Isomalk-2 new complexes design, construction and commissioning experience



L-35-5/300 reforming unit conversion to Isomalk-2 isomerization process

The unit in JSC Ufaneftekhim is the first commercial unit where Isomalk-2 technology for C5-C6 fractions isomerization process was introduced. The unit was started up in October 2003. Initially L-35-5 reforming unit was converted for isomerization process according to “once-through" scheme with pre-hydrotreatment at L-24/300-1 unit. Given the high space velocity (3.5-4.0 h-1), this unit produced isomerate with 79-80 RON in the amount of 300 KTA. Conversion included re-piping of isomerization feed furnace; “quench” line installation, addition of recycle hydrogen gas drying section with NaA type adsorbent (consists of two drying adsorbers and furnace for adsorbent regeneration), SI-2 catalyst loading into 2 reactors.

In June 2008, the unit was revamped to increase feed capacity and convert to scheme with unconverted hexanes recycle.

In August 2011, SI-2 catalyst was regenerated and additional quantity of fresh catalyst (6.5 tons) was loaded to reactor R-3.

In December 2012, the unit was revamped, including additional equipping with deisopentanization section for recovery of isopentane fraction (overhead product) and pentane fraction (side cut) as well as construction of new furnace P-1 with one pass heating upstream of reactor R-1.

2012 revamp allowed increasing the unit product octane number up to 90-91 RON with space velocity of 2.4-2.8 h-1 and enhancing the throughput up to 500 KTA.

References for unit operation


The unit conversion from SI-1 zeolite catalyst to SI-2 oxide catalyst

In 1999, JSC Ryazan Oil Refining Company started up the first isomerization unit according to the Russian technology called Isomalk-1. “Detol” isomerization unit was operated over SI-1 zeolite catalyst.

In August 2005, the unit was converted to Isomalk-2 technology over SI-2 oxide catalyst. The revamp involved replacement of zeolite catalyst with low-temperature oxide catalyst SI-2, implementation of scheme of make-up hydrogen gas supply through a dryer, “quench” line installation, re-piping of the dryer from compressors discharge to suction, and construction of new hydrotreatment section for feed pre-hydrotreating.

The conversion of isomerization unit to SI-2 catalyst allowed decreasing the process temperature to 130-140 °С and increasing “once-through” isomerate octane number up to 83 RON that is 6 numbers higher than zeolite catalyst performances.

First catalyst regeneration was performed in 2009. The subsequent regeneration was performed in 2017. Thus, the service cycle was 4 and 8 years. Currently, the unit is not being operated due to the start-up of the new complex Isomalk-2 at this refinery. The unit operated over SI-2 catalyst for more than 12 years, providing high performances.

  References for unit operation over SI-2 catalyst.


Conversion of L-35-11/300 reforming unit to Isomalk-2 technology according to “once-through” scheme

In 2005, L-35 -11/300 reforming unit that had been operated earlier according to isoselectoforming technology was converted to “once-through” low-temperature isomerization process using SI-2 oxide catalyst. Unit revamp included P-1 furnace and reactors re-piping; additional equipping of operating P-1 furnace sections with pilot burners, having flame alarms; hydrogen gas supply line installation to reactors inlet; additional cooler installation on hydrogen gas supply line to reactors; stripper reflux drum replacement, and re-piping of drying adsorbers. The unit feed capacity was 500 KTA. The produced isomerate RON was 83-84.

In 2008, the unit was revamped that involved regeneration of KGM-70 hydrotreating catalyst and equipment replacement in hydrotreatment section because of physical depreciation.

In 2012, the unit turnaround was performed without SI-2 catalyst regeneration.

Due to the commissioning of the new isomerization unit with higher capacity, this unit was shut down. Total service time of SI-2 catalyst at this unit was more than 12 years.

The conversion of isomerization unit to SI-2 catalyst allowed increasing the isomerate octane number by 7-8 numbers that significantly enhanced operating efficiency of KINEF, LTD. and made it possible to start producing gasolines of high ecological class. During 12 years of operation, the catalyst was not regenerated, whereas isomerate octane number at the end of 12-year run was 82 RON.

 References for unit operation.


Unit conversion from LPI-100 catalyst to SI-2 catalyst

In December 2006, pentane-hexane fractions isomerization unit that had been operated earlier over LPI-100 catalyst according to Par-Isom technology was reloaded to SI-2 catalyst without revamp. The catalyst was replaced in two reactors. The unit is being operated according to Isomalk-2 technology with feed deisopentanization and low-branched hexanes recycle. The unit capacity is 180 KTA. RON of isopenatane fraction is 93, RON of isomerate is 86-87.

The unit conversion to Isomalk-2 technology allowed increasing the octane number of isocomponents mixed fraction by 3-4 RON and proved high activity of SI-2 catalyst as compared with analogous oxide catalysts.

In February 2013, the unit was shut down for turnaround with isomerization reactors replacement, therefore the catalyst was regenerated. The time period from the start-up to the first regeneration was 6 years and 2 months.

At the present time, the unit is still in operation.

Reference for unit operation.


Isomerization unit conversion from zeolite catalyst to SI-2 catalyst

Isomerization unit at Novo-Ufimsky Refinery represents section 300 of L-35-11-1000 unit, converted to isomerization process in 1997. Initially the unit was started up according to “once-through” scheme, and isomerization process was performed over zeolite catalyst. Hydrotreatment was performed in section 100 (feed treatment section of L-35-11-1000 unit). At the first stage, the revamp was limited to re-piping and reloading the reactor section. Subsequently, the unit was additionally equipped with deisohexanization column.

In February 2009, the isomerization unit was converted to Isomalk-2 with low-branched hexanes recycle (DIH). The revamp included replacement of zeolite catalyst with low-temperature oxide catalyst SI-2, addition of recycle H2 gas drying section to the scheme, installation of reactor section emergency purge scheme, and replacement of isomerization reactors internals.

In November 2012, the revamp was performed that involved internals replacement in hydrotreating section stripper, isomerization and reforming feed treatment column, as well as deisopentanization (DIP) section installation at absorbing gas fractionating unit AGFU-1.

The unit conversion to SI-2 catalyst allowed achieving the isomerate octane number of 87-88 RON, which is 7-8 numbers higher than that of zeolite catalyst.

References for unit operation

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