Thermochemical assessment of chemical looping assisted by oxygen uncoupling with a MnFe-based oxygen carrier
Thermochemical assessment of chemical looping assisted by oxygen uncoupling with a MnFe-based oxygen carrier
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DOI：
10.1016/j.apenergy.2019.113340
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发表时间：
2019-10
期刊：
影响因子：
11.2
通讯作者：
A. Abad;R. Pérez-Vega;L. F. D. Diego;P. Gayán;M. Izquierdo;F. García-Labiano;J. Adánez
中科院分区：
文献类型：
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作者：
A. Abad;R. Pérez-Vega;L. F. D. Diego;P. Gayán;M. Izquierdo;F. García-Labiano;J. Adánez
先前开发的掺杂有TiO 2的锰-铁混合氧化物由于其氧解偶联能力（即，在高温下产生气态氧的能力，以及通过与晶格氧反应氧化气态燃料如H2、CO或CH 4的能力）而显示出用于固体燃料的燃烧的有前景的性质，所述固体燃料具有通过氧解偶联辅助的化学Lopping（CLaqing）进行的固有CO2捕获。在这项工作中，确定了一个合适的操作条件的窗口，以促进这种材料在CLaerobic单元中的使用。为此目的，考虑热化学参数的理论值，如在CLaerobic相关反应的平衡常数和反应固体的形成焓，对整个CLaerobic单元进行质量和焓平衡。空气反应器温度为1148 K和高的空气过量比建议，以促进通过氧解偶联机制，这将是优选的固体燃料的燃烧的氧的转移。对于空气过量率值λ < 3，可保证CLaerosol装置的自热操作。空气反应器中的氧载体与燃料的比率（OFR）和氧载体再生对燃料反应器温度有很大影响。假设氧解偶联能力的再生为50-75%，且λ = 4-6，则燃料反应器温度将比空气反应器温度高35 - 50 K。燃料反应器内较高的温度可以促进燃料的转化，而较低的空气反应器温度可以保证氧载体的再生。
A previously developed manganese-iron mixed oxide doped with TiO2 shows promising properties for the combustion of solid fuels with intrinsic CO2 capture by Chemical Lopping assisted by Oxygen Uncoupling (CLaOU) owing to its oxygen uncoupling capability, i.e. ability to generate gaseous oxygen at high temperature, and to oxidize gaseous fuels such as H2, CO or CH4 by reacting with lattice oxygen. In this work, a window of suitable operating conditions was determined to facilitate the use of this material in a CLaOU unit. For this purpose, mass and enthalpy balances were performed for the whole CLaOU unit considering theoretical values of thermochemical parameters, such as the equilibrium constant of relevant reactions in CLaOU and the formation enthalpies of reacting solids. An air reactor temperature of 1148 K and a high air excess ratio are suggested in order to promote the transfer of oxygen via the oxygen uncoupling mechanism, which would be preferable for the combustion of solid fuels. Auto-thermal operation of the CLaOU unit is guaranteed for air excess ratio values λ < 3. The fuel reactor temperature is highly influenced by the oxygen carrier-to-fuel ratio (ϕ) and the oxygen carrier regeneration in the air reactor. Assuming a 50–75% regeneration of the oxygen uncoupling capability, and ϕ = 4–6, the fuel reactor temperature would be between 35 and 50 K above the air reactor temperature. The higher temperature in the fuel reactor could promote the fuel conversion, while oxygen carrier regeneration would be guaranteed by the lower air reactor temperature.