CO2捕捉转极性溶剂体系及其流动与传质强化

Absorption is the main CO2 capture method to reduce the carbon emission. Most of the energy was consumed in regeneration process. It is desirable to develop novel absorption solvent systems with low desorption heat and low volatility. The mixture of DBU and glycerol is a promising CO2 absorbent due to its high CO2 absorption capacity and low specific heat. However, the viscosity of the DBU/glycerol solvent increases with the absorption of CO2 which could lead to serious flow and mass transfer problems. This proposal is aimed to develop a novel rotating disk reactor with intensified mixing and mass transfer performance for highly viscous gas-liquid system by high shear force. To develop a novel CO2 capture system with low energy cost and obtain the necessary process data, the physical chemical properties of DBU/glycerol solution and their changes during the absorption process will be studied. The kinetics of absorption and desorption will be investigated. Also the gas-liquid flow model in the rotating disk reactor will be developed and the operation parameters will be optimized. Studying on the formation mechanism of liquid film, interphase mass transfer rate, modeling the liquid phase concentration field under various flow conditions will provide fundamental understanding on the mass transfer and reaction mechanism of the DBU/glycerol/ CO2 system. The correlation between the inner structure of the reactor and the removal efficiency of CO2 will be built up by examining the flow pattern and mass transfer intensification mechanism. This project will provide basic thermodynamic properties, kinetic data and theoretical support for the application of the highly viscous gas-liquid system and the development of highly efficient contactor for such system.

CO2捕集减排过程中，溶剂再生是CO2吸收能耗最高的环节。DBU/甘油等CO2解吸能低的新型吸收剂体系，可以大幅降低溶剂再生能耗。构建新型旋转盘式吸收反应器，可以在较低气相阻力下实现高粘度吸收体系的两相分散，同时利用旋转形成的高剪切作用的流场强化气液传质。研究DBU/甘油溶剂体系吸收CO2的基础物化性质变化规律，测定吸收-再生反应动力学数据，建立旋转盘式吸收反应器内气液两相流动模型，优化操作条件，为低能耗CO2捕捉新工艺开发提供必要的基础数据。通过对旋转盘式高粘度液膜分散性能、气液两相膜界面传质速率测试、液膜内浓度分布模拟，对新吸收溶剂体系的反应和传质机理进行全面的认识，为高粘度气液体系的传质和反应过程提供重要的科学依据。研究结果将为高粘度吸收体系的应用和高效吸收设备的开发提供基础数据和理论支持。

本项目针对醇胺溶液捕集二氧化碳再生能耗高的问题，提出以具有高CO2吸收容量的DBU-甘油溶液为吸收剂，降低体系的比热和再生过程中溶剂的汽化热，进而降低解吸能耗。针对DBU-甘油粘度大的问题，建立旋转盘式吸收反应器在较低气相阻力下强化高粘度体系的分散，强化两相传质。本项目对DBU-甘油体系吸收CO2前后的基础热力学物性数据进行了详细的测量和系统的研究，建立了密度、表面张力、粘度以及电导率与组成、CO2吸收量之间的定量关系；通过对体系吸收解吸CO2过程的详细探索和研究，获得了具有高效低再生能耗的用于CO2捕集的DBU/甘油体系的组成，建立了DBU-甘油体系吸收和解吸CO2的动力学方程；设计并建立了一套旋转盘式吸收反应器，优化DBU-甘油体系吸收CO2操作条件，并对反应器内的气液流动状态和传质速率进行测定，研究了反应器内部结构对液体流动状态和吸收速率的影响，为新型吸收剂的进一步应用和高粘度体系气液传质过程反应器的开发提供了详实的基础数据和理论支持。