摘要
Fe2O3作为载氧体可以在载氧燃烧过程中实现CO2的分离。在固定床试验台(内径40mm,高1600mm)上,通过改变载氧体在反应器中所处的还原氧化氛围模拟载氧燃烧过程,研究载氧体Fe2O3的载氧燃烧特性。实验载氧体量385g,CO+CO2+N2为还原气体,O2+N2为氧化气体。在900℃下针对CO2对反应的影响进行研究,对载氧体粒径和反应温度的影响进行探讨。为了分析载氧体的反应活性与稳定性,在900℃下对载氧体颗粒进行多次还原氧化循环实验。结果表明,在纯CO的氛围下,Boudouard反应会导致还原过程发生析碳,CO还原气中加入CO2可以抑制析碳的产生。还原反应中载氧体颗粒的比表面积和孔隙率越大,CO的转化率越高。在Fe2O3-Fe3O4阶段,高温不利于CO的转化,但有助于CO在Fe3O4-Fe0.947O/Fe阶段中的转换。通过5～6次的循环实验发现,载氧体在经过第1次反应后会出现一定程度的失活,此后性质保持稳定。
Hematite Fe2O3 can be used as oxygen carrier in chemical-looping combustion with inherent CO2 separation.Experiments were carried out in a fixed bed reactor（i.d.40mm,H1600mm） to investigate the behaviors of Fe2O3 as oxygen carrier.Chemical-looping combustion was simulated by exposing the oxygen carrier to alternating reducing（CO＋ CO2＋N2 as the reduction gas） and oxidizing（O2＋N2 as the oxidation gas） conditions.In each experiment,385 g oxygen carrier was used.Impacts of CO2 on the reduction were tested at 900℃ as a preliminary.The influences of particle size and operation temperature on the reaction were also investigated.To analyze the reactivity and stability of the oxygen carrier,multi reduction-oxidation cycles were conducted at 900℃ with different reducing atmospheres.Experimental results show that carbon deposition caused by Boudouard reaction occurred under pure CO atmosphere and CO2 can be used to suppress carbon formation.The CO conversion is higher with higher BET surface area and more developed porous particles.Elevated temperature restrains the CO conversion in the Fe2O3-Fe3O4 phase,but higher temperature benefits the CO conversion in the Fe3O4-Fe0.947O/Fe phase.Multi-cycles experiments show that the characteristics of oxygen carrier become stable after the first cycle.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2010年第20期44-50,共7页
Proceedings of the CSEE
基金
国家重点基础研究发展计划项目(973计划)(2007CB210101)
国家自然科学基金项目(50776018)~~
关键词
载氧燃烧
载氧体
铁氧化物
CO
CO2
chemical-looping combustion （CLC）
oxygen carrier
iron oxide
carbon monoxide
carbon dioxide
