Natural gas and methane are often used as synonyms, but they are not exactly perfect substitutes. Methane is a colorless, odorless, and flammable greenhouse gas, whereas natural gas, is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes and carbon dioxide, nitrogen, hydrogen sulfide, and helium.
Methane is a chemical compound with the formula CH4. It is the simplest hydrocarbon and the major component of natural gas. It is widely used in; organic synthesis, the production of hydrogen by thermal cracking, and as a fuel.
Natural gas, on the other hand, is a mixture of various hydrocarbons, including methane, ethane, propane, and butane, as well as other gases such as nitrogen, carbon dioxide, and hydrogen sulfide. It is usually extracted from underground reservoirs, and it can be used as fuel for heating, cooking, and generating electricity.
The main differences between methane vs natural gas are tabulated below:
|A chemical compound in which one carbon is covalently attached to four hydrogen||Mixture of hydrocarbons, primarily CH4|
|100% Pure||Typically 70-90% CH4, with other hydrocarbons|
|Genrally extracted as a single gas||Extracted as a mixture of hydrocarbons and other gases|
|Found in coal mines and marshy fields||Found in underground reservoirs|
|Colorless and odorless||Colorless but has a sulfurous odor|
|Fuel for heating, cooking, and electricity generation, industrial processes||Same as methane gas, but with additional uses as a feedstock for chemical production|
Types of natural gas
Natural gas is produced by wood and fossils, in an anaerobic reduction reaction under high pressure. The table shows the percentage of the components of natural gas:
|Methane (CH4)||70 - 90 %|
|Ethane (C2H6) - Propane (C3H8) - Butane (C4H10)||0 - 20 %|
|Carbon Dioxide (CO2)||0 - 8 %|
|Nitrogen (N2)||0 - 5 %|
|Hydrogen Sulfide (H2S)||0 - 5 %|
|Oxygen (O2)||0 - 0.2%|
|Rare Gases (Ar , He , Ne)||Trace|
Conventional Natural Gas
This is the most common type of natural gas, which is typically found in underground reservoirs. Conventional natural gas is primarily composed of methane, with small amounts of other hydrocarbons, such as ethane, propane, and butane. Based on composition, it is further classified into the following subtypes.
Dry natural gas: It refers to a purified product that is almost entirely methane.
Wet natural gas: contains compounds other than methane and ethane.
Sour natural gas: It contains larger amounts of hydrogen sulfide, which is highly undesirable due to corrosion and results in SO2 formation upon combustion.
Fossil fuel and Biogas
Natural gas is a fossil fuel formed by the anaerobic digestion of organic waste to biogas, also called the thermogenic process.
Anaerobic digestion is the decomposition of organic materials (plant and animal products) by bacteria in an oxygen-free environment with intense heat and pressure underground over millions of years to produce:
- Biogas: contains both energies (gas).
- Valuable soil products (liquids and solids).
The biogas is captured, to produce heat and electricity for use in engines, and fuel cells. Biogas can also be upgraded into biomethane, also called renewable natural gas or RNG, and injected into natural gas pipelines or used as a vehicle fuel. The liquid and solid digested material, called digest state, is frequently used as a soil amendment.
Renewable Natural Gas
Renewable natural gas (RNG) is a type of natural gas that is produced from renewable sources, such as landfills, agricultural waste, and wastewater treatment plants. Note that, RNG is similar in composition to conventional natural gas, However, it has a lower carbon content therefore considered a more sustainable energy source.
Methods for Methane formation
Thermogenic formation: The gas is formed in the same manner as natural gas.
Biogenic formation: Methane is produced by biological activity as microorganisms attempt to decompose the remains of marine life (as above, primarily marine phytoplankton and zooplankton). In this case, methane is produced by the anoxic behaviors of methanogenic bacteria.
Industrial formation: Given its cheap abundance of natural gas, there is little incentive to produce methane industrially. Methane can be produced by hydrogenating carbon dioxide through the Sabatier process. Methane is also a side product of the hydrogenation of carbon monoxide in the Fischer-Tropsch process, which is practiced on a large scale to produce longer-chain molecules than methane.
Is methane gas the same as natural gas?
Methane is the primary constituent of natural gas. The two are not the same though.
How did natural gas form?
Most natural gas has been formed through either biogenic or thermogenic processes.
Biogenic process: is formed when methanogenic organisms in landfills and shallow sediments anaerobically decompose without being subjected to high temperatures and pressures.
Thermogenic process: Takes a much longer period of time to form and is created when organic matter is heated and compressed deep underground.
Where is natural gas found?
Natural gas is found in rock formations deep below the surface of the Earth.
Is natural gas the cleanest fuel?
Yes, Compared with some other fossil fuels, natural gas emits the least amount of carbon dioxide into the air when combusted, making natural gas the cleanest burning fossil fuel of all.
Is natural gas a fossil fuel?
Coal, crude oil, and natural gas are all considered fossil fuels because they were formed from the buried remains of plants and animals that lived millions of years ago
What’s the difference between natural gas and Petroleum gas?
Natural gas is methane(CH4) with various combinations of other hydrocarbons which are formed by the decomposition of plant and animal matter under intense pressure.
Petroleum gas is gaseous petroleum that mainly contains butane or propane. It uses natural gas as its raw material and then purifies it to much cleaner gas.
How is methane stored?
Methane is mainly stored in micropores (<2 nm) or mesopores (2–50 nm) at supercritical temperatures (above 273.15 K) over a wide range of pressures (up to 50 MPa) in shale gas reservoirs and vehicular applications.