User:Milton Beychok/Sandbox: Difference between revisions

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'''Sour gas''' is [[natural gas]], petroleum refinery byproduct gas or any other gas containing  significant amounts of [[hydrogen sulfide]] (H<sub>2</sub>S).  Natural gas is usually considered sour if there are more than 5.7 [[milligram]]s of H<sub>2</sub>S per cubic meter of natural gas at 20 °C, which is equivalent to approximately 4 [[Parts-per notation|ppm]] by volume<ref name=NatGasOrg>[http://www.naturalgas.org/naturalgas/processing_ng.asp NaturalGas.org website page] ''Processing Natural Gas''</ref>.
'''Acid gas''' is [[natural gas]] or any other gas mixture which contains significant amounts of [[hydrogen sulfide]] (H<sub>2</sub>S), [[carbon dioxide]] (CO<sub>2</sub>), or similar contaminants. The terms ''acid gas'' and ''sour gas'' are often incorrectly treated as synonyms. Strictly speaking, a [[sour gas]] is any gas that contains hydrogen sulfide in significant amounts; an acid gas is any gas that contains significant amounts of [[acidic]] gases such as [[carbon dioxide]] (CO<sub>2</sub>) or hydrogen sulfide. Thus, carbon dioxide by itself is an acid gas but not a sour gas.  


Although the terms ''[[acid gas]]'' and ''sour gas'' are used interchangeably, strictly speaking, a sour gas is any gas that contains hydrogen sulfide in significant amounts, whereas an [[acid gas]] is any gas that contains significant amounts of [[acidic]] gases such as [[carbon dioxide]] (CO<sub>2</sub>) or hydrogen sulfide. Thus, carbon dioxide by itself is an acid gas but it is not a sour gas.
Before a raw natural gas containing hydrogen sulfide and/or carbon dioxide can be used, the raw gas must be treated to reduce impurities to acceptable levels and this is commonly done with an [[amine gas treating]] process.<ref>[http://www.naturalgas.org/naturalgas/processing_ng.asp NaturalGas.org website page] ''Processing Natural Gas''</ref><ref>[http://www.eia.doe.gov/pub/oil_gas/natural_gas/feature_articles/2006/ngprocess/ngprocess.pdf Energy Information Agency website page] ''Natural Gas Processing: The Crucial Link Between Natural Gas Production and Its Transportation to Market''</ref> The removed H<sub>2</sub>S is most often subsequently converted to by-product elemental [[sulfur]] in a [[Claus process]].  
 
==Discussion==
 
Before a raw natural gas containing hydrogen sulfide and/or carbon dioxide can be used, the raw gas must be treated to remove those impurities to acceptable levels, commonly by an [[Amine gas treating|amine gas treater]] or similar process.<ref name=NatGasOrg/><ref>[http://www.eia.doe.gov/pub/oil_gas/natural_gas/feature_articles/2006/ngprocess/ngprocess.pdf Energy Information Agency website page] ''Natural Gas Processing: The Crucial Link Between Natural Gas Production and Its Transportation to Market''</ref> The removed H<sub>2</sub>S is most often subsequently converted to by-product elemental [[sulfur]] in a [[Claus process]].  


Processes within oil refineries or natural gas processing plants that remove [[mercaptans]] and/or hydrogen sulfide are commonly referred to as '''''sweetening''''' processes because they result in products which no longer have the sour, foul odors of [[mercaptan]]s and hydrogen sulfide.  
Processes within oil refineries or natural gas processing plants that remove [[mercaptans]] and/or hydrogen sulfide are commonly referred to as '''''sweetening''''' processes because they result in products which no longer have the sour, foul odors of [[mercaptan]]s and hydrogen sulfide.  


Hydrogen sulfide is a [[Hydrogen sulfide#toxicity|toxic]] gas. It also places restrictions on the materials than can be used for [[piping]] and other equipment handling sour gas, as many metals are sensitive to [[sulfide stress cracking]]. The presence of hydrogen sulfide in gas causes lower quality burning and the production of [[sulfur dioxide]], and so is regulated in commercially sold gas.
Hydrogen sulfide is a [[Hydrogen sulfide#toxicity|toxic]] gas. It also restricts the materials that can be used for [[piping]] and other equipment for handling sour gas, as many metals are sensitive to [[sulfide stress cracking]].  


==References==
==References==
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<references/>

Revision as of 15:24, 9 August 2008

Acid gas is natural gas or any other gas mixture which contains significant amounts of hydrogen sulfide (H2S), carbon dioxide (CO2), or similar contaminants. The terms acid gas and sour gas are often incorrectly treated as synonyms. Strictly speaking, a sour gas is any gas that contains hydrogen sulfide in significant amounts; an acid gas is any gas that contains significant amounts of acidic gases such as carbon dioxide (CO2) or hydrogen sulfide. Thus, carbon dioxide by itself is an acid gas but not a sour gas.

Before a raw natural gas containing hydrogen sulfide and/or carbon dioxide can be used, the raw gas must be treated to reduce impurities to acceptable levels and this is commonly done with an amine gas treating process.[1][2] The removed H2S is most often subsequently converted to by-product elemental sulfur in a Claus process.

Processes within oil refineries or natural gas processing plants that remove mercaptans and/or hydrogen sulfide are commonly referred to as sweetening processes because they result in products which no longer have the sour, foul odors of mercaptans and hydrogen sulfide.

Hydrogen sulfide is a toxic gas. It also restricts the materials that can be used for piping and other equipment for handling sour gas, as many metals are sensitive to sulfide stress cracking.

References

  1. NaturalGas.org website page Processing Natural Gas
  2. Energy Information Agency website page Natural Gas Processing: The Crucial Link Between Natural Gas Production and Its Transportation to Market