Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7719543 | International Journal of Hydrogen Energy | 2014 | 12 Pages |
Abstract
This paper contains the results of research on chemical-looping combustion (CLC). CLC is one of the most promising combustion technologies and has the main advantage of producing a concentrated CO2 stream, which is obtained after water condensation and without any energy penalty for CO2 separation. The objective of this work was to study the chemical-looping reaction performance of novel perovskite-type oxygen carriers. The Sr(Mn1âxNix)O3 family was tested for its suitability as an oxygen carrier in hydrogen (syngas component) combustion for power generation. Sr(Mn1âxNix)O3 perovskite-type oxides with x = 0, 0.2, 0.5, 0.8, and 1.0 were prepared. Thermogravimetric measurements were performed to investigate the oxidation/reduction of the obtained materials. Reactivity tests were performed under isothermal conditions during multiple redox cycles using a thermogravimetric analyzer (TGA). For the reduction reaction, 3% H2 in Ar was used, and air was used for the oxidation cycle. The effect of reaction temperature (600-800 °C) and the number of reducing/oxidizing cycles (up to 5 cycles) on the performance of the oxygen-carrier samples developed in this study were evaluated. The stability, oxygen transport capacity, and reaction rates were analyzed on the basis of thermogravimetric TG results. The Sr(Mn1âxNix)O3 oxides showed stable chemical-looping performance with rapid changes in their oxygen content (2-3 min) while maintaining their chemical properties. The cyclic redox reaction revealed that Sr(Mn1âxNix)O3 exhibits excellent structural stability and provides a continuous oxygen supply during redox reactions. Good oxygen capacity was maintained during the cycling hydrogen combustion tests. These new perovskite-type materials were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements and by surface area (BET), particle size distribution (PSD) and melting behavior analyses. The Sr(Mn1âxNix)O3 oxides exhibited high melting temperatures and small surface areas. The promising results obtained from chemical-looping combustion experiments indicate that the Sr(Mn1âxNix)O3 oxides are potentially useful oxygen carriers for chemical-looping combustion processes where hydrogen is one of the fuel components.
Related Topics
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Authors
Ewelina Ksepko,