Statoil has responded by building a new and modern processing plant at its Mongstad refinery near Bergen in western Norway to remove polluting sulphurous components from cracker naphtha – one of the constituents of finished petrol.

In addition, a process plant was opened in 2002 at Statoil’s Kalundborg refinery in Denmark to remove sulphurous components from automotive diesel oil and reduce its aromatics content. Both contribute to the formation of soot in diesel exhaust fumes.

Opened in 2003, the Mongstad facility allows the refinery to produce petrol containing less than 10 parts per million (ppm) of sulphur – a 95% reduction compared with current levels.

Staff at the Statoil research centre were involved in the preparatory work, including screening alternatives and recommending the best process for this application.

Their work led to several improvements which significantly reduced investment and operating costs.

Comprehensive testing of catalysts, operating conditions and product quality was carried out at the research centre laboratory with the aid of a test rig nicknamed “Hydroloten”.

This is a model version of a hydro-treater at the Mongstad refinery.

The Kalundborg plant permits the production of automotive diesel oil with a sulphur content of less than 10 ppm.

Much experimental work for this facility was again carried out at the research centre, especially to improve the catalyst system. 

The outcome was the commercial development of a new and considerably cheaper version with better performance and capability.

Having undergone exhaustive laboratory testing, the new catalyst has been qualified for commercial operation.