Exclusion area for safety from high-pressure sour gas leaks.

Abstract

A discussion of considerations necessary to the preparation of a safety program which can save lives when hydrogen sulfide leaks occur during the transportation of sour oil and gas covers hydrogen sulfide toxicity; conditions such as pressure and exit velocity of gas containing hydrogen sulfide and leaking from a split in a pipe or connection; calculation of the maximum dilution factor for the case in which the leak permits free expansion; calculation of the adiabatic cooling of the expanding gas stream; hazard increase through formation of a fog, which forms if the temperature of the leaked gas mixture falls below the dew-point temperature; density; calculation of maximum concentration downwind of a ground-level source; calculation of a safety exclusion radius for any desired hazard level; calculation of the area with a time-concentration exposure greater than that specified for safety; determination of the probability that any point within the exposure distance of a leak will receive the maximum calculated exposure value; other considerations such as terrain and weather; and other related work, including rule 36 of the Texas Railroad Commission regulations on sour gas.