RATIONAL DESIGN AND DEVELOPMENT OF ENERGY EFFICIENT CO2-BINDING ORGANIC LIQUIDS FOR FLUE GAS CLEAN UP

摘要

Carbon dioxide is the most important anthropogenic greenhouse gas and its concentration in the atmosphere has significantly increased from 280 ppm in mid-18~(th) century to 402.5 ppm today. It's critical to capture and sequester CO2 in order to mitigate the potential impacts on environment as well as climate change. In this context, liquid systems lie at the heart of CO2 capture, and aqueous amines, such as monoethanolamine (MEA), are amongst the forerunners for CO2 capture from flue gas. Although, they have low CO2-rich viscosity, fast kinetics and favorable thermodynamics, their energy requirements are prohibitively high. The high heat capacity of water in these solvents leads to tremendous increase in costs of thermal solvent regeneration. Water-lean transformational solvent platforms have been identified as an alternative to address these critical challenges. These systems include nano-material organic hybrids (NOHMs), task-specific, protic and reversible ionic liquids, and phase change solvents. They use current knowledge and infrastructure, and therefore present attractive substitute for MEA technology. In the past few years our group has developed, water-lean transformational solvents known as CO2 binding organic liquids (CO2BOLS) that have the potential to be energetically-viable CO2 capture solvents. The CO2BOL solvent platforms operate on the principles of switchable ionic liquid technology, which enables the distinctive Polarity Swing Assisted Regeneration (PSAR) to facilitate the regeneration of CO2BOL solvents (Figure 1) by decreasing reboiler temperatures as much as 73 °C. These zwitterionic liquids are formed when non-ionic alkanolguanidines react with CO2 to form guanidinium alkyl carbonate as ionic liquids with high polarity. These solvent systems have shown excellent CO2 uptake, acceptable mass transfer, and favorable thermodynamics, albeit at higher viscosities.