretical value and practical significance.

除湿器和再生器是溶液除湿系统两大核心部件。填料塔式除湿器存在空气“带液”问题，很有必要发展半渗透膜溶液除湿器，但半渗透膜传质阻力大使得除湿器工作效率低，为此，一方面需研发水蒸气渗透率高的半渗透膜材料，另一方面可改善半渗透膜溶液除湿器工作条件(如增加溶液进口浓度)。超声波雾化将产生比填料大许多倍的单位体积气-液反应面积，有望开发超高性能溶液再生器，为半渗透膜溶液除湿器提供更高浓度的除湿溶液。基于此，本课题提出以超声波雾化再生器和半渗透膜溶液除湿器为基础的新型热泵驱动型溶液除湿系统，并对该系统及关键部件进行基础理论研究，包括雾化液滴碰撞机制及传热传质动态特性研究，超声波雾化再生器热力学研究，半渗透纤维膜材料研究，半渗透纤维膜传质机理及其组件热力学研究，除湿系统与热泵系统之间匹配优化及动态耦合特性研究。本课题研究为开发安全高效溶液除湿系统奠定理论基础，具有很高的科学理论价值和实际意义。

本课题针对当前溶液除湿技术存在的空气“带液”问题和除湿效率低的问题，提出以超声波雾化再生器和半渗透膜溶液除湿器为基础的新型热泵驱动型溶液除湿系统，并对该系统及关键部件进行基础理论研究，包括雾化液滴碰撞机制及传热传质动态特性研究，超声波雾化再生器热力学研究，半渗透纤维膜材料研究，半渗透纤维膜传质机理及其组件热力学研究，除湿系统与热泵系统之间匹配优化及动态耦合特性研究。研究内容主要包括：.（1）研究了除湿溶液超声波雾化液滴粒径影响因素，包括工作频率，流量，功率，液相粘度及液相张力；.（2）研究了除湿溶液超声波雾化再生热力学模型，结合实验数据对超声波雾化再生器进行热力学参数分析和结构优化研究；.（3）研究了溶液膜除湿器动态特性模型，结合实验数据对溶液膜除湿器动态特性进行热力学参数分析研究；.（4）研究了基于PVDF疏水材料的溶液除湿半渗透膜性能；.（5）研究了内冷型半渗透膜溶液除湿器热力学性能；.（6）研究了关键运行参数对除湿系统性能影响，利用热力学㶲理论分析了除湿循环各过程的能量损失本质。.研究成果主要有：.（1）成功研发了适合于除湿溶液再生的PVDF-TPU半渗透复合纤维膜，具有水蒸气渗透系数高，不容易被除湿溶液污染，且机械强度高等，在溶液除湿系统中将具有较高的推广引用价值；.（2）构建了逆流式超声雾化溶液再生器优化设计模型，为后续应用奠定了理论基础。.（3）构建了错流半渗透膜溶液除湿器优化设计模型，为后续应用奠定了理论基础。.（4）构建了以热泵系统为驱动力，半渗透膜溶液除湿器和超声波雾化再生器为核心组件的热泵溶液除湿系统理论分析模型，为该系统推广应用提供了重要理论依据。