Chemical Composition Of Liquid Fuel

The main chemical components in petroleum products are hydrocarbons, and there are four main categories:
1. Alkanes
The general molecular formula is CnH2n+2, and C5~C15 are the main components of liquid fuel. Alkanes, also known as paraffinic hydrocarbons, can be divided into normal alkanes (straight chain structure) and isoalkanes (side chain structure) starting from C5. Generally speaking, alkanes have a high hydrogen/carbon ratio, low density (light), high calorific value by weight, and good thermal stability. The combustion of alkanes usually has no exhaust smoke and carbon deposits.
2. Olefin
The molecular formula is CnH2n. Alkenes are unsaturated hydrocarbons, and their molecular structure contains less hydrogen than the maximum possible, so they are chemically active and easily react with many compounds, and their chemical stability and thermal stability are worse than alkanes. Under high temperature and catalysis, it is easily converted into aromatic hydrocarbons. Generally, there are not many olefins in crude oil, and olefins are usually produced by the cracking process. The petroleum products obtained by the direct fractionation method do not contain much olefins, and the oil obtained by the cracking method can contain as many as 25% olefins.
3. Cycloalkanes
It is a ring structure, containing one or more ring structures of 6 carbon atoms. Although structurally they appear to be somewhat similar to naphthenes, they contain less hydrogen and thus have a much lower calorific value per unit weight. Other major disadvantages are the high propensity to smoke and carbon deposits, and the high hygroscopicity, which can lead to the deposition of ice crystals when the fuel is at a low temperature.
4. Aromatic hydrocarbons
Aromatic hydrocarbons have a strong solubility for rubber products. The general formula of monocyclic aromatic hydrocarbons is CnH2n+5, and more complex aromatic hydrocarbons can have one hydrogen atom in the above molecular structure replaced by other groups.