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MgO-based double salt absorbent for warm temperature CO2 capture


EMSL Project ID
48155

Abstract

CO2 absorbent development has gained great attention as a part of syngas clean up from fossil fuel gasification power plants, as well as other industrial applications which produce a highly concentrated stream of CO2 as a byproduct. For syngas clean-up, a warm temperature (300-500 degrees C) is preferred as it can eliminate the cooling/heating treatment of the gas stream that is required with liquid phase absorbents, where the cleaned-up syngas must be reheated for application. This improves thermal efficiency. Capture of CO2 from this syngas is also highly desirable, both to reduce greenhouse gas emissions and in some cases to facilitate syngas conversions that are equilibrium limited. To maintain the efficiency advantage, CO2 must also be captured and released at these warm temperatures. A MgO-based absorbent was reported by S. G. Mayorga (in a patent) to be able to capture CO2 at 375 degrees C with a capacity of 11 mmol/g. Others have had difficulty reproducing this performance and as well as even producing a consistent material. We have carried out work to develop an understanding of the role of nitrate salts (such as NaNO3) in facilitating this CO2 capture and release. More recently, we have found that mixed carbonate salts also function to facilitate CO2 capture in the absence of nitrates, and in some cases this facilitation occurs without generating a molten phase. There is a lack understanding of the absorption mechanism with these new materials, suggesting that detailed studies are required to improve the reproducibility, capacity, and understanding of these materials for CO2 capture.

Project Details

Start Date
2013-11-26
End Date
2014-09-30
Status
Closed

Team

Principal Investigator

David King
Institution
Pacific Northwest National Laboratory

Team Members

Keling Zhang
Institution
University of Connecticut

Prabhakar Singh
Institution
University of Connecticut

Mark Engelhard
Institution
Environmental Molecular Sciences Laboratory

Robert Dagle
Institution
Pacific Northwest National Laboratory

Xiaohong Li
Institution
Pacific Northwest National Laboratory