(471c) The Energetics of Chemical Looping Processes for Post Combustion CO2 Capture

Hugo S. Caram^*, Ramesh Gupta^#, Fan Ni^* and Hans Thomann^#

(*) Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA

(#)ExxonMobil Research and Engineering Inc., Annandale, NJ

A number of processes have been discussed where the CO₂ is removed from flue gases by chemical reaction with a solid sorbent. While calcium looping is the most celebrated, many others including carbonate-bicarbonate, reactions with mixed oxides, treated hydrotalcites and organic impregnated solids, such as MOFS, have been proposed. The equivalent work requirement, that is the most important variable, power that will be drawn from the power plant are usually only examined when a detailed process design and pilot testing has been completed.

In this work, a simple thermodynamic tool is proposed that will allow determination of the

minimum equivalent work needed by the process. The tool only requires thermochemical properties at room temperature and evaluates major thermal and irreversible losses. It can be used to determine the effect of process parameters, equipment configuration (such as fluidized vs. fixed or moving bed operation), steam usage and other variables. Applications to some of the existing processes, where the method could apply, will be presented.