摘要
采用热重分析仪和质谱仪联用对使用机械混合法制备Fe2O3和Al2O3载体的还原反应过程进行研究。还原反应中使用3种10%还原气体(CH4,H2,CO),氧化反应中使用5%氧气以避免较大的温升。从载体的还原失重曲线中可明显地看出铁基载体的还原过程分为3个阶段,且反应速率各不相同。还原的3个阶段中第一阶段的反应速率最快,且燃料能够完全被氧化生成CO2,随着反应进行速率降低,燃料不完全转化程度增加。通过XRD(X射线衍射)分析各个还原阶段的产物,发现与以前认识的载氧体活性相与惰性相不同,Al2O3在反应过程中会参与反应,生成新的化合物FeAl2O4,而此化合物不稳定能够进一步分解,被还原成Fe。3种还原气体中,H2的还原反应速率最快,并且无积碳,而CH4的还原反应中存在较为严重的积碳现象。
Studied was the reduction reaction process of Fe2O3and Al2O3prepared by adopting the mechanical mixing method and using a thermogravimetric analyzer together with a mass spectrometer. During the reduction reaction,threekinds of 10% reduction gases( CH4,H2and CO) were used and during the oxidization reaction,5% oxygen was employed to avoid a relatively big temperature rise. From the reduction weight loss curves of the carriers,it can be obviously seen that the reduction process of the Fe-based carriers can be divided into three stages and their reaction speeds can vary. Among the three reduction stages,the first one has the quickest reaction speed and the fuel can be completely oxidized to produce CO2. With a decrease of the reaction speed,the incomplete conversion extent of the fuel will increase. By using a XRD( X-ray diffraction) meter,the authors analyzed the products in various reduction stages and found that the active and inertia phase of the oxygen carriers are different from those known before,Al2O3will take part in the reaction in the process of reaction to produce a new compound FeAl2O4,which is unstable and will be further decomposed and reduced to Fe. Among the three kinds of the above-said reduction gases,the hydrogen has the quickest reduction reaction speed and produces no carbon deposition while CH4produces relatively serious carbon deposition.
出处
《热能动力工程》
CAS
CSCD
北大核心
2014年第1期81-85,110-111,共5页
Journal of Engineering for Thermal Energy and Power
关键词
机械混合法
铁基载体
还原过程
化学链燃烧
mechanical mixing method,Fe-based carrier,reduction process,chemical chain combustion
