Quite a large amount of Hydrogen is consumed in desulphurisation of fuels and hydrotreatments for product quality improvement which generate Hydrogen sulphide. A more economic process is required like catalytic decomposition of hydrogen sulphide into hydrogen and sulphur and the separation of the products of said decomposition to H2 and Elemental Sulphur. This would enable recovery of costly hydrogen and same can be re-utilised in the process of treatment. Are there any catalyst development taking place for such purposes?
Egbert van Hoorn, Hocon B V, Egbertvh@hotmail.com
Please note that the actual amount of hydrogen which is consumed by the reaction with sulphur is quite small. You can see this for yourself by taking the daily sulphur production of your refinery and divide this by 16. For 200 tons of da ily sulphur production you are only using 200/16= 12.5 tons of hydrogen.
The rest of the hydrogen is used for hydrogenation of aromatics and unsaturated hydrocarbons.
A significant portion of the hydrogen is also lost to fuel gas because Hydrogen and methane/ethane are difficult to separate.
One way of doing without hydrogen is visbreaking, thermal cracking or cocking, however the quality of the products is not what we want these days.
Research has been done in this direction, but always the quality of the products is a problem.
If you look at the chemistry, you will see that you cannot desulphurise and obtain saturated products if you do not supply hydrogen.
I expect that the current desulphurisation processed will continue to dominate the refineries.
The Merox process works for kerosine and naphtha without hydrogen. The only problem is that the sulphur components are not removed.