Evaluation of CuAl2O4 as an Oxygen Carrier in Chemical-Looping Combustion
Evaluation of CuAl2O4 as an Oxygen Carrier in Chemical-Looping Combustion
复制标题
DOI：
10.1021/ie300427w
复制
发表时间：
2012-10-31
影响因子：
4.2
通讯作者：
Lyngfelt, Anders
中科院分区：
文献类型：
--
作者：
Arjmand, Mehdi;Azad, Abdul-Majeed;Lyngfelt, Anders
化学链燃烧(CLC)技术是一种能有效分离二氧化碳的新型高效燃烧技术。该方法使用金属氧化物作为氧气载体，将氧气从空气转移到燃料反应堆，在那里燃料或燃料的气化产物与固体氧载体反应。在这项工作中，铜(II)铝酸盐(CuAl2O4)是一种潜在的氧载体，以甲烷为燃料。载体粒子通过冷冻造粒和在1050℃下焙烧6h，在实验室规模的沸腾床反应器中，在900-950℃的温度范围内，在45个交替的氧化还原循环中评价了其化学环特性。氧载体在该温度范围内表现出可重复性和稳定性的反应行为。在900-925℃进行的任何循环中都没有观察到团聚或脱流。然而，在950℃的反应性测试之后，观察到软团聚和颗粒破碎。系统地分析了氧化还原循环过程中铜-铝-氧体系的物相组成与还原时间和氧化期氧气浓度的关系。研究发现，CuAl_2O_4被还原为铜(I)铝酸盐(CuAlO_2；氟磷矿)、Cu2O和元素铜。CuAlO2相具有缓慢的氧化生成CuO和CuAl2O4的动力学特征。尽管存在这一动力学限制，甲烷的完全转化还是实现了，而且氧载体的反应活性是可重复的。因此，CuAl2O4可能是一种潜在的化学链燃烧氧载体。
The chemical-looping combustion (CLC) process is a novel solution for efficient combustion with intrinsic separation of carbon dioxide. The process uses a metal oxide as an oxygen carrier to transfer oxygen from an air to a fuel reactor where the fuel, or gasification products of the fuel, reacts with the solid oxygen carrier. In this work, copper(II) aluminate (CuAl2O4) was assessed as a potential oxygen carrier using methane as fuel. The carrier particles were produced by freeze-granulation and calcined at 1050 degrees C for a duration of 6 h. The chemical-looping characteristics were evaluated in a laboratory-scale fluidized-bed reactor in the temperature range of 900-950 degrees C during 45 alternating redox cycles. The oxygen carrier exhibited reproducible and stable reactivity behavior in this temperature range. Neither agglomeration nor defluidization was noticed in any of the cycles carried out at 900-925 degrees C. However, after reactivity tests at 950 degrees C, soft agglomeration and particle fragmentation were observed. Systematic phase analysis of the Cu-Al-O system during the redox cycle was carried out as a function of duration of reduction and oxygen concentration during the oxidation period. It was found that the CuAl2O4 is reduced to copper(I) aluminate (CuAlO2; delafossite), Cu2O, and elemental Cu. The CuAlO2 phase is characterized by slow kinetics for oxidation into CuO and CuAl2O4. Despite this kinetic limitation, complete conversion of methane with reproducible reactivity of the oxygen carrier is achieved. Thus, CuAl2O4 could be a potential oxygen carrier for chemical-looping combustion.