What Is the Octamax Process? How IndianOil Makes 100 RON Petrol in India

What Is the Octamax Process? How IndianOil Makes 100 RON Petrol in India

Most Indian drivers know XP100 as the ethanol-free 100 RON petrol that costs Rs 160 per litre and is available at a handful of IOCL pumps. Fewer know that it exists only because of a proprietary refining technology developed entirely by IndianOil’s own R&D team, and that this technology, called Octamax, earned its inventors the National Technology Award in 2022.

The commercial availability of 100 RON petrol at Indian pumps is not simply a matter of importing premium fuel components or buying a foreign-licensed process. It is the result of Indian refining engineers solving a specific and difficult problem: how to produce ultra-high-octane gasoline in a BS6-compliant refinery without using toxic lead additives and without making the fuel prohibitively expensive.

This article explains what the Octamax process is, what problem it solved, and why it matters to every Indian vehicle owner who has ever wondered why 100 RON petrol costs what it costs.

Table of Contents

The Octane Problem That BS6 Created

Before understanding what Octamax does, it helps to understand the problem it was built to solve.

Petroleum refineries produce petrol by processing crude oil through several conversion units. Fluid Catalytic Cracking (FCC) units crack heavy hydrocarbon molecules into lighter fractions. Catalytic reformers convert low-octane naphtha into high-octane aromatic compounds. Isomerisation units upgrade light naphtha. The gasoline pool, the blended output from all these units, has a natural octane rating that depends on the specific crudes processed and the severity of the refining operations.

When India moved to BS6 emission standards, refineries were required to dramatically reduce the sulphur content of petrol from 50 parts per million (BS4) to 10 parts per million (BS6). Achieving this required deep hydrodesulphurisation of the FCC gasoline stream, the largest single contributor to the gasoline pool. Hydrodesulphurisation removes sulphur by reacting it with hydrogen at elevated temperature and pressure. The process is effective at sulphur removal but has a side effect: it also saturates some of the aromatic and olefinic molecules in the FCC stream that were contributing to octane. The resulting desulphurised FCC gasoline has lower octane than its pre-treatment feedstock.

This is the octane penalty of BS6. Refineries that had been producing 91 RON regular petrol comfortably found that BS6 desulphurisation had tightened their octane headroom. Producing 100 RON petrol, which requires a gasoline pool well above 100 RON to allow for blending losses, became significantly more difficult without either importing premium blending components, using metallic octane boosters (which have their own problems, as covered in the octane boosters article), or developing a new high-octane production process.

IOCL chose the third path.

What the Octamax Process Does

The Octamax process converts C4 hydrocarbon streams into a high-octane gasoline blending component. C4 streams, butanes and butylenes, are generated in significant quantities as byproducts of FCC units and naphtha crackers. In many refineries, these light hydrocarbons are consumed as refinery fuel, blended into LPG, or sold as chemical feedstocks at relatively low value.

Octamax captures these C4 streams and processes them through a proprietary catalytic reaction to produce an ultra-high-octane gasoline blending component. The specific chemistry of the reaction is proprietary to IOCL, but the category of process involves oligomerisation or alkylation-type reactions that build larger, highly branched molecules from the C4 feedstock. Highly branched molecules are the chemical basis of high octane, iso-octane, the 100 RON reference standard itself, is a highly branched eight-carbon molecule.

The resulting Octamax product has a blending RON of greater than 120. When this component is blended into the gasoline pool at appropriate concentrations, it upgrades the overall pool octane without requiring imported high-octane components, without using metallic additives, and without ethanol. Combined with MTBE as the oxygenate, it provides the octane foundation for XP100’s 100 RON rating.

The first Octamax unit at Mathura processed 55 kilo-tonnes per annum of C4 feedstock when commissioned. The first product samples from the unit yielded a blending octane number of 118, comfortably above the 108 RON guaranteed in the project specification and above the 120 RON design target for the blending component (the blending value in the pool is different from the product’s pure octane, depending on blend concentration).

The Mathura Refinery Commissioning, January 2018

The first commercial Octamax unit was commissioned at IOCL’s Mathura Refinery in Uttar Pradesh in January 2018. Mathura is one of IOCL’s largest refining facilities and is strategically located for supplying the Delhi-NCR market, which is also the primary initial market for premium XP100 fuel.

The commissioning was executed without cost overruns, which IOCL’s R&D and project teams noted as significant given that the process had no prior commercial precedent. The technology was designed, built, and operated with indigenous expertise, no foreign technology licence was required, no foreign catalyst was procured. The catalyst used in the Octamax process is non-toxic, an improvement over the hydrofluoric or sulphuric acid catalysts used in conventional alkylation units that perform a similar function in Western refineries.

The operating parameters of the Octamax unit, moderate temperature, moderate pressure, non-hazardous catalyst, give it a lower operational risk profile than conventional alkylation, which handles highly toxic acids under pressure. This translates to lower insurance and safety compliance costs and a more manageable maintenance profile.

The commercial launch of XP100 followed the Mathura commissioning. The fuel’s initial availability in ten tier-1 cities in 2020 was enabled directly by the Octamax blending component produced at Mathura. As IOCL expands XP100 availability and as additional Octamax capacity may come online at other refineries, the production constraint on XP100 becomes less a question of refining capability and more a question of distribution infrastructure and market demand.

Why Octamax Outperforms Conventional Alkylation

The standard industry approach to producing high-octane gasoline blending components without ethanol is conventional alkylation. Alkylation units react isobutane with olefins (primarily butylene) in the presence of a strong acid catalyst, either sulphuric acid (H2SO4) or hydrofluoric acid (HF), to produce alkylate, a high-octane, low-vapour-pressure blending component with a RON typically between 92 and 98.

Alkylate is an excellent fuel component. It contains highly branched paraffinic molecules, burns cleanly, has low sulphur content, and raises the octane of the gasoline pool effectively. Every major Western refinery with a significant premium fuel programme uses alkylation.

The problem with conventional alkylation is the acid. Both sulphuric and hydrofluoric acid are acutely hazardous materials that require specialised handling infrastructure, comprehensive safety protocols, acid management systems, and significant regulatory compliance overhead. HF alkylation is particularly concerning because HF can form a toxic aerosol cloud in the event of a release, a risk that has led to regulatory pressure and facility shutdowns at several global refineries.

Octamax achieves a similar output, high-octane, branched-molecule gasoline blending components, through a non-acid catalytic process. The non-toxic catalyst eliminates the acid handling infrastructure, reduces occupational safety risk, simplifies regulatory compliance, and lowers the capital and operating cost barrier compared to conventional alkylation. For a refinery operating in India’s regulatory environment, this is a meaningful commercial advantage.

The Octamax product’s blending RON of greater than 120 also compares favourably to conventional alkylate at 92 to 98 RON. The higher intrinsic octane means less Octamax product is required to achieve the same pool octane upgrade, a volume efficiency advantage in the blending operation.

What This Means for the Price and Availability of XP100

XP100 is expensive for two reasons. The first is the cost of MTBE, which is imported and priced in international markets that reflect global chemical feedstock prices. The second is the capital and operating cost of the Octamax unit itself, a specialised conversion unit that adds refinery complexity and requires maintenance and catalyst management.

Neither cost is discretionary. They are structural to the product’s chemistry and the refining process that produces it. IOCL’s COCO-only distribution model adds further cost through the requirement for direct operational oversight of every selling point. And XP100’s low volume means it cannot benefit from the economies of scale that bring the cost of regular petrol down, the Octamax production runs, the MTBE procurement, and the distribution operations are spread across a much smaller number of litres sold.

The Rs 160 per litre price at mid-2026, following an Rs 11 single-day price hike triggered by West Asia crude market volatility, reflects all these structural costs plus the market premium IOCL can command for a genuinely unique product. There is no other source of 100 RON, ethanol-free petrol in the Indian market. XP100, Power 100 (HPCL), and Speed 100 (BPCL) are the only options, and all three OMC products face the same underlying cost structure.

The implication for buyers is that XP100’s price is not likely to fall materially as long as its cost structure remains what it is. The product will remain niche, expensive, and available at a limited number of COCO outlets, by design rather than by oversight.

India as a Technology Licensor, The Broader Significance

The National Technology Award that IOCL’s Octamax team received in 2022 under the category “Successful Commercialization of Indigenous Technology” is not merely a domestic recognition. It positions IOCL as a potential technology licensor to other refineries globally that face the same octane-penalty problem from BS6-equivalent deep desulphurisation.

Countries in Southeast Asia, Africa, and the Middle East are implementing progressively stricter fuel quality standards that create the same refinery octane challenge India faced. A non-acid, non-toxic catalytic process for high-octane gasoline blending that is commercially proven at scale, and available for licence rather than requiring independent development, has export value.

For the Indian vehicle owner, the significance is more immediate: the existence of a domestically developed, domestically produced 100 RON petrol at a commercial scale means that XP100 will continue to be available as long as IOCL maintains the Octamax units and the product demand justifies the distribution cost. The supply chain is not dependent on imported technology, imported catalysts, or foreign technology agreements that could be disrupted by trade conditions. It is, as IOCL notes in its product positioning, a genuinely Indian fuel.

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