Sour gas

Sour gas is <a href="/facts/Natural_gas/9MYQ7NAP">natural gas</a> or any other gas containing significant amounts of <a href="/facts/Hydrogen_sulfide/UbCqjMMk">hydrogen sulfide</a> (H2S).
Natural gas is usually considered sour if there are more than 5.7 <a href="/facts/Milligram/lU2zbPk8">milligrams</a> of H2S per cubic meter of natural gas, which is equivalent to approximately 4 <a href="/facts/Parts_per_million/PozRuoLM">ppm</a> by volume under standard temperature and pressure. However, this threshold varies by country, state, or even agency or application. For instance, the <a href="/facts/Texas_Railroad_Commission/NvdEKhFn">Texas Railroad Commission</a> considers a sour gas pipeline one that carries gas over 100 ppm by volume of H2S. However, the <a href="/facts/Texas_Commission_on_Environmental_Quality/dwK7F3yk">Texas Commission on Environmental Quality</a> has historically defined sour gas for <a href="/facts/Upstream_(petroleum_industry)/AL7ztvwe">upstream operations</a> – which requires permitting, reporting, and possibly additional emission controls – as gas that contains more than 24 ppm by volume. Natural gas that does not contain significant amounts of hydrogen sulfide is called "sweet gas".
Although the terms "<a href="/facts/Acid_gas/IN9jzyMg">acid gas</a>" and "sour gas" are sometimes used interchangeably, strictly speaking, a sour gas is any gas that specifically contains hydrogen sulfide in significant amounts, whereas an acid gas is any gas that contains significant amounts of <a href="/facts/Acid/FySU18n1">acidic</a> gases such as <a href="/facts/Carbon_dioxide/xGzpppEp">carbon dioxide</a> (CO2) or hydrogen sulfide. Thus, carbon dioxide by itself is an acid gas, not a sour gas. In addition to being <a href="/facts/Hydrogen_sulfide/UbCqjMMk">toxic</a>, hydrogen sulfide in the presence of water also damages <a href="/facts/Piping/Y8UEQBXx">piping</a> and other equipment handling sour gas by <a href="/facts/Sulfide_stress_cracking/QHaqw7Gh">sulfide stress cracking</a>. Natural gas typically contains several ppm of volatile sulfur compounds, but gas from one well in <a href="/facts/Canada/cWWFM8oc">Canada</a> is known to contain 90% hydrogen sulfide and others may have H2S contents in the tens of percent range.

Sour gas open-in-new

Sour gas