Evaluation of Solid Sorbents for Post-Combustion CO2 Capture

Solids-based temperature swing systems for post-combustion CO₂ capture have the potential to significantly reduce projected CO₂ control costs.  Many sorbents have low heat capacity and relatively high CO₂ working capacity, which could result in a lower regeneration energy compared to leading solvent-based systems.  ADA Environmental Solutions, through a DOE Cooperative Agreement and support from EPRI and several power industry partners, is evaluating the viability of solid sorbent processes for post-combustion CO₂ removal on coal-fired power plants.  Such an evaluation includes not only assessment of the sorbents, but also the related process and equipment.  As a first step, fixed bed laboratory-scale screening of over 140 materials has been used to draw general conclusions concerning the state of development of different types of materials.  The isotherms for several different materials as well as a discussion of how these isotherms were used will be provided.  Laboratory results were used to select the most promising materials for characterization in a bench-scale (1 kW) system.  This 1 kW pilot was installed on a slipstream of flue gas extracted from a power plant firing a blend of lignite and Powder River Basin coals.  This presentation will include an overview of the characteristics of promising sorbents, a description of a preliminary commercial scale process concept, and results of parametric testing to date.  Technical hurdles that must be overcome before this technology can move towards commercialization will also be discussed.