Indian refineries gear up to meet BS VI emission norms

Indian refineries are gearing up to meet the April 2020 deadline set for supplying superior fuels for BS VI emission norms.

While countries around the world have been making minor changes in fuel specifications depending upon their specific requirements, India will be switching over to 100 percent BS IV emission norms by April 2017 and then leapfrogging BS V to achieve BS VI level within a span of three years. Such a quantum jump in a short span of time is being attempted perhaps for the first time by any country in the world, according to Sanjiv Singh, director, Refineries, Indian Oil Corporation.

Over the years, fuel specifications have seen significant improvement since the emission control program took off in India in 2003. For petrol engines, one of the most critical specifications is Research Octane No. (RON), which has improved from 88 in BS II to 91, which is at par with regular 91 octane petrol required for Euro VI emission norms. Other critical specifications such as benzene and aromatics have also undergone considerable improvement from earlier limits specified in BS II. For benzene, these limits have been brought down to 1 percent volume max and for aromatics to 35 percent volume max, which are in line with Euro VI fuel specifications. The sulphur specification for petrol is also being reduced 50 times from a level of 500 ppm for BS II fuel to 10 ppm in BS VI, which is the same as Euro VI specification. Almost all other specifications for petrol being proposed for BS VI fuel are aligned to Euro VI gasoline specification.

Similarly for diesel , the major specification with reference to sulphur and cetane number are in line with Euro VI specification. The sulphur level in diesel is proposed to be brought down to 10 ppm from a level of 500 ppm in BS II and the cetane number in BS IV and BS VI 51 as against 48 in BS II. According to IOC, “The minor change proposed in BS VI diesel in comparison to Euro VI is density, which is proposed to be in the range of 820-860 kg/m3 as against 820-845 kg/m3 in Euro VI. Various States have indicated almost negligible impact of this density on engine emissions.” 

According to IOC, marginally higher density will result in more quantity of fuel per litre. “Directionally this should improve the fuel economy with no negative impact on emission. Other developing countries have also kept similar variation.” It is understood that Japan has a similar limit of 860 while the USA has no such limit in its diesel specification. The flash point for BS VI is proposed as 35 as against the limit of 55 for Euro VI. IOC says, “there is no advantage of raising this limit further.”

India for long has been a diesel-driven economy and unlike refineries in the US and Europe, the refineries here are designed to produce more diesel, as compared to motor gasoline/petrol.

Importantly, while BS VI fuel used in BS VI-compliant vehicles would result in emissions in line with design, using BS VI fuel in other vehicles would not result in low emissions. Though the country would be switching to BS VI vehicles from 2020, the impact on vehicular emission may not be significant immediately. The benefit of superior engines running with superior fuels would be gradual and it will be significant only when a substantial percentage of BS VI compliant vehicles would run on road.