After bringing the natural gas out, impurities like sand, water and unnecessary gases are removed. It is worth mentioning that 5,149.6 trillion cubic feet of trapped natural gas is left. Only United States consumes 23.2 per cent of natural gas. More companies, like cng , are making natural gas accessible to consumers. To improve our knowledge of natural gas let us review it from the very beginning.
In its pure form natural gas is odorless and colorless. The interest in natural gas lies in its high level of heat production as a result of combustion. It is not biodegrading due to lower emission of harmful air pollutants and byproducts. The merging need of energy has made the role of natural gas in our society more vital.
Natural gas is composed of hydrocarbon gases. Primarily it has methane as a component but it can also contain ethane, propane butane and pentane. The composition of natural gas differs in different samples, the variation is settled down by the process of refining. Typically natural gas has methane (CH4) from 70 to 90 per cent, ethane (C2H6) and propane from zero to 20 per cent, butane (C4H10) and carbon dioxide (CO2) from zero to eight per cent, oxygen (O2) zero to 0.2 per cent, nitrogen (N2) zero to five percent, hydrogen sulphide (H2S) from zero to five per cent and traces of rare gases (A, He, Ne, Xe).
The natural gas which we use in our homes is in its natural form and has pure methane (CH4). Methane has one carbon and four hydrogen atoms. The absence of other hydrocarbons makes the gas ‘dry’. The natural gas is called ‘wet’ in the presence of other hydrocarbons.
Now come to the process of electricity generation by the help of various latest and outdated methods.
- Steam generating Units: The most basic natural gas powered electricity generator has a steam generating unit. In this unit the fossil fuel is burnt to give away heat that produce steam from water which is used to run a turbine that in turn produce electricity. These units are more common to burn coal than the natural gas. These units are low energy efficient.
- Centralized Gas Turbines: Combustion engines and gas turbines can also be employed to produce electricity. This unit exempts the need of heating water to get steam. It uses the burning gases of the fossil fuel (natural gas) to run the turbine so the electricity can be generated. Theses units are used to meet the demand of peak load as they can be turn on in less time and more quickly. However they are less energy efficient as compared to power plants driven by steam.
- Combined Cycle Units: These are comparatively new power plants run by the natural gas. The generating technique makes use of both steam unit and gas turbine. The function of gas turbine remains all the same as the heated gases are used to run the turbines and to produce electricity. The leftover heat of the gas turbine is send to generate steam in combined cycle plant which produces electricity by the virtue of steam. The combined cycle unit has a thermal efficiency of 50 to 60 per cent because they make a two way use of the heat energy released during the combustion of fossil fuel.
- Distributed Generation: These power generating units are individual relatively small size power generating units that can be feasibly placed in any industrial, commercial or residential site. They produce energy on small scale and are fired by natural gas and function with small combustion units or fuel cell of natural gas. It is until now that the large and centralized plants to produce power were implanted. But now the trend is changing and focus is moving towards distribution cell.
The charm of distributed generators lies in its efficiency, cost effectiveness, smaller size and reliability as compared to purchasing power from larger utilities. Natural gas is best fuel for these units due to its environment friendly attitude. To meet the needs of on-site electricity, natural gas can be used in a number of ways such as micro turbines, industrial natural gas fired turbines, and gas fired reciprocating engines and fuel cells.
- Industrial Natural Gas Fired: The principle of industrial natural gas fired turbines is similar to larger turbines of gas (already discussed). Instead of installed at some remote location, these units are placed quite near to the place where they have to provide electricity. These industrial turbines are easy to turn on, simple to operate, compact and light in weight. Current is produced by using high pressure gas at high temperature. Large and medium organization such as hospitals, universities and commercial building can use these units to meet their needs effectively. Their efficiency is commonly between 21 to 40 per cent.
- Micro Turbines: With a comparatively low power out put and small size. They are the small version of industrial gas turbines. Their capacity is to give away 25 to 500 kilo watts of energy.
- Gas Fired Reciprocating Engines: Typically known as Combustion Engines, theses unit get mechanical energy out of natural gas which moves the piston to produce electricity. Their capacity is to produce five to seven kilo watts of energy and can be used in small scale for residence.
- Fuel Cells: They can be simply understood as batteries that are rechargeable but they do not use a charger. They are recharged by the fuel (natural gas) directly. Their use is gaining much popularity.
Now let us discuss the formation of natural gas that is a fossil fuel like coal and oil. The fossil fuels are made up of those partially decomposed microorganisms, plants and animals that lived million of years ago and buried under the layer of mist and transformed into fuels by the virtue of high pressure and heat.
Now let us discuss the advantages of natural gas.
- Heating value: The heating value of natural gas is very high. It is 24,000 Btu per pound.
- Eco-friendly: Natural gas is composed of methane (CH4) which has only one carbon atom. The carbon dioxide emission of natural gas is 70 per cent less than other fossil fuels. It is environment friendly because there are no byproducts. It also helps in improving the quality of water and air.
- Easy to use: Natural gas can be easily obtained and utilized. The gas is sucked out of the earth crest where it is easily pumped into houses.
- Cost effective: The abundance of natural gas makes it cost effective for the industries of United States. Unlike oil, there is no need to export oil from far flung countries. It is cheaper than the coal. No technique or training is required to use natural gas, even a house wife can meet the needs of her household (like cooking and heating) by the help of natural gas.
- Odorless: The natural gas facilitates its extractors as it has no odor to disturb them during work.
The disadvantages of natural gas are also worth mentioning.
- Finite reserves: Although the fuel is clean to burn but still it has limited reserves where the extraction of natural gas is leaving behind huge craters in earth. Where the lack of technology and poor economics are the hurdles in getting access to even the existing natural gas.
- Non renewable: It is the non renewable source of energy. It means that the exploitation of natural gas exhaust the existing reserves that cannot be gained back.
- Explosive: Mishandling of the natural gas can explode it. In case of leakage, the natural gas can burnt a whole building or room in no time. The severity of explosion depends upon the amount of natural gas that has come out of the leakage.
- Toxic: Natural gas is toxic in case it is inhaled and can cause severe health risks. Homes must have monoxide detectors that can point out leakage if there is any. The most common cause of death by carbon monoxide is the use of natural gas. The colorless gas on coming out of its channel can cause death without any warning due to suffocation.
Despite of limitations attached to the natural gas, it is still the most dependable non-renewable fossil fuel due to its environment friendly nature. It is necessary that the technique to extract natural gas must be improved to exploit the remaining reserves of natural gas.Advertisement
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- Methods for producing electricity using Natural Gas
- Formation of Natural Gas
- Advantages of Natural Gas
- Disadvantages of Natural Gas