CaMn0.875Ti0.125O3 as oxygen carrier for chemical-looping combustion with oxygen uncoupling (CLOU)—Experiments in a continuously operating fluidized-bed reactor system

Type
Article

Authors
Rydén, Magnus
Lyngfelt, Anders
Mattisson, Tobias

KAUST Grant Number
KUK-F1-023-02

Date
2011-03

Abstract
Particles of the perovskite material CaMn0.875Ti0.125O3 has been examined as oxygen carrier for chemical-looping with oxygen uncoupling, and for chemical-looping combustion of natural gas, by 70h of experiments in a circulating fluidized-bed reactor system. For the oxygen uncoupling experiments, it was found that the particles released O2 in gas phase at temperatures above 720°C when the fuel reactor was fluidized with CO2. The effect increased with increased temperature, and with the O2 partial pressure in the air reactor. At 950°C, the O2 concentration in the outlet from the fuel reactor was in the order of 4.0vol%, if the particles were oxidized in air. For the chemical-looping combustion experiments the combustion efficiency with standard process parameters was in the order of 95% at 950°C, using 1000kg oxygen carrier per MW natural gas, of which about 30% was located in the fuel reactor. Reducing the fuel flow so that 1900kg oxygen carrier per MW natural gas was used improved the combustion efficiency to roughly 99.8%. The particles retained their physical properties, reactivity with CH4 and ability to release gas-phase O2 reasonably well throughout the testing period and there were no problems with the fluidization or formation of solid carbon in the reactor. X-ray diffraction showed that the particles underwent changes in their phase composition though. © 2010 Elsevier Ltd.

Citation
Rydén M, Lyngfelt A, Mattisson T (2011) CaMn0.875Ti0.125O3 as oxygen carrier for chemical-looping combustion with oxygen uncoupling (CLOU)—Experiments in a continuously operating fluidized-bed reactor system. International Journal of Greenhouse Gas Control 5: 356–366. Available: http://dx.doi.org/10.1016/j.ijggc.2010.08.004.

Acknowledgements
This publication was based on work supported by Award No. KUK-F1-023-02, made by King Abdullah University of Science and Technology (KAUST). The CaMn0.875Ti0.125O3 particles used for the study were developed and manufactured by SINTEF. The batch experiments described in Section 4.4 was conducted by Sebastian Sundqvist and is a part of a larger work which is being carried out at the department of Chemical and Biological Engineering at Chalmers University of Technology.

Publisher
Elsevier BV

Journal
International Journal of Greenhouse Gas Control

DOI
10.1016/j.ijggc.2010.08.004

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