CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

This report describes research conducted between January 1, 2004 and March 31, 2004 on the use of dry regenerable sorbents for removal of carbon dioxide from flue gas. RTI has produced laboratory scale batches (approximately 300 grams) of supported sorbents (composed of 20 to 40% sodium carbonate) with high surface area and acceptable activity. Initial rates of weight gain of the supported sorbents when exposed to a simulated flue gas exceeded that of 100% calcined sodium bicarbonate. One of these sorbents was tested through six cycles of carbonation/calcination by thermogravimetric analysis and found to have consistent carbonation activity. Kinetic modeling of the regeneration cycle on the basis of diffusion resistance at the particle surface is impractical, because the evolving gases have an identical composition to those assumed for the bulk fluidization gas. A kinetic model of the reaction has been developed on the basis of bulk motion of water and carbon dioxide at the particle surface (as opposed to control by gas diffusion). The model will be used to define the operating conditions in future laboratory- and pilot-scale testing