What is Natural Gas?
Natural gas, commonly known as methane gas or natural methane gas, is a colourless, highly flammable gas composed largely of methane and ethane. It's a form of petroleum that's commonly found with crude oil. Natural gas is a fossil fuel that is used to generate electricity, heat, cook, and fuel for certain vehicles. It is used as a chemical feedstock in the production of plastics, as well as a range of other chemical products such as fertilizer and dyes.
This is the simple definition of natural gas. Examples of natural gas include Methane, Nitrogen Carbon Dioxide and so on.
Now that we have learned about what is natural gas. Let us study the other concepts of natural gas, the example of natural gas and more from this article.
Where is natural gas found?
There are many locations of natural gas. Let us dig into where is natural gas found here.
At the high pressures present in a reservoir, natural gas is frequently found dissolved in oil, and it can also be present as a gas cap above the oil. The pressure of natural gas exerted on the subterranean oil reserve provides the drive to force oil to the surface in many cases. Associated gas is a type of natural gas that is commonly thought to be the gaseous phase of crude oil and this natural gas contains light liquids like propane and butane. As a result, related gas is sometimes referred to as "wet gas."
There are also reserves with gas but no oil. Nonassociated gas is the name given to this type of gas. Dry gas is a type of nonassociated gas that is produced in reservoirs that aren't connected to any known liquid petroleum source. Also, natural gas contains minor amounts of non-hydrocarbon gases including carbon dioxide and water vapour, as well as natural gas liquids (NGLs), which are also hydrocarbon gas liquids.
History of use
Discovery and early application of natural gas
Between 6000 and 2000 BCE, the first natural gas seeps were discovered in Iran. Many early writers described natural petroleum seeps in the Middle East, particularly in what is now Azerbaijan's Baku region. The "eternal fires" of the ancient Persians' fire-worshipping religion were supplied by the gas leaks, which were probably first ignited by lightning.
Natural gas was first mentioned in China around 900 BCE. The first known natural gas well was drilled in China in 211 BCE, to recorded depths of 150 metres (500 feet). The Chinese used bamboo poles and primitive percussion bits to drill wells in limestones from the Late Triassic Epoch (approximately 237 million to 201.3 million years ago) in an anticline (a stratified rock arch) west of current Chongqing in order to look for gas. The gas was used to dry the interbedded rock salt in the limestone.
Wells was eventually drilled to depths of over 1,000 metres (3,300 feet), with over 1,100 wells drilled into the anticline by 1900.
Natural gas was unknown in Europe until 1659 when it was discovered in England, and even then it was not widely used. Instead, from 1790 onwards, gas derived from activated carbon coal (known as town gas) became the primary fuel for lighting streets and homes over much of Europe.
Natural gas from a shallow well near Fredonia, New York, was the first commercial application of a petroleum product in North America in 1821. The gas was delivered to consumers via a small-bore lead pipe for lighting and cooking.
As stated above, the definition of natural gas is simple. Natural gas is an abundant and essential component of the global energy supply. It is one of the cleanest and most powerful kinds of energy available when burning natural gas. It enables us to cook, use electricity, and carry out daily tasks. Natural gas is mostly methane and carbon dioxide, but other hydrocarbons also play a role in its composition. Individual hydrocarbons can be used as various sources of energy after natural gas has been refined.
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Types of Natural Gas
Let us study a few of the types of natural gas here.
Methane
Before being used by consumers, natural gas is broken down to methane. It is the most abundant component of pure natural gas, is extremely flammable, and can be used for a variety of energy applications.
Ethane
Ethane is the second most abundant energy component in natural gas. It is a hydrocarbon that is produced as a byproduct of the petroleum refining process. It is used in a variety of ways after being separated from natural gas because it has a higher heating value than methane.
Propane
Propane is an abundant energy source found in natural gas that may be processed as either a gas or a liquid. Propane, which is commonly found in pipeline gas, can be used for a variety of applications. It's frequently used to fuel engines, cook on stoves, and heat homes and larger buildings.
Butane
Butane, which is found in natural gas, is not as abundant as other hydrocarbons, but it is still a useful energy source with a wide range of applications. Butane is a gas that is isolated during natural gas processing and makes up around 20% of the natural gas composition.
Composition and properties of natural gas
Hydrocarbon content
Natural gas is a hydrocarbon mixture made up mostly of saturated light paraffin like methane and ethane, which are both gaseous at room temperature. Other hydrocarbons, such as propane, butane, pentane, and hexane, may be present in the mixture. Because of the higher pressures in natural gas reservoirs, even the heavier hydrocarbons are mostly found in gaseous form.
Non Hydrocarbon content
Nitrogen, carbon dioxide, hydrogen, and noble gases such as helium and argon are commonly found in association with hydrocarbon gases. Nitrogen and carbon dioxide are non-combustible gases that can be found in large quantities. Nitrogen is inert, but it affects the heating value of a mixture if it is present in significant amounts; as a result, it must be eliminated before the gas can be sold commercially. To increase heating value, reduce volume, and maintain even combustion qualities, carbon dioxide is removed.
Application of Natural Gas
Let us look at the application of natural gas here.
Natural gas is used to produce energy, which is the most common application. Industrial, home, and commercial natural gas use follow power generation—primarily as a source of energy, but also as a feedstock for chemical compounds, for example. Over time, a number of specialised applications have developed. The clean-burning of natural gas features have made it a popular choice as a nonpolluting transportation fuel, despite the fact that it produces the greenhouse gas carbon dioxide. Compressed natural gas is being used by many buses and commercial automotive fleets.
Key Advantages
Let us look at the key advantages of natural gas.
Natural gas is widespread. The International Energy Agency (IEA) estimates that there are enough recoverable resources to last roughly 230 years if consumption remains constant.
It's versatile. A gas-fired power plant begins and ends much faster than a coal-fired unit. This flexibility makes it an effective addition to renewable energy sources like solar and wind, which are only available when the sun shines and the wind blows.
Gas creates half the carbon dioxide (CO2) and a tenth of the air pollutants produced by coal when burning natural gas to generate electricity. Using gas instead of coal has huge potential for reducing CO2 emissions and air pollution in the near future.
Gas, in the form of LNG, is now so widely available that it can assist countries in dealing with short-term supply disruptions. Following the Fukushima disaster, Japan shut down its nuclear reactors and depended heavily on LNG to replace lost electricity.
FAQs on Natural Gas: Definition, Types and Importance
1. What is natural gas and what is it primarily composed of?
Natural gas is a naturally occurring, highly flammable fossil fuel found deep beneath the earth's surface. It is a hydrocarbon gas mixture consisting primarily of methane (CH₄). While it is mostly methane, it also contains smaller amounts of other hydrocarbon liquids (NGLs) and non-hydrocarbon gases. Key components include:
- Methane: The main component, making up 70-90% of natural gas.
- Ethane: The second-largest component.
- Propane and Butane: Heavier hydrocarbons also present in the mixture.
- Non-hydrocarbons: Gases like carbon dioxide, nitrogen, and water vapour.
2. How is natural gas classified based on its source of origin?
Natural gas is mainly classified based on whether it is found with crude oil deposits. The two primary classifications are:
- Associated Gas: This is natural gas that is found dissolved in crude oil or as a 'gas cap' above the oil in a reservoir. It is often called 'wet gas' because it contains a higher proportion of liquid hydrocarbons like propane and butane.
- Non-associated Gas: This is gas found in reservoirs that do not contain significant amounts of crude oil. This type is often referred to as 'dry gas' as it consists of almost pure methane.
3. What are the most important uses of natural gas in our daily lives and industry?
Natural gas is a versatile energy source with several key applications. Its major uses include:
- Electricity Generation: A significant portion of natural gas is used in power plants to generate electricity.
- Residential Use: It is widely used for heating homes, cooking food, and heating water.
- Industrial Use: Industries use it as a heat source for various processes and as a chemical feedstock for producing plastics, fertilisers, and other chemicals.
- Transportation Fuel: Compressed Natural Gas (CNG) is used as a cleaner alternative fuel for vehicles like buses and cars.
4. Why is natural gas often considered a more advantageous fuel compared to other fossil fuels like coal?
Natural gas holds several key advantages over other fossil fuels, particularly coal. When burned, it produces significantly fewer air pollutants. For instance, to generate the same amount of energy, natural gas emits about half the carbon dioxide (CO₂) and only one-tenth of the air pollutants that coal does. Furthermore, gas-fired power plants are more flexible; they can be started and stopped much faster than coal plants, making them an excellent partner for intermittent renewable energy sources like solar and wind.
5. How is natural gas formed beneath the Earth's surface?
Natural gas is a fossil fuel formed over millions of years from the remains of ancient plants and animals. This organic matter was buried under thick layers of sediment, sand, and rock. The immense pressure and heat from these layers gradually transformed the organic material into hydrocarbons. This process, occurring deep within the Earth's crust, creates both crude oil and natural gas, which get trapped in porous rock formations.
6. If natural gas is called a 'cleaner' fuel, why is it still considered a contributor to greenhouse gases?
The term 'cleaner' is relative and used mainly in comparison to coal and oil. While natural gas combustion releases fewer pollutants like sulphur dioxide and nitrogen oxides, it is primarily composed of methane (CH₄). Methane itself is a potent greenhouse gas, and its unburned release can be harmful. Moreover, when natural gas is burned, it still produces carbon dioxide (CO₂), which is the primary greenhouse gas contributing to climate change, although it produces less CO₂ per unit of energy than other fossil fuels.
7. What processing steps does natural gas undergo before it can be used commercially?
Raw natural gas from a well cannot be used directly. It must be processed to meet quality standards and remove impurities. The key steps involve separating the various hydrocarbons and fluids. This includes removing water vapour, non-hydrocarbon gases like carbon dioxide and nitrogen, and separating valuable Natural Gas Liquids (NGLs) like ethane, propane, and butane. The remaining gas, which is almost pure methane, is then transported to consumers.
8. Why is a strong-smelling substance typically added to the natural gas used in homes?
Pure natural gas, which is mostly methane, is both colourless and odourless. This lack of smell makes it impossible to detect a gas leak by scent, creating a significant safety hazard. To solve this, utility companies add an odorant, usually a compound called mercaptan, to the gas. Mercaptan has a very distinct and unpleasant smell, often compared to rotten eggs or sulphur, which allows people to quickly detect a leak and take necessary precautions.
