(71c) New Water-Lean Amine-Based Solvents for Carbon Dioxide Capture with Low Regeneration Energy

Authors: 
Koech, P. K., Pacific Northwest National Laboratory
Malhotra, D., Pacific Northwest National Laboratory
Heldebrant, D. J., Pacific Northwest National Laboratory
Cantu, D. C., Pacific Northwest National Laboratory
Glezakou, V. A., Pacific Northwest National Laboratory
Zheng, F., Pacific Northwest National Laboratory
Rousseau, R., Pacific Northwest National Laboratory
Bearden, M., Pacific Northwest National Laboratory
Carbon dioxide capture and storage (CCS) of anthropogenic CO2 released from large point sources such as coal fired power plants is required in order to mitigate adverse environmental effects like climate change. Toward this goal numerous CO2 capture processes have been developed, the most advanced technology utilizes aqueous solutions of primary and secondary alkanolamines such as MEA or diethanolamine (DEA) for chemical absorption of CO2. The regeneration energy of these aqueous amine solvents is very high due to the high heat capacity of water. To address this problem water-lean transformational solvent systems have been developed. As part of an ongoing program studying multiple solvent chemistries and combining the key findings from different solvent classes, we have developed a new class of water-lean non-aqueous amine-based solvents with potential to be energy efficient CO2 capture materials. These amines bind CO2 at standard temperature and pressure (STP) to form liquid carbamate salts with high gravimetric capacity ~ 20 wt%. These solvents have low thermal regeneration temperature (70-100 °C) and low CO2â??rich solvent viscosity compared to other water-lean materials. The regeneration temperature can be lowered to 60 °C by applying polarity swing assisted regeneration (PSAR) making it feasible to utilize lower grade heat from the power plant for CO2 stripping resulting in energy savings.