Fuel is the element from which energy is extracted so that an engine can run. Fuel in the broad sense of the word is a substance that can release energy during certain processes, which can be used for technical purposes. The chemical fuel releases energy during exothermic chemical reactions during combustion.
The definition of fuel is very broad and covers many different technologies. For example, we can talk about nuclear fuel to refer to uranium and plutonium that is used in nuclear power plants. However, we will focus especially on the chemical fuels used in heat engines.
Some fuels (eg, homogeneous gunpowder or solid rocket fuels) are capable of self-combustion in the absence of an oxidizing agent. However, most fuels used in domestic and industrial applications require oxygen for combustion.
Where do fuels come from? Fossil fuels
The most common combustible materials are organic fuels, which contain carbon and hydrogen. Fuels are divided according to the state of aggregation of the substance into solids, liquids and gases, and according to the production method, they are divided into natural (coal, oil, gas) and artificial.
Fossil fuels are the main source of energy for modern society. This is related to these global problems of modern civilization such as the depletion of non-renewable energy resources, environmental pollution and global warming.
Where does the fuel concept come from?
The concept of fuel arose from the ability of certain substances to burn, while generating chemical energy. In most cases, combustion is a chemical oxidation reaction, while for other fuels, such as wood or oxidizing gasoline, it is often oxygen from the air. Other substances, such as liquid oxygen, can also be used as oxidizing agents in special devices.
Since many devices use oxygen consumed from ambient air without special efforts (an "invisible" oxidant) as an oxidizing agent, in everyday life there is a mix of concepts and fuel is often (and mistakenly) called fuel.
Thermal engines have the function of converting the heat energy of the fuel into kinetic energy. In the case of electrical generators in electrical energy, but also passing through kinetic energy.
The main fuel indicator is heat capacity.
What are the types of fuels?
There are different types of fuels that can be classified by their thermodynamic state, by their structure, by their origin or by their function.
For its structure we distinguish:
- Solid fuels, where wood, peat, coal and nitrogen compounds stand out.
- Liquid fuels, where oils, alcohols, ethers, emulsions, synthetic fuels and, above all, petroleum-based fuels stand out.
- Gaseous fuels, of which we highlight natural gas, propane, butane, methane and hydrogen.
The fuels used in the thermal engines studied in these sections are derived from petroleum. Among these types of fuels we highlight the following:
- Diesel fuel (diesel), used in diesel engines.
- Dark stove fuel (domestic stove).
- Light heating oil.
- Fuel oil.
- Fuel oil.
- Gasolina (motor Otto)