Development of efficient CO2 removal sorbents from flue gas is very critical for achieving successful processes for CO2 emission control from existing coal combustion power plants. The moisture content of the power plant's flue gas has long been an issue for many types sorbents used for CO2 separation because the sites which attract the CO2, also attract H2O.  Materials such as zeolite 13X, have shown great promise for CO2 capture with acceptable CO2 capture capacities, low heat of reactions, and low sensible heat which contribute to low energy penalty for CO2 removal.  However, when moisture is present in the gas stream a high temperature is required to regenerate the strongly adsorbed H2O molecules on the zeolite making the process more energy intensive.  Many amine based sorbents also suffer from high moisture content via irreversible reactions resulting in unstable performance. The purpose of this study is to find a cost effective method for removing the moisture from the flue gas stream to effectively use the sorbents for CO2 separation.  Molecular sieve 4A from Van Air Industries has shown great promise for moisture removal in this study with a capacity over 11 moles of H2O per kilogram of sorbent (molH2O/kg).  However, to achieve this high of capacity requires high regeneration temperatures reducing the overall efficiency of the power plant. In order to reduce the energy consumption a partial regeneration by heating the sorbent to 120 �C was used and it resulted in an acceptable CO2 capture capacity of 4 molH2O/kg.  Furthermore, removing the moisture from the gas stream allows an effective use of a sorbent like zeolite13X for CO2 capture.  Preliminary energetic calculations indicate this process will be at least equal to, and potentially lower in energy consumption than current process modeled in NETL's baseline study.

Moisture removal for enhanced CO<sub>2</sub> separation from post-combustion flue gas

245th National Meeting (2013)

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Moisture removal for enhanced CO2 separation from post-combustion flue gas

Moisture removal for enhanced CO₂ separation from post-combustion flue gas