Light Naphtha Isomerization Technology

The Isomalk℠ technologies are based on the use of mixed metal oxide (non-chlorinated) catalysts that operate at low-temperatures allowing refiners to enjoy the high conversions to the key iso-components, while maintaining prolonged catalyst service lifetimes, simple operation and resistance to process impurities. This includes Isomalk-2℠ for C5-C6 isomerization, Isomalk-3℠ for C4 isomerization and isomalk-4℠—a unique offer for C7 paraffins isomerization.

Isomalk-2 is a low-temperature isomerization technology that has been applied in grass-roots applications, revamps of semi-regenerative reforming units, and replacement of other isomerization technologies. This flexible process utilizes a robust platinum-containing mixed metal oxide SI-2™ catalyst that works effectively at the low temperatures of 120-140°C (250-285°F), while delivering great stability against the influence of catalytic poisons. Isomalk-2 is a competitive alternative to the three most commonly used light gasoline isomerization processes: zeolite, chlorinated aluminum oxide and sulfated zirconium oxide catalysts, applicable to a simple replacement of these catalyst types. This technology has been commercialized in all possible modes of configuration. By applying the full recycle configuration, an isomerate with a 92.5 RON value has been achieved in a world-scale reference unit.

Isomalk-3 is a low-temperature C4 isomerization technology based on a use a mixed metal oxide SI-3™ catalyst with high selectivity to i-butane. Operating at the temperature of 150-170°C—the yield and OPEX are optimized. Isomalk-3 has a catalyst lifetime of over 10 years with no need for chlorine injection, off-gas caustic scrubbing or feed dryers. The water, sulfur and nitrogen specs for the feed are significantly relaxed. As with the other catalysts from the Isomalk family, operation is simple and robust; start-up, turn-around and shutdown time is minimal due to the high resistance to catalytic poisons.

Isomalk-4 is a low-temperature isomerization technology for processing C7 paraffins that are contained in wide range naphtha streams. In a conventional refinery set-up, C7 paraffins are sent to the C5-C6 isomerization unit and the reformer. For both of these units, the lighter fraction of P7s is an X-factor type feed that reduces the overall yield of the liquid products; the RON of the gasoline; and forms unwanted amounts of benzene. GTC’s innovative process allows the isomerization of this fraction to achieve a low-RVP gasoline component with 84-86 RON, along with improving the operation of the other naphtha processing units. By applying Isomalk-4 technology, the wide range naphtha can yield over 90 wt% of a 95-98 RON blending component with benzene content <0.6 vol.%—thus meeting required gasoline specifications.