H2S or Hydrogen Sulfide is an especially dangerous and hazardous chemical that is very challenging to deal with. Hydrogen Sulfide has a set of properties and characteristics that effect personnel, and equipment in a multitude of negative ways. We will look at how Hydrogen Sulfide comes to exist, and the properties and characteristics that make H2S so challenging.
Hydrogen Sulfide (H2S) can be very dangerous to people and equipment in gas form, and as a liquid, occurring when H2S is in solution. H2S is often formed by anaerobic digestion, which is the bacterial breakdown of organic material in the absence of oxygen. Hydrogen Sulfide is naturally occurring and can be found in well waters, geological formations, and in volcanic gases. Scientifically H2S is known as Hydrogen Sulfide, Dihydrogen Monosulfide, and H2S to name a few. In industry though, H2S is referred to as Stink damp, sour gas, swamp gas, and rotten egg gas. In the oil and gas industry sour gas refers to natural gas with a high concentration of H2S, and the term sour crude the same idea, but referring to crude oil with high concentrations of Hydrogen Sulfide.
H2S Properties and Characteristics
Color- H2S is colorless, and because of this Hydrogen Sulfide by itself has no visual warning signs of its presence.
Odor- Hydrogen Sulfide has an odor that is described as "rotten eggs". This is a smell that is commonly associated with a multitude of sulfur compounds, and it is a challenge to determine whether or not the smell is in fact H2S. Hydrogen Sulfide however, only has this "rotten egg" smell at low concentrations, and H2S will cause Olfactory paralysis (inability to smell) at these low concentrations. Because of this challenge, You Cannot rely on your sense of smell to indicate the presence of H2S.
Solubility- H2S is soluble, and can remain suspended in water, oil, and mud until agitated or heated.
Flammability- H2S is incredibly flammable at low concentrations. The lower explosive limit (LEL) for H2S is 4.6% concentration, and will spontaneously ignite at around 518F. As Hydrogen Sulfide burns, it produces Sulfur Dioxide (SO2) gas which is also a very hazardous gas.
Density- Hydrogen Sulfide is heavier than air at similar temperatures. H2S will collect in in low-lying areas, and confined spaces.
Corrosive- H2S corrosive to materials like iron, and will produce iron sulfite as it corrodes iron products, like steel and even stainless steel. Iron Sulfite is explosive when exposed to air, and the corrosive action that produces Iron Sulfite also causes atomic hydrogen to penetrate the metal lattice structure of the material it's corroding.