The Isomerization Process
What it does:
Converts straight-chain hydrocarbons into branched-chain isomers, which have higher octane ratings and better anti-knock properties.
Specifically used to improve the quality of gasoline by increasing its octane number.
Key steps:
Feedstock preparation: Light naphtha, a gasoline blending component, is preheated and mixed with hydrogen gas.
Reactor:
The mixture enters a reactor containing a catalyst, typically a platinum-based one or zeolite.
Under moderate temperatures (around 200-300°C) and moderate pressures (around 20-40 bar), the catalyst promotes the rearrangement of carbon atoms within the straight-chain molecules, forming branched-chain isomers.
Separation:
The product stream leaving the reactor is cooled and sent to distillation columns:
Unreacted straight-chain hydrocarbons are separated and recycled back to the process.
The isomerized product, with a higher octane number, is blended into the final gasoline pool.
Benefits of Isomerization:
Improves the octane rating of gasoline, leading to better engine performance and reduced emissions.
Enables the use of lower-octane components in gasoline blending, optimizing refinery operations.
Relatively energy-efficient process compared to some other octane-boosting methods.
Additional points:
Isomerization is a crucial process in modern refineries for producing high-quality gasoline with desired anti-knock properties.
Different types of isomerization processes exist, with variations in catalyst types and operating conditions.
The process can be tailored to target specific isomers based on desired product properties.
Here are some resources for further exploration:
Isomerization process: https://www.sulzer.com/en/shared/applications/refining-isomerization-unit
What is Isomerization?: https://ektinteractive.com/what-is-isomerization/