氨水合物反应体系氨逃逸约束和二氧化碳吸收强化的定向传质调控研究

Ammonia hydrate based chemical reaction system plays important roles in the removal of pollutant and greenhouse gases, but the ammonia escape from hydrate may result in a serious fine particulate matter pollution in ambient environment. Based on the carbon dioxide absorption in ammonia solution with the targeted mass transfer regulation for the ammonia escape restriction and carbon dioxide absorption enhancement, the modeling and solution approaches for the gas-liquid two phase multi-component and multi-physics transportation accompanying chemical reaction will be developed, and the novel potentials between the molecular diffusion mass transfer driving potential and the chemical covalent bond energy are introduced. By means of the hydrogen bond between the organic additive and ammonia, as well as the coordinate bond between the inorganic additive and ammonia, the ammonia escape will be restrained. The bond energy will be used to obtain the available organic and inorganic additives, and the types and proportions of additives to enhance the carbon dioxide absorption and restrain the ammonia escape will be achieved. The metal organic framework will be fabricated by the metallic ion and organic base as the packing of carbon dioxide absorption. By the experimental test and numerical simulation, the reliable integration of metallic ion and organic base as well as the optimized three dimensional configuration for the metal organic framework will be recommended to improve the carbon dioxide absorption and restrict the ammonia escape. This project can enhance the interdisciplinary integration of engineering thermal physics and chemical engineering, and provide the viable guidance and suggestions for the environmental protection and greenhouse gas control in China.

氨水合物化学反应体系在污染物和温室气体脱除中发挥着重要作用，但存在氨逃逸致大气环境细颗粒物污染加剧的缺陷。项目以氨法CO2吸收过程为对象，以氨逃逸约束和CO2吸收强化的定向传质调控为目标，开发伴有化学反应的气液两相多组分多物理量输运过程的建模和求解方法，提出引入介于氨分子扩散传质势差和化学共价键键能之间的弱化学作用势以实现定向传质调控的思路。针对氨水合物中有机添加剂和氨形成氢键，无机添加剂和氨形成配位键的技术途径，通过键能优化匹配比选，获得提高CO2吸收性能及抑制氨逃逸传质速率的有机和无机添加剂类型及配比。以金属离子和有机配体制备金属有机骨架结构作为CO2吸收反应的填料，借助实验和数值模拟研究，得到金属有机骨架填料的材料合理组合形式及优化的三维空间结构，实现高效CO2吸收和氨逃逸约束。本项目将促进工程热物理和化学工程学科的交叉融合，为我国环境保护和温室气体减排提供一定的理论和实践指导意义。

以氨作为吸收剂的脱硫、脱硝、脱碳方法普遍存在氨逃逸问题，有效地控制氨逃逸成为当前我国环境保护必须解决的一个重要问题，对我国碳捕集技术的发展与进步具有重要意义。项目以氨法脱碳系统为研究对象，基于拟单相模型和双膜理论，并结合表征体元法建立了填料塔内部伴有化学反应的气液两相流动的组分输运数值计算模型，将气液两相流动、CO2化学吸收过程、氨逃逸传质过程以及气液两相热量输运过程进行了耦合计算，并充分考虑了系统能耗。在深入分析气液两相间热质输运特性的基础上，揭示了跨尺度气液两相间多组分输运规律和反应器结构参数对多组分输运影响机理，提出了适应复杂多组分输运特性的反应器设计原则。项目执行期间，搭建了氨法碳捕集与解吸实验台，考察了在不同有机添加剂浓度与种类条件下氨水吸收CO2过程中CO2吸收效果与氨逃逸约束的变化规律，分析与揭示了造成相应影响与变化的微观化学机理。以氨法脱碳鼓泡塔系统为基础，探究了低温条件下无机离子添加剂对氨法脱碳的影响规律以及冷冻氨工艺和无机离子添加剂抑制氨逃逸工艺结合的可能性。本项目的开展，在一定程度上深化了对气液两相流输运过程物理机理的认识，为碳捕集技术中氨逃逸抑制的利用提供了新的思路和方法。项目获得的气液两相间多组分输运规律和反应器结构参数对多组分输运影响机理，以及低温条件与添加剂共同氨逃逸抑制耦合作用机理，为氨法脱碳技术的发展奠定了理论基础。