BS VI fuel to H-CNG, efforts to clear city air
New Delhi 29-Oct-2018
It is that time of the year when the air quality in the National Capital Region and surrounding areas hit the headlines, sending administrators and legislators scurrying for a quick fix. Facing flak time and again is one of the transportation fuels, diesel. But, as India moves from BS-IV to BS-VI standard, and the National Capital Territory (NCT) having already moved to BS-VI diesel, it is time for diesel to move away from the dreaded polluter tag. “Diesel can’t be demonised. It is true, it is not fiction. It is scientifically proven,” says Dr. SSV Ramakumar, Director R&D at Indian Oil Corporation.
The Corporation is spending more than Rs. 15,000 crore on upgradation of fuels from BS-IV to BS-VI and across the country, public sector oil refineries are being upgraded to BS-VI standards at the cost of Rs 30,000 crore. “When we finalise the BS-VI emission standards, we call it a fuel-neutral scenario,” says Dr. Ramakumar. This means, in terms of exhaust emissions, petrol, diesel and CNG stand neutral. Emission control limits of key pollutants are the same for BS-VI standard liquid fuels namely petrol & diesel and CNG. “For Carbon monoxide, a key pollutant, it is 4g per KWh, exactly the same for diesel or CNG. Similarly, the limits on NOX and Particulate Matter/Number are same for both the fuels,” he said. Oil companies, who are spending large amounts of money on fuel quality upgradation, cannot pass on the cost to consumers, and naturally, the fuel needs to be defended against unfair criticism. In fact, there is an element of ‘methane slippage’ possible in CNG vehicles, which is not applicable to diesel or petrol vehicles.
“I am not belittling CNG, but I am saying don’t demonise diesel,” said Dr. Ramakumar, who is also working on a pilot project to introduce Hydrogen CNG vehicles in NCR. Hydrogen CNG technology, indigenously developed and patented by IndianOil, is the process by which CNG, when subjected to controlled reforming, yields direct Hydrogen CNG mixture in which Hydrogen content is at a pre-decided level. HCNG would be used to improve fuel efficiency as well as emission control. “This technology, called H-CNG, is gaining popularity worldwide. Globally, hydrogen is being blended (20-30%) with natural gas and then compressed to dispense into vehicles. US, Brazil, Canada, South Korea have all conducted trials and found that they get the reduction in emissions from buses using H-CNG,” says Indian Environment Portal in its paper on India’s Hydrogen Fuel Cell buses programme. Carbon monoxide emissions were found to be 70 percent lower in HCNG vehicles compared to those running on neat CNG, though NOX remains the same. That can also be fixed through minor modifications in the catalytic elements of the catalytic converter in vehicles. As per the current estimates, at a cost of around Rs 0.70 /km, the HCNG vehicles can give better fuel economy to the tune of four to five per cent.
