Octane number and unleaded gasoline
Recently, the term octane number and unleaded gasoline have been widely used in the media, as many people do not know what these words mean, knowing that the majority deal with them daily by visiting gas filling stations spread throughout the world.
In this article, I would like to explain in a simple way, away from scientific complications, what these words mean, to form some simple information and a scientific background for what these terms mean that we see installed daily in gas filling stations.
The quality of gasoline used as fuel for transportation is measured by the octane number. The higher the number, the higher the quality and efficiency of the gasoline, and vice versa. Premium gasoline has a higher octane number than regular gasoline, and this number varies from one country to another.
Some countries consider premium gasoline to have an octane number of 59 and regular 09, and other countries consider premium 79 and regular 09, and so on. In some countries, signs are placed on the pumps or colored in colors indicating the quality of gasoline, which makes it easier for the consumer to go to the appropriate pump for his car’s gasoline.
I will explain here what the octane number means and how to raise it in gasoline. I will go back a little to the process of fuel combustion in a car engine. It is known that gasoline begins to ignite in the combustion chamber (cylinder) by means of the spark that the spark plug gives when the car is running, and in the case of gasoline, that is by increasing the octane number. To get rid of knocking and regulate the operation of the car engine.
After using heptane as fuel, it causes rattling and problems in the car’s engine, but if we use iso-octane, there is no rattling and the engine runs regularly. Therefore, the octane number of zero has been adopted for heptane, and the octane number for iso-octane is equal to one hundred, and this has been adopted as a measure of the octane number.
Therefore, many people believe that gasoline contains lead, and some chemicals are added to remove lead from it, and this belief is wrong.
The truth is that gasoline does not contain lead, but as we mentioned previously, the octane number of gasoline must be raised to prevent knocking, and this matter requires adding chemicals to gasoline to raise the octane number.
In recent years, oil refineries have added a chemical called lead tetraethyl to gasoline to raise the octane number, and from here lead came to gasoline. In the recent period, it has been scientifically proven that lead has significant negative effects on the environment and public health, and this has led to the occurrence of incurable diseases for humans, especially children. It has been proven that the high percentage of lead in the air comes from the combustion of automobile fuel. Therefore, lead compounds were replaced with compounds that are less harmful to public health and more environmentally friendly. Among these materials currently used as an alternative is the compound methyl tert-butyl (MTBE), which is produced by large international companies, including the Saudi Industries Company. Basic (SABIC) and in very large quantities.
Studies and scientific research have recently shown some doubts about the substance (MTBE), as it has been proven that it causes pollution of surface and groundwater when it seeps into it and thus leads to the occurrence of diseases in humans. Therefore, thinking has now begun to replace it with a less harmful substance, and one of the currently proposed substances is phenol (PHNOL). Therefore, some Countries have begun to wait to use MTBE until the final research results appear.