Orient Catalyst Co., Tokyo, has developed a catalyst system that reduces the sulphur level of light oil to below 50 ppm, without significant changes in the present equipment and reaction conditions. This process involves the use of two catalysts. One, a cobalt-molybdenum catalyst on an alumina support, treats such organic sulphur compounds as alkyl sulphides, mercaptans and alkyl polysulphides.

The other catalyst, nickel-molybdenum on alumina, decomposes and removes the sulphur from polycyclic compounds, such as alkyl dibenzothiophene and alkyl dibenzothiophane. The combination of the catalysts depends on the type of oil, the equipment and the desulphurisation conditions. If the catalysts are mixed and used in an appropriate ratio, desulphurisation can be achieved at conventional reaction conditions.

Source: Chemical Engineering, 1, 2001.