High Precision Evaluation of Gas Composition and Current Efficiency for High Temperature H_2O and CO_2 Electrolysis

摘要

A method to evaluate current efficiency was developed for high temperature electrolysis using solid oxide cells (SOECs). For a fuel electrode, depending on range, our gas analysis system achieved ±0.4-0.6% uncertainty for 10-90% mole fraction analysis of H_2 and H_2O. For an air electrode, O_2 and N_2 was measured with ± 0.2% and ±0.4% uncertainty, respectively. Case studies for both electrodes clarified that current efficiency can be evaluated with ± 1.1-2.8% uncertainty at practical 90-50% steam utilizations in the case of ± 1.0% uncertainty in gas-flow-rate measurement.