Main Sources of Methane Emissions

The main source of methane emissions is natural gas sources and gases from the oil wells. The marsh gas methane is the simplest hydrocarbon use formula CH4 with regular tetrahedral structure and properties to form luminous flame uses largely in the chemical production process and everyday life.

Therefore methane formed by the action of bacteria on swamps and marshes in nature and this gas is called the marsh gas.

Sewage sludge fermented by bacteria yields this gas about 70 percent and thus this is used as a liquid fuel. It also forms 40 percent by the volume of the coal gas.

Formula and Structure Methane

Natural sources, formula structure and uses of methane gas

Methane is the simplest natural unsaturated hydrocarbon in an alkane series with the molecular formula CH4 with regular tetrahedral structure and molecular weight 16 gm mol-1.

If we assuming the quadrivalence of carbon atom it shows the following structure.

Properties of these four hydrogen atoms in the methane molecule are equivalent. Thus if we prepared CH2Cl2 from methane, we write the structure in two different modes.

But these two structures are identical when arranged these structures in the three-dimensional diagram.

If we taking the carbon atom, promotion of a 2S electron to the third 2P and then mixing the S and P orbitals provide four equivalent SP3 hybrid orbitals each containing one electron.

Thus the overlap of these orbitals with 1S orbital of four hydrogen atom will give four equivalent carbon-hydrogen chemical bonding arranged tetrahedrally. Thus the bond length of all CH bond and bond angle in all HCH is the same shown in the above figure.

Production Process of Marsh Gas

Methane is the main part of the natural marsh gas because the combustion of swage and marshes is the main source of this gas.

Another production process of CH4 by striking an electric field between the carbon electrode in atmosphere hydrogen.

  • Sabatier and Senderens in 1897 invented the process of methane production by passing a mixture of hydrogen and carbon monoxide or carbon dioxide over finely divided nickel at about 3000C.

    \[ CO+3H_{2}\xrightarrow{Ni/300^{0}C}CH_{4}+H_{2}O \]

    \[ CO_{2}+4H_{2}\xrightarrow{Ni/400^{0}C}CH_{4}+2H_{2}O \]

  • But it conventionally prepared by heating 1:3 mixture of sodium acetate and soda-lime.

CH3COONa + (NaOH + CaO) → CH4 + Na2CO3

  • It prepared at normal temperature when metal carbide or methyl magnesium iodide dissolving with water.

Al4C3 + 12H2O → 3CH4 + 4Al(OH)3
CH3MgI + H2O → CH4 + MgI(OH)

Physical Properties of Marsh gas

  1. At normal temperature, CH4 is a colorless, orderless, non-poisonous gaseous physical properties.
  2. Boiling point = -1640C and melting point -1840C in 760 mmHg.
  3. This gas is less soluble in water but more soluble in organic solvents(alcohol and ether). Thus 100 ml of water use to dissolving about 5 ml of this gas at 200C.
  4. It burns with non- luminous flame in air or oxygen by forming carbon dioxide and water.

CH4 + 2O2 → CO2 + 2H2O

Catalytic oxidation of methane

Catalytic oxidation of methane used for the production of formaldehyde or methanol depending upon the condition of the reaction.

Thus when this gas oxidizes by air in the presence of metallic oxides it produces formaldehyde.

    \[ CH_{4}+O_{2}\xrightarrow[MoO]{400^{0}C/pressure}HCHO+H_{2}O \]

But when a mixture of methane and oxygen passing through a copper tube at 100 atm pressure and 2000C temperature. The gas mixture produced methanol.

    \[ 2CH_{4}+O_{2}\xrightarrow[100\, atm\, pressure]{200^{0}C/Cu\, tube}2CH_{3}OH \]

Uses of Methane Gas in Everyday Life

Uses of finely divided carbon going through incomplete combustion of methane gas at 10000C.

    \[ C+2H_{2}O\xleftarrow{O_{2}}CH_{4}\xrightarrow{1000^{0}C}C+2H_{2} \]

  1. Hence the carbon prepared by this way known as carbon black. This carbon black is used as a printer ink to make prints in our everyday life. It is also used in the rubber industry for motor tires.
  2. Methane gas uses as an organic fuel in our everyday life.
  3. Methyl chloride, acetylene, formaldehyde, and methanol which obtained from methane use largely in the chemical industry.
  4. It used as a source of synthesis gas. Hence a mixture of this gas and steam passed over the heated nickel supported on alumina to produce synthesis gas. Methane gas largely used as the natural source of hydrogen gas in the chemical industry.

CH4 + H2O → CO + 3H2
CH4 + 2H2O → CO2 + 4H2

Methane in greenhouse gases

Now a serious concern about the increase in the use of methane, carbon dioxide, CFC, ozone, nitrous oxide gases, and water vapor of the atmosphere causes to raise the global temperature. This effect is called the greenhouse effect. But the greenhouse used to maintain in winter counties by artificial heating.

Greenhouse gas Contribution to global warming
Carbon dioxide 50%
Methane 16-20%
CFC 13-18%
Ozone 7-8%
Nitrous oxide 4-5%
Water vapor ≈ 2%

The concentration of methane in greenhouse gases has been increasing due to global activity

  1. Industrial revolution.
  2. Emissions sources of methane from biomass and natural gas.

Increases of uses of greenhouse gases like methane lead to trapping more heat on the earth. Therefore this gas preventing the escaping of heat into space, leading to increased global temperature.

If the present rate of warming continues, the average temperature of the earth’s atmosphere rises about 2.50C in the next 30 years. Thus it resulting in a major climate change.

When the polar ice caps will melt, it consequent increase in sea level. Therefore many seaside localities including some big Iceland completely submerged.

Hence to save our civilization use non-fossil fuel like wind energy, atomic energy as the sources of energy in our civilization.