How is kerosene made

Kerosene

Lexicon> letter K> kerosene

Definition: a petroleum-based fuel that is used extensively, especially in aviation

Alternative terms: aviation fuel, aviation turbine fuel, aviation turbine fuel, jet fuel, light petroleum, luminous oil

More general terms: fossil fuels, fuel

English: jet fuel

Category: Energy sources

Author: Dr. Rüdiger Paschotta

How to quote; suggest additional literature

Original creation: 03/15/2010; last change: 10/17/2020

URL: https://www.energie-lexikon.info/kerosin.html

Kerosene (also Aviation fuel, Aviation turbine fuel, Aviation turbine fuel) is a liquid fuel, which is mainly used for aircraft engines, also in helicopters, often also for gas turbines and less often in specially designed diesel engines. The vast majority is consumed in air traffic.

Properties of kerosene

Kerosene mainly consists of hydrocarbons (alkanes, cycloalkanes, aromatics and olefins). It is chemically similar to diesel fuel, but contains more and more slightly lighter molecules and accordingly has a slightly lower density (approx. 0.8 kg / l). As with other fuels, there are a number of different variants of kerosene (see below).

Compared to diesel fuel or gasoline, kerosene has a more uniform composition, which manifests itself in a rather flat boiling curve: a large part of the components boils in a relatively narrow temperature range. This also has the effect that on the one hand a premature ignition of light components in an engine is avoided and on the other hand heavy components are largely missing, which burn incompletely and could lead to deposits in the engine.

The calorific value of kerosene is around 43 MJ / kg and can vary slightly depending on the type.

The quality requirements for kerosene as an aircraft fuel (e.g. Jet-A1 for civil aircraft) are very high due to its relevance to the safety of air traffic and include a long list of properties. However, this does not include ignitability (cetane number), which is not relevant when used in jet engines, but when used as a substitute for diesel fuel in some aircraft engines.

When kerosene is burned, mainly carbon dioxide (CO2) and water vapor. Substances such as sulfur dioxide are produced in smaller quantities from the sulfur content of kerosene and nitrogen oxides.

Varieties of kerosene

There are a number of different variants of kerosene, the specifications of which are tailored to specific typical applications, the most important of which are listed below:

  • Most civil aviation uses kerosene with the specification Jet-A1 (with jet = jet in a jet engine). Jet A is only still very common in the USA. Jet B, which has a lower freezing point, is sometimes used for flights in extremely cold regions. However, the engines must be specially suitable for this.
  • For military aircraft there are various types such as JP-4, JP-5 and JP-8; here “JT” stands for “jet propellant” (aircraft fuel). Various other types such as JP-1 or JP-6 are no longer used, and certain types have been specially developed for certain aircraft models - for example for spy aircraft that have to fly at very high altitudes.

The specifications for such grades contain a whole range of different properties such as freezing point, flash point, boiling range, sulfur content and shelf life as well as influences on the corrosion of metal parts.

Production of kerosene

Kerosene is obtained in petroleum refineries, essentially through fractional distillation (using a narrow fraction of the middle distillate), desulfurization and the addition of additives. These additives are tailored for use in turbines and are therefore different from z. B. in diesel fuel. They influence a number of properties such as the tendency to oxidize during storage, the development of static electrical charges, and corrosive effects on metals.

Because it is made from petroleum, kerosene is a fossil fuel. The carbon dioxide produced during its combustion contributes to global warming. An even greater climate-damaging effect results from the water vapor produced when the exhaust gases are emitted at high altitudes, with the formation of contrails. The effect of contrails does not last long, but it makes up a large part of the climate-damaging effects of current air traffic.

In the future, kerosene could partly be replaced by certain biofuels (Biokerosene) or electricity-based synthetic fuels can be replaced. It would have to be drop-in fuels, which means that no changes to the aircraft engines would be necessary. A wide variety of technologies for this are currently being developed. For example, one possibility would be the hydrogenation of vegetable oils, also the Fischer-Tropsch synthesis with synthesis gas from biomass gasification or obtained through power to gas (e.g. with sun-to-liquid technology).

In principle, synthetic kerosene can produce CO2-Be neutral, but mostly not climate-neutral.

In theory, such drop-in fuels can produce completely CO2-neutral, with no more CO during combustion2 (Carbon dioxide) is created when it was bound during manufacture. However, climate-neutral flying would still not be possible, as the climate-damaging effects of the exhaust gases are only partly caused by carbon dioxide. In particular, the formation of contrails during flights at high altitudes is a major problem that cannot be solved with synthetic kerosene.

Another problem is the production costs, which for the foreseeable future will be much higher than those of petroleum-based kerosene. It is therefore not to be expected that electricity-based kerosene, for example, will be able to replace conventional kerosene on a large scale in the near future, although one could theoretically convince of this (e.g. in sunny locations that enable high yields from photovoltaics).

Taxes

Kerosene, in particular, used in commercial aircraft has so far not been subject to taxation in most countries. This preference, for example over diesel fuels and gasoline, represents an originally politically desired promotion of air traffic. However, it is increasingly controversial, since global air traffic specifically has higher and rapidly increasing CO2-Emissions that clearly run counter to efforts to protect the climate. Efforts for internationally coordinated kerosene taxation are under way, but not very far advanced. As a rule, there is no taxation, especially on intercontinental flights that consume a lot of kerosene.

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See also: fuel, fuel, jet engine, gas turbine
as well as other articles in the energy source category