Efficient Splitting of CO2 in an Isothermal Redox Cycle Based on Ceria

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• 作者：Luke J. Venstrom ; Robert M. De Smith ; Yong Hao ; Sossina M. Haile ; Jane H. Davidson
• 刊名：Energy & Fuels
• 出版年：2014
• 出版时间：April 17, 2014
• 年：2014
• 卷：28
• 期：4
• 页码：2732-2742
• 全文大小：553K
• 年卷期：v.28,no.4(April 17, 2014)
• ISSN：1520-5029

文摘

An isothermal thermochemical cycle to split CO₂ based on nonstoichiometric reduction and oxidation of ceria is demonstrated. Carbon monoxide is produced via an oxygen partial pressure swing by alternating inert sweep gas and CO₂ flows over the ceria. The rates of reduction and oxidation at 1500 掳C in a porous ceria particle bed are measured for sweep gas and CO₂ flow rates from 50 to 600 mL min^鈥? g^鈥? and analyzed to identify cycle operating conditions (gas flow rates and reduction and oxidation durations) that maximize process efficiency. For a solar reactor assumed to operate at 3000 suns concentration and with 90% of the sensible heat of the gases recovered, the optimal cycle uses 150 mL min^鈥? g^鈥? sweep gas and 50 mL min^鈥? g^鈥? CO₂ at reduction and oxidation periods of 100 and 155 s, respectively. This cycle is demonstrated in an IR imaging furnace over 102 cycles, yielding a stable average rate of CO production of 0.079 渭mol s^鈥? g^鈥? and a projected reactor efficiency of 4%. The optimal conditions apply at large scale if the flow rates are scaled in proportion to the ceria mass.