Improvement of dry desulfurization performance using activated calcium carbonate by amorphous citric acid complex method for diesel gas purification

Sulfur dioxide (SO₂) in combustion exhaust gas from medium-scale facilities must be removed because it pollutes the air. In this study, dry-DeSO_x filters, particularly calcium carbonate, that used simple desulfurization materials to capture SO₂ is focused on. Physically modified calcium compound, which is the main ingredient of marine waste such as scallop shell, was synthesized using the amorphous citric acid complex method to improve low-temperature desulfurization. The effects of reaction conditions such as calcination temperature and concentration of citric acid were investigated to obtain materials with high specific surface areas and desirable pore-diameter distribution. Calcium carbonate, with a specific surface area of 166 m²/g and pore diameter of 8 Å, was obtained under a 4:1 molar ratio of organic acid molecules to Ca²⁺ ions and 823 K calcination temperature. The desulfurization of the modified calcium carbonate was evaluated by thermogravimetric analysis for particle performance with calcium carbonate wash-coated onto a monolith to represent real-use conditions. All these results indicated that the desulfurization performance of the modified calcium carbonate was superior to that of commercially available calcium carbonate.