The crude oil, which has been heated in Separation Process, will be continued processing to Conversion stage. Basically, Conversion stage will transform size and structure of hydrocarbon molecule. There will be three main processes in Conversion stage, consist of cracking, reforming, and allkylation


Cracking is the process where the bigger hydrocarbon molecule will be transformed to be smaller hydrocarbon molecule. This process has a main purpose to fix the gasoline quality and gasoline fraction result.

There are three methods for cracking :

  • Thermal cracking : Using high temperature and low pressure
  • Catalytic Cracking : Using catalyst
  • Hydro Cracking : Combination between cracking and hydrogenation. Yield Saturated compound.


Reforming or Isomerization is the process to tranform straight carbon chain (has bad quality) become diverged carbon chain (has good quality)

There are two methods for Reforming :

  • Catalytic reforming : Using Platinum Catalyst to boost octane number from naphta
  • Thermal Reforming : using high temperature for Naphta


Allkylation is the addition process to increase number of atom in molecule. The result of this process is the molecule will be longer and diverge.

Strong catalyst are usually used, such as H2SO4, HCl, an AlCl3


Downey, Morgan. 2009. Oil 101. New York. Wooden Table Press LLC

Risdiyanta, ST., MT. Mengenal Kilang Pengolahan Minyak Bumi (Refinery) di Indonesia. Jurnal Pertamina



Please follow and like us: