Question

How is CNG obtained? What are its main uses?

Answer 1

Hint: To solve this question let us first understand what is CNG. CNG stands for compressed natural gas. As the name suggests, it is made by compression of natural gas and is distributed and stored in strong (usually cylindrical) containers at high pressure.

Complete answer:
Compressed natural gas is an eco-friendly as well as an economical replacement to fuels like petrol and diesel.
It is obtained by compressing a gas, mainly methane ($C{H}_4$), to less than 1% of its original volume i.e., the volume occupied by it at STP (standard atmospheric pressure).
Natural gas is obtained from underground deposits by drilling holes in rocks.
Let us look at the uses of CNG (compressed natural gas)
1. Motor vehicles
A vehicle can be converted into a dual fuel engine such that it can utilize both CNG through a cylinder and other fuels like petrol or diesel to operate.
The cost of CNG is about half of that of petrol. It also emits about 90% fewer emissions than petrol.
2. Locomotives
Several locomotives operate on CNG. Usually, the CNG locomotives are the ones that have been converted from diesel-electric locomotives to use CNG as a generator instead of diesel to generate electricity.
CNG engines give a higher fuel efficiency than diesel engines as they can be fired selectively when there is a need for power.
3. Natural gas transport
Natural gas can be transported for immediate distances by sea using CNG carrier ships, especially when LNG or pipeline infrastructure is not available.

Note:
It should be noted that while CNG has advantages like cost-effectiveness, more efficiency, and lower pollution, it also has disadvantages like it takes up greater space to store and use and that its leakage i.e., leakage of unburned methane contributes to climate change and global warming.