Oxidation of Ammonia by Ilmenite under Conditions Relevant to Chemical-Looping Combustion

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• 作者：Mao Cheng ; Fredrik Normann ; Dongmei Zhao ; Zhenshan Li ; Ningsheng Cai ; Henrik Leion
• 刊名：Energy & Fuels
• 出版年：2015
• 出版时间：December 17, 2015
• 年：2015
• 卷：29
• 期：12
• 页码：8126-8134
• 全文大小：683K
• ISSN：1520-5029

文摘

The oxidation of ammonia to NO_x and N₂ was investigated under conditions that pertain to the fuel reactor during the chemical-lopping combustion of coal with ilmenite. The catalytic decomposition of NH₃, the oxidation of NH₃ over ilmenite, and the reduction of NO by reduced ilmenite and NH₃ were studied experimentally. The catalytic decomposition of NH₃, NO reduction by NH₃, and reduced ilmenite were found to be important for N₂ formation. NH₃ oxidation over ilmenite was the only way in which NO could be formed in this system, with around 18% of the NH₃ being converted to NO at 850鈥?50 掳C. The oxidation of NH₃ was only slightly influenced by the reactor temperature but was strongly influenced by the concentrations of NH₃ and syngas. NO formation was promoted by high concentrations of NH₃ and decreased by high concentrations of syngas. The selectivity of the NH₃ toward NO formation was favored at low concentrations of NH₃ and syngas. The conversion of NH₃ was complete in most cases, although 15鈥?5% of the NH₃ was not converted when the inlet syngas concentration increased to levels higher than 10鈥?0%.