Based on the laboratory and pilot-scale findings, detailed process simulations were developed using a commercial simulation package. The simulation model was rigorously validated against experimental and operating data to mitigate scale-up uncertainties. Outcomes from the validated simulation were used to formulate and substantiate catalyst performance guarantees for commercial deployment. The comparison of the IV-IZOMax CAT with competing technology based on Pt/chlorinated alumina catalyst is shown in Table 2 . Implementation at Bongaigaon Refinery The BGR light naphtha ISOM unit, licensed by IndianOil R&D in collaboration with Engineers India Limited (EIL) in 2011, was originally designed for the production of BS-III and BS-IV grade motor spirit, including benzene saturation. The unit had been operating continuously with a Pt-zeolite catalyst since commissioning, which was due for replacement in 2024. Following successful feasibility studies using BGR naphtha feed, it was decided to replace
Contaminants limits for IV-IZOMax CAT
Parameter specification Total sulphur in naphtha feed Total nitrogen in naphtha feed Moisture in naphtha feed Heavy metals in naphtha feed Benzene + toluene in naphtha feed C₇ + hydrocarbons in naphtha feed
Maximum limit
5 ppmw
0.5 ppmw
5 ppmw 1 ppbw
6 wt%
10 wt%
Hydrogen purity
70-80 vol%
Moisture in hydrogen
2 ppmv
Chloride content in hydrogen
0.5 ppmv 20 ppmv
CO + CO₂ in hydrogen
Table 1
moisture, CO/CO₂, and sulphur species to assess both reversible and irreversible impacts of contaminants on the catalytic activity. Notably, the catalyst demonstrated substantially greater tolerance to feed contaminants than conventional platinum-on-chlorinated alumina catalysts. The contaminant tolerance limits of IV-IZOMax CAT are summarised in Table 1 .
Distinct innovative features of IV-IZOMax CAT compared with other genre catalyst
Competing technology based on Pt/chlorinated alumina catalyst
IV-IZOMax CAT based on Pt/MMO catalyst
Sensitivity to feed contaminants
Very sensitive
Sensitive
Tolerable limit, ppm (max) Sulphur
0.1 0.5 0.1
<0.5
Moisture
<2
Basic nitrogen
<0.5
Feed hydrotreatment
Mandatory Mandatory
Mandatory
Feed drying
Partially required
Increase in feed impurity level
Catalyst gets permanently deactivated and is to be replaced with fresh charge
Catalyst activity can be recoverable up to certain impurities level
due to process upsets
Continuous chloride injection for maintaining catalyst activity In situ catalyst regeneration
Mandatory
Not required
No
Yes
Start-up
Acidisation is required for every start-up due to extreme moisture sensitivity of the catalyst. Start-up usually takes a long time to bring the moisture level down to the allowable range Usually, a caustic scrubber for effluent gases and associated facilities are required
Start-up is much easier and faster due to higher moisture tolerance
Effluent treatment section
Not required
Table 2
Refining India
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