Tracking the journey: How refineries and outlets made BS-VI switch possible

A young woman in a Port Blair laboratory has spent several weeks testing fuel samples. The laboratory belongs to the Indian Oil Corporation (IndianOil), which has been carrying out the bone-drying of fuel tanks in remote places in the country so they would be ready to receive BS VI-compliant fuel.

“We had to be ready much before the April 1 deadline. It was a race against time,” said Sanjiv Mazumdar, executive director-quality check, at IndianOil. The new norms require the sulphur content in the fuel to be a maximum of 10 parts per million or ppm. For over three years now, Mazumdar’s team has been the final link in a long process chain, which has made the delivery of the cleaner fuel possible.

Like IndianOil, other state-owned oil marketing firms Bharat Petroleum Corporation (BPCL), and Hindustan Petroleum Corporation (HPCL) have several testing sites to make sure that the fuel in their retail outlets is BS-VI-ready. The three firms have spent close to Rs 35,000 crore to upgrade their refineries for producing BS-VI-compliant fuel.

One of the biggest challenges has been to execute the change in outlets situated in remote areas with lower off-take. In pumps where the off-take is higher, it was easy to flush the BS-IV fuel out from the system, thanks to regular consumption and intermixing, said R Ramachandran, director (refineries) at BPCL. For pumps with lesser off-take, however, oil firms had to adopt the bone-drying approach.

Most of the refineries started making BS-VI fuel from January to ensure that it reaches every petrol pump before April 1. “We had to add a separate process unit at the refineries for selective de-sulphurisation of the fuel,” said the head for one such refinery who did not wish to be named. The upgrade took around three years. This additional process unit removes sulphur from the fuel to an extent that it meets the norms.

The residual sulphur does not go to waste. “The elemental sulphur, which is the residue, is sold for use in the production of chemical fertiliser and other products,” explained the refinery head. The fuel supply chain starts at the refinery and goes through a complex maze of multi-product pipelines, terminals, tankers and depots to finally reach the fuel tank of a retail outlet.

Once the product is received through a multi-product pipeline at a terminal, it is separated into different tankages. “As refineries started sending BS-VI, we realised that our tanks still had some BS-IV fuel in it. Bone-drying the tanks was not possible, because then the retail outlets would have gone dry,” said Mazumdar. “So we started the process of dilution.”  Dilution involves filling different tanks with different levels of BS-IV and then BS-VI. After multiple dilutions, the fuel becomes BS VI-compliant.

 A similar strategy has been deployed for tanks at petrol pumps. IndianOil, BPCL, and HPCL have confirmed that all their retail outlets  were now BS VI-compliant. That includes one of India’s highest altitude petrol pumps at Kaza in Spiti Valley in Himachal Pradesh, which is run by IndianOil.

*Research Octane Number signifies improved performance of automobile engine. The loss in octane number because of phasing out of lead made up changes in refinery processing; **Premium petrol has higher RON of 95; Source: Oil marketing companies

The method of inter-mixing BS-IV and BS-VI fuels involved multiple sampling at different times to check if the older fuel has been completely exhausted through sale. “In the past month, we were swamped with samples from outlets,” said Mazumdar, a challenge they did not anticipate.  His teams have managed to do their job, working over multiple shifts and by moving infrastructure and manpower to laboratories with higher work loads.