Petrol vs Diesel
Most of us are aware of petrol and diesel as commonly used fuels in our automobiles. However, many are not aware of the differences between the two though their price difference and the mileage that these two different petroleum products give are all too well known. This article aims to highlight the difference between petrol and diesel to enable people to go for a fuel that suits their requirements.
Both petrol (also called gasoline in western world) and diesel are by products derived from crude oil that is pumped out of oil rigs. This crude oil, which is black in color, contains various hydrocarbons that differ in composition. Simple hydrocarbons, such as CH4, C2H6, C3H8, and C4H10 are all light gases that are easily collected and used as solvents in paints and also used for dry cleaning purposes. Higher hydrocarbons from C5 to C12 are heavier and have longer chains. These are liquids at room temperature and collected through distillation of crude oil. Petrol mainly consists of hydrocarbons C5 to C12 that are blended together to make an inflammable liquid used as fuel in cars. A typical petrol mixture contains paraffins, napthenes, aromatics and olefins. Diesel on the other hand is composed of about 75% saturated hydrocarbons and 25% aromatic hydrocarbons. Both petrol and diesel are obtained from crude oil at different temperatures. While petrol is separated at a temperature range of 35 degrees to 200 degrees, diesel gets separated in the range of 250-350 degree centigrade.
Diesel contains hydrocarbons with longer carbon chains than petrol and is thus less volatile. This is also because of the additives present in diesel. As far as energy content is concerned, petrol contains about 34.6 megajoules per liter while diesel contains about 38.6 megajoules per liter. This means diesel has a higher power than petrol and this is precisely why it is used in heavy vehicles that require more power. Diesel is also more fuel efficient giving out a mileage that is nearly 50% more than petrol. This explains the desire of the people to go for diesel engines.
In some countries like India, diesel prices are subsidized as it is mostly used for transportation. This makes it cheaper than petrol. But in the western world, it is priced at par with petrol but still people prefer it over petrol as it gives more mileage than petrol.
• Both diesel and petrol are by products of crude oil
• While petrol is made up of lighter hydrocarbons (C5 to C12), diesel contains higher hydrocarbons thus making it less inflammable and volatile than petrol
• Diesel has higher energy coefficient than petrol which is why it is used in heavy vehicles for transportation
• Diesel also gives more mileage than petrol