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Low-Temperature Carbon Capture Using Aqueous Ammonia and Organic Solvents
journal contribution
posted on 2016-07-28, 18:50 authored by Ethan
J. Novek, Evyatar Shaulsky, Zachary S. Fishman, Lisa D. Pfefferle, Menachem ElimelechCurrent postcombustion CO2 capture technologies are
energy intensive, require high-temperature heat sources, and dramatically
increase the cost of power generation. In this work, we introduce
a new carbon capture process requiring significantly lower temperatures
and less energy, creating further impetus to reduce CO2 emissions from power generation. In this process, high-purity CO2 is generated through the addition of an organic solvent (acetone,
dimethoxymethane, or acetaldehyde) to a CO2 rich, aqueous
ammonia/carbon dioxide solution under room-temperature and -pressure
conditions. The organic solvent and CO2-absorbing solution
are then regenerated using low-temperature heat. When acetone, dimethoxymethane,
or acetaldehyde was added at a concentration of 16.7% (v/v) to 2 M
aqueous ammonium bicarbonate, 39.8, 48.6, or 86.5%, respectively,
of the aqueous CO2 species transformed into high-purity
CO2 gas over 3 h. Thermal energy and temperature requirements
for recovering acetaldehyde, the best-performing organic solvent investigated,
and the CO2-absorbing solution were 1.39 MJ/kg of CO2 generated and 68 °C, respectively, 75% less energy than
the amount used in a pilot chilled ammonia process and a temperature
53 °C lower. Our findings exhibit the promise of economically
viable carbon capture powered entirely by abundant low-temperature
waste heat.