What is Methane Gas?
Methane (CH4) is a colorless odorless gas commonly used as a fuel – the main component of natural gas. It is a hydrocarbon and, therefore, organic in nature. It is also one of the carbon originating gases that play a major role in the greenhouse effect. As claimed by the U.S. Environmental Protection Agency (EPA), 10 percent of the greenhouse gas emissions is from the use of methane gas. The gas is lighter than air and can only be in gaseous form.
It is a form of fossil fuel that is naturally occurring below the earth’s surface as an end product of anaerobic decomposition by methanogens where it is found together with other fossils fuels such as coal and oil. Methane gas can also be produced in a laboratory by heating a mixture of sodium ethanoate and soda lime. Due to its hydrocarbon quality and quantity, it is a very flammable gas. It burns readily in air with a pale non-luminous flame by reacting with oxygen to give off carbon dioxide, water vapour, and a lot of heat. This article seeks to highlight the sources, uses and effects of Methane gas.
Sources of Methane Gas
1. Fossil fuels
Fossil fuel is by far the greatest source of energy in the world – used to drive engines in cars, turbines and other machinery. Fossil fuels is extracted from decayed organic matter that has decomposed over millions of years under intense heat leading to the disintegration of matter to fuel.
As a result, it is mainly made up of carbon is a major source of methane gas. Methane gas is naturally occurring below the earth’s surface and since it is in gaseous form, it is not easy to trap or extract. It is generated from the other hydrocarbons in liquid and solid state such as oil and coal respectively.
Artificial wetlands such as dams and ponds may influence the presence of methane gas. It is common to find that such areas were cleared of vegetation to reclaim it for construction. After, the dead organic matter continues to decompose at the base of these structures leading to the production of methane gas in water.
The presence of water and lack of fresh open air fastens the process of rotting of the dead organic matter. This decomposition process is what leads to the generation of methane gas at the bottom of the wetland. Naturally occurring wetlands have the same effect.
One of the most recommended modes of waste disposal is composing, especially for organic waste. Composting involves layering of different types of organic matter to recycle the waste back to the earth in a safe and friendly way.
Consequently, the mixture of dead organic matter leads to production of methane gas to the atmosphere. However, composting releases small amounts of the gas in comparison to other sources of gas and is hence not a hazard.
4. Animal waste
In a bid to save on non-renewable sources of energy, the globe has encouraged livestock production systems to take up the practice of producing biogas to provide cheap and affordable energy. Livestock production has led to the growth of this renewable energy source since it provides all the materials necessary for the setting up of the plant. This has seen more release of methane into the atmosphere through the fermentation of animal waste.
5. Anaerobic decomposition
Methane gas is produced when there is anaerobic bacterial decomposition. This means that the process of decomposition of organic matter does not require oxygen rather; it requires a suitable media for the bacteria to thrive. It often occurs during the decomposition of organic waste in landfills.
6. Waste management
Sewage raw waste water is treated for it to be deemed safe for release back into the water ways. During treatment, sludge is left behind as residue and since the sludge is often a mixture of compounds especially organic matter; suitable bacteria make this their home and help in decomposition leading to the production of methane gas.
7. Coal mining
Coal is the densest form of fossil fuel extracted from the earth’s surface and because of this, it is solid in state and occupies a lot of space thereby trapping methane gas below. Mining of coal leads to freeing of methane gas into the atmosphere as it is not easily trapped.
8. Rice fields
For rice to grow, it is grown in padded fields which are flooded with water. Too much water depletes the oxygen present in the soil and also leads to decomposition of organic material present which provides a suitable media for the production of methane gas. The gas is released through diffusion into the atmosphere. Paddy rice fields are among the biggest sources of methane gas release into the environment.
9. Burning of wood fuel
The use of firewood and charcoal is common because it is a cheap way of generating cooking and heating energy. Yet, whenever wood fuel is used, it releases methane gas into the atmosphere. Forest fires also release of the gas to the atmosphere.
Uses of Methane Gas
1. Used in cooking
Methane is a hydrocarbon and lighter than air. Therefore, it produces more energy per unit weight in comparison to oil and coal. It is also preferred for cooking since it does not have any smell and does not leave soot on the cooking utensils.
2. Used to provide lighting
Methane gas can be harnessed to generate electricity for homes as well as offices and industries.
3. Used in production of other compounds
Methane gas is essential for the formation of methanol (methyl alcohol), which is a key component of alcohol. It is also important in the artificial manufacture of hydrogen to be used in various industries.
Hydrochloric acid, one of the most common acids used in laboratories, is manufactured with methane gas as an ingredient. Trichloromethane is another compound that requires methane gas. Also known as chloroform, it is used extensively as both solvent and an anesthetic.
4. Used to run industrial machinery
Methane gas is used to run or power engines and turbines in factories. It is also used to provide energy for lighting purposes.
5. Used to produce carbon black
Methane gas can be burned incompletely leading to unusual carbon deposits. These deposits are known as carbon black and are used to strengthen rubber which is used to make vehicle tires. This same carbon black is used to make paints and printing ink.
6. It is a fertilizer ingredient
With the addition of hydrogen, methane gas is used to manufacture ammonia, which is a key compound in the manufacture of fertilizers.
7. Used as rocket fuel
Its gaseous state translates to less carbon deposits when combusted, making it ideal for rocket fuel. It also leaves no residue. Other forms of fuel such as kerosene emit a lot of carbon, making the rocket combustion chamber faulty.
Effects of Methane Gas on Our Environment
Mixture of methane and air is very explosive in nature. About 20% of air is oxygen and it becomes very reactive when it comes in contact with methane. There have been cases of explosions, especially in coal mines where the mines collapse merely due to the reaction between the methane gas in the mine and the oxygen in the air.
Explosions have also been witnessed in landfills where organic waste had been compacted and methane gas is being released in large amounts. Spontaneous reaction with the air around the landfill that may lead to an outbreak of fire has been reported.
2. Greenhouse effect
On its own, methane gas is of no harm to the environment or to life. Nonetheless, in increased concentration of the gas coupled up with the presence of carbon dioxide and water vapor, there is massive absorption and trapping of heat in the atmosphere that is harmful to the environment. The result is termed as the greenhouse gas effect associated with climate change and global warming.
In its extremely cold form, methane gas can cause burns whenever it gets into contact with the skin and yes.
In high concentrations and in an enclosed space, the gas can react with all the oxygen present and rid the area of all oxygen leading to suffocation.
Engines emit hydrocarbons and fumes due to combustion of methane gas, which can be hazardous once inhaled in the body. On the other hand, exposure to high levels of methane can lead to headache, vomiting, nausea and loss of consciousness.