Performance of Perovskite-Type Oxides as Oxygen-Carrier Materials for Chemical Looping Combustion in the Presence of H sub(2)S

• Published in: Energy technology (Weinheim, Germany) Germany), 2016-10, Vol.4 (10), p.1305-1316
• Main Authors: Pishahang, Mehdi, Larring, Yngve, Sunding, Martin, Jacobs, Marijke, Snijkers, Frans
• Format: Article
• Language: English
• Subjects: Exchange; Fluidized bed combustion; Fluidized beds; Fluidizing; Oxides; Oxygen; Shape; Sulfur
• ISSN: 2194-4288; 2194-4296
• DOI: 10.1002/ente.201600177

In this study, the redox behavior and the effect of the presence of sulfur on the performance of the CaTi sub(x)Mn sub(0.9-x)Mg sub(0.1)O sub(3) perovskite-type system were investigated. A detailed thermodynamic and thermogravimetric approach combined with post-characterization was utilized. Ti doping positively influenced the reduction reaction rate and broadened the operation window of the oxygen carrier material (OCM) to lower temperatures. Although sulfur accumulation during the chemical looping with oxygen uncoupling conditions was thermodynamically inevitable owing to sulfate formation, deep redox cycles were shown to remove the accumulated sulfur from the OCM after the sour cycles. Post-characterization by scanning electron microscopy and sulfur mapping confirmed the effectiveness of this treatment. Sphere factor: Sphericity is an important factor affecting the fluidization properties of the oxygen-carrier materials (OCMs) in fluidized bed chemical looping combustion. Perovskite-based CaTi sub(x)Mn sub(0.9-x)Mg sub(0.1)O sub(3) (x=0 and 0.125) fabricated by spray-drying are produced as perfectly spherical particles in the size range of 125 to 180 mu m. The tailor-made micropores in the OCMs boost the oxygen exchange rate with the reactive gas.