Flue Gas Carbon Dioxide Sequestration during Water Softening with Ion-Exchange Fibers

Abstract

This study examines the use of ion-exchange fibers (IX fibers) to permanently sequester carbon dioxide present in flue gas into an aqueous phase as calcium or magnesium alkalinity while concurrently softening hard water. The only process inputs besides carbon dioxide (or flue gas) are snowmelt (or rainwater); no other chemicals are required for the regeneration of the IX fibers. Importantly, the process is not energy intensive and carbon dioxide does not need to be compressed to excessive pressures (>150 psi) for efficient use. Sources of carbon dioxide do not require concentration and, therefore, the use of raw flue gas ( ∼17% C O2 ) is feasible with the rate of sequestration governed only by the partial pressure of carbon dioxide. While valid for flue gas obtained from any combustion process (e.g., coal, oil, natural gas, etc.), emissions from oil or gas combustion may be more appropriate for use in the described process due to the absence of mercury and particulates. It should also be noted that the pr...