Optical sensor development for MCFCs: HCl detection through wavelength modulation diode laser absorption spectroscopy.

摘要

Contaminants in coal gas can degrade the performance of molten carbonate fuel cells. A laser diode sensor and a wavelength modulation spectrometer have been developed capable of detecting, in situ, HCl gas at ppM levels and below on time scales < 1 min, using 25 cm path lengths. Due to intensity and overlap of (sup 18)OCO with P10 transition of HCl, sensitivity is somewhat limited (close to 100 ppB, however) because of limited S/N ratios; this will be improved by eliminating all etalon effects. Alternative HCl lines with possibly reduced spectral interference will be looked for. Detection of H(sub 2)S and H(sub 2)Se will also be investigated. It was found that room-temperature Li/K carbonate can be used as prefilter for HCl contaminants.