Cyclic effects of sulfur deposition on CO2 by vacuum pressure swing adsorption from blast furnace gas

Abstract

Vacuum pressure swing adsorption has a high potential to reduce CO₂ from blast furnace gas, while there are also H₂S and COS exist in the blast furnace gas, and the sulfur deposition effect on CO₂ adsorption over zeolite was quite necessary to be investigated. In this work, laboratory fixed bed evaluation and two-tower pressure swing adsorption apparatus were employed and it has been found that sulfur deposition occurs only in the presence of coexisting H₂S and O₂ without water and the highest sulfur accumulation is 13.21 % for the adsorbent under CO₂+H₂S+COS+O₂ atmosphere. Cyclic evaluation of H₂S and COS on CO₂ cyclic adsorption was first reported, and the sulfur is ultimately converted into S monomers and sulfate, which can be deposited inside the pore channel, with the specific surface area reduced 82.26 % of the adsorbent. Furthermore, sulfur deposition gradually diffused with the upward shift of the adsorption mass transfer zone, and the sulfur deposition densities are calculated to be approximately 0.34 g/cm³. These mechanisms and data demonstrate the significant impact of sulfur deposition on sustainable CO₂ capture in industrial processes, and provide important guidance for the design of CO₂ capture technologies, which is of great importance for carbon reduction.