Gasoline is gas/petrol, the chemistry of gasoline, the use of gasoline in engines
what is gasoline/petrol
Gasoline is a refined fuel obtained from petroleum/crude oil. Gasoline is also known as petrol. Gasoline is used in internal combustion engines. Gasoline is a transparently flammable liquid so it is used as a primary fuel in most spark-ignited combustion engines as automobiles. Also used as a solvent for fats and oils. Gasoline consists of mostly organic compounds obtained by fractional distillation of petroleum/crude oil. Petroleum refineries/industries apply various processes to get high-performing gasoline as
- Crude oil distillation
- Catalytic reforming
- Fluid catalytic reforming FFC
- Thermal cracking
- Hydrocracking
- Alkylation
- Isomerization and catalytic polymerization
Thermal cracking was designed to raise the yield of gasoline after distillation. But the thermal cracking was replaced by catalytic cracking. This way the catalysts are used that can speed up the chemical reactions yielding more gasoline.
Other processes such as polymerization, alkylation, reforming, and isomerization are used to improve the quality of gasoline.
This way different grades of gasoline can be obtained by applying these refining processes.
Mostly the refineries produce gasoline blendstocks also known as unfinished motor fuel. It requires blending with other liquids to make motor gasoline also known as finished motor gasoline. It is suitable for use in spark engines. Some companies also use detergents and additives blended into gasoline for finished gasoline.
U.S petroleum refineries produce finished motor gasoline. But this finished motor gasoline mostly produced at blending terminals, where gasoline blendstocks, finished motor gasoline, and fuel ethanol are mixed to sell the final finished product for consumer use. So these days the blending terminals are more popular than the refineries. These terminals have equipment for filling tankers that can supply the finished motor gasoline to the retail outlets.
On the basis of type standards of crude oil, separating techniques of petroleum fractions in petroleum refineries, and blending with other liquids and additives the finished motor fuel has three main grades.
- Regular ( the lowest octane fuel-generally 87)
- Midgrade ( the middle range octane fuel generally-89-90 )
- Premium (the highest octane fuel-generally 91-94 )
chemistry of gasoline/petrol
Gasoline is a mixture of 100 types of complex hydrocarbons. These hydrocarbons may be branched, straight-chain, saturated, or unsaturated hydrocarbon. Most of the hydrocarbons are saturated containing 4-12 carbon atoms per molecule. Additives like tetraethyl lead and other lead compounds, and oxygen containing compounds ethanol ,METB,ETBE are also added to enhance the combustion of gasoline.
But formulation of gasoline may differ depending on location and season where it is sold. It means gasoline is not a homogeneous worldwide. Some countries prefer to the high quality gasoline to overcome air pollution caused by unburned hydrocarbons.
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