Reducing CO 2 Emissions of a Coal-Fired Power Plant via Accelerated Weathering of Limestone: Carbon Capture Efficiency and Environmental Safety

• Published in: Environmental science & technology 2020-04, Vol.54 (7), p.4528-4535
• Main Authors: Kirchner, Julia S, Berry, Andrew, Ohnemüller, Frank, Schnetger, Bernhard, Erich, Egon, Brumsack, Hans-Jürgen, Lettmann, Karsten A
• Format: Article
• Language: English
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/acs.est.9b07009

Reducing CO emissions is a key task of modern society to attenuate climate change and its environmental effects. Accelerated weathering of limestone (AWL) has been proposed as a tool to capture CO from effluent gas streams and store it primarily as bicarbonate in the marine environment. We evaluated the performance of the biggest AWL-reactor to date that was installed at a coal-fired power plant in Germany. Depending on the gas flow rate, approximately 55% of the CO could be removed from the flue gas. The generated product water was characterized by an up to 5-fold increase in alkalinity, which indicates the successful weathering of limestone and the long-term storage of the captured CO . A rise of potentially harmful substances in the product water (NO , NO , NH , SO , and heavy metals) or in unreacted limestone particles (heavy metals) to levels of environmental concern could not be observed, most likely as a result of a desulfurization of the flue gas before it entered the AWL reactor. At locations where limestone and water availability is high, AWL could be used for a safe and long-term storage of CO .