open access

https://hdl.handle.net/2115/67371

Conversion of CO2 to CO gas using molten CaCl2 and ZrO2 anode

英語

2017-10

The Iron and Steel Institute of Japan

Proceedings of 1st International Conference on Energy and Material Efficiency and CO2 Reduction in the Steel Industry (EMECR2017)

350-353

Preferential decomposition of CO2 gas to CO gas was examined by using a combination of CaCl2-CaO melt as a reaction media and ZrO2-8mol% Y2O3 solid-state electrolyte as anode. The conversion ratio of CO2 to CO became larger at the higher temperature, and approached the maximum (88.2%) at 1273 K. The highest CO concentration was generated at cell voltage of 2.55 V, which is close to theoretical decomposition voltage of CaO. Therefore, in addition to calciothermic reaction between precipitated Ca and CO2 gas bubbles, CO2 decomposes preferentially via the decomposition reaction of carbonate ions. Namely CO2 gas dissolves to form CO3 2- under coexistence of CaO in the melt, CO3 2- precipitates carbon or CO gas bubbles on the cathode, and a part of carbon reacts with the blown CO2 gas to form CO. CO gas is used as an effective fuel with easy handling in steel plants.

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