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

摘要

In the Research Center Jiilich,Germany,a prototype of a high pressure water electrolyzer was constructed.For safe running the explosion limits of hydrogen/oxygen mixtures were determined experimentally at 20 deg C and 80 deg C and at initial pressures from 1 bar up to 200 bar.The measurements were carried out according to a modified bomb method following the draft of the new European standard for the determination of the explosion limits (prEN 1839).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.With the exceeding of the lower explosion limit (LEL)the explosion pressures and pressure rising rates increase only weakly.This property of hydrogen is in opposite to the behavior of other flammable gases,e.g.,hydrocarbons.On the other hand,close to the upper explosion limit,high explosion pressures could be observed at a slight exceeding of the limit.Furthermore it was shown that the impurities in the product gases of the electrolyzer did not exceed 50 % of the LEL in any case.