Natural
Gas
Compressed
natural gas CNG) is methane stored under high pressure. It is made by
compressing methane to less than 1% of its volume. It is a non-toxic and
relatively safe form of energy. It is mainly used in vehicles. This is
important because as the world progressed, more petrol started to be consumed,
which has proven to be toxic to the environment. In this context, CNG offers a
more eco-friendly alternative to petrol.
History
In
about 500 BC, the Chinese discovered places where natural gas seeped to the
surface. They built crude pipelines using bamboo to transport the gas and used it
to boil seawater. This separated the water from the salt, making the water
potable and providing salt to season food.
The
first commercial experiments with CNG took place in France in the 1850s. It
eventually grew in popularity and during World War I, it was used as fuel for
transport vehicles. By the 1960s, tests were being conducted by the Columbian
government to see if the gas could power large carrier ships. The ships were to
carry CNG in vertical pressure bottles. However, this design failed because of
the high cost of the pressure vessels. In the following years, there were
several attempts to develop CNG that could be used commercially. Once these
attempts succeeded, CNG started to be transported across the world for
commercial use.
The
Process
Natural
gas is usually found under the Earth’s surface. Sometimes, the pressure
underground is high enough that the gas can flow naturally to the surface in
liquid form. However, in most gas reservoirs, a pump helps extract the gas to
the surface. The most common form of these pumps has a long rod attached to a
deep piston well. The rod is pushed upwards and downwards, causing a difference
in pressure, in which the gas fills. This eventually causes the gas to reach
the surface. This gas usually contains some dirt and other impurities, which
are filtered. After it has been filtered, the gas may be sent to a compression
machine and transported via pipelines.
Sometimes,
the gas may contain gas impurities such as butane or propane that are filtered
and sold separately. This is done by bubbling the raw gas in a closed tower
containing a cold absorption oil, which condenses the other unneeded gases and
traps them. This absorption oil is then distilled and separated into individual
components and sold. At this point, the purified gas is injected with a
strong-smelling odour, which allows it to be easily identified in case of a
leak. The gas is then transported through pipelines.
Applications
Natural
gas can be used at home as well as in industry. It can be used to produce
electricity by burning the natural gas, which helps spin turbine generators to
produce electricity. In some cars, CNG can be used as a substitute for petrol.
It
can also be used for heating as it is more effective than electric heating
pumps. The heat from natural gas is delivered from forced-air systems at
temperatures between 50 and 60°C. The air from an electric heating pump is
typically delivered at 30 to 35°C, which is warm enough to heat a room, but
much cooler than the average human temperature of 36 to 37°C. CNG can also be
used for cooking at home and heating water.
Advantages
Natural
gas is a cleaner fuel as compared to other fossil fuels, which are detrimental
to the planet.
It
is cheaper and safer to use. It is also extremely abundant.
Nine
out of 10 chefs prefer to cook on natural gas stoves as they have even heat
distribution and accurate temperature control, helping food cook more evenly.
Disadvantages
Natural
gas is highly combustible, which means it could be potentially dangerous.
However, a strong odour is added to it, which helps detects leaks.
It
is extremely difficult to mine.
Even
though natural gas is easier to store and transport, it has one significant
disadvantage. Its volume happens to be four times that of petrol, which makes
it more expensive to store since more needs to be spent on additional storage.
