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Diesel fuel hydrodesulfurization removes three quarters of a million tonnes of SO2 each year


Hydrodesulfurization removes sulfur from diesel during the refining process using catalysts, typically cobalt-molybdenum (CoMo) or nickel-molybdenum (NiMo). A lifecycle analysis study compared the total environmental impacts of burning diesel fuel containing 2000 parts per million (ppm) of sulfur – the Euro 1 limit imposed by the EU in 1993 – with today’s Ultra Low Sulfur Diesel (ULSD) containing 10 ppm, the Euro V standard.

The study considered a number of environmental metrics relevant to vehicle use and performance. Using ULSD delivered a 24% reduction in acidification potential compared to 2000 ppm diesel. Atmospheric acidification leads to acid rain which damages ecosystems and buildings and was the driving force behind the imposition of sulfur limits for fuel.

The impact of particulate matter and respiratory inorganics, associated with risks to health and to the environment, was 44% lower with ULSD compared to the 2000 ppm fuel. The study also demonstrated that the potential for smog creation was nearly 5% lower with ULSD.

Tim Outteridge, IMOA Secretary-General said: “Hydrodesulfurization of diesel fuel has been extremely effective in reducing SO2 emissions from vehicles. Sulfur dioxide emissions from this sector are now at least 100 times lower than they were in 1993, despite demand for diesel doubling in the last 20 years, and without any meaningful impact from the additional catalyst used in the process. Overall, the results demonstrate the important environmental benefits gained over the last twenty years from sulfur removal by hydrodesulfurization using molybdenum-based catalysts.”



Notes for editors

The study was commissioned by IMOA and conducted by PE International in association with Haldor Topsøe. The full case study is available on the IMOA website.

IMOA is a non-profit trade association representing the interests of most of the world’s molybdenum producers and converters, as well as consumers and traders.

Molybdenum is added to steels and cast irons to improve strength, toughness, hardenability and weldability for numerous applications in the automotive, shipbuilding, construction, mining, chemical, oil & gas and energy generation industries.   

In stainless steels and superalloys, it improves corrosion resistance and high-temperature performance and finds uses in many industrial applications.  It is also used in a variety of products from catalysts and lubricants to pigments and paint.


For more information contact:

Alan Hughes
T: +44 (0)1606 852011
M: +44 (0)7759 243969


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