离子液体高效低能耗选择性脱硫新过程

High sulfur coals with over 1wt% sulfur content, which are going to be the main coal resource instead of low sulfur coals, can produce high concentration of SO2 ( > 5000 ppm). Although limestone scrubbing and amine scrubbing as two attractive approaches have been applied widely in industries, there still are some inherent drawbacks, such as unrecoverable SO2 resulting in serious waste of sulfur resources and high energy consumption. Therefore, the development of new low energy consumption technologies for efficient and reversible capture of SO2 is of critical importance. In recent years, capturing SO2 with ionic liquids (ILs) is believed as one of the effective methods, but there are also some drawbacks, such as lower gravimetric absorption capacity, higher viscosity and poor stability. In order to solve these problems, the two key issues of the intermolecular interactions between ILs and SO2 and quantitative structure-property relationship will be focused. By a combination of simulation caculations and experimental methods, the interaction site, mode and intensity between ILs and SO2 will be systematically studied, and the interaction mechanisms will be obtained from the micro scale and molecular level. The project will also investigate the effect of cations and anions, clusters as well as interactions on physicochemical properties (such as thermal stability, viscosity) and SO2 absorption/desorption performances (such as gravimetric absorption capacity, selectivity and enthalpy), and establish the quantitative relationship of IL structures-physicochemical property-SO2 separation performances. Based on these studies, a series of novel functionalized pyridinium-based ILs with excellent absorption/desorption performances, high thermal stability, and low viscosity will be designed and synthesized. This project will provide theoretical guidance to develop a new energy saving technology for efficient and reversible capture and separation of SO2 by pyridinium-based ILs as absorbents.

中高硫煤逐渐替代低硫煤成为燃煤主体，导致其产生的SO2含量显著提高，传统脱硫方法已无法满足需求，如石灰石/石膏法SO2不可回收，硫资源严重浪费；有机胺法能耗高等。因此，开发高效低能耗可回收SO2的脱硫新方法是解决当前问题的关键。本项目拟利用离子液体结构和性质可精细调控、几乎不挥发的特点，重点围绕离子液体-SO2间相互作用机制和离子液体构效关系展开。结合实验表征与模拟计算，研究SO2与离子液体相互作用位点、方式和强度，获得离子液体与SO2间微观作用机理；研究阴阳离子、团簇结构、相互作用对其物性（稳定性、粘度等）和SO2吸收/解吸性能（质量吸收量、选择性和吸收焓等）的影响，建立离子液体结构-性质-分离性能定量关系。在此基础上，设计合成系列SO2吸收量大、易再生、选择性高、物化性质稳定、粘度低的吡啶类离子液体，为形成高效低能耗SO2分离新技术提供理论基础。