Synthetic natural gas - Revision history

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	[[Category:Done ~~2015~~-06-11]]		[[Category:Done 2018-05-18]]
	[[File:640px-Gasometer_in_East_London.jpg\|400px\|framed\|right\|Figure 1. A coal gasifier used in the production of synthesis gas that is then used to make synthetic natural gas.<ref>Wikimedia Commons. (May 26, 2015). ''Gasometer'' [Online]. Available: http://en.wikipedia.org/wiki/Coal_gasification#/media/File:Gasometer_in_East_London.jpg</ref>]]		[[File:640px-Gasometer_in_East_London.jpg\|400px\|framed\|right\|Figure 1. A coal gasifier used in the production of synthesis gas that is then used to make synthetic natural gas.<ref>Wikimedia Commons. (May 26, 2015). ''Gasometer'' [Online]. Available: http://en.wikipedia.org/wiki/Coal_gasification#/media/File:Gasometer_in_East_London.jpg</ref>]]
	<onlyinclude>'''Synthetic natural gas''' is a type of [[gas]] created from [[coal]] that serves as a substitute for [[natural gas]] and is suitable for transmission in natural gas [[pipeline]]s. This natural gas substitute must have a minimum of 95% [[methane]] in it.</onlyinclude><ref name="RE1">L.Albright, L.Angenent, F.Vanek. (May 22, 2015). ''Energy Systems Engineering: Evaluation and Implementation'', 2nd ed. New York, U.S.A.: McGraw Hill, 2012, pp. 148</ref> An intermediate step in the process of creating synthetic natural gas is the production of [[synthesis gas]], also known as syngas.		<onlyinclude>'''Synthetic natural gas''' is a type of [[gas]] created from [[coal]] that serves as a substitute for [[natural gas]] and is suitable for transmission in natural gas [[pipeline]]s. This natural gas substitute must have a minimum of 95% [[methane]] in it.</onlyinclude><ref name="RE1">L.Albright, L.Angenent, F.Vanek. (May 22, 2015). ''Energy Systems Engineering: Evaluation and Implementation'', 2nd ed. New York, U.S.A.: McGraw Hill, 2012, pp. 148</ref> An intermediate step in the process of creating synthetic natural gas is the production of [[synthesis gas]], also known as syngas.
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	==Production==		==Production==
	Synthetic natural gas is created through a ''thermo-chemical conversion''. The first step in this conversion is the '''gasification''' of the solid carbon source, whether it be coal or [[biomass]] (which would create Bio-SNG), with steam or oxygen.<ref name=jr1/> Here the coal is [[combustion\|burned]] with a limited supply of [[oxygen]] or [[air]] and the main product is [[carbon dioxide]]:<ref name=sys>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>		Synthetic natural gas is created through a ''thermo-chemical conversion''. The first step in this conversion is the '''gasification''' of the solid carbon source, whether it be coal or [[biomass]] (which would create Bio-SNG), with steam or oxygen.<ref name=jr1/> Here the coal is [[combustion\|burned]] with a limited supply of [[oxygen]] or [[air]] and the main product is [[carbon dioxide]]:<ref name=sys>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>
	<center><m>2C + O_2 \rightarrow 2CO</m></center>		<center><chem>2C + O_2 \rightarrow 2CO</chem></center>

	To reduce the amount of [[nitrogen]] in this gas, modern gas plants use pure oxygen for combustion. If steam is added to this pure oxygen then a '''water gas reaction''' occurs instead of the traditional combustion:<ref name=sys/>		To reduce the amount of [[nitrogen]] in this gas, modern gas plants use pure oxygen for combustion. If steam is added to this pure oxygen then a '''water gas reaction''' occurs instead of the traditional combustion:<ref name=sys/>
	<center><m>C + H_2O \rightleftharpoons CO + H_2</m></center>		<center><chem>C + H_2O \rightleftharpoons CO + H_2</chem></center>

	These processes drive off some of the [[volatile]] material, and the product is known as a ''producer gas''. Generally, this occurs in a gasifier which feeds coal into a high [[pressure]], high [[temperature]] vessel and distributes steam or oxygen evenly while removing ash to gasify the coal.<ref name=sys/> This producer gas is a mixture containing H<sub>2</sub>, CO, CO<sub>2</sub>, H<sub>2</sub>O, and CH<sub>4</sub> along with other hydrocarbons and some impurities. The exact composition of this gas depends on the type of reactor used, operating conditions, and other processes during the gasification process.<ref name="jr1"/> This gas also contains impurities such as oils, tars, hydrogen sulfide, and ammonia which must be removed - although ammonia levels are lower if the water gas reaction takes place.<ref name=sys/>		These processes drive off some of the [[volatile]] material, and the product is known as a ''producer gas''. Generally, this occurs in a gasifier which feeds coal into a high [[pressure]], high [[temperature]] vessel and distributes steam or oxygen evenly while removing ash to gasify the coal.<ref name=sys/> This producer gas is a mixture containing H<sub>2</sub>, CO, CO<sub>2</sub>, H<sub>2</sub>O, and CH<sub>4</sub> along with other hydrocarbons and some impurities. The exact composition of this gas depends on the type of reactor used, operating conditions, and other processes during the gasification process.<ref name="jr1"/> This gas also contains impurities such as oils, tars, hydrogen sulfide, and ammonia which must be removed - although ammonia levels are lower if the water gas reaction takes place.<ref name=sys/>
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	To finish making the synthetic natural gas, the syngas must undergo '''water gas shift reactions''' and '''methanation'''. The water gas shift reaction combines carbon monoxide with steam to create carbon dioxide and hydrogen in the following reaction:<ref name=sys/>		To finish making the synthetic natural gas, the syngas must undergo '''water gas shift reactions''' and '''methanation'''. The water gas shift reaction combines carbon monoxide with steam to create carbon dioxide and hydrogen in the following reaction:<ref name=sys/>
	<center><m>CO + H_2O \rightleftharpoons CO_2 + H_2</m></center>		<center><chem>CO + H_2O \rightleftharpoons CO_2 + H_2</chem></center>
	This reaction requires a metal catalyst to occur. Since the end "goal" of this gas is to obtain methane (the main component of natural gas) some of the carbon monoxide is retained, so the reaction does not go through to completion. At this point, the carbon dioxide is separated out using a type of scrubbing and only the final methanation step remains. During methanation, carbon monoxide reacts with the hydrogen that was created with the help of a nickel catalyst to create methane and steam in the following reaction:<ref name=sys/>		This reaction requires a metal catalyst to occur. Since the end "goal" of this gas is to obtain methane (the main component of natural gas) some of the carbon monoxide is retained, so the reaction does not go through to completion. At this point, the carbon dioxide is separated out using a type of scrubbing and only the final methanation step remains. During methanation, carbon monoxide reacts with the hydrogen that was created with the help of a nickel catalyst to create methane and steam in the following reaction:<ref name=sys/>
	<center><m>CO + 3H_2 \rightarrow CH_4+ H_2O</m></center>		<center><chem>CO + 3H_2 \rightarrow CH_4+ H_2O</chem></center>
	At this point, the synthetic natural gas is complete after half of the original carbon in the coal has turned into methane. The rest of the carbon is turned into carbon dioxide.		At this point, the synthetic natural gas is complete after half of the original carbon in the coal has turned into methane. The rest of the carbon is turned into carbon dioxide.

	==Bio-SNG==		==Bio-SNG==
	Bio-SNG is produced similarly to regular synthetic natural gas, but is instead made through the gasification of biomass. Biomass such as forestry residues or energy crops are used. To make Bio-SNG, biomass is initially dried and goes through initial gasification. After this, it undergoes gas conditioning, SNG synthesis, and finally gas upgrading.<ref name="~~RE2~~">European Biofuels. (May 22, 2015). ''Bio-SNG'' [Online]. Available: http://biofuelstp.eu/bio-sng.html</ref>		Bio-SNG is produced similarly to regular synthetic natural gas, but is instead made through the gasification of biomass. Biomass such as forestry residues or energy crops are used. To make Bio-SNG, biomass is initially dried and goes through initial gasification. After this, it undergoes gas conditioning, SNG synthesis, and finally gas upgrading.<ref name="RE3">European Biofuels. (May 22, 2015). ''Bio-SNG'' [Online]. Available: http://biofuelstp.eu/bio-sng.html</ref>

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

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2015-08-26T21:31:42Z

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J.williams at 17:00, 12 August 2015

2015-08-12T17:00:10Z

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[[Category:Done 2015-06-11]]
[[File:640px-Gasometer_in_East_London.jpg|400px|framed|right|Figure 1. A coal gasifier used in the production of synthesis gas that is then used to make synthetic natural gas.<ref>Wikimedia Commons. (May 26, 2015). ''Gasometer'' [Online]. Available: http://en.wikipedia.org/wiki/Coal_gasification#/media/File:Gasometer_in_East_London.jpg</ref>]]
<onlyinclude>'''Synthetic natural gas''' is a type of [[gas]] created from [[coal]] that serves as a substitute for [[natural gas]] and is suitable for transmission in natural gas [[pipeline]]s. This natural gas substitute must have a minimum of 95% [[methane]] in it.</onlyinclude><ref name="RE1">L.Albright, L.Angenent, F.Vanek. (May 22, 2015). ''Energy Systems Engineering: Evaluation and Implementation'', 2nd ed. New York, U.S.A.: McGraw Hill, 2012, pp. 148</ref> An intermediate step in the process of creating synthetic natural gas is the production of [[synthesis gas]], also known as syngas.

Natural gas is a major component of the world's [[energy]] supply, as it is used widely in residential, commercial, and industrial applications. However, the supply is limited and thus synthetic natural gas is desireable where there is an absence or shortage of natural gas in a region. This type of natural gas is desireable as it has combustion characteristics similar to natural gas, and because of this minimal changes need to be made to use synthetic natural gas.<ref name="RE2">National Gas. (May 22, 2015). ''Synthetic Natura; Gas'' [Online]. Available: http://www.nationalgasco.net/OurBusiness/SyntheticNaturalGas.aspx</ref>

==Production==
Synthetic natural gas is created through a ''thermo-chemical conversion''. The first step in this conversion is the '''gasification''' of the solid carbon source, whether it be coal or [[biomass]] (which would create Bio-SNG), with steam or oxygen.<ref name=jr1/> Here the coal is [[combustion|burned]] with a limited supply of [[oxygen]] or [[air]] and the main product is [[carbon dioxide]]:<ref name=sys>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>
<center><m>2C + O_2 \rightarrow 2CO</m></center>

To reduce the amount of [[nitrogen]] in this gas, modern gas plants use pure oxygen for combustion. If steam is added to this pure oxygen then a '''water gas reaction''' occurs instead of the traditional combustion:<ref name=sys/>
<center><m>C + H_2O \rightleftharpoons CO + H_2</m></center>

These processes drive off some of the [[volatile]] material, and the product is known as a ''producer gas''. Generally, this occurs in a gasifier which feeds coal into a high [[pressure]], high [[temperature]] vessel and distributes steam or oxygen evenly while removing ash to gasify the coal.<ref name=sys/> This producer gas is a mixture containing H2, CO, CO2, H2O, and CH4 along with other hydrocarbons and some impurities. The exact composition of this gas depends on the type of reactor used, operating conditions, and other processes during the gasification process.<ref name="jr1"/> This gas also contains impurities such as oils, tars, hydrogen sulfide, and ammonia which must be removed - although ammonia levels are lower if the water gas reaction takes place.<ref name=sys/>

To purify this gas, it must undergo ''gas cleaning'' and ''gas conditioning''. During gas cleaning, impurities such as ammonia and [[sulfur]] are removed from the producer gas whereas in gas conditioning is the process by which parts of the producer gas are converted so that the final composition of the gas is suitable for its use.<ref name=jr1>S. Biollaz, T. Schildhauer, J.Kopyscinski. (May 26, 2015). ''Production of synthetic natural gas (SNG) from coal and dry biomass – A technology review from 1950 to 2009'' [Online]. ''Fuel''. August 2010, vol 89, pp.1763–1783 </ref> What is left after this cleaning and conditioning is useful '''synthesis gas''' (carbon monoxide and hydrogen) plus some methane, and carbon dioxide.<ref name=sys/>

To finish making the synthetic natural gas, the syngas must undergo '''water gas shift reactions''' and '''methanation'''. The water gas shift reaction combines carbon monoxide with steam to create carbon dioxide and hydrogen in the following reaction:<ref name=sys/>
<center><m>CO + H_2O \rightleftharpoons CO_2 + H_2</m></center>
This reaction requires a metal catalyst to occur. Since the end "goal" of this gas is to obtain methane (the main component of natural gas) some of the carbon monoxide is retained, so the reaction does not go through to completion. At this point, the carbon dioxide is separated out using a type of scrubbing and only the final methanation step remains. During methanation, carbon monoxide reacts with the hydrogen that was created with the help of a nickel catalyst to create methane and steam in the following reaction:<ref name=sys/>
<center><m>CO + 3H_2 \rightarrow CH_4+ H_2O</m></center>
At this point, the synthetic natural gas is complete after half of the original carbon in the coal has turned into methane. The rest of the carbon is turned into carbon dioxide.

==Bio-SNG==
Bio-SNG is produced similarly to regular synthetic natural gas, but is instead made through the gasification of biomass. Biomass such as forestry residues or energy crops are used. To make Bio-SNG, biomass is initially dried and goes through initial gasification. After this, it undergoes gas conditioning, SNG synthesis, and finally gas upgrading.<ref name="RE2">European Biofuels. (May 22, 2015). ''Bio-SNG'' [Online]. Available: http://biofuelstp.eu/bio-sng.html</ref>

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