Sulfurization- Desulfurization of Iron-Calcium Oxygen Carriers during Chemical Looping Combustion of Syngas

• Published in: Aerosol and air quality research Vol. 24; no. 2; pp. 220398 - 11
• Main Authors: Chen, Yu-Lun, Ku, Young, Chang, Ya-Chun
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.02.2024; Springer
• Subjects: Atmospheric Protection/Air Quality Control/Air Pollution; CaO/Fe2O3 oxygen carrier; Chemical looping combustion; Climate Change/Climate Change Impacts; Environment; Environmental Health; Original Research; Sulfurization desulfurization; oxygen carrier; Sulfurization desulfurization; CaO/Fe; Chemical looping combustion; O
• ISSN: 1680-8584; 2071-1409
• DOI: 10.4209/aaqr.220398

Chemical looping combustion of SO 2 -containing syngas with various fabricated iron-calcium oxygen carriers was studied to comprehend the sulfurization and desulfurization of oxygen carriers during combustion. Experimental results indicated calcium-iron oxygen carriers fabricated with CaO:Fe 2 O 3 weight ratio of 3:7 and calcined at 800°C (CaFe-378) was suitable for chemical looping combustion of syngas. CaFe 2 O 4 was noticed to be the dominant crystalline phase in CaFe-378 even after 10 redox operations. Reduction kinetics for chemical looping combustion of both H 2 or CO in syngas with CaFe-378 were adequately described by the 2-dimension diffusion model. The activation energies of H 2 and CO with CaFe-378 were determined to be 35.4 kJ mol −1 and 46.0 kJ mol −1 , respectively. Calcium sulfide (CaS) was generated during the chemical looping combustion of SO 2 -containing syngas with CaFe-378. CaS was further oxidized to CaSO 4 on the surface of CaFe-378 during air regeneration, which might inhibit the complete regeneration of iron oxides. Satisfactory regeneration of sulfurized oxygen carriers was accomplished by introducing hydrogen after the air-regeneration because of the reduction of calcium sulfate to calcium oxide.