论文部分内容阅读
高性能的氧载体是化学链燃烧技术实施的关键。本文采用溶胶凝胶法制备的Fe_2O_3/Al_2O_3氧载体,在固定床反应器中研究了它与CH_4/空气在900℃下的循环反应性,并利用XRD、ESEM和BET对反应前后的氧载体进行了物化表征。试验结果表明,溶胶凝胶法制备的Fe_2O_3/Al_2O_3氧载体具有良好的循环反应能力。随着循环次数的增多,氧载体与CH_4反应生成CO_2的最大浓度值从44.9%～51.2%逐渐增加,氧载体的还原氧化反应性逐渐增大。循环反应后,氧载体表面出现了一定程度的烧结现象,氧载体的比表面积、内孔容积和平均孔径均有所减小,但仍足够大。这些结果初步证明采用溶胶凝胶法制备的Fe_2O_3/Al_2O_3氧载体具有实现气体燃料化学链燃烧技术的可行性,用于双连通循环流化床的化学连燃烧过程时,床料量约为51～212 kg/MWth,循环倍率约为8.2 kg/s,MWth。
High-performance oxygen carrier is the key to the implementation of chemical combustion technology. In this paper, the reactivity of Fe_2O_3 / Al_2O_3 oxygen carrier prepared by sol-gel method was studied in a fixed bed reactor at 900 ℃ with CH_4 / air. The oxygen carrier before and after the reaction was characterized by XRD, ESEM and BET The physical and chemical characterization. The experimental results show that the Fe_2O_3 / Al_2O_3 oxygen carrier prepared by sol-gel method has good cyclic reaction ability. With the increase of the number of cycles, the maximum concentration of CO_2 generated by the reaction between oxygen carrier and CH_4 increased gradually from 44.9% to 51.2%, and the reduction and oxidation reactivity of oxygen carrier gradually increased. After the cyclic reaction, a certain degree of sintering appeared on the surface of the oxygen carrier. The specific surface area, the internal volume and the average pore diameter of the oxygen carrier decreased but were still large enough. These results preliminarily prove that the Fe 2 O 3 / Al 2 O 3 oxygen carrier prepared by sol-gel method has the feasibility of chemical gas combustion technology. When used in the chemical continuous combustion process of the two-way circulating fluidized bed, the amount of bed material is about 51 ~ 212 kg / MWth, the cycle rate is about 8.2 kg / s, MWth.