纳米颗粒强化CO2吸收的作用规律及微观机理研究

Nowadays, researchers pay more attentions to strengthen the gas absorption in the absorption solution by adding nanoparticles, which is of great significance for CO2 capture and other industrial processes. Previous studies mainly obtain the macroscopic effect of absorption enhancement by nanoparticles based on macroscopic experiments, but the understanding of the microscopic characteristics of nanoparticles in the absorption process is largely deficient, hindering in-depth study of gas-liquid mass transfer process. This project will focus on the process of CO2 absorption by nanoparticle-added organic amine. On one hand, macroscopic experiments of CO2 absorption in nanofluids in both a stirred tank reactor and a bubble reactor will be carried out to study the influence of macroscopic experimental parameters on the mass transfer rate, and establish relations between the mass transfer rate and the experimental parameters. On the other hand, microscopic observation of nanoparticles in the absorption process will be carried out on the TIRF testbed, and microscopic characteristics such as particle distribution, particle speed will be determined and relations between the mass transfer rate and microscopic characteristics of nanoparticles are to be established. Finally, the obtained microscopic and macroscopic characteristics of CO2 absorption in nanofluids will be compared with the existing strengthening mechanism of gas-liquid mass transfer, to explore the microscopic mechanism of gas-liquid mass transfer enhanced by nanoparticles. Based on in-depth microscopic experimental observation, this project aims at obtaining the mechanism of gas-liquid mass transfer enhanced by nanoparticles, and providing theoretical guidance for strengthening gas-liquid absorption.

在吸收液中添加纳米颗粒来强化气体吸收受到广泛关注，对CO2捕集等工业过程具有重要意义。之前研究主要基于宏观实验来获得纳米颗粒强化吸收的宏观效果，对纳米颗粒在吸收过程的微观特性缺乏充分认识，影响了对气液传质过程的深入研究。本项目以加入纳米颗粒的有机胺溶液吸收CO2过程为研究对象。一方面，在搅拌釜和鼓泡反应器中进行纳米流体吸收CO2宏观实验，研究宏观实验参数对传质速率的影响规律，建立传质速率与各宏观实验参数的关联式。另一方面，在TIRF实验台上对吸收过程的纳米颗粒进行微观观测，确定颗粒分布、速度等微观特性，并建立传质速率与颗粒微观特性参数的定量关系。最后，结合获得的颗粒微观特性和宏观实验结果，分析当前存在的强化气液传质机理与本实验发现的匹配结果，探索纳米颗粒强化气液传质的微观作用机理。旨在基于深入地微观特性实验观测，获得纳米颗粒强化气液传质的作用规律及机理发现，为强化气液吸收提供理论指导。

气液传质广泛存在于工业领域中，强化气液传质不仅可以提高系统的传质效率，降低传质设备的尺寸，而且可以减少传质过程中的能耗，实现低能耗高效率的生产。正是基于以上原因，需要对气液传质过程进行强化。在气液两相体系中加入第三分散相固体颗粒是强化气液传质的一个重要方法。本项目不仅通过纳米颗粒强化MEA/MDEA鼓泡吸收二氧化碳的实验揭示了纳米颗粒种类、固含量、粒径、混合气体流速、混合气体中二氧化碳浓度等宏观实验参数对气液传质的影响规律，同时，针对纳米流体鼓泡吸收二氧化碳建立了相关模型并对其可靠性进行了验证。纳米颗粒的微观运动虽然很小，但较液体分子的运动来说仍然较大，其对纳米流体的传质机理有着至关重要的作用，为此项目组通过可视化微观实验对强化传质过程中纳米颗粒的微观特性进行了充分的研究，并且通过相关实验建立了纳米颗粒微观特性和传质系数之间的联系。此外，项目组还结合实验结果以及对强化传质过程中纳米颗粒微观特性的认识，进一步从微观上探索了纳米颗粒强化气液传质的机理，从而为纳米颗粒强化气液传质的深入研究提供理论基础和技术参考。