Cobalt plays a vital role in catalysing the removal of sulphur from oil, contributing to a more sustainable society.
The use of cobalt in desulphurisation reactions represents the highest tonnage of cobalt use in the catalyst sector.
All crude oils contain between 0.1% and 2.5% of sulphur dependant on their source of origin. Upon combustion, the sulphur from these crude oils is converted into SOx. SOx as well as contributing to global warming, can dissolve in rainwater creating acid rain. The sulphur moiety is also an occupational hazard for employees working in oil refineries.
Another important reason for removing sulphur from the naphtha streams (the liquid stream derived from the refining of the crude oil) within a petroleum refinery is that sulphur, even in extremely low concentrations, poisons the ‘noble metal’ catalysts (platinum and rhenium). These noble metal catalysts are used in the catalytic reactions to upgrade the octane rating of the naphtha streams, which is required for the high-performance petrol engine.
By using a cobalt oxide-molybdenum oxide catalyst (CoMOX), the sulphur can be converted into hydrogen sulphide (H2S). The H2S can then be converted into either elemental sulphur or into sulphuric acid (H2SO4), which is then used for other industrial processes. CoMOX catalysts contain 3-5% tricobalt tetraoxide (Co3O4), 14% molybdenum trioxide (MoO3) and 83-85% alumina (Al2O3). As CoMOX catalysts are very resistant to poisoning and degradation they are the ideal choice for use in desulphurisation reactions.