title: Sequestration of flue gas CO₂ by direct gas-solid carbonation of air pollution control system residues.
abstract: Direct gas-solid carbonation reactions of residues from an air pollution control system (APCr) were conducted using different combinations of simulated flue gas to study the impact on CO₂ sequestration. X-ray diffraction analysis of APCr determined the existence of CaClOH, whose maximum theoretical CO₂ sequestration potential of 58.13 g CO₂/kg APCr was calculated by the reference intensity ratio method. The reaction mechanism obeyed a model of a fast kinetics-controlled process followed by a slow product layer diffusion-controlled process. Temperature is the key factor in direct gas-solid carbonation and had a notable influence on both the carbonation conversion and the CO₂ sequestration rate. The optimal CO₂ sequestrating temperature of 395 °C was easily obtained for APCr using a continuous heating experiment. CO₂ content in the flue gas had a definite influence on the CO₂ sequestration rate of the kinetics-controlled process, but almost no influence on the final carbonation conversion. Typical concentrations of SO₂ in the flue gas could not only accelerate the carbonation reaction rate of the product layer diffusion-controlled process, but also could improve the final carbonation conversion. Maximum carbonation conversions of between 68.6% and 77.1% were achieved in a typical flue gas. Features of rapid CO₂ sequestration rate, strong impurities resistance, and high capture conversion for direct gas-solid carbonation were proved in this study, which presents a theoretical foundation for the applied use of this encouraging technology on carbon capture and storage.
authors.affiliation: School of Environment,  Tsinghua University , 100084 Beijing, PR China.
authors.forename: Sicong
authors.initials: S
authors.lastname: Tian
authors.forename: Jianguo
authors.initials: J
authors.lastname: Jiang
mesh_terms: D000397:Air Pollution / Q000517:prevention & control*; D002245:Carbon Dioxide / Q000032:analysis*; D002254:Carbonates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000032:analysis; D013458:Sulfur Dioxide / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D002254:Carbonates; D008903:Minerals; D013458:Sulfur Dioxide; D002245:Carbon Dioxide