Chemical-looping combustion in a 100-kW unit using a mixture of ilmenite and manganese ore as oxygen carrier
Chemical-looping combustion in a 100-kW unit using a mixture of ilmenite and manganese ore as oxygen carrier
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DOI：
10.1016/j.fuel.2015.11.015
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发表时间：
2016-02
期刊：
影响因子：
7.4
通讯作者：
Carl Linderholm;M. Schmitz;P. Knutsson;A. Lyngfelt
中科院分区：
文献类型：
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作者：
Carl Linderholm;M. Schmitz;P. Knutsson;A. Lyngfelt
化学链燃烧是一种新型的碳捕集技术，具有大幅降低CO2捕集成本的潜力。CLC系统依靠互联流化床技术，可以通过使用载氧床材料来实现CO2捕获。这种所谓的氧载体将氧从燃烧空气输送到燃料，从而使碳捕获成为CLC工艺所固有的。在这项研究中，我们提出了一个100千瓦的固体燃料化学链燃烧室的调查结果。100千瓦机组采用双循环流化床概念，其中空气反应器和燃料反应器均设计为循环流化床。本研究中使用的氧载体材料由钛铁矿（已在CLC的几项研究中使用）和锰矿的混合物组成。以往的研究表明，用锰矿颗粒作为氧载体，可以显著提高气体转化率。然而，先前的测试还表明，当使用锰矿石时，细粉的产生，即颗粒磨损，可能很高。因此，混合这两种材料的原因是为了获得具有高反应性的携氧材料，并且在燃料操作期间不会产生太多的细粉。实验中使用了三种燃料：两种烟煤和木焦。气体转化率高，并随着载氧混合物中锰矿分数的增加而增加。在实验结束时，床料中的锰矿分数约为8%，这也是所有测试期间的最高分数。与仅钛铁矿相比，钛铁矿和锰矿石的混合物在气体转化方面得到显著改善。在100 kW装置中，在类似条件下，用烟煤进行试验期间观察到的最高气体转化率为91.5%，而仅用钛铁矿作为氧载体时为84%。因此，与仅使用锰矿相比，将机械稳定的钛铁矿与更具反应性的锰矿混合可以降低成本，并且与钛铁矿相比仍然显着降低需氧量。在本发明的情况下-钛铁矿和锰矿石的混合-高反应性也可以与材料的改进的可操作性联合收割机结合，主要表现为较低的细粉生产率。
Chemical-looping combustion (CLC) is a novel carbon-capture technology with potential to drastically reduce the cost of CO2capture. Relying on interconnected fluidized bed technology, CLC systems can achieve CO2capture by using oxygen carrying bed material. This so-called oxygen carrier transports oxygen from combustion air to fuel, thus making carbon capture inherent to the CLC process. In this study, we present findings from a 100 kW chemical-looping combustor for solid fuels. The 100 kW unit uses the dual-CFB concept, where both air reactor and fuel reactor are designed as circulating fluidized beds.The oxygen carrier material used in this study consisted of a mixture of ilmenite – which has been used in several studies in CLC – and a manganese ore. Previous studies have shown that gas conversion can be significantly increased by using manganese ore particles as oxygen carrier. However, previous testing has also shown that the production of fines,i.e. particle attrition, may be high when using manganese ore. The reason for mixing the two materials is thus to obtain an oxygen carrying material that has high reactivity, and yet does not produce too much fines during fuel operation.The 100 kW unit was operated in total for 18 h with fuel. Three fuels were used in the experiments: two bituminous coals and wood char. Gas conversion was high, and increased with increasing fraction of manganese ore in the oxygen-carrier mixture. At the end of the experiments, the fraction of manganese ore in the bed material was approximately 8%, which also was the highest fraction during all tests. The mixture of ilmenite and manganese ore gave significant improvements in gas conversion in comparison to only ilmenite. The highest gas conversion observed during testing with bituminous coal was 91.5%, as compared to 84% with only ilmenite as oxygen carrier during similar conditions in the 100 kW unit.These test results indicate that the addition of manganese ore could almost halve the fraction of unconverted gas. Thus, mixing mechanically stable ilmenite with more reactive manganese ore can give reductions in costs as compared to using manganese ore only, and still give significantly reduced oxygen demand as compared to ilmenite. In the present case – mixing of ilmenite and manganese ore – the high reactivity was also possible to combine with improved operability of the material, primarily manifested as lower production rate of fines.