Evaluation of coal conversion pathways in fluidized bed chemical looping combustion with oxygen uncoupling (CLOU)

FUEL

卷:258

Article

Merrett, Kirsten M.¹  Whitty, Kevin J.¹ 

[1] Univ Utah, Dept Chem Engn, 50 S Cent Campus Dr,Room 3290, Salt Lake City, UT 84112 USA

关键词: Chemical looping;    Combustion;    CLOU;    Coal;    Conversion;    Fluidized bed;   

DOI  :  10.1016/j.fuel.2019.116157

来源: Elsevier

【 摘 要 】

Chemical looping with oxygen uncoupling (CLOU) is a variant of chemical looping combustion that uses oxygen carriers that release gaseous O-2 in the fuel reactor to efficiently combust solid char. There are many different pathways by which fuel carbon can be converted in a CLOU system, including reaction of volatiles, oxidation of char and gasification of char followed by conversion of the gaseous products. Therefore, there is competition between volatiles and solid char for both gaseous and metal bound oxygen. This study presents an experimental method of analysis to better understand the conversion pathway and fate of fuel carbon in a fluidized bed reactor system. The analysis is applied to a Cu-based CLOU carrier in a bench-scale reactor, feeding either coal or coal char in small batches. The effect of coal particle size and reactor temperature on the relative contributions of different carbon conversion pathways is evaluated. Under the conditions studied, higher temperatures and smaller char particles were more effectively converted by gaseous O-2 released by the CLOU carrier, resulting in less unconverted char. However, there was more unconverted volatiles exiting the reactor from small coal particles and the resulting char had a higher tendency to exit the fuel reactor unconverted. Larger char particles relied more on conversion by gasification and subsequent oxidation of combustible products. Results for other systems will depend on operating conditions and properties of the fuel, but conversion pathways can be systematically evaluated using the method described.

【 授权许可】

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