報告書番号

W00001

タイトル（和文）

MCFCにおける単極反応熱の解析 -不可逆過程の熱力学適用による電解質内温度分布の解明-

タイトル（英文）

Numerical analysis of single electrode heat effect on Molten Carbonate Fuel Cell -temperature analysis of electrolyte plate applying thermodynamics of irreversible process-

概要 （図表や脚注は「報告書全文」に掲載しております）

MCFCスタック内温度分布解析モデルを改良し単極に伴う発熱分布の解析可能なモデルを作成した。解析の結果MCFC発電時にはカソードで発熱反応、アノードで吸熱反応が起きており、カソードで発熱し再びアノードで吸収される熱量は電池の出力密度と同程度となる。また、単極反応熱が電解質内部の温度分布に与える影響を評価するため、不可逆過程の熱力学を適用し電解質内部の温度分布解析を行った。解析の結果、両電極間の温度差は電解質の熱伝導率が2W/mK程度以下であれば、300mA/cm2の高電流密度運転時であっても１℃前後と小さいことが明らかとなった。従って従来の仮定通り、電極及び電解質板の温度を一点で代表させてもスタック内部解析精度に影響を与えない。また、電解質内トムソン係数について感度解析を行い発熱量の収支解析を行った結果、MCFC内部のトムソン係数は±0.1mV/K程度であることが分かった。

概要 （英文）

The temperature analysis model of MCFC stack has been modified to estimate the value of heat evolution which is produced in a single electrode generating reaction. The heat evolves at the cathode and reabsorbed at the anode. The heat value which produced at the cathode and reabsorbed at the anode has been evaluated to be similar value to the generating power level. This results leads that the single electrode heat evolution has possibility to exist temperature difference between the cathode and the anode, then the stack analysis model needs to estimate this temperature difference. Temperature distribution in the electrolyte plate has been studied applying thermodynamics of irreversible process. By the manner that considering thermodynamics of irreversible processes, the production and transportation of entropy could be evaluated. Supposing the coefficient of thermal conductivity to be 2 W/mK, the calculation results proved that the temperature difference between the two electrode lies below 1 degree celcius even in the condition that MCFC is operated under the current density 300mA/cm2. This result allows to suppose the electrode and electrolyte to be a single component and to represent by one temperature, when the stack temperature analysis model will be developed. Finally, the enthalpy balance within the reactive component in MCFC has been studied. The temperature distribution in the electrolyte which has been calculated with applying thermodynamics of irreversible process, has been compared with the temperature distribution which considers no single electrode heat effect. Using this method, the value of Thomson coefficient in the MCFC electrolyte plate has been estimated to be within -0.1 upto 0.1mV/K, and this value has no experimental data.

報告者

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