Heavy water - Revision history

Jmdonev at 21:54, 2 April 2023

2023-04-02T21:54:42Z

← Older revision		Revision as of 21:54, 2 April 2023
Line 24:		Line 24:
	The ''Girdler sulfide process'' is a method that works based on an exchange of deuterium between H<sub>2</sub>S and regular [[light water]]. In this process, there are two separate columns. One column is at [[Celsius\|30°C]] and is known as the "cold tower" while the other one is at 130 °C, known as the "hot tower". The separation occurs based on an equilibrium and the differences in equilibrium at the two different temperatures. The equilibrium equation is:<ref name=ref3/>		The ''Girdler sulfide process'' is a method that works based on an exchange of deuterium between H<sub>2</sub>S and regular [[light water]]. In this process, there are two separate columns. One column is at [[Celsius\|30°C]] and is known as the "cold tower" while the other one is at 130 °C, known as the "hot tower". The separation occurs based on an equilibrium and the differences in equilibrium at the two different temperatures. The equilibrium equation is:<ref name=ref3/>

	<chem>H_2O + HDS \rightleftharpoons HDO + H_2S </chem>		<center> <chem> H_2O + HDS \rightleftharpoons HDO + H_2S </chem> </center>

	The main reason that this process works is a result of hydrogen sulfide gas being circulated between hot and cold towers. First, fresh water flows into the low temperature stage along with deuterium-enriched hydrogen sulfide gas. As a result of the equilibrium properties at this temperature, deuterium migrates preferentially from the enriched hydrogen sulfide to the water, creating heavy water. This enriched water is then taken off, and more fresh water enters the high temperature stage along with the hydrogen sulfide gas (now slightly depleted in deuterium). Here, any deuterium from the fresh water moves preferentially to the hydrogen sulfide gas, enriching it. This enriched gas then moves back to the low temperature stage, and works to further enrich the heavy water. Normal water from the high temperature stage, now depleted, is drawn off. A cascade is then set up so "enriched" water—water with more deuterium— is fed into the cold tower and enriched again.<ref name=ref3/>		The main reason that this process works is a result of hydrogen sulfide gas being circulated between hot and cold towers. First, fresh water flows into the low temperature stage along with deuterium-enriched hydrogen sulfide gas. As a result of the equilibrium properties at this temperature, deuterium migrates preferentially from the enriched hydrogen sulfide to the water, creating heavy water. This enriched water is then taken off, and more fresh water enters the high temperature stage along with the hydrogen sulfide gas (now slightly depleted in deuterium). Here, any deuterium from the fresh water moves preferentially to the hydrogen sulfide gas, enriching it. This enriched gas then moves back to the low temperature stage, and works to further enrich the heavy water. Normal water from the high temperature stage, now depleted, is drawn off. A cascade is then set up so "enriched" water—water with more deuterium— is fed into the cold tower and enriched again.<ref name=ref3/>

Jmdonev at 21:54, 2 April 2023

2023-04-02T21:54:16Z

← Older revision		Revision as of 21:54, 2 April 2023
Line 24:		Line 24:
	The ''Girdler sulfide process'' is a method that works based on an exchange of deuterium between H<sub>2</sub>S and regular [[light water]]. In this process, there are two separate columns. One column is at [[Celsius\|30°C]] and is known as the "cold tower" while the other one is at 130 °C, known as the "hot tower". The separation occurs based on an equilibrium and the differences in equilibrium at the two different temperatures. The equilibrium equation is:<ref name=ref3/>		The ''Girdler sulfide process'' is a method that works based on an exchange of deuterium between H<sub>2</sub>S and regular [[light water]]. In this process, there are two separate columns. One column is at [[Celsius\|30°C]] and is known as the "cold tower" while the other one is at 130 °C, known as the "hot tower". The separation occurs based on an equilibrium and the differences in equilibrium at the two different temperatures. The equilibrium equation is:<ref name=ref3/>

	~~<center>~~<chem>H_2O + HDS \rightleftharpoons HDO + H_2S </chem~~></center~~>		<chem>H_2O + HDS \rightleftharpoons HDO + H_2S </chem>

	The main reason that this process works is a result of hydrogen sulfide gas being circulated between hot and cold towers. First, fresh water flows into the low temperature stage along with deuterium-enriched hydrogen sulfide gas. As a result of the equilibrium properties at this temperature, deuterium migrates preferentially from the enriched hydrogen sulfide to the water, creating heavy water. This enriched water is then taken off, and more fresh water enters the high temperature stage along with the hydrogen sulfide gas (now slightly depleted in deuterium). Here, any deuterium from the fresh water moves preferentially to the hydrogen sulfide gas, enriching it. This enriched gas then moves back to the low temperature stage, and works to further enrich the heavy water. Normal water from the high temperature stage, now depleted, is drawn off. A cascade is then set up so "enriched" water—water with more deuterium— is fed into the cold tower and enriched again.<ref name=ref3/>		The main reason that this process works is a result of hydrogen sulfide gas being circulated between hot and cold towers. First, fresh water flows into the low temperature stage along with deuterium-enriched hydrogen sulfide gas. As a result of the equilibrium properties at this temperature, deuterium migrates preferentially from the enriched hydrogen sulfide to the water, creating heavy water. This enriched water is then taken off, and more fresh water enters the high temperature stage along with the hydrogen sulfide gas (now slightly depleted in deuterium). Here, any deuterium from the fresh water moves preferentially to the hydrogen sulfide gas, enriching it. This enriched gas then moves back to the low temperature stage, and works to further enrich the heavy water. Normal water from the high temperature stage, now depleted, is drawn off. A cascade is then set up so "enriched" water—water with more deuterium— is fed into the cold tower and enriched again.<ref name=ref3/>

Jmdonev: 1 revision imported

2021-09-27T00:03:01Z

1 revision imported

← Older revision	Revision as of 00:03, 27 September 2021
(No difference)

energy>Ethan.boechler at 19:05, 18 June 2021

2021-06-18T19:05:39Z

← Older revision		Revision as of 19:05, 18 June 2021
Line 1:		Line 1:
	[[Category:Done 2018-05-18]]		[[Category:Done 2018-05-18]]
	[[File:heavywater2.png\|400px\|framed\|right\|Figure 1. A heavy water molecule.<ref>Wikimedia Commons. (June 16, 2015). ''Heavy Water'' [Online]. Available: https://upload.wikimedia.org/wikipedia/commons/e/e4/Heavy-water-3D-vdW.svg</ref>]]		[[File:heavywater2.png\|400px\|framed\|right\|Figure 1. A heavy water molecule.<ref>Wikimedia Commons. (June 16, 2015). ''Heavy Water'' [Online]. Available: https://upload.wikimedia.org/wikipedia/commons/e/e4/Heavy-water-3D-vdW.svg</ref>]]
			[[Category:Translated to French]]
			[[fr:Eau lourde]]

	<onlyinclude>'''Heavy water''' is water that contains heavy hydrogen - also known as '''[[deuterium]]''' - in place of regular [[hydrogen]]. It can also be written as '''<sup>2</sup>H<sub>2</sub>O''' or '''D<sub>2</sub>O'''.</onlyinclude> Deuterium is different than the hydrogen that usually occurs in water—known as '''[[protium]]''', since each [[atom]] of deuterium contains a [[proton]] and a [[neutron]], while more commonly occurring hydrogen contains only a proton.<ref>Anne Marie Helmenstine. (June 16, 2015). ''What Is Heavy Water?'' [Online]. Available: http://chemistry.about.com/od/waterchemistry/f/What-Is-Heavy-Water.htm</ref>		<onlyinclude>'''Heavy water''' is water that contains heavy hydrogen - also known as '''[[deuterium]]''' - in place of regular [[hydrogen]]. It can also be written as '''<sup>2</sup>H<sub>2</sub>O''' or '''D<sub>2</sub>O'''.</onlyinclude> Deuterium is different than the hydrogen that usually occurs in water—known as '''[[protium]]''', since each [[atom]] of deuterium contains a [[proton]] and a [[neutron]], while more commonly occurring hydrogen contains only a proton.<ref>Anne Marie Helmenstine. (June 16, 2015). ''What Is Heavy Water?'' [Online]. Available: http://chemistry.about.com/od/waterchemistry/f/What-Is-Heavy-Water.htm</ref>

Jmdonev: 1 revision imported

2018-05-18T22:53:09Z

1 revision imported

← Older revision	Revision as of 22:53, 18 May 2018
(No difference)

Jmdonev at 21:28, 11 May 2018

2018-05-11T21:28:54Z

J.williams: 1 revision imported

2015-08-26T21:31:10Z

1 revision imported

← Older revision	Revision as of 21:31, 26 August 2015
(No difference)

J.williams at 16:54, 12 August 2015

2015-08-12T16:54:42Z

New page

[[Category:Done 2015-07-01]]
[[File:heavywater2.png|400px|framed|right|Figure 1. A heavy water molecule.<ref>Wikimedia Commons. (June 16, 2015). ''Heavy Water'' [Online]. Available: https://upload.wikimedia.org/wikipedia/commons/e/e4/Heavy-water-3D-vdW.svg</ref>]]

<onlyinclude>'''Heavy water''' is water that contains heavy hydrogen - also known as '''[[deuterium]]''' - in place of regular [[hydrogen]]. It can also be written as '''2H2O''' or '''D2O'''.</onlyinclude> Deuterium is different than the hydrogen that usually occurs in water - known as '''[[protium]]''' - as each [[atom]] of deuterium contains a [[proton]] and a [[neutron]], while more commonly occurring hydrogen contains only a proton.<ref>Anne Marie Helmenstine. (June 16, 2015). ''What Is Heavy Water?'' [Online]. Available: http://chemistry.about.com/od/waterchemistry/f/What-Is-Heavy-Water.htm</ref>

Heavy water does occur naturally, however in much smaller quantities than regular water. Around one water molecule in twenty million water molecules are heavy water. Since deuterium is a stable [[isotope]], heavy water is not [[radioactive]].<ref>Anne Marie Helmenstine. (June 16, 2015). ''Is Heavy Water Radioactive?'' [Online]. Available: http://chemistry.about.com/od/waterchemistry/f/Is-Heavy-Water-Radioactive.htm</ref>

In addition to being useful for nuclear reactors, heavy water has also been used in Canada to detect [[neutrino]]s from the [[sun]] at the [https://www.snolab.ca/science/experiments/sno Sudbury Neutrino Observatory], providing important insights to subatomic physics.
==Use as a Moderator==
:: [[Neutron moderator|''main page'']]
In [[nuclear fission]] reactors, the neutrons must be slowed down to ensure an effective [[fission chain reaction]] occurs. This process of slowing neutrons down is known as [[moderation]], and the material that slows down these neutrons is known as a [[neutron moderator]]. Heavy water is one of the two moderators that can be used which allow a nuclear reactor to operate using natural [[uranium]]. The other moderator is [[graphite]].<ref name=ref3/>

A [[heavy water reactor]] makes use of heavy water as its coolant and moderator. Deuterium works as a moderator as it absorbs fewer [[neutron]]s than hydrogen, which is extremely important as nuclear fission reactions require neutrons to carry out their chain reactions.<ref name=wolf>R. Wolfson, "Nuclear fission" in ''Energy, Environment, and Climate'', 2nd ed., New York, NY: W.W. Norton & Company, 2012, ch. 7, sec. 4, pp.173</ref> The heavy water is kept under [[pressure]] which increases its [[boiling point]] so that it can operate at high [[temperature]]s without boiling. [[CANDU]] reactors utilize heavy water as their moderator and thus do not require enriched uranium, rather uranium can be used as a fuel in its natural state.

==Production==
[[File:GSheavywater2.png|400px|framed|right|Figure 2. Sample setup of the [[Girdler sulfide process]], showing the hot and cool columns along with where enriched and depleted water is drawn off.<ref>Wikimedia Commons. (June 18, 2015). ''Girdler Process'' [Online]. Available: https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Girdler.svg/640px-Girdler.svg.png</ref>]]

The cost of the heavy water is a significant part of the building cost of a [[heavy water reactor]], but makes the reactors cheaper to operate (since uranium enrichment is unneeded). Technically speaking, deuterium is not "made" in a specific process, rather [[molecule]]s of heavy water are separated from large quantities of water containing H2O or singly deuterated water in the Girdler sulfide process. The water that is not heavy is discarded and is known as "depleted water". An alternative method exists where water is electrolyzed to make [[oxygen]] and hydrogen that contains normal [[gas]] along with deuterium.<ref name=ref3>Federation of American Scientists. (June 17, 2015). ''Heavy Water Production'' [Online]. Available: https://fas.org/nuke/intro/nuke/heavy.htm</ref> The hydrogen is then liquefied and distilled to separate the two components, then the deuterium is reacted with oxygen to form heavy water.

Producing heavy water requires advanced infrastructure, and heavy water is actively produced in Argentina, Canada, India, and Norway. The largest plant was the Bruce Plant in Canada, but has shut down. Technically, there is a slight difference in the [[boiling point]]s of heavy water and water, so this difference could be taken advantage of when extracting heavy water.<ref name=ref3/> However, since deuterium exists in such small numbers an enormous amount of water would need to be boiled to obtain significant amounts of deuterium. This would require a lot of [[fuel]] or [[electricity]], so instead facilities exploit chemical differences between the two. The most important [[chemical]] method for producing heavy water is the Girdler sulfide process.

The Girdler sulfide process is a method that works based on an exchange of deuterium between H2S and regular [[light water]]. In this process, there are two separate columns. One column is at [[Celsius|30°C]] and is known as the "cold tower" while the other one is at 130 °C and is known as the "hot tower". The separation occurs based on an equilibrium and the differences in equilibrium at the two different temperatures. The equilibrium equation is:<ref name=ref3/>

<center><m>H_2O + HDS \rightleftharpoons HDO + H_2S </m></center>

The main reason that this process works is a result of hydrogen sulfide gas being circulated between hot and cold towers. First, fresh water flows into the low temperature stage along with deuterium-enriched hydrogen sulfide gas. As a result of the equilibrium properties at this temperature, deuterium migrates preferentially from the enriched hydrogen sulfide to the water, creating heavy water. This enriched water is then taken off, and more fresh water enters the high temperature stage along with the hydrogen sulfide gas (now slightly depleted in deuterium). Here, any deuterium from the fresh water moves preferentially to the hydrogen sulfide gas, enriching it. This enriched gas then moves back to the low temperature stage, and works to further enrich the heavy water. Normal water from the high temperature stage, now depleted, is drawn off. A cascade is then set up so "enriched" water - water with more deuterium - is fed into the cold tower and enriched again.<ref name=ref3/>

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

← Older revision		Revision as of 21:28, 11 May 2018
Line 1:		Line 1:
	[[Category:Done ~~2015~~-07-01]]		[[Category:Done 2018-05-18]]
	[[File:heavywater2.png\|400px\|framed\|right\|Figure 1. A heavy water molecule.<ref>Wikimedia Commons. (June 16, 2015). ''Heavy Water'' [Online]. Available: https://upload.wikimedia.org/wikipedia/commons/e/e4/Heavy-water-3D-vdW.svg</ref>]]		[[File:heavywater2.png\|400px\|framed\|right\|Figure 1. A heavy water molecule.<ref>Wikimedia Commons. (June 16, 2015). ''Heavy Water'' [Online]. Available: https://upload.wikimedia.org/wikipedia/commons/e/e4/Heavy-water-3D-vdW.svg</ref>]]

	<onlyinclude>'''Heavy water''' is water that contains heavy hydrogen - also known as '''[[deuterium]]''' - in place of regular [[hydrogen]]. It can also be written as '''<sup>2</sup>H<sub>2</sub>O''' or '''D<sub>2</sub>O'''.</onlyinclude> Deuterium is different than the hydrogen that usually occurs in ~~water - known~~ as '''[[protium]]''' ~~- as~~ each [[atom]] of deuterium contains a [[proton]] and a [[neutron]], while more commonly occurring hydrogen contains only a proton.<ref>Anne Marie Helmenstine. (June 16, 2015). ''What Is Heavy Water?'' [Online]. Available: http://chemistry.about.com/od/waterchemistry/f/What-Is-Heavy-Water.htm</ref>		<onlyinclude>'''Heavy water''' is water that contains heavy hydrogen - also known as '''[[deuterium]]''' - in place of regular [[hydrogen]]. It can also be written as '''<sup>2</sup>H<sub>2</sub>O''' or '''D<sub>2</sub>O'''.</onlyinclude> Deuterium is different than the hydrogen that usually occurs in water—known as '''[[protium]]''', since each [[atom]] of deuterium contains a [[proton]] and a [[neutron]], while more commonly occurring hydrogen contains only a proton.<ref>Anne Marie Helmenstine. (June 16, 2015). ''What Is Heavy Water?'' [Online]. Available: http://chemistry.about.com/od/waterchemistry/f/What-Is-Heavy-Water.htm</ref>

	Heavy water does occur naturally, however in much smaller quantities than regular water. ~~Around~~ one water molecule in twenty million water molecules ~~are~~ heavy water. Since deuterium is a stable [[isotope]], heavy water is not [[radioactive]].<ref>Anne Marie Helmenstine. (June 16, 2015). ''Is Heavy Water Radioactive?'' [Online]. Available: http://chemistry.about.com/od/waterchemistry/f/Is-Heavy-Water-Radioactive.htm</ref>		Heavy water does occur naturally, however in much smaller quantities than regular water. Approximately, one water molecule for every twenty million water molecules is heavy water. Since deuterium is a stable [[isotope]], heavy water is not [[radioactive]].<ref>Anne Marie Helmenstine. (June 16, 2015). ''Is Heavy Water Radioactive?'' [Online]. Available: http://chemistry.about.com/od/waterchemistry/f/Is-Heavy-Water-Radioactive.htm</ref>

	In addition to being useful for nuclear reactors, heavy water has also been used in Canada to detect [[neutrino]]s from the [[sun]] at the [https://www.snolab.ca/science/experiments/sno Sudbury Neutrino Observatory], providing important insights to subatomic physics.		In addition to being useful for nuclear reactors, heavy water has also been used in Canada to detect [[neutrino]]s from the [[sun]] at the [https://www.snolab.ca/science/experiments/sno Sudbury Neutrino Observatory], providing important insights to subatomic physics.
Line 11:		Line 11:
	In [[nuclear fission]] reactors, the neutrons must be slowed down to ensure an effective [[fission chain reaction]] occurs. This process of slowing neutrons down is known as [[moderation]], and the material that slows down these neutrons is known as a [[neutron moderator]]. Heavy water is one of the two moderators that can be used which allow a nuclear reactor to operate using natural [[uranium]]. The other moderator is [[graphite]].<ref name=ref3/>		In [[nuclear fission]] reactors, the neutrons must be slowed down to ensure an effective [[fission chain reaction]] occurs. This process of slowing neutrons down is known as [[moderation]], and the material that slows down these neutrons is known as a [[neutron moderator]]. Heavy water is one of the two moderators that can be used which allow a nuclear reactor to operate using natural [[uranium]]. The other moderator is [[graphite]].<ref name=ref3/>

	A [[heavy water reactor]] makes use of heavy water as its coolant and moderator. Deuterium works as a moderator as it absorbs fewer [[neutron]]s than hydrogen, which is extremely important as nuclear fission reactions require neutrons to carry out their chain reactions.<ref name=wolf>R. Wolfson, "Nuclear fission" in ''Energy, Environment, and Climate'', 2nd ed., New York, NY: W.W. Norton & Company, 2012, ch. 7, sec. 4, pp.173</ref> The heavy water is kept under [[pressure]] which increases its [[boiling point]] so that it can operate at high [[temperature]]s without boiling. [[CANDU]] reactors utilize heavy water as their moderator and thus do not require enriched uranium, rather uranium ~~can be used as a fuel~~ in its natural state.		A [[heavy water reactor]] makes use of heavy water as its coolant and moderator. Deuterium works as a moderator as it absorbs fewer [[neutron]]s than hydrogen, which is extremely important as nuclear fission reactions require neutrons to carry out their chain reactions.<ref name=wolf>R. Wolfson, "Nuclear fission" in ''Energy, Environment, and Climate'', 2nd ed., New York, NY: W.W. Norton & Company, 2012, ch. 7, sec. 4, pp.173</ref> The heavy water is kept under [[pressure]] which increases its [[boiling point]] so that it can operate at high [[temperature]]s without boiling. [[CANDU]] reactors utilize heavy water as their moderator and thus do not require enriched uranium, rather uranium in its natural state can be used.

	==Production==		==Production==
	[[File:GSheavywater2.png\|400px\|framed\|right\|Figure 2. Sample setup of the [[Girdler sulfide process]], showing the hot and cool columns along with where enriched and depleted water is drawn off.<ref>Wikimedia Commons. (June 18, 2015). ''Girdler Process'' [Online]. Available: https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Girdler.svg/640px-Girdler.svg.png</ref>]]		[[File:GSheavywater2.png\|400px\|framed\|right\|Figure 2. Sample setup of the [[Girdler sulfide process]], showing the hot and cool columns along with where enriched and depleted water is drawn off.<ref>Wikimedia Commons. (June 18, 2015). ''Girdler Process'' [Online]. Available: https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Girdler.svg/640px-Girdler.svg.png</ref>]]

	The cost of the heavy water is a significant part of the building cost of a [[heavy water reactor]], but makes the reactors cheaper to operate (since uranium enrichment is unneeded). Technically speaking, deuterium is not "made" in a specific process, rather [[molecule]]s of heavy water are separated from large quantities of water containing H<sub>2</sub>O or singly deuterated water in the Girdler sulfide process. The water that is not heavy is discarded and is known as "depleted water". An alternative method exists ~~where~~ water is electrolyzed to make [[oxygen]] and hydrogen that contains normal [[gas]] along with deuterium.<ref name=ref3>Federation of American Scientists. (June 17, 2015). ''Heavy Water Production'' [Online]. Available: https://fas.org/nuke/intro/nuke/heavy.htm</ref> The hydrogen is then liquefied and distilled to separate the two components, then the deuterium is reacted with oxygen to form heavy water.		The cost of the heavy water is a significant part of the building cost of a [[heavy water reactor]], but makes the reactors cheaper to operate (since uranium enrichment is unneeded). Technically speaking, deuterium is not "made" in a specific process, rather [[molecule]]s of heavy water are separated from large quantities of water containing H<sub>2</sub>O or singly deuterated water in the ''Girdler sulfide process'' (which will be discussed in detail in the next two paragraphs). The water that is not heavy is discarded and is known as "depleted water". An alternative method exists when water is electrolyzed to make [[oxygen]] and hydrogen that contains normal [[gas]], along with deuterium.<ref name=ref3>Federation of American Scientists. (June 17, 2015). ''Heavy Water Production'' [Online]. Available: https://fas.org/nuke/intro/nuke/heavy.htm</ref> The hydrogen is then liquefied and distilled to separate the two components, then the deuterium is reacted with oxygen to form heavy water.

	Producing heavy water requires advanced infrastructure, and heavy water is actively produced in Argentina, Canada, India, and Norway. The largest plant was the Bruce Plant in Canada, but has shut down. Technically, there is a slight difference in the [[boiling point]]s of heavy water and water, so this difference could be taken advantage of when extracting heavy water.<ref name=ref3/> However, since deuterium exists in such small numbers an enormous amount of water would need to be boiled to obtain significant amounts of deuterium. This would require a lot of [[fuel]] or [[electricity]], so instead facilities exploit chemical differences between the two. The most important [[chemical]] method for producing heavy water is the Girdler sulfide process.		Producing heavy water requires advanced infrastructure, and heavy water is actively produced in Argentina, Canada, India, and Norway. The largest plant was the Bruce Plant in Canada, but has shut down. Technically, there is a slight difference in the [[boiling point]]s of heavy water and water, so this difference could be taken advantage of when extracting heavy water.<ref name=ref3/> However, since deuterium exists in such small numbers an enormous amount of water would need to be boiled to obtain significant amounts of deuterium. This would require a lot of [[fuel]] or [[electricity]], so instead facilities exploit chemical differences between the two. The most important [[chemical]] method for producing heavy water is the Girdler sulfide process.

	The Girdler sulfide process is a method that works based on an exchange of deuterium between H<sub>2</sub>S and regular [[light water]]. In this process, there are two separate columns. One column is at [[Celsius\|30°C]] and is known as the "cold tower" while the other one is at 130 °C ~~and is~~ known as the "hot tower". The separation occurs based on an equilibrium and the differences in equilibrium at the two different temperatures. The equilibrium equation is:<ref name=ref3/>		The ''Girdler sulfide process'' is a method that works based on an exchange of deuterium between H<sub>2</sub>S and regular [[light water]]. In this process, there are two separate columns. One column is at [[Celsius\|30°C]] and is known as the "cold tower" while the other one is at 130 °C, known as the "hot tower". The separation occurs based on an equilibrium and the differences in equilibrium at the two different temperatures. The equilibrium equation is:<ref name=ref3/>

	<center><m>H_2O + HDS \rightleftharpoons HDO + H_2S </m></center>		<center><chem>H_2O + HDS \rightleftharpoons HDO + H_2S </chem></center>

	The main reason that this process works is a result of hydrogen sulfide gas being circulated between hot and cold towers. First, fresh water flows into the low temperature stage along with deuterium-enriched hydrogen sulfide gas. As a result of the equilibrium properties at this temperature, deuterium migrates preferentially from the enriched hydrogen sulfide to the water, creating heavy water. This enriched water is then taken off, and more fresh water enters the high temperature stage along with the hydrogen sulfide gas (now slightly depleted in deuterium). Here, any deuterium from the fresh water moves preferentially to the hydrogen sulfide gas, enriching it. This enriched gas then moves back to the low temperature stage, and works to further enrich the heavy water. Normal water from the high temperature stage, now depleted, is drawn off. A cascade is then set up so "enriched" ~~water - water~~ with more ~~deuterium -~~ is fed into the cold tower and enriched again.<ref name=ref3/>		The main reason that this process works is a result of hydrogen sulfide gas being circulated between hot and cold towers. First, fresh water flows into the low temperature stage along with deuterium-enriched hydrogen sulfide gas. As a result of the equilibrium properties at this temperature, deuterium migrates preferentially from the enriched hydrogen sulfide to the water, creating heavy water. This enriched water is then taken off, and more fresh water enters the high temperature stage along with the hydrogen sulfide gas (now slightly depleted in deuterium). Here, any deuterium from the fresh water moves preferentially to the hydrogen sulfide gas, enriching it. This enriched gas then moves back to the low temperature stage, and works to further enrich the heavy water. Normal water from the high temperature stage, now depleted, is drawn off. A cascade is then set up so "enriched" water—water with more deuterium— is fed into the cold tower and enriched again.<ref name=ref3/>

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