Explosions limits of H2S/CO2/air and H2S/N2/air

For the evaluation of the dangers of explosions, which can take place while handling H2S, only literature values exist, which had not been determined according to actual standard methods. Therefore the explosion limits of the two ternary gas systems H2S/CO2/air and H2S/N-2/air were determined at 20 degrees C and 1 bar(a) according to the bomb method of the new European standard EN 1839. A comparison of these measured values with the literature values results in a clear expansion of the explosion range for both gas systems. Thus the explosion limits for H2S/air were found at 3.9 mol-% (LEL) and 49.8 mol-% (UEL) in relation to literature values of 4.3 mol-% and 45.5 mol-%. Adding CO2 or N-2 to the gas systems in particular the UEL was found at higher amounts of H2S than reported in the literature. Hence the LOC values are smaller. For the system H2S/CO2/air a LOC value of 10.5 mol-% (literature value: 12.1 mol-%), for H2S/N-2/air 9.1 mol-% (literature value: 10.8 mol-%) was determined.