Throughout most of human history fuels derived from plants or animal fat were only used by humans. 6,000 BCE for melting metals. European forests started to become depleted around the 18th century. Coal was first used as a fuel coke oven battery heating process pdf 1000 BCE in China.
United Kingdom in 1769, coal came into more common use as a power source. Fossil fuels were rapidly adopted during the Industrial Revolution, because they were more concentrated and flexible than traditional energy sources, such as water power. They have become a pivotal part of our contemporary society, with most countries in the world burning fossil fuels in order to produce power. Most of the chemical energy released in combustion was not stored in the chemical bonds of the fuel, but in the weak double bond of molecular oxygen. Chemical fuels are divided in two ways. First, by their physical properties, as a solid, liquid or gas. The use of other solid fuels as wood is decreasing as heating technology and the availability of good quality fuel improves.
They are also used to start a coal fire. It is the fumes of liquid fuels that are flammable instead of the fluid. Many liquid fuels play a primary role in transportation and the economy. Some common properties of liquid fuels are that they are easy to transport, and that can be handled easily. Also they are relatively easy to use for all engineering applications, and home use.