Explosion Limits of Hydrogen/Oxygen Mixtures at Initial Pressures up to 200 bar

Abstract

The exact experimental determination of the pressure dependence of the explosion limits of hydrogen/oxygen mixtures at 20 °C and 80 °C was investigated. The anomaly in the pressure dependence of hydrogen explosion limits (decrease of the upper explosion limit with increase in pressure), known for hydrogen/air mixtures, could be confirmed for hydrogen/oxygen mixtures. Furthermore it was shown that the impurities in the product gases of the electrolyzer did not exceed 50 % of the lower explosion level in any case.

Biohydrogen for a New Generation of H2/O2 Biofuel Cells: A Sustainable Energy Perspective

“…Second, the use of highly specific enzymes and of an O 2 -tolerant Hase allows a biofuel cell to be envisioned with no membrane separator. A H 2 /O 2 gas mixture in nonexplosive proportions must then be used (the range of explosive proportions is 4.1-78 % of H 2 in air or 4.0-95.2 % for H 2 -O 2 [302] ). Armstrong's group recently explored these conditions [298] and demonstrated that the EBFC could operate in a gas mixture enriched in H 2 over O 2 .…”

High temperature and pressure electrochemical test station

“…Mixtures of H 2 and air at 1 bar and room temperature may ignite when the H 2 concentration is between 4.1 and 74.4 vol.%. 13 The corresponding values for mixtures of H 2 and O 2 are 4.0 and 95.2 vol.%, respectively. 13 Thus, 4 vol.% is referred to as the lower explosion limit (LEL) for H 2 .…”

“…13 The corresponding values for mixtures of H 2 and O 2 are 4.0 and 95.2 vol.%, respectively. 13 Thus, 4 vol.% is referred to as the lower explosion limit (LEL) for H 2 . Depletion with an inert gas insignificantly affects the LEL.…”

“…The LEL decreases almost linearly with increasing temperature but the temperature dependence is very weak (−0.003 vol.%/K). 13 The self-ignition temperature in air is about 500 • C at 1 bar pressure. 14 The LEL of H 2 increases with increasing pressure.…”

“…14 The LEL of H 2 increases with increasing pressure. 13 Between 1 and 100 bars, the LEL of H 2 is in the range of 4-5.7 vol.% at 20 • C. Any leakage of H 2 inside the GHC will be detected by a gas sensor (G-01 in Figure 1) placed in the GHC. H 2 leaking outside the GHC will be detected by gas sensors in the laboratory building.…”