User:Milton Beychok/Sandbox: Difference between revisions

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'''Acid gas''' is [[natural gas]], petroleum byproduct gas or any other gas mixture containing significant amounts of [[acidic]] gases.


The terms ''acid gas'' and ''[[sour gas]]'' are often incorrectly treated as synonyms. Strictly speaking, a sour gas is any gas  containing [[hydrogen sulfide]] (H<sub>2</sub>S) in significant amounts whereas an acid gas is any gas containing significant amounts of [[acidic]] substances such as gaseous [[carbon dioxide]] (CO<sub>2</sub>),  hydrogen sulfide or [[mercaptan]]s (RSH). Thus, carbon dioxide by itself is an acid gas but not a sour gas.
==Discussion==
Before a raw natural gas containing hydrogen sulfide or carbon dioxide can be used, the raw gas must be treated to reduce those 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]]. Any mercaptans present are commonly removed with a ''sweetening'' 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.
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]].
Carbon dioxide at concentrations of 7% to 10% cause dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour. Concentrations above 17% are lethal with exposure of 1 minute or more.<ref>
[[U.S. Environmental Protection Agency]]: [http://www.epa.gov/ozone/snap/fire/co2/co2report.html "Carbon Dioxide as a Fire Suppressant: Examining the Risks"]</ref>
==References==
{{reflist}}

Revision as of 17:16, 9 August 2008

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