Methane

From NOWA-CL
Jump to navigation Jump to search
 
Methane
Chemical formula CH4
OTP appearance clear, odorless gas 
Molar Mass(g/mol) 16 
Melting Point(°C) -182 
Boiling Point(°C) -164 
Density(g/cc) 0.6556 
Fuel Value(MJ/kg) 47.1 
Speed of sound
20°C, 1atm (m/s)
446
NFPA 704
NFPA704.png
4
1
0
 

Uses

Primary

Other

Natural occurrence

  • Methane occurs naturally in the presence of decaying biological materials.
    • 1kg biowaste through a digester (10-40 days) produces 1m3 of methane ~= 6kWh = 21.6MJ

Hazards

  • Fire and explosion
  • Asphyxiant

Production

Extraction

Biologic

Anaerobic decomposition of biowaste in a digester results in the production of methane.

Synthesis

alkali degradation

hydrogenation

of carbon monoxide

The Sabatier reaction hydrogenates carbon monoxide as feedstock and produces water as well as methane.

CO + 2 H2
{Ni
1atm, 200-300°C}
CH4 + H2O
of carbon dioxide

Similar to Sabatier (above), hydrogenation of carbon dioxide produces water as well as methane

CO2 + 4 H2
{Ni
1atm, 200-300°C}
CH4 + 2 H2O
  • Urushibara nickel is a popular choice of catalyst, at temperatures of 350°C and above atmospheric pressure
  • The reaction can be carried out at OTP using Ruthenium oxide / Titanium oxide catalysts, particularly with photoexcitation.[1]
of hydrocarbons

Larger hydrocarbons can be hydrogenated (usually over a catalyst like Urushibara nickel) into methane:

  • Acetylene
    HCCH + 3 H2 2 CH4
  • Pentane
    C5H12 + 4 H2 5 CH4

See also

References

  1. Ravindranathan Thampi, K; Kiwi, John; Grätzel, Michael (1987) "Methanation and photo-methanation of carbon dioxide at room temperature and atmospheric pressure".
    Nature 327; pp506-508. 
    DOI:10.1038/327506a0