关键词: 化学链燃烧, 煤, 燃料氮, 转化特性

Abstract: The present paper presents the investigation of fuel nitrogen transfer of anthracite in chemical looping combustion (CLC) with an iron ore oxygen carrier based on a small scale fluidized bed reactor. With respect to its volatile nitrogen and char nitrogen conversion behavior, the combustion characteristics of volatile matter and its corresponding char were experimentally investigated. The nitrogen intermediates (HCN and NH₃) from fuel nitrogen had a high chemical affinity with the bed materials of the iron ore oxygen carrier towards formation of N₂ and NO. During the volatile nitrogen conversion of the Huaibei anthracite, NO was the sole product of nitrogen oxide. Meanwhile, some HCN and NH₃ were released and the NH₃ concentration was higher than HCN. In the reduction process of char combustion, part of NO was formed due to the oxidation of HCN and NH₃ by the iron ore, and there was no N₂O formation in the process. A high reduction temperature accelerated formation of NO. To reduce the amount of char into the oxidation process, that is oxygen carrier regeneration process, could totally reduce evolution of NO and N₂O in the air reactor.

Key words: chemical looping combustion (CLC), coal, fuel nitrogen, transfer