燃油纯化用纳米蛛网复合滤纸的可控构筑及其破乳/渗流机制研究

The current fuel paper with disadvantages of large pore size and low separation precision is incapable for the removing of emulsified water leading to serious engine corrosion, fuel nozzle blockage and other issues, which could not satisfy the requirements of the engine. Herein, we will investigate the boundary conditions of the formation of stacking nano-web membrane and the controllable construction of its composite filter paper, and reveal the influence of the synergistic effect of channels and wettability for the emulsified water separation performance, finally to obtain the fuel paper with high separation efficiency. Recently, we have preliminary prepared nano-web composite fuel paper via regulating the phase separation of electrostatic atomized droplets. However, its current performance can not fulfill the practical application requirements yet due to the defects of the nano-web. Consequently, we will study the controllable fabrication and oil/water emulsion separation performance optimization of the nano-web composite fuel paper, reveal the mechanism of the formation of the nano-web and structure regulation of fuel paper, as well as clarify the mechanism of emulsion coalescence-demulsification and oil percolation in the micro-nanoscaled gradient channels. Moreover, we will investigate the relationship between the bulk structure and application performance, achieving the target of separation efficiency ≥ 99.4% with a high flux ≥ 3000 L m-2 h-1, to fulfill the practical application in fuel purification.

当前燃油滤纸普遍存在孔径大、分离精度低的缺陷，无法高效去除燃油中的乳化水，易导致发动机锈蚀、喷油嘴堵塞等问题，难以满足发动机对高效燃油滤纸的迫切需求。本项目拟研究纳米蛛网堆叠膜的成型边界条件及其复合滤纸的可控构筑，明晰复合滤纸的孔道结构及润湿性的协同作用对乳化水分离性能的影响规律，从而获得具有高分离效率的燃油滤纸。近期申请者利用静电雾化液滴的相分离成网，初步获得了纳米蛛网复合滤纸，但其蛛网结构仍存在缺陷导致其乳化水分离性能未达到实际应用需求。本项目将开展纳米蛛网复合滤纸的可控构筑及其油/水乳液分离性能的优化研究，揭示纳米蛛网成型机制及其复合滤纸结构的调控规律，阐明复合滤纸微纳梯度孔道中的乳化水聚结破乳及油相渗流机制，明晰纳米蛛网复合滤纸的本体结构与应用性能间的内在关联，实现其高渗油通量（≥3000Lm-2h-1）条件下乳化水分离效率≥99.4%的目标，以满足其在燃油纯化领域的应用需求。

本课题“燃油纯化用纳米蛛网复合滤纸的可控构筑及其破乳/渗流机制研究”旨在明确纳米蛛网堆叠膜的蛛网结构成型的边界条件及其调控规律，揭示纳米蛛网复合膜表面润湿性及孔结构的优化调控机制，实现高分离效率高分离通量的纳米蛛网材料的可控制备及其在燃油纯化领域的应用。从2018年初到2021年底，开展了大量的实验研究工作：我们系统考察了高压电场作用下低粘度纺丝溶液的雾化过程，并深入研究了泰勒锥尖端荷电流体所受库伦斥力和表面张力间的竞争关系，探索了接收基材对喷网过程中微电场的影响规律，确立了纳米蛛网堆叠膜成型的边界条件，掌握了调控荷电液滴的形变/相变/自组装的科学方法；进一步分析了不同电流体动力学喷射模式下纳米蛛网复合膜表面粗糙结构的成型原因，探索了纳米蛛网复合膜孔结构的理化特性对乳化液滴的截留作用，揭示了孔道中乳化液滴的聚结破乳及油相渗流机制，实现了纳米蛛网复合膜表面润湿性和孔结构的有效调控；在上述研究的基础上，制备了多级粗糙结构纳米纤维膜、异质结构纳米纤维膜、类蜂窝结构纳米纤维膜等油水分离材料，通过研究材料的本体结构与其油/水乳液分离性能间的构效关系，揭示了纳米蛛网复合材料分离效率和渗流通量的协同优化机制。经过四年的研究，我们顺利完成了任务书中规定的任务，制备的纳米蛛网材料实现了分离通量≥3000L m-2 h-1、分离效率≥99.4%的目标。项目执行期间共培养博士6名，硕士3名。发表学术论文29篇，申请发明专利5项，授权专利5项。本课题的完成对探究纳米蛛网材料的破乳/渗流机制、实现其在燃油纯化领域的应用具有重要意义。