C7-fraction Isomerization Isomalk-4

Introduction of strict requirements to the quality of motor gasoline in Russia required inclusion of C5-C6-fractions isomerization units into processing scheme at every refinery.

Over the last 10 years 17 new isomerization units have been put into operation at Russian refineries, the same number of the units is currently at different stages of design and construction.

However, not all of the refineries’ problems have been solved with the inclusion of C5-C6-fractions isomerization units into processing scheme.

The main problems are the following:

  • high content of benzene and aromatic hydrocarbons in the basic autocomponent – reformate;
  • low share of high-octane non-aromatic autocomponents in the total gasoline pool;
  • octane number of the total naphtha pool is not high enough.

On completion of research, carried out in SIE Neftehim, LLC, it has been concluded that production efficiency of high-octane motor gasoline according to EURO-4 and EURO-5 standards considerably increases with recovery of C7-fraction (70-105°C) and directing it not to reforming, but to the isomerization unit (Also refer to: IBP-180°C fraction combined processing)

C7-fraction isomerization technology developed by SIE Neftehim, LLC is named Isomalk-4. This technology has passed experimental and pilot testing and has no analogues in the world.

The unique SI-4 catalyst, which provides proceeding selective process of heptanes isomerization at temperatures of 160-200 °C, is put in basis of the Isomalk-4 technology. The catalyst doesn't require supply of additional reagents and possesses high stability and catalytic poisons resistance.


SI-4 catalyst specifications

Isomalk-4 technology for heptane fraction (70-105°С fraction) isomerization has equipment similar to the traditional scheme of Isomalk-2. The low-branched heptanes recycle scheme allows producing isomerate with 83-85 RON. 

Isomalk-4 heptane fraction isomerization technology doesn’t require special licensed equipment, special feed pre-treatment solutions (feed pre-treatment is carried out in standard hydrotreatment section) and can be implemented by both grass root and revamping of existing facilities of semi-regenerative reforming / isomerization.


Requirements for Isomalk-4 process feed:

Light gasoline fractions isomerization