Physics and Technology – Technology – Fossil Fuels: Coal, Oil, and Natural Gas
Fossil fuels provide the bulk of the energy that powers the industrialized and developing world. As demand for fossil fuels increases, the technical undertakings needed to satisfy it must be constantly adapted.
Oil is the most important fuel, heat source, and raw material in the chemical industry, but before it can be efficiently utilized, it must be refined. Refineries first remove sulfur from the oil. The resulting oil is then separated through distillation into its lighter and heavier components: gasoline, diesel, heating oil, and tar. To improve engine performance and reduce wear, various substances are added to gasoline. Coal, on the other hand, often needs only a mechanical cleaning before it can be used.
With so-called “cracking” techniques, it is also possible to produce liquid fuel from coal, for instance, to power vehicles. However, this process is technically complex and not yet cost-effective. Natural gas contains 85-98 percent methane, along with other hydrocarbons, carbon dioxide, and sometimes helium. For easier transport and for use as a fuel, it is compressed and partly liquefied.
The heat produced during this compression process can be used for many purposes, including to heat homes or swimming pools.
Chemical energy stored in gasoline and other fuel is released and used in a multitude of ways. Many power plants produce energy using combustion engines. The fuel’s energy is converted to heat, which turns water into steam, which then exerts pressure to turn a turbine. The turbine drives a generator to produce electricity through the principle of induction. Thus, the energy from coal, oil, or natural gas must undergo numerous transformations before it can be used in the form of electricity.
During electricity production, excess heat is also given off, which can be transferred to other locations, for example, to heat buildings. This process of power-heat coupling, or cogeneration, makes better use of the same amount of fuel. Increased efficiency is important as combustion releases large amounts of CO2 into the atmosphere, a major contributor to the greenhouse effect.
EXTRACTION OF OIL AND NATURAL GAS
Tens of thousands of production facilities worldwide tap the Earth’s reserves of oil and natural gas on land and at sea. Producing countries estimate their combined reserves at approximately 1.2 billion barrels of oil (160 billion tons) Based on this figure the supply should last for another 40 to 50 years. Oil fields lying deep under the surface of the Earth or the sea are mined using pipes equipped with diamond-tipped drill heads.
At first, the pressure exerted on the deposits from the Earth is often enough to bring the oil to the surface. Later, pumps or injections of natural gas or water may be needed, followed by complicated special procedures as the reserve is depleted. Even with the latest technology, an oil field cannot be fully exploited: about 20-40 percent of the oil remains in the ground.
Tanker ships or pipe-lines transport the oil and natural gas to refineries that process the materials to produce usable substances.