Fuel
Other times, the heat itself is valued for warmth, cooking, or industrial processes, as well as the illumination that accompanies combustion.
Hydrocarbons and related organic molecules are by far the most common source of fuel used by humans, but other substances, including radioactive metals, are also utilized.
[citation needed] Crude oil was distilled by Persian chemists, with clear descriptions given in Arabic handbooks such as those of Muhammad ibn Zakarīya Rāzi.
[2] He described the process of distilling crude oil/petroleum into kerosene, as well as other hydrocarbon compounds, in his Kitab al-Asrar (Book of Secrets).
Rāzi also gave the first description of a kerosene lamp using crude mineral oil, referring to it as the "naffatah".
[6] Fossil fuels were rapidly adopted during the Industrial Revolution, because they were more concentrated and flexible than traditional energy sources, such as water power.
Coal was the fuel source which enabled the Industrial Revolution, from firing furnaces, to running steam engines.
The use of some solid fuels (e.g. coal) is restricted or prohibited in some urban areas, due to unsafe levels of toxic emissions.
Most liquid fuels in widespread use are derived from the fossilized remains of dead plants and animals by exposure to heat and pressure inside the Earth's crust.
LP gas is a mixture of propane and butane, both of which are easily compressible gases under standard atmospheric conditions.
Commonly used for cooking and space heating, LP gas and compressed propane are seeing increased use in motorized vehicles.
Many fuel gases are composed of hydrocarbons (such as methane or propane), hydrogen, carbon monoxide, or mixtures thereof.
[9] Recently biofuelss have been developed for use in automotive transport (for example bioethanol and biodiesel), but there is widespread public debate about how carbon neutral these fuels are.
[citation needed] Fossil fuels are hydrocarbons, primarily coal and petroleum (liquid petroleum or natural gas), formed from the fossilized remains of ancient plants and animals[10] by exposure to high heat and pressure in the absence of oxygen in the Earth's crust over hundreds of millions of years.
[11] Commonly, the term fossil fuel also includes hydrocarbon-containing natural resources that are not derived entirely from biological sources, such as tar sands.
Fossil fuels contain high percentages of carbon and include coal, petroleum, and natural gas.
[13] This biogenic theory was first introduced by German scholar Georg Agricola in 1556 and later by Mikhail Lomonosov in the 18th century.
[14] Non-fossil sources in 2006 included hydroelectric 6.3%, nuclear 8.5%, and others (geothermal, solar, tidal, wind, wood, waste) amounting to 0.9%.
Fossil fuels are non-renewable resources because they take millions of years to form, and reserves are being depleted much faster than new ones are being made.
[16] Carbon dioxide is one of the greenhouse gases that enhances radiative forcing and contributes to global warming, causing the average surface temperature of the Earth to rise in response, which the vast majority of climate scientists agree will cause major adverse effects.
Additionally, the IEA anticipates a notable increase in liquefied natural gas capacity, enhancing Europe’s energy diversification.
λ is the air-fuel equivalence ratio, and λ=1 means that it is assumed that the fuel and the oxidising agent (oxygen in air) are present in exactly the correct proportions so that they are both fully consumed in the reaction.
However, the materials commonly referred to as nuclear fuels are those that will produce energy without being placed under extreme duress.
Plutonium-238 and some other elements are used to produce small amounts of nuclear energy by radioactive decay in radioisotope thermoelectric generators and other types of atomic batteries.
In stars that undergo nuclear fusion, fuel consists of atomic nuclei that can release energy by the absorption of a proton or neutron.
In most stars the fuel is provided by hydrogen, which can combine to form helium through the proton-proton chain reaction or by the CNO cycle.
In attempts by humans, fusion is only carried out with hydrogen (2H (deuterium) or 3H (tritium)) to form helium-4 as this reaction gives out the most net energy.
