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C7-fraction Isomerization Isomalk-4

In the world production there is a constant tendency to toughening the operational and environmental specifications of motor gasoline. International standards for gasolines significantly limit the content of benzene, aromatic hydrocarbons, olefin hydrocarbons, and sulfur. Incorporation of the isomerization process into the processing configuration is one of the most cost-effective ways to produce high-octane gasoline with high environmental properties in accordance with EN 228.

Over the past 10 years, 18 new C5-C6 isomerization units have been put into operation in Russia, as many are at different stages of design and construction. However, not all refinery problems are solved by this construction.

The main refinery problems are as follows:

  • High share of benzene and aromatics in the basic autocomponent – reformate;
  • Low share of high-octane non-aromatic autocomponents in the total gasoline pool;
  • The octane number of the total naphtha pool is not high enough.

SIE Neftehim, LLC conducted extensive study of feed and production basis on a number of refineries. Based on the result of the study, it has been concluded that the production efficiency of K5 (Euro-5) high-octane gasoline can be significantly increased if С7-fraction (70-105°С) is recovered from straight run gasoline and fed to С7-fraction isomerization unit.

Comparative evaluation of different options for directing 70-105°С fraction for processing within motor gasoline production is presented in Table 1.

Table 1. Comparative evaluation of different options for directing 70-105°С fraction for processing

Note: Hydrotreated straight run IBP-180°С with typical composition is assumed as 100% feed, in case of feed change, the specifications for all the options will be different.

As a result of many years of research and experiments, SIE Neftehim, LLC developed a catalyst and technology that allow producing a high-octane product (isomerate) from the low-octane C7 fraction (70-105° C fractions). The developed isomerization technology was named Isomalk-4. This technology has passed the experimental and pilot testing and has no world analogues. In 2017, the C7-fraction isomerization technology Isomalk-4 was given the status of the National Project.

Isomalk-4 technology is based on a unique catalyst SI-4, which ensures performance of selective heptane isomerization process at 160-200°С. The catalyst does not require injection of additional reagents and has high stability and tolerance to catalytic poisons.

Hardware implementation of heptane fraction (70-105°С fraction) isomerization technology Isomalk-4 is close to that of Isomalk-2 conventional design. Configuration with unbranched heptanes’ recycle makes it possible to produce 83-85 RON isomerate.

Heptane fraction isomerization technology Isomalk-4 requires neither application of specific licensed equipment, nor any special solutions for feed pre-treatment (feed is pre-treated in a typical hydrotreatment section), so it may be implemented both as a grass root, and revamp of existing semi-regenerative reforming/isomerization facilities.    

Construction of the first Isomalk-4 unit in Russia is scheduled by 2020.

 SIE Neftehim, LLC guarantees the following:

  • high quality of catalyst and rendered services;
  • provision of complete technical documentation on catalyst loading, activation, start-up, normal operation, shutdown, regeneration and unloading; recommendations on analytical control of the process;
  • rendering technical assistance and consultations during catalyst loading to reactor, initial unit start-up, as well as during scheduled shutdowns for maintenance and catalyst regeneration, directly on the unit site;
  • monitoring and prompt consultations on all the raised issues within the entire operation life of the catalyst.