Methane as fuel: Difference between revisions

Revision as of 07:44, 23 July 2012

Methane, CH₄, is the lightest (least dense) and simplest hydrocarbon. It is the major constituent of natural gas, and a potent greenhouse gas. It may be captured as biogas and refined to pure methane.

Production

Many biological processes produce it as it is a a byproduct of fermentation and composting. This method of production is called methanogenesis. The method hence does not use electricity at all, but in some cases this may also be a disadvantage is it then doesn't allow to store the electricity ie generated using PV-panels.

It can also be produced artificially using electricity (Sabatier process) This process basically combines CO² and hydrogen (H). See http://en.wikipedia.org/wiki/Sabatier_process This may be useful as although hydrogen can be made at home using electricity and is even in its current state a useful fuel, it has many problems regarding the storage. Methane has fewer storage problems ?

Advantages

It can be used very easily for low pressure/relatively low heat uses, such as mantle lighting or cooking.

It can be used as a vehicle fuel, yet then requires pressurisation (so a gas compressor needs to be added to the system^[1]^[2]). It can be compressed to a specific pressure at which methane is still a gas (say 3600 psi for the tank/125psi injected to motor). It can also be compressed untill it becomes a liquid fuel; however at these pressures the fuel has actually consumed more energy for the compression than what it can actually release in work when combusted.^[3]

Disadvantages

If allowed to escape it has a negative impact on the climate. This, as it's a very potent GHG-gas. It breaks down when burned, so not a problem if burned; yet it can be a problem ie in case of leaks. Although it is a potent greenhouse gas, it does not last as long in the atmosphere as many other such gases, eventually breaking down into carbon dioxide and water vapor.

Reflist

Template:References

External links

Wikipedia:methane
Methane digestor at EcoReality.

[1] Biogas composed of 95 percent methane useful as vehicle fuel, can also be used in regular CNG systems

[2] Compressor used in very similar fuels, ie natural gas for transport

[3] [Journeytoforever on methane for vehicle use

[1]

[2]

[3]

@@ Line 1: / Line 1: @@
-'''Methane''', CH<sub>4</sub>, is the lightest (least dense) and simplest [[hydrocarbon]]. It is the major constituent of [[natural gas]], and a potent [[greenhouse gas]]. It may be captured as [[biogas]].
+'''Methane''', CH<sub>4</sub>, is the lightest (least dense) and simplest [[hydrocarbon]]. It is the major constituent of [[natural gas]], and a potent [[greenhouse gas]]. It may be captured as [[biogas]] and refined to pure methane.
+==Production==
 Many biological processes produce it as it is a a byproduct of [[fermentation]] and [[composting]]. This method of production is called [[methanogenesis]]. The method hence does not use electricity at all, but in some cases this may also be a disadvantage is it then doesn't allow to store the electricity ie generated using PV-panels.
 It can also be produced artificially using electricity ([[Sabatier process]]) This process basically combines CO² and hydrogen (H). See http://en.wikipedia.org/wiki/Sabatier_process This may be useful as although hydrogen can be made at home using electricity and is even in its current state a useful fuel, it has many problems regarding the storage. Methane has fewer storage problems ?
+==Advantages==
+* It can be used very easily for low pressure/relatively low heat uses, such as [[mantle lighting]] or [[cooking]].
+* It can be used as a vehicle [[fuel]], yet then requires pressurisation (so a [[gas compressor]] needs to be added to the system<ref>[http://www.environmental-protection.org.uk%2Fassets%2Flibrary%2Fdocuments%2Fbiogas_as_transport_fuel_june06.pdf Biogas composed of 95 percent methane useful as vehicle fuel, can also be used in regular CNG systems]</ref><ref>[http://www.popularmechanics.com/cars/how-to/maintenance/should-you-convert-your-car-to-natural-gas Compressor used in very similar fuels, ie natural gas for transport]</ref>). It can be compressed to a specific pressure at which methane is still a gas (say 3600 psi for the tank/125psi injected to motor). It can also be compressed untill it becomes a liquid fuel; however at these pressures the fuel has actually consumed more energy for the compression than what it can actually release in work when combusted.<ref>[[http://journeytoforever.org/biofuel_library/MethaneDigesters/MD4.html Journeytoforever on methane for vehicle use]</ref>
 ==Disadvantages==
@@ Line 9: / Line 15: @@
 If allowed to escape it has a negative impact on the climate. This, as it's a very potent GHG-gas. It breaks down when burned, so not a problem if burned; yet it can be a problem ie in case of leaks. Although it is a potent greenhouse gas, it does not last as long in the atmosphere as many other such gases, eventually breaking down into [[carbon dioxide]] and [[water vapor]].
-However, it has many drawbacks as a mass energy source ([[fuel]]). Because it is so ephemeral, it contains relatively little energy per unit volume at easily obtainable pressures. Also due to its lightness, it has a very low boiling point, and it takes tremendous pressure and/or refrigeration to liquefy it. [http://journeytoforever.org/biofuel_library/MethaneDigesters/MD4.html One analysis] indicates that, when compressed adequately to have energy density required by moving vehicles, it actually consumes more energy to compress it than is released in work when combusted.
+==Reflist==
+{{references}}
-This does not mean it is without use! It can be handy for low pressure, relatively low heat uses, such as [[mantle lighting]] or [[cooking]].
 ==See also==