English
高级检索

循环流化床粉煤灰作为载体的免烧Cu−Fe复合载氧体造粒成型及性能研究

Pelletizing and performance of non-calcined Cu−Fe composite oxygen carriers using circulating fluidized bed fly ash as support

    摘要
  • 摘要: 化学链燃烧是一种新型高效碳捕集技术。Cu−Fe复合载氧体反应活性较高、循环稳定性较好且环境友好，但是制备成本较高。循环流化床(Circulating Fluidized Bed，CFB)粉煤灰富含SiO2和Al2O3，是一种潜在的低成本载体材料。以循环流化床(CFB)粉煤灰为载体，以Fe2O3和CuO为活性组分，以Ca(OH)2为激发剂激发CFB粉煤灰的火山灰活性，采用挤出−滚圆法制备了免烧Cu−Fe复合载氧体颗粒，并对载氧体颗粒进行了自然养护以提升颗粒机械性能。首先，分析了CuO质量分数(1%、3%、5%、8%、10%)对Cu−Fe复合载氧体机械性能的影响。研究发现，随着自然养护时间的增加，载氧体抗压强度明显增大。随着CuO质量分数增加，载氧体抗压强度呈现先增加后减小的趋势，CuO质量分数为5%时抗压强度最大，磨损率最小，机械性能最好。其次，探究了CuO质量分数(3%、5%、8%)对Cu−Fe复合载氧体反应性能的影响。CuO质量分数5%和8%的载氧体CH4转化率相近，明显高于CuO质量分数3%的载氧体。3种载氧体在20次循环中CO2选择性选择性高达80%以上，积碳选择性均在20%以下。CuO质量分数5%的Cu−Fe载氧体综合性能最好，兼具良好的机械性能和反应性能。最后，对Cu−Fe复合载氧体进行了结构表征分析。添加CuO活性组分可以形成CuFe2O4，有利于提高载氧体的反应活性，且20次循环后载氧体颗粒未发生粉末化现象，但是产生明显烧结，导致循环稳定性降低。

     

    Abstract: Chemical looping combustion is a new and efficient carbon capture technology. The Cu−Fe composite oxygen carriers have high reactivity, good cycle stability and environmental friendliness, but the preparation cost is high. Circulating Fluidized Bed (CFB) fly ash, which is rich in SiO2 and Al2O3, is a potential low-cost support. Using circulating fluidized bed (CFB) fly ash as the support, Fe2O3 and CuO as active components, Ca(OH)2 as the activator to activate the pozzolanic activity of CFB fly ash, non-calcined Cu−Fe composite oxygen carrier particles were prepared by extrusion-spheronization method, and the oxygen carrier particles were naturally cured to improve the strength. Firstly, the effect of CuO content (1%, 3%, 5%, 8%, 10%) on the mechanical property of Cu−Fe composite oxygen carriers was analyzed. It was found that the compressive strength of oxygen carriers increased obviously with the increase of natural curing time. With the increase of CuO content, the compressive strength of oxygen carriers increased first and then decreased. When the CuO content was 5%, the compressive strength was the largest and the wear rate was the smallest, implying the mechanical property was the best. Secondly, the effect of CuO content (3%, 5%, 8%) on the reactivity of Cu−Fe composite oxygen carrier was investigated. The CH4 conversion rates of oxygen carriers with 5% and 8% CuO contents were similar, which was significantly higher than that oxygen carrier with 3% CuO content. The CO2 selectivity of three oxygen carriers in 20 cycles was more than 80%, and carbon deposition selectivity was less than 20%. The comprehensive performance of oxygen carrier with 5% CuO was the best with good mechanical property and reactivity. Finally, the structure characterization of Cu−Fe composite oxygen carriers was analyzed. The addition of CuO active component can form CuFe2O4, which was conducive to improving the reactivity of oxygen carriers. No pulverization of oxygen carrier particles occurred after 20 cycles, but the sintering was obvious, decreasing the cycle stability.

     

    • HTML全文
    • 参考文献(25)
    • 相关文章
    • 施引文献
  • 资源附件(0)

/

返回文章
返回

相关链接