Town gas - Revision history

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	[[Category:Done ~~2017~~-07-01]]		[[Category:Done 2026-08-01]]
	[[File:640px-Hong_Kong_To_Kwa_Wan_Towngas_Centre.jpg\|400px\|framed\|right\|Figure 1. The To Kwa Wan plant in Hong Kong that produces town gas from oil.<ref>Wikimedia Commons. (May 26, 2015). ''Hong Kong To Kwa Wan Towngas Centre'' [Online]. Available: http://commons.wikimedia.org/wiki/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG#/media/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG</ref>]]		[[File:640px-Hong_Kong_To_Kwa_Wan_Towngas_Centre.jpg\|400px\|framed\|right\|Figure 1. The To Kwa Wan plant in Hong Kong that produces town gas from oil.<ref>Wikimedia Commons. (May 26, 2015). ''Hong Kong To Kwa Wan Towngas Centre'' [Online]. Available: http://commons.wikimedia.org/wiki/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG#/media/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG</ref>]]
			<onlyinclude>'''Town gas,''' or '''coal gas,''' refers to a [[gas\|gaseous]] [[fuel]] mixture produced by heating [[bituminous]] [[coal]] in the absence of air. More recently, some [[power plant]]s have created town gas using heavy [[oil]] and [[naphtha]] as feedstocks instead of coal.</onlyinclude><ref name="RE2">Towngas. (May 26, 2015). ''Town Gas Production'' [Online]. Available: https://www.towngas.com/Eng/Corp/AbtTG/HKBus/Production.aspx</ref> Town gas was introduced as a fuel for [[lighting]] and cooking in the early 19th century. Town gas became popular for cooking because gas cookers could be turned on and off quickly, unlike coal stoves.<ref name="RE1">G.Boyle, B.Everett, S.Peake, J.Ramage. (May 26, 2015). ''Energy Systems and Sustainability: Power for a Sustainable Future'', 2nd Ed. Oxford, UK: Oxford University Press, 2012.</ref> Town gas is generally considered a relatively safe fuel because it rises and will dissipate into the air if a leak occurs. Additionally, [[odorant]]s are added to the town gas so that leaks can be easily detected.<ref name="RE2"/> However, most distribution networks have been converted to supply [[natural gas]] rather than town gas, so its use is no longer widespread.
	<onlyinclude>'''Town gas''' or '''coal gas''' refers to a [[gas\|gaseous]] ~~mixture, used as a~~ [[fuel]]~~, that is released when~~ [[bituminous]] [[coal]] ~~is burned~~. ~~Recently~~, some [[power plant]]s have ~~begun creating~~ town gas ~~''not'' using coal, rather~~ using heavy [[oil]] and [[naphtha]] as ~~their~~ feedstocks.</onlyinclude><ref name="RE2">Towngas. (May 26, 2015). ''Town Gas Production'' [Online]. Available: https://www.towngas.com/Eng/Corp/AbtTG/HKBus/Production.aspx</ref> Town gas was introduced as a fuel for [[lighting]] and cooking in the early 19th century. ~~The use of town~~ gas ~~to cook was desirable as a~~ gas ~~cooker~~ could be turned on and off quickly, unlike ~~with a~~ coal ~~stove~~.<ref name="RE1">G.Boyle, B.Everett, S.Peake, J.Ramage. (May 26, 2015). ''Energy Systems and Sustainability: Power for a Sustainable Future'', 2nd Ed. Oxford, UK: Oxford University Press, 2012.</ref> Town gas is a ~~useful and~~ relatively safe ~~gas as~~ it rises and will dissipate into the air if ~~leakages occur~~. ~~As well~~, [[odorant]]s are added to the town gas so that ~~if a leak exists it~~ can be easily detected.<ref name="RE2"/> However, most distribution networks have been converted to ~~deal with~~ [[natural gas]] rather than town gas so its use is ~~not~~ widespread.

	==Town Gas from Coal==		==Town Gas from Coal==
	When coal is heated in the absence of [[air]], ~~the~~ [[volatile]] ~~matter comes off (without~~ undergoing [[combustion]]~~, since~~ there's no [[oxygen]]), ~~releasing~~ a ~~useful~~ gas for [[light]]ing ~~as well as~~ leaving a residue known as [[coke]]. ~~This~~ coke was ~~generally~~ used ~~(once created)~~ to fuel the [[furnace]]s that burn ~~the~~ coal. ~~This burning breaks~~ down ~~a large amount~~ of the tarry, bituminous ~~content~~.<ref name="RE1"/> ~~From here, an~~ impure gas ~~- mainly~~ composed of [[carbon monoxide]] and [[hydrogen]] ~~- rises up~~ through tubes. ~~However, the~~ gas ~~that is released~~ also contains ~~all the~~ [[sulfur]] ~~impurities within the coal -~~ particularly toxic hydrogen sulfide - as well as ammonia. In order for this gas to be usable, it must be cleaned. ~~To "clean" this~~ gas~~, it~~ is bubbled through water~~, removing the~~ ammonia and ~~any~~ residual oils or tars ~~in the gas~~. Hydrogen sulfide is removed by passing the gas over iron oxide. The gas ~~can~~ then undergo ~~one more~~ final "scrubbing" process to remove ~~any aromatics~~, such as [[benzene]] ~~from it~~.<ref name="RE1"/>		When coal is heated in the absence of [[air]], [[volatile]] compounds are released when undergoing [[combustion]] where there is no [[oxygen]] present, producing a gas suitable for [[light]]ing and leaving behind a solid residue known as [[coke]]. The coke was then commonly used to fuel the [[furnace]]s or other industrial processes that burn coal. The high temperatures also break down much of the coal's tarry, bituminous material.<ref name="RE1"/> The resulting impure gas, composed primarily of [[carbon monoxide]] and [[hydrogen]], is then collected through a series of pipes or tubes. The gas also contains [[sulfur]] compounds, particularly toxic hydrogen sulfide, as well as ammonia and other impurities. In order for this gas to be usable, it must be cleaned. The gas is first bubbled through water to remove ammonia and residual oils or tars vapours. Hydrogen sulfide is removed by passing the gas over iron oxide. The gas may then undergo a final scrubbing process to remove aromatic compounds, such as [[benzene]].<ref name="RE1"/>

	==Town Gas from Oil==		==Town Gas from Oil==
	In the 1960s, a new process was developed that allowed town gas to be ~~made~~ from naphtha ~~- one of the~~ light distillates ~~produced~~ during the [[fractional distillation]] of [[crude oil]]. ~~This naphtha~~ generally ~~is composed~~ of ~~molecules~~ containing 5-12 [[carbon]] atoms. Using naphtha creates a cleaner gas than if coal ~~is used,~~ and ~~the gas also has~~ a ~~higher efficiency~~.<ref name="RE3">Towngas. (May 26, 2015). ''Clean Production'' [Online]. Available: https://www.towngas.com/eng/corp/socresp/envprot/cleanprodtion.aspx</ref> ~~By treating this~~ naphtha with a high [[pressure]] [[steam]] at high temperatures, carbon-carbon bonds ~~are broken and~~ the ~~chains of the naphtha are broken~~. This process is known as '''steam reforming''' ~~and the resulting product is~~ a mixture containing carbon monoxide, hydrogen, and a small amount of [[methane]].<ref name="RE1"/> After ~~this~~ gas is formed, ~~some~~ of the mixture ~~must be~~ converted into methane and carbon dioxide through a '''methanation''' ~~process (~~a process ~~by which~~ methane ~~is generated~~ from ~~a mixture of various gases)~~. The final result is a sulfur-free alternative to coal based town gas that contains hydrogen, methane, carbon dioxide, and relatively small amounts of ~~both carbon dioxide and~~ nitrogen.		In the 1960s, a new process was developed that allowed town gas to be produced from naphtha, a light distillates obtained during the [[fractional distillation]] of [[crude oil]]. Naphtha generally consists of hydrocarbons containing between 5 and 12 [[carbon]] atoms. Using naphtha creates a cleaner-burning gas than coal and results in a more efficient fuel.<ref name="RE3">Towngas. (May 26, 2015). ''Clean Production'' [Online]. Available: https://www.towngas.com/eng/corp/socresp/envprot/cleanprodtion.aspx</ref> During steam reforming, naphtha is treated with high-[[pressure]] [[steam]] at high temperatures, breaking the carbon-carbon bonds within the hydrocarbon molecules. This process, known as '''steam reforming,''' produces a gas mixture containing carbon monoxide, hydrogen, and a small amount of [[methane]].<ref name="RE1"/> After the gas is formed, part of the mixture is converted into methane and carbon dioxide through '''methanation,''' a process that generates methane from carbon monoxide and hydrogen. The final result is a sulfur-free alternative to coal-based town gas that contains hydrogen, methane, carbon dioxide, and relatively small amounts of nitrogen.

	==Environmental Issues==		==Environmental Issues==
	~~Since~~ town gas is ~~essentially~~ manufactured natural gas, it poses ~~similar~~ environmental ~~threats~~. Although cleaner burning than coal or oil, there are still [[emission]]s associated with the production and use of town gas. Natural gas ~~gives off~~ 53 [[kilogram]]s (or 117 [[pound]]s) of carbon dioxide per 293.07 [[kilowatt-hour\|kWh]] ~~(or million [[BTU]])~~ of energy ~~provided by it~~, which is significantly less than other fossil fuels. ~~Due to~~ town gas' similar composition, its ~~values~~ are ~~relatively close to this~~. ~~Comparatively~~ [[anthracite]] coal ~~gives off~~ 103.7 kilograms (or 228.6 pounds) ~~and~~ gasoline ~~gives off~~ 71.3 kilograms (or 157.2 pounds).<ref>EIA. (June 8 , 2015). ''How much carbon dioxide is produced when different fuels are burned?'' [Online]. Available: http://www.eia.gov/tools/faqs/faq.cfm?id=73&t=11</ref> Additionally, ~~the~~ small amounts of carbon monoxide, sulfur, and other impurities ~~can~~ be released when town gas is used - contributing to [[pollution]] and [[acid rain]].		Because town gas is a manufactured gaseous fuel with properties similar to natural gas, it poses many of the same environmental concerns. Although cleaner burning than coal or oil, there are still [[emission]]s associated with the production and use of town gas. Natural gas emits approximately 53 [[kilogram]]s (117 [[pound]]s) of carbon dioxide per million [[BTU]] (293.07 [[kilowatt-hour\|kWh]] of energy produced, which is significantly less than many other fossil fuels. Because town gas has a similar composition, its carbon dioxide emissions are generally comparable. For comparison, [[anthracite]] coal emits 103.7 kilograms (228.6 pounds), gasoline emits 71.3 kilograms (157.2 pounds) of carbon dioxide per million BTU.<ref>EIA. (June 8 , 2015). ''How much carbon dioxide is produced when different fuels are burned?'' [Online]. Available: http://www.eia.gov/tools/faqs/faq.cfm?id=73&t=11</ref> Additionally, small amounts of carbon monoxide, sulfur compounds, and other impurities may be released when town gas is used, contributing to air [[pollution]] and [[acid rain]].

			== For Further Reading ==

			* [[Bituminous coal]]
			* [[Naphtha]]
			* [[Combustion]]
			* [[Steam reforming]]
			* [[Anthracite]]
			* or explore a [[Special:Random\|random page]]

	==References==		==References==
	{{reflist}}		{{reflist}}
	[[Category:Uploaded]]		[[Category:Uploaded]]

Jmdonev: 1 revision imported

2017-08-29T01:46:45Z

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Jmdonev at 17:40, 14 July 2017

2017-07-14T17:40:19Z

← Older revision		Revision as of 17:40, 14 July 2017
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	[[File:640px-Hong_Kong_To_Kwa_Wan_Towngas_Centre.jpg\|400px\|framed\|right\|Figure 1. The To Kwa Wan plant in Hong Kong that produces town gas from oil.<ref>Wikimedia Commons. (May 26, 2015). ''Hong Kong To Kwa Wan Towngas Centre'' [Online]. Available: http://commons.wikimedia.org/wiki/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG#/media/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG</ref>]]		[[File:640px-Hong_Kong_To_Kwa_Wan_Towngas_Centre.jpg\|400px\|framed\|right\|Figure 1. The To Kwa Wan plant in Hong Kong that produces town gas from oil.<ref>Wikimedia Commons. (May 26, 2015). ''Hong Kong To Kwa Wan Towngas Centre'' [Online]. Available: http://commons.wikimedia.org/wiki/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG#/media/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG</ref>]]

	<onlyinclude>'''Town gas''' or '''coal gas''' refers to a [[gas\|gaseous]] mixture, used as a [[fuel]], that is released when [[bituminous]] [[coal]] is burned. Recently, some power ~~plants~~ have begun creating town gas ''not'' using coal, rather using heavy [[oil]] and [[naphtha]] as their feedstocks.</onlyinclude><ref name="RE2">Towngas. (May 26, 2015). ''Town Gas Production'' [Online]. Available: https://www.towngas.com/Eng/Corp/AbtTG/HKBus/Production.aspx</ref> Town gas was introduced as a fuel for [[lighting]] and cooking in the early 19th century. The use of town gas to cook was desirable as a gas cooker could be turned on and off quickly, unlike with a coal stove.<ref name="RE1">G.Boyle, B.Everett, S.Peake, J.Ramage. (May 26, 2015). ''Energy Systems and Sustainability: Power for a Sustainable Future'', 2nd Ed. Oxford, UK: Oxford University Press, 2012.</ref> Town gas is a useful and relatively safe gas as it rises and will dissipate into the air if leakages occur. As well, [[odorant]]s are added to the town gas so that if a leak exists it can be easily detected.<ref name="RE2"/> However, most distribution networks have been converted to deal with [[natural gas]] rather than town gas so its use is not widespread.		<onlyinclude>'''Town gas''' or '''coal gas''' refers to a [[gas\|gaseous]] mixture, used as a [[fuel]], that is released when [[bituminous]] [[coal]] is burned. Recently, some [[power plant]]s have begun creating town gas ''not'' using coal, rather using heavy [[oil]] and [[naphtha]] as their feedstocks.</onlyinclude><ref name="RE2">Towngas. (May 26, 2015). ''Town Gas Production'' [Online]. Available: https://www.towngas.com/Eng/Corp/AbtTG/HKBus/Production.aspx</ref> Town gas was introduced as a fuel for [[lighting]] and cooking in the early 19th century. The use of town gas to cook was desirable as a gas cooker could be turned on and off quickly, unlike with a coal stove.<ref name="RE1">G.Boyle, B.Everett, S.Peake, J.Ramage. (May 26, 2015). ''Energy Systems and Sustainability: Power for a Sustainable Future'', 2nd Ed. Oxford, UK: Oxford University Press, 2012.</ref> Town gas is a useful and relatively safe gas as it rises and will dissipate into the air if leakages occur. As well, [[odorant]]s are added to the town gas so that if a leak exists it can be easily detected.<ref name="RE2"/> However, most distribution networks have been converted to deal with [[natural gas]] rather than town gas so its use is not widespread.

	==Town Gas from Coal==		==Town Gas from Coal==

J.williams: 1 revision imported

2015-09-18T16:51:46Z

1 revision imported

← Older revision	Revision as of 16:51, 18 September 2015
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Kjstenho at 21:05, 3 September 2015

2015-09-03T21:05:58Z

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	[[File:640px-Hong_Kong_To_Kwa_Wan_Towngas_Centre.jpg\|400px\|framed\|right\|Figure 1. The To Kwa Wan plant in Hong Kong that produces town gas from oil.<ref>Wikimedia Commons. (May 26, 2015). ''Hong Kong To Kwa Wan Towngas Centre'' [Online]. Available: http://commons.wikimedia.org/wiki/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG#/media/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG</ref>]]		[[File:640px-Hong_Kong_To_Kwa_Wan_Towngas_Centre.jpg\|400px\|framed\|right\|Figure 1. The To Kwa Wan plant in Hong Kong that produces town gas from oil.<ref>Wikimedia Commons. (May 26, 2015). ''Hong Kong To Kwa Wan Towngas Centre'' [Online]. Available: http://commons.wikimedia.org/wiki/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG#/media/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG</ref>]]

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	==Town Gas from Oil==		==Town Gas from Oil==
	In the 1960s, a new process was developed that allowed town gas to be made from naphtha - one of the light distillates produced during the [[fractional distillation]] of [[crude oil]]. This naphtha generally is composed of molecules containing 5-12 carbon atoms. Using naphtha creates a cleaner gas than if coal is used, and the gas also has a higher efficiency.<ref name="RE3">Towngas. (May 26, 2015). ''Clean Production'' [Online]. Available: https://www.towngas.com/eng/corp/socresp/envprot/cleanprodtion.aspx</ref> By treating this naphtha with a high pressure steam at high temperatures, carbon-carbon bonds are broken and the chains of the naphtha are broken. This process is known as '''steam reforming''' and the resulting product is a mixture containing carbon monoxide, hydrogen, and a small amount of [[methane]].<ref name="RE1"/> After this gas is formed, some of the mixture must be converted into methane and carbon dioxide through a '''methanation''' process (a process by which methane is generated from a mixture of various gases). The final result is a sulfur-free alternative to coal based town gas that contains hydrogen, methane, carbon dioxide, and relatively small amounts of both carbon dioxide and nitrogen.		In the 1960s, a new process was developed that allowed town gas to be made from naphtha - one of the light distillates produced during the [[fractional distillation]] of [[crude oil]]. This naphtha generally is composed of molecules containing 5-12 [[carbon]] atoms. Using naphtha creates a cleaner gas than if coal is used, and the gas also has a higher efficiency.<ref name="RE3">Towngas. (May 26, 2015). ''Clean Production'' [Online]. Available: https://www.towngas.com/eng/corp/socresp/envprot/cleanprodtion.aspx</ref> By treating this naphtha with a high [[pressure]] [[steam]] at high temperatures, carbon-carbon bonds are broken and the chains of the naphtha are broken. This process is known as '''steam reforming''' and the resulting product is a mixture containing carbon monoxide, hydrogen, and a small amount of [[methane]].<ref name="RE1"/> After this gas is formed, some of the mixture must be converted into methane and carbon dioxide through a '''methanation''' process (a process by which methane is generated from a mixture of various gases). The final result is a sulfur-free alternative to coal based town gas that contains hydrogen, methane, carbon dioxide, and relatively small amounts of both carbon dioxide and nitrogen.

	==Environmental Issues==		==Environmental Issues==

J.williams: 1 revision imported

2015-09-03T18:22:41Z

1 revision imported

← Older revision	Revision as of 18:22, 3 September 2015
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Jmdonev at 23:26, 28 August 2015

2015-08-28T23:26:07Z

← Older revision		Revision as of 23:26, 28 August 2015
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	[[Category:Done 2015-06-11]]		[[Category:Done 2015-09-05]]
	[[File:640px-Hong_Kong_To_Kwa_Wan_Towngas_Centre.jpg\|400px\|framed\|right\|Figure 1. The To Kwa Wan plant in Hong Kong that produces town gas from oil.<ref>Wikimedia Commons. (May 26, 2015). ''Hong Kong To Kwa Wan Towngas Centre'' [Online]. Available: http://commons.wikimedia.org/wiki/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG#/media/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG</ref>]]		[[File:640px-Hong_Kong_To_Kwa_Wan_Towngas_Centre.jpg\|400px\|framed\|right\|Figure 1. The To Kwa Wan plant in Hong Kong that produces town gas from oil.<ref>Wikimedia Commons. (May 26, 2015). ''Hong Kong To Kwa Wan Towngas Centre'' [Online]. Available: http://commons.wikimedia.org/wiki/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG#/media/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG</ref>]]

	<onlyinclude>'''Town gas''' or '''coal gas''' refers to a [[gas\|gaseous]] mixture, used as a [[fuel]], that is released when [[bituminous]] [[coal]] is burned. Recently, some power plants have begun creating town gas ''not'' using coal, rather using heavy [[oil]] and [[~~naptha~~]] as their feedstocks.</onlyinclude><ref name="RE2">Towngas. (May 26, 2015). ''Town Gas Production'' [Online]. Available: https://www.towngas.com/Eng/Corp/AbtTG/HKBus/Production.aspx</ref> Town gas was introduced as a fuel for [[lighting]] and cooking in the early 19th century. The use of town gas to cook was desirable as a gas cooker could be turned on and off quickly, unlike with a coal stove.<ref name="RE1">G.Boyle, B.Everett, S.Peake, J.Ramage. (May 26, 2015). ''Energy Systems and Sustainability: Power for a Sustainable Future'', 2nd Ed. Oxford, UK: Oxford University Press, 2012.</ref> Town gas is a useful and relatively safe gas as it rises and will dissipate into the air if leakages occur. As well, [[odorant]]s are added to the town gas so that if a leak exists it can be easily detected.<ref name="RE2"/> However, most distribution networks have been converted to deal with [[natural gas]] rather than town gas so its use is not widespread.		<onlyinclude>'''Town gas''' or '''coal gas''' refers to a [[gas\|gaseous]] mixture, used as a [[fuel]], that is released when [[bituminous]] [[coal]] is burned. Recently, some power plants have begun creating town gas ''not'' using coal, rather using heavy [[oil]] and [[naphtha]] as their feedstocks.</onlyinclude><ref name="RE2">Towngas. (May 26, 2015). ''Town Gas Production'' [Online]. Available: https://www.towngas.com/Eng/Corp/AbtTG/HKBus/Production.aspx</ref> Town gas was introduced as a fuel for [[lighting]] and cooking in the early 19th century. The use of town gas to cook was desirable as a gas cooker could be turned on and off quickly, unlike with a coal stove.<ref name="RE1">G.Boyle, B.Everett, S.Peake, J.Ramage. (May 26, 2015). ''Energy Systems and Sustainability: Power for a Sustainable Future'', 2nd Ed. Oxford, UK: Oxford University Press, 2012.</ref> Town gas is a useful and relatively safe gas as it rises and will dissipate into the air if leakages occur. As well, [[odorant]]s are added to the town gas so that if a leak exists it can be easily detected.<ref name="RE2"/> However, most distribution networks have been converted to deal with [[natural gas]] rather than town gas so its use is not widespread.

	==Town Gas from Coal==		==Town Gas from Coal==
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	==Town Gas from Oil==		==Town Gas from Oil==
	In the 1960s, a new process was developed that allowed town gas to be made from ~~[[naptha]]~~ - one of the light distillates produced during the [[fractional distillation]] of [[crude oil]]. This ~~naptha~~ generally is composed of molecules containing 5-12 carbon atoms. Using ~~naptha~~ creates a cleaner gas than if coal is used, and the gas also has a higher efficiency.<ref name="RE3">Towngas. (May 26, 2015). ''Clean Production'' [Online]. Available: https://www.towngas.com/eng/corp/socresp/envprot/cleanprodtion.aspx</ref> By treating this ~~naptha~~ with a high pressure steam at high temperatures, carbon-carbon bonds are broken and the chains of the ~~naptha~~ are broken. This process is known as '''steam reforming''' and the resulting product is a mixture containing carbon monoxide, hydrogen, and a small amount of [[methane]].<ref name="RE1"/> After this gas is formed, some of the mixture must be converted into methane and carbon dioxide through a '''methanation''' process (a process by which methane is generated from a mixture of various gases). The final result is a sulfur-free alternative to coal based town gas that contains hydrogen, methane, carbon dioxide, and relatively small amounts of both carbon dioxide and nitrogen.		In the 1960s, a new process was developed that allowed town gas to be made from naphtha - one of the light distillates produced during the [[fractional distillation]] of [[crude oil]]. This naphtha generally is composed of molecules containing 5-12 carbon atoms. Using naphtha creates a cleaner gas than if coal is used, and the gas also has a higher efficiency.<ref name="RE3">Towngas. (May 26, 2015). ''Clean Production'' [Online]. Available: https://www.towngas.com/eng/corp/socresp/envprot/cleanprodtion.aspx</ref> By treating this naphtha with a high pressure steam at high temperatures, carbon-carbon bonds are broken and the chains of the naphtha are broken. This process is known as '''steam reforming''' and the resulting product is a mixture containing carbon monoxide, hydrogen, and a small amount of [[methane]].<ref name="RE1"/> After this gas is formed, some of the mixture must be converted into methane and carbon dioxide through a '''methanation''' process (a process by which methane is generated from a mixture of various gases). The final result is a sulfur-free alternative to coal based town gas that contains hydrogen, methane, carbon dioxide, and relatively small amounts of both carbon dioxide and nitrogen.

	==Environmental Issues==		==Environmental Issues==

J.williams: 1 revision imported

2015-08-26T21:31:45Z

1 revision imported

← Older revision	Revision as of 21:31, 26 August 2015
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J.williams at 17:00, 12 August 2015

2015-08-12T17:00:21Z

New page

[[Category:Done 2015-06-11]]
[[File:640px-Hong_Kong_To_Kwa_Wan_Towngas_Centre.jpg|400px|framed|right|Figure 1. The To Kwa Wan plant in Hong Kong that produces town gas from oil.<ref>Wikimedia Commons. (May 26, 2015). ''Hong Kong To Kwa Wan Towngas Centre'' [Online]. Available: http://commons.wikimedia.org/wiki/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG#/media/File:Hong_Kong_To_Kwa_Wan_Towngas_Centre.JPG</ref>]]

<onlyinclude>'''Town gas''' or '''coal gas''' refers to a [[gas|gaseous]] mixture, used as a [[fuel]], that is released when [[bituminous]] [[coal]] is burned. Recently, some power plants have begun creating town gas ''not'' using coal, rather using heavy [[oil]] and [[naptha]] as their feedstocks.</onlyinclude><ref name="RE2">Towngas. (May 26, 2015). ''Town Gas Production'' [Online]. Available: https://www.towngas.com/Eng/Corp/AbtTG/HKBus/Production.aspx</ref> Town gas was introduced as a fuel for [[lighting]] and cooking in the early 19th century. The use of town gas to cook was desirable as a gas cooker could be turned on and off quickly, unlike with a coal stove.<ref name="RE1">G.Boyle, B.Everett, S.Peake, J.Ramage. (May 26, 2015). ''Energy Systems and Sustainability: Power for a Sustainable Future'', 2nd Ed. Oxford, UK: Oxford University Press, 2012.</ref> Town gas is a useful and relatively safe gas as it rises and will dissipate into the air if leakages occur. As well, [[odorant]]s are added to the town gas so that if a leak exists it can be easily detected.<ref name="RE2"/> However, most distribution networks have been converted to deal with [[natural gas]] rather than town gas so its use is not widespread.

==Town Gas from Coal==
When coal is heated in the absence of [[air]], the [[volatile]] matter comes off (without undergoing [[combustion]], since there's no [[oxygen]]), releasing a useful gas for [[light]]ing as well as leaving a residue known as [[coke]]. This coke was generally used (once created) to fuel the [[furnace]]s that burn the coal. This burning breaks down a large amount of the tarry, bituminous content.<ref name="RE1"/> From here, an impure gas - mainly composed of [[carbon monoxide]] and [[hydrogen]] - rises up through tubes. However, the gas that is released also contains all the [[sulfur]] impurities within the coal - particularly toxic hydrogen sulfide - as well as ammonia. In order for this gas to be usable, it must be cleaned. To "clean" this gas, it is bubbled through water, removing the ammonia and any residual oils or tars in the gas. Hydrogen sulfide is removed by passing the gas over iron oxide. The gas can then undergo one more final "scrubbing" process to remove any aromatics, such as [[benzene]] from it.<ref name="RE1"/>

==Town Gas from Oil==
In the 1960s, a new process was developed that allowed town gas to be made from [[naptha]] - one of the light distillates produced during the [[fractional distillation]] of [[crude oil]]. This naptha generally is composed of molecules containing 5-12 carbon atoms. Using naptha creates a cleaner gas than if coal is used, and the gas also has a higher efficiency.<ref name="RE3">Towngas. (May 26, 2015). ''Clean Production'' [Online]. Available: https://www.towngas.com/eng/corp/socresp/envprot/cleanprodtion.aspx</ref> By treating this naptha with a high pressure steam at high temperatures, carbon-carbon bonds are broken and the chains of the naptha are broken. This process is known as '''steam reforming''' and the resulting product is a mixture containing carbon monoxide, hydrogen, and a small amount of [[methane]].<ref name="RE1"/> After this gas is formed, some of the mixture must be converted into methane and carbon dioxide through a '''methanation''' process (a process by which methane is generated from a mixture of various gases). The final result is a sulfur-free alternative to coal based town gas that contains hydrogen, methane, carbon dioxide, and relatively small amounts of both carbon dioxide and nitrogen.

==Environmental Issues==
Since town gas is essentially manufactured natural gas, it poses similar environmental threats. Although cleaner burning than coal or oil, there are still [[emission]]s associated with the production and use of town gas. Natural gas gives off 53 [[kilogram]]s (or 117 [[pound]]s) of carbon dioxide per 293.07 [[kilowatt-hour|kWh]] (or million [[BTU]]) of energy provided by it, which is significantly less than other fossil fuels. Due to town gas' similar composition, its values are relatively close to this. Comparatively [[anthracite]] coal gives off 103.7 kilograms (or 228.6 pounds) and gasoline gives off 71.3 kilograms (or 157.2 pounds).<ref>EIA. (June 8 , 2015). ''How much carbon dioxide is produced when different fuels are burned?'' [Online]. Available: http://www.eia.gov/tools/faqs/faq.cfm?id=73&t=11</ref> Additionally, the small amounts of carbon monoxide, sulfur, and other impurities can be released when town gas is used - contributing to [[pollution]] and [[acid rain]].

==References==
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