Sciencemadness Discussion Board

Zinc Oxide used for Desulfurisation of feedstock gases

Hanfgeist - 25-11-2009 at 08:53

Does anybody know if the ZnO filters used in the petrochemical industry to remove hydrogen sulfide from feedstock gases, in the gas to liquid processes can be treated to remove the sulfur and reused or do they have to buy more ZnO after the filters become saturated with sulfur in this reaction?

ZnO + H2S ------> ZnS + H2O

(I'm asking cause I'm interested in building a small 'hobby' sized system to make some fuel by this and similar methods, and yes I already know it won't be easy)

Picric-A - 25-11-2009 at 11:01

The ZnS can be burnt in air, releasing SO2 and reforming ZnO.
The SO2 is then bottled and sold.

2ZnS + 2O2 --> 2ZnO + SO2

DJF90 - 25-11-2009 at 11:09

I'm pretty sure the SO2 will not be bottled and sold, but directly used as feedstock for the Contact process.

Picric-A - 25-11-2009 at 11:12

why transport large quantities of ZnS to the contact plant when it can be burnt and reused in-situe and selling the SO2? SO2 is used in vast quantities for making bleaches ect...
TBH it depends on how close the two plants are...

DJF90 - 25-11-2009 at 13:08

I was making a point...

Hanfgeist - 25-11-2009 at 14:37

guys,

Thanks for the most informative replies

watson.fawkes - 29-11-2009 at 07:57

I would be curious to know if ZnO filter can be reconditioned in place without losing its mechanical stability. I would image that it would require a mechanical reactant support, and possibly a mixture with a chemically-passive oxide or salt to lower the melting point in order to it in liquid phase. If so, such a filter could be used in a twin-tank arrangement, where they switch between filtration and reconditioning. (This is how some air desiccators work.)

Hanfgeist - 29-11-2009 at 09:13

I have been doing some further reading on the subject of feedstock gas 'sweetening' and it seems that you can also use 'amines' like monoethanolamine (MEA) to remove H2S from the input gas stream. It can then be released from the amines and passed through a Claus process plant to recover most of the elemental sulphur......