Testing of minerals and industrial by-products as oxygen carriers for chemical-looping combustion in a circulating fluidized-bed 300 W laboratory reactor

FUEL

卷:93

Article

Moldenhauer, Patrick¹  Ryden, Magnus¹  Lyngfelt, Anders¹ 

[1] Chalmers Univ Technol, Environm & Energy Dept, Div Energy Technol, S-41296 Gothenburg, Sweden

关键词: Chemical-looping combustion (CLC);    Iron oxide scale;    CO2 capture;    Oxygen carrier;    Ilmenite;   

DOI  :  10.1016/j.fuel.2011.11.009

来源: Elsevier

【 摘 要 】

Chemical-looping combustion (CLC) is a promising technology for future energy production with inherent CO2 separation. One approach is to use minerals or industrial by-products as oxygen carriers to reduce the costs of the process. This study focuses on the investigation of two iron-based oxygen carriers, which were examined under continuous operation in a 300 W laboratory reactor. Ilmenite is an iron-titanium oxide mineral, whereas iron oxide scale (IOS) is obtained as a by-product from the rolling of sheet steel. Syngas was used as a fuel - pure and with steam addition to suppress the formation of solid carbon. During the experiments the variables reactor temperature, fuel flow and air flow were changed. Furthermore the effect of steam addition to the fuel was investigated. Particle properties were compared over the span of 85 h of continuous operation for ilmenite and 37 h for IOS. The analysis is based on gas measurements from the actual CLC operation, but also on scanning electron microscopy, X-ray powder diffractometry and measurements of BET surface area and density. With ilmenite oxygen carrier it was possible to achieve full conversion of syngas up to about 190 W-th fuel equivalent at 900 degrees C. With design fuel flow of about 300 W-th at 900 degrees C the combustion efficiency was above 98%. There was almost no visible difference in reactivity of fresh activated particles and those used for 85 h. Combustion efficiency up to 99% was achieved with IOS oxygen carrier at 900 degrees C and about 100 W-th fuel equivalent. At 300 W-th fuel equivalent and 900 degrees C a combustion efficiency of only 90% could be reached. Both oxygen carriers were operated for tens of hours, which allowed for a better understanding of lifetime behavior and other basic characteristics. Whereas ilmenite oxygen-carrier particles were mostly stable over the course of 85 h of experiments, a large fraction of IOS oxygen-carrier particles had disintegrated to fines after only 37 h of experiments. The gathered data indicates that both oxygen carriers could be an alternative to synthesized particles, though with more drawbacks for IOS than for ilmenite. (C) 2011 Elsevier Ltd. All rights reserved.

【 授权许可】

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