Biobutanol - Revision history

Engineeringguru: /* Energy content and effects on fuel economy */

2010-11-12T20:54:12Z

Energy content and effects on fuel economy

← Older revision		Revision as of 20:54, 12 November 2010
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	Butanol is reported to yield 36 MJ/kg (15,500 BTU/lb) when burned. This can be expressed volumetrically as 29.3 MJ/l (104,800 BTU/US gal).		Butanol is reported to yield 36 MJ/kg (15,500 BTU/lb) when burned. This can be expressed volumetrically as 29.3 MJ/l (104,800 BTU/US gal).

	Switching a gasoline engine over to butanol would in theory result in a fuel consumption penalty of about 10% ~~{{Fact\|date=February 2007}}~~ but butanol's effect on mileage is yet to be determined by a scientific study. Potential of higher gas mileage seems reasonable as biobutanol is a mono component fuel--only one type of molecule. In theory such fuel can be compressed to higher ratio and then achieve higher degree of burn or higher efficiency.<ref>[http://www.biobutanol.com/Butanol-Fuel-RoadTest.html Biobutanol.com]</ref> While the energy density for any mixture of gasoline and butanol can be calculated, tests with other alcohol fuels have demonstrated that the effect on fuel economy is not proportional to the change in energy density.<ref>[http://www.ethanol.org/documents/ACEFuelEconomyStudy.pdf ethanol.org]</ref>		Switching a gasoline engine over to butanol would in theory result in a fuel consumption penalty of about 10% but butanol's effect on mileage is yet to be determined by a scientific study. Potential of higher gas mileage seems reasonable as biobutanol is a mono component fuel--only one type of molecule. In theory such fuel can be compressed to higher ratio and then achieve higher degree of burn or higher efficiency.<ref>[http://www.biobutanol.com/Butanol-Fuel-RoadTest.html Biobutanol.com]</ref> While the energy density for any mixture of gasoline and butanol can be calculated, tests with other alcohol fuels have demonstrated that the effect on fuel economy is not proportional to the change in energy density.<ref>[http://www.ethanol.org/documents/ACEFuelEconomyStudy.pdf ethanol.org]</ref>

	===Octane rating===		===Octane rating===

Engineeringguru: /* Energy content and effects on fuel economy */

2010-11-12T20:53:42Z

Energy content and effects on fuel economy

← Older revision		Revision as of 20:53, 12 November 2010
Line 60:		Line 60:
	Butanol is reported to yield 36 MJ/kg (15,500 BTU/lb) when burned. This can be expressed volumetrically as 29.3 MJ/l (104,800 BTU/US gal).		Butanol is reported to yield 36 MJ/kg (15,500 BTU/lb) when burned. This can be expressed volumetrically as 29.3 MJ/l (104,800 BTU/US gal).

	Switching a gasoline engine over to butanol would in theory result in a fuel consumption penalty of about 10% {{Fact\|date=February 2007}} but butanol's effect on mileage is yet to be determined by a scientific study. While the energy density for any mixture of gasoline and butanol can be calculated, tests with other alcohol fuels have demonstrated that the effect on fuel economy is not proportional to the change in energy density.<ref>[http://www.ethanol.org/documents/ACEFuelEconomyStudy.pdf ethanol.org]</ref>		Switching a gasoline engine over to butanol would in theory result in a fuel consumption penalty of about 10% {{Fact\|date=February 2007}} but butanol's effect on mileage is yet to be determined by a scientific study. Potential of higher gas mileage seems reasonable as biobutanol is a mono component fuel--only one type of molecule. In theory such fuel can be compressed to higher ratio and then achieve higher degree of burn or higher efficiency.<ref>[http://www.biobutanol.com/Butanol-Fuel-RoadTest.html Biobutanol.com]</ref> While the energy density for any mixture of gasoline and butanol can be calculated, tests with other alcohol fuels have demonstrated that the effect on fuel economy is not proportional to the change in energy density.<ref>[http://www.ethanol.org/documents/ACEFuelEconomyStudy.pdf ethanol.org]</ref>

	===Octane rating===		===Octane rating===

Engineeringguru: /* Production of butanol from biomass */

2010-11-12T19:49:48Z

Production of butanol from biomass

← Older revision		Revision as of 19:49, 12 November 2010
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	Butanol can be produced by fermentation of biomass. The process uses the bacterium Clostridium acetobutylicum, also known as the Weizmann organism. It was Chaim Weizmann who first used this bacteria for the production of acetone from starch (with the main use of acetone being the making of Cordite) in 1916. The butanol was a by-product of this fermentation (twice as much butanol was produced). The process also creates a recoverable amount of H2 and a number of other by-products: acetic, lactic and propionic acids, acetone, isopropanol and ethanol.		Butanol can be produced by fermentation of biomass. The process uses the bacterium Clostridium acetobutylicum, also known as the Weizmann organism. It was Chaim Weizmann who first used this bacteria for the production of acetone from starch (with the main use of acetone being the making of Cordite) in 1916. The butanol was a by-product of this fermentation (twice as much butanol was produced). The process also creates a recoverable amount of H2 and a number of other by-products: acetic, lactic and propionic acids, acetone, isopropanol and ethanol.

	The difference from ethanol production is primarily in the fermentation of the feedstock — producing butanol rather than ethanol like primary fermentation product and minor changes in distillation. The feedstocks are the same as for ethanol — energy crops such as sugar beets, sugar cane, corn grain, wheat and cassava as well as agricultural byproducts such as straw and corn stalks. According to DuPont, existing bioethanol plants can cost-effectively be retrofitted to biobutanol production.<ref>[http://www.dupont.com/ag/news/releases/BP_DuPont_Fact_Sheet_Biobutanol.pdf Dupont Fact Sheet on Biobutanol]</ref>		The difference from ethanol production is primarily in the fermentation of the feedstock — producing butanol rather than ethanol like primary fermentation product and minor changes in distillation. The feedstocks are the same as for ethanol — energy crops such as sugar beets, sugar cane, corn grain, wheat and cassava as well as agricultural byproducts such as straw and corn stalks. According to DuPont, existing bioethanol plants can cost-effectively be retrofitted to biobutanol production.<ref>[http://www.dupont.com/ag/news/releases/BP_DuPont_Fact_Sheet_Biobutanol.pdf Dupont Fact Sheet on Biobutanol]</ref>

			There are a dozen companies pursuing production of biobutanol via fermentation and pyrolysis. Pyrolysis is a process where biomass and organic waste can be heated to decompose matter into basic building blocks and then reformulated into fuel. The process is analogous to hydrocracking and reformulation of hydrocarbon chains. <ref>[http://www.biobutanol.com Biobutanol Uses, Production and News]</ref>

	==Distribution==		==Distribution==

Red marquis at 21:14, 22 August 2009

2009-08-22T21:14:35Z

← Older revision		Revision as of 21:14, 22 August 2009
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	Biobutanol is a fuel from natural sources (no petroleum). [[Butanol]] may be used as a [[fuel]] in an [[internal combustion engine]]. It is more similar to [[gasoline]] than [[ethanol]]. Butanol has been demonstrated to work in some vehicles designed for use with gasoline without any modification.<ref>[http://www.butanol.com butanol.com]</ref> It can be produced from [[biomass]] as well as [[fossil fuel]]s. Some call this [[biofuel]] biobutanol to reflect its origin, although it has the same chemical properties as butanol produced from [[petroleum]].		Biobutanol is a fuel from natural sources (no petroleum). [[Butanol]] may be used as a [[fuel]] in an [[internal combustion engine]]. It is more similar to [[gasoline]] than [[ethanol]]. Butanol has been demonstrated to work in some vehicles designed for use with gasoline without any modification.<ref>[http://www.butanol.com butanol.com]</ref> It can be produced from biomass as well as [[fossil fuel]]s. Some call this [[biofuel]] biobutanol to reflect its origin, although it has the same chemical properties as butanol produced from [[petroleum]].

	==Production of butanol from biomass==		==Production of butanol from biomass==
	Butanol can be produced by ~~[[Fermentation (biochemistry)\|~~fermentation]] of biomass. The process uses the [[bacterium~~]] ''[[~~Clostridium acetobutylicum~~]]''~~, also known as the ''Weizmann organism''. It was [[Chaim Weizmann]] who first used this bacteria for the production of [[acetone]] from [[starch]] (with the main use of [[acetone]] being the making of [[Cordite]]) in [[1916]]. The butanol was a by-product of this fermentation (twice as much butanol was produced). The process also creates a recoverable amount of ~~[[Hydrogen\|H]]<sub>2</sub>~~ and a number of other [[by-~~product]]s~~: [[acetic ~~acid\|acetic]]~~, ~~[[lactic acid\|~~lactic]] and [[propionic ~~acid]]s~~, acetone, [[isopropanol]] and ethanol.		Butanol can be produced by fermentation of biomass. The process uses the bacterium Clostridium acetobutylicum, also known as the Weizmann organism. It was Chaim Weizmann who first used this bacteria for the production of acetone from starch (with the main use of acetone being the making of Cordite) in 1916. The butanol was a by-product of this fermentation (twice as much butanol was produced). The process also creates a recoverable amount of H2 and a number of other by-products: acetic, lactic and propionic acids, acetone, isopropanol and ethanol.

	The difference from ethanol production is primarily in the fermentation of the [[feedstock]] — producing butanol rather than ethanol like primary fermentation product and minor changes in distillation. The feedstocks are the same as for ethanol — [[energy ~~crop]]s~~ such as [[sugar ~~beet]]s~~, [[sugar cane]], ~~[[maize\|~~corn~~]] [[~~grain]], [[wheat]] and [[cassava]] as well as [[agricultural ~~byproduct]]s~~ such as [[straw]] and ~~[[maize\|~~corn~~]] [[stalk]]s~~. According to DuPont, existing bioethanol plants can cost-effectively be retrofitted to biobutanol production.<ref>[http://www.dupont.com/ag/news/releases/BP_DuPont_Fact_Sheet_Biobutanol.pdf Dupont Fact Sheet on Biobutanol]</ref>		The difference from ethanol production is primarily in the fermentation of the feedstock — producing butanol rather than ethanol like primary fermentation product and minor changes in distillation. The feedstocks are the same as for ethanol — energy crops such as sugar beets, sugar cane, corn grain, wheat and cassava as well as agricultural byproducts such as straw and corn stalks. According to DuPont, existing bioethanol plants can cost-effectively be retrofitted to biobutanol production.<ref>[http://www.dupont.com/ag/news/releases/BP_DuPont_Fact_Sheet_Biobutanol.pdf Dupont Fact Sheet on Biobutanol]</ref>

	==Distribution==		==Distribution==
	Butanol better tolerates water contamination and is less corrosive than ethanol and more suitable for distribution through existing ~~[[Pipeline transport\|pipeline]]s~~ for gasoline~~{{Fact\|date=February 2007}}~~. In blends with [[diesel]] or gasoline, butanol is less likely to separate from this fuel than ethanol if the fuel is contaminated with water~~{{Fact\|date=February 2007}}~~. There is also a [[vapor pressure]] co-blend synergy with butanol and gasoline containing ethanol, which facilitates ethanol blending. This facilitates storage and distribution of blended fuels.<ref>[http://www.dupont.com/ag/news/releases/BP_DuPont_Fact_Sheet_Biobutanol.pdf Dupont Fact Sheet Biobutanol]</ref>		Butanol better tolerates water contamination and is less corrosive than ethanol and more suitable for distribution through existing pipelines for gasoline. In blends with [[diesel]] or gasoline, butanol is less likely to separate from this fuel than ethanol if the fuel is contaminated with water. There is also a vapor pressure co-blend synergy with butanol and gasoline containing ethanol, which facilitates ethanol blending. This facilitates storage and distribution of blended fuels.<ref>[http://www.dupont.com/ag/news/releases/BP_DuPont_Fact_Sheet_Biobutanol.pdf Dupont Fact Sheet Biobutanol]</ref>
	<ref>[http://www.ext.colostate.edu/PUBS/FARMMGT/05010.html ext.colostate.edu]</ref><ref>[http://www.usatoday.com/money/industries/energy/2006-06-20-butanol_x.htm?csp=34 USAtoday]</ref>		<ref>[http://www.ext.colostate.edu/PUBS/FARMMGT/05010.html ext.colostate.edu]</ref><ref>[http://www.usatoday.com/money/industries/energy/2006-06-20-butanol_x.htm?csp=34 USAtoday]</ref>

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	{\| class="wikitable"		{\| class="wikitable"
	! [[Fuel]]		! [[Fuel]]
	! [[Energy ~~density\|Energy]]~~<br>~~[[Energy density\|~~density]]		! Energy<br>density
	! [[air-fuel ratio\|Air-fuel]]<br>[[air-fuel ratio\|ratio]]		! [[air-fuel ratio\|Air-fuel]]<br>[[air-fuel ratio\|ratio]]
	! [[Specific ~~energy\|Specific]]~~<br>~~[[Specific~~ energy~~\|energy]]~~		! Specific<br>energy
	! ~~[[Heat of vaporization\|~~Heat of]]<br>~~[[Heat of vaporization\|~~vaporization]]		! Heat of<br>vaporization
	! [[Octane rating\|RON]]		! [[Octane rating\|RON]]
	! [[Octane rating\|MON]]		! [[Octane rating\|MON]]
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	===Energy content and effects on fuel economy===		===Energy content and effects on fuel economy===
	Butanol is reported to yield 36 ~~[[megajoule\|~~MJ]]/kg (15,500 [[BTU]]/lb) when burned. This can be expressed volumetrically as 29.3 MJ/~~[[litre\|~~l]] (104,800 BTU/~~[[gallon\|~~US gal]]).		Butanol is reported to yield 36 MJ/kg (15,500 BTU/lb) when burned. This can be expressed volumetrically as 29.3 MJ/l (104,800 BTU/US gal).

	Switching a gasoline engine over to butanol would in theory result in a fuel consumption penalty of about 10% {{Fact\|date=February 2007}} but butanol's effect on mileage is yet to be determined by a scientific study. While the energy density for any mixture of gasoline and butanol can be calculated, tests with other alcohol fuels have demonstrated that the effect on fuel economy is not proportional to the change in energy density.<ref>[http://www.ethanol.org/documents/ACEFuelEconomyStudy.pdf ethanol.org]</ref>		Switching a gasoline engine over to butanol would in theory result in a fuel consumption penalty of about 10% {{Fact\|date=February 2007}} but butanol's effect on mileage is yet to be determined by a scientific study. While the energy density for any mixture of gasoline and butanol can be calculated, tests with other alcohol fuels have demonstrated that the effect on fuel economy is not proportional to the change in energy density.<ref>[http://www.ethanol.org/documents/ACEFuelEconomyStudy.pdf ethanol.org]</ref>
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	*To match the combustion characteristics of gasoline, the utilization of butanol fuel as a substitute for gasoline requires fuel-flow increases.		*To match the combustion characteristics of gasoline, the utilization of butanol fuel as a substitute for gasoline requires fuel-flow increases.
	*Alcohol-based fuels are not compatible with some fuel system components.		*Alcohol-based fuels are not compatible with some fuel system components.
	*Alcohol fuels may cause erroneous gas gauge readings in vehicles with [[capacitance]] fuel level gauging.		*Alcohol fuels may cause erroneous gas gauge readings in vehicles with capacitance fuel level gauging.
	*The viscosity of butanol is much higher than for gasoline or ethanol, which could have negative effects on the fuel system.		*The viscosity of butanol is much higher than for gasoline or ethanol, which could have negative effects on the fuel system.
	*While ethanol and methanol have lower energy densities than butanol, their higher octane number allows for greater compression ratio and efficiency. Higher combustion engine efficiency allows for lesser greenhouse gas emissions per unit motive energy extracted.		*While ethanol and methanol have lower energy densities than butanol, their higher octane number allows for greater compression ratio and efficiency. Higher combustion engine efficiency allows for lesser greenhouse gas emissions per unit motive energy extracted.
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	==See also==		==See also==
	* [[Agricultural byproduct]]
	* [[Air-fuel ratio]]		* [[Air-fuel ratio]]
	* [[Associated British Foods plc]] and its [[subsidiary]] [[British Sugar plc]].
	* [[Bioalcohol]]		* [[Bioalcohol]]
	* [[Biofuel]]		* [[Biofuel]]
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	* [[Biohydrogen]]		* [[Biohydrogen]]
	* [[Bioconversion of biomass to mixed alcohol fuels]]		* [[Bioconversion of biomass to mixed alcohol fuels]]
	* [[Catalyst]]
	* [[Distillation]]
	* [[Emission standards]]		* [[Emission standards]]
	* [[Energy crop]]
	* [[Energy density]]
	* [[Ethanol fuel]]		* [[Ethanol fuel]]
	* [[Industrial fermentation\|Fermentation]] [[facility]]
	* [[List of vegetable oils]] section on oils used as biofuel		* [[List of vegetable oils]] section on oils used as biofuel
	* [[Solvent]]

	===External links===		===External links===
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	<references/>		<references/>

	* Continuous two-stage ~~[[A.B.E. process\|~~ABE]]-fermentation using ''Clostridium beijerinckii'' [[NRLL]] B592 operating with a growth rate in the first stage [[vessel]] close to its maximal value, J Mol Microbiol Biotechnol. 2000 Jan;2(1):101-5.		* Continuous two-stage ABE-fermentation using ''Clostridium beijerinckii'' NRLL B592 operating with a growth rate in the first stage vessel close to its maximal value, J Mol Microbiol Biotechnol. 2000 Jan;2(1):101-5.
	*[http://www.aces.uiuc.edu/news/stories/news3615.html As Gas Prices Climb, Butanol Research Reaches Exciting Stage]		*[http://www.aces.uiuc.edu/news/stories/news3615.html As Gas Prices Climb, Butanol Research Reaches Exciting Stage]

Mac at 08:09, 20 March 2007

2007-03-20T08:09:31Z

New page

Biobutanol is a fuel from natural sources (no petroleum). [[Butanol]] may be used as a [[fuel]] in an [[internal combustion engine]]. It is more similar to [[gasoline]] than [[ethanol]]. Butanol has been demonstrated to work in some vehicles designed for use with gasoline without any modification.<ref>[http://www.butanol.com butanol.com]</ref> It can be produced from [[biomass]] as well as [[fossil fuel]]s. Some call this [[biofuel]] biobutanol to reflect its origin, although it has the same chemical properties as butanol produced from [[petroleum]].

==Production of butanol from biomass==
Butanol can be produced by [[Fermentation (biochemistry)|fermentation]] of biomass. The process uses the [[bacterium]] ''[[Clostridium acetobutylicum]]'', also known as the ''Weizmann organism''. It was [[Chaim Weizmann]] who first used this bacteria for the production of [[acetone]] from [[starch]] (with the main use of [[acetone]] being the making of [[Cordite]]) in [[1916]]. The butanol was a by-product of this fermentation (twice as much butanol was produced). The process also creates a recoverable amount of [[Hydrogen|H]]2 and a number of other [[by-product]]s: [[acetic acid|acetic]], [[lactic acid|lactic]] and [[propionic acid]]s, acetone, [[isopropanol]] and ethanol.

The difference from ethanol production is primarily in the fermentation of the [[feedstock]] — producing butanol rather than ethanol like primary fermentation product and minor changes in distillation. The feedstocks are the same as for ethanol — [[energy crop]]s such as [[sugar beet]]s, [[sugar cane]], [[maize|corn]] [[grain]], [[wheat]] and [[cassava]] as well as [[agricultural byproduct]]s such as [[straw]] and [[maize|corn]] [[stalk]]s. According to DuPont, existing bioethanol plants can cost-effectively be retrofitted to biobutanol production.<ref>[http://www.dupont.com/ag/news/releases/BP_DuPont_Fact_Sheet_Biobutanol.pdf Dupont Fact Sheet on Biobutanol]</ref>

==Distribution==
Butanol better tolerates water contamination and is less corrosive than ethanol and more suitable for distribution through existing [[Pipeline transport|pipeline]]s for gasoline{{Fact|date=February 2007}}. In blends with [[diesel]] or gasoline, butanol is less likely to separate from this fuel than ethanol if the fuel is contaminated with water{{Fact|date=February 2007}}. There is also a [[vapor pressure]] co-blend synergy with butanol and gasoline containing ethanol, which facilitates ethanol blending. This facilitates storage and distribution of blended fuels.<ref>[http://www.dupont.com/ag/news/releases/BP_DuPont_Fact_Sheet_Biobutanol.pdf Dupont Fact Sheet Biobutanol]</ref>
<ref>[http://www.ext.colostate.edu/PUBS/FARMMGT/05010.html ext.colostate.edu]</ref><ref>[http://www.usatoday.com/money/industries/energy/2006-06-20-butanol_x.htm?csp=34 USAtoday]</ref>

==Properties of common fuels==

{| class="wikitable"
! [[Fuel]]
! [[Energy density|Energy]] [[Energy density|density]]
! [[air-fuel ratio|Air-fuel]] [[air-fuel ratio|ratio]]
! [[Specific energy|Specific]] [[Specific energy|energy]]
! [[Heat of vaporization|Heat of]] [[Heat of vaporization|vaporization]]
! [[Octane rating|RON]]
! [[Octane rating|MON]]
|-
| [[Gasoline]]
| 32 MJ/L
| 14.6
| 2.9 MJ/kg air
| 0.36 MJ/kg
|   91–99
|   81–89
|-
| [[Butanol]]
| 29.2 MJ/L
| 11.2
| 3.2 MJ/kg air
| 0.43 MJ/kg
|   96
|   78
|-
| [[Ethanol]]
| 19.6 MJ/L
|   9.0
| 3.0 MJ/kg air
| 0.92 MJ/kg
| 130
|   96
|-
| [[Methanol]]
| 16 MJ/L
|   6.5
| 3.1 MJ/kg air
| 1.2 MJ/kg
| 136
| 104
|-
|}

===Energy content and effects on fuel economy===
Butanol is reported to yield 36 [[megajoule|MJ]]/kg (15,500 [[BTU]]/lb) when burned. This can be expressed volumetrically as 29.3 MJ/[[litre|l]] (104,800 BTU/[[gallon|US gal]]).

Switching a gasoline engine over to butanol would in theory result in a fuel consumption penalty of about 10% {{Fact|date=February 2007}} but butanol's effect on mileage is yet to be determined by a scientific study. While the energy density for any mixture of gasoline and butanol can be calculated, tests with other alcohol fuels have demonstrated that the effect on fuel economy is not proportional to the change in energy density.<ref>[http://www.ethanol.org/documents/ACEFuelEconomyStudy.pdf ethanol.org]</ref>

===Octane rating===
The [[octane rating]] of n-butanol is very similar to that of gasoline but lower than that of ethanol and methanol. n-Butanol has a RON ([[Octane rating|Research Octane number]]) of 96 and a MON ([[Octane rating|Motor octane number]]) of 78 while t-butanol has octane ratings of 105 RON and 89 MON.<ref>[http://www.unep.org/PCFV/Documents/PubGraboskiReport.pdf UNEP.org-Properties of oxygenates]</ref> t-Butanol is used as an additive in gasoline but can't be used as a fuel in its pure form since the melting point is 25.5 °C - in other words it gels when cool. <ref>[http://virtual.yosemite.cc.ca.us/smurov/orgsoltab.htm]</ref>

A fuel with a higher octane rating is less prone to knocking (extremely rapid and spontaneous combustion by compression) and the control system of any modern car engine can take advantage of this by adjusting the ignition timing. This will improve energy efficiency, leading to a better fuel economy than the comparisons of energy content different fuels indicate. By increasing the compression ratio, further gains in fuel economy, power and torque can be achieved. Conversely, a fuel with lower octane rating is more prone to knocking and will lower efficiency. Knocking can also cause engine damage.

===Air-fuel ratio===
Alcohol fuels, including butanol and ethanol, are partially oxidized and therefore need to run at richer mixtures than gasoline. Standard gasoline engines in cars can adjust the air-fuel ratio to accommodate variations in the fuel, but only within certain limits depending on model. If the limit is exceeded by running the engine on pure butanol or a gasoline blend with a high percentage of butanol, the engine will run lean, something which can damage it. Compared to ethanol, butanol can be mixed in higher ratios with gasoline for use in existing cars without the need for retrofit as the air-fuel ratio and energy content is closer to that of gasoline. <ref>[http://www.ext.colostate.edu/PUBS/FARMMGT/05010.html ext.colostate.edu]</ref><ref>[http://www.usatoday.com/money/industries/energy/2006-06-20-butanol_x.htm?csp=34 USA today]</ref>

===Specific energy===
Alcohol fuels have less energy per unit weight and unit volume than gasoline but at the same time require richer mixtures. To make it possible to compare the net energy released per cycle a measure called the fuels specific energy is sometimes used. It is defined as the energy released per air fuel ratio. The net energy released per cycle is higher for butanol than ethanol or methanol and about 10% higher than for gasoline.

===Viscosity===
{| class="wikitable" align="right"
!Substance
!Kinematic viscosity at 20°C
|-
|Butanol
|3.64 cSt
|-
|Ethanol
|1.52 cSt
|-
|Methanol
|0.64 cSt
|-
|Gasoline
|0.4–0.8 cSt
|-
|Diesel
|>3 cSt
|-
|Water
|1.0 cSt
|-
|}

The viscosity of alcohols increase with longer carbon chains. For this reason, butanol is used as an alternative to shorter alcohols when a more viscous solvent is desired. The kinematic viscosity of butanol is several times higher than that of gasoline and about as viscous as high quality diesel fuel.<ref>[http://www.engineeringtoolbox.com/kinematic-viscosity-d_397.html Engineering Toolbox]</ref>

===Heat of vaporization===
The fuel in an engine has to be vaporized before it will burn. Insufficient vaporization is a known problem with alcohol fuels during cold starts in cold weather. As the latent heat of vaporization of butanol is less than half of that of ethanol, an engine running on butanol should be easier to start in cold weather than one running on ethanol or methanol.<ref>[http://www.ext.colostate.edu/PUBS/FARMMGT/05010.html ext.colostate.edu]</ref>

==Potential problems with the use of butanol fuel==
The potential problems with the use of butanol are similar to those of ethanol:
*To match the combustion characteristics of gasoline, the utilization of butanol fuel as a substitute for gasoline requires fuel-flow increases.
*Alcohol-based fuels are not compatible with some fuel system components.
*Alcohol fuels may cause erroneous gas gauge readings in vehicles with [[capacitance]] fuel level gauging.
*The viscosity of butanol is much higher than for gasoline or ethanol, which could have negative effects on the fuel system.
*While ethanol and methanol have lower energy densities than butanol, their higher octane number allows for greater compression ratio and efficiency. Higher combustion engine efficiency allows for lesser greenhouse gas emissions per unit motive energy extracted.
*As an advantage, butanol production from biomass could be more efficient (i.e. unit engine motive power delivered per unit solar energy consumed) than ethanol or methanol routes. Also, the bacterium producing butanol is able to digest cellulose, not just starch and sugars.

==Possible butanol fuel mixtures==
Standards for the blending of ethanol and methanol in gasoline exist in many countries, including the EU, the US and Brazil. Approximate equivalent butanol blends can be calculated from the relations between the stochiometric fuel-air ratio of butanol, ethanol and gasoline. [[Common ethanol fuel mixtures]] for fuel sold as gasoline currently range from 5% to 10%. The share of butanol can be 60% greater than the equivalent ethanol share, which gives a range from 8% to 32%. "Equivalent" in this case refers only to the vehicles ability to adjust to the fuel. Other properties such as energy density, viscosity and heat of vaporisation will vary and may further limit the percentage of butanol that can be blended with gasoline.

==Current butanol vehicles==
Currently no production vehicle is known to be approved by the manufacturer for use with 100% butanol. '''The use of butanol in a vehicle which is not approved for this is not recommended as it may cause damage to the vehicle.'''

==See also==
* [[Agricultural byproduct]]
* [[Air-fuel ratio]]
* [[Associated British Foods plc]] and its [[subsidiary]] [[British Sugar plc]].
* [[Bioalcohol]]
* [[Biofuel]]
* [[Biodiesel]]
* [[Biohydrogen]]
* [[Bioconversion of biomass to mixed alcohol fuels]]
* [[Catalyst]]
* [[Distillation]]
* [[Emission standards]]
* [[Energy crop]]
* [[Energy density]]
* [[Ethanol fuel]]
* [[Industrial fermentation|Fermentation]] [[facility]]
* [[List of vegetable oils]] section on oils used as biofuel
* [[Solvent]]

===External links===
* [http://www.bpdupontbiofuels.com/ BP DuPont Biofuels]
* [http://i-r-squared.blogspot.com/2006/05/bio-butanol.html Bio-Butanol]
* [http://www.greencarcongress.com/2006/06/bp_and_dupont_t.html BP and Dupont Biobutanol]
* [http://www.thestate.com/mld/thestate/business/14861760.htm Dupont, BP join to produce biofuels].
* [http://www.dupont.com/ag/news/releases/BP_DuPont_Fact_Sheet_Biobutanol.pdf Biobutanol Fact Sheet] ([[PDF]])
* [http://www.butanol.com/ Environmental Energy Inc's Butanol Webpage: butanol.com]
* [http://www.greencarcongress.com/2005/07/boosting_biomas.html Green Car Congress: Boosting Biomass-to...Butanol?]
* [http://www.welsch.com/e/index.php?chap=6_1&modulekey=wpmoleculeviewer&specialmol=71-36-3 Butanol 3D view and pdb-file]
* [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=373084&tools=bot Acetone-butanol fermentation revisited].

== References ==
<references/>

* Continuous two-stage [[A.B.E. process|ABE]]-fermentation using ''Clostridium beijerinckii'' [[NRLL]] B592 operating with a growth rate in the first stage [[vessel]] close to its maximal value, J Mol Microbiol Biotechnol. 2000 Jan;2(1):101-5.
*[http://www.aces.uiuc.edu/news/stories/news3615.html As Gas Prices Climb, Butanol Research Reaches Exciting Stage]

[[Category:Biofuels]]
[[Category:Climate change]]
[[Category:Environment]]