Q & A > Question Details
What are the differences between hydrogenation and hydrodesulphurization?
 
Answers
15/05/2018 A: Bruce Carr, Suncor Inc, bcarr@suncor.com
Hydrogenation is used to add hydrogen molecules to cracked material. The cracking process breaks paraffins, saturated long chain hydrocarbon molecules into smaller molecules but the broken chain leaves the molecules short of a hydrogen molecule on both ends. So you end up with Olefins which are not much use for anything..... The hydrogenation process supplies hydrogen to bond to the olefins to make them paraffins again which have a greater value..
Hydrodesulphurization uses hydrogen to bond with elemental Sulphur. Elemental Sulphur is near impossible to remove in its original state. By adding hydrogen molecules to the sulphur you create hydrogen sulphide which is water soluble and can easily be remove by water washing..... normally the feedstock will also contain nitrogen which can be detrimental to catalyst so the hydrogen bonds with it to form ammonia which is also water soluble...
15/05/2018 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
An example of hydrogenation: C H2=CH2 + H2 goes to C H3-CH3. An example of hydrodesulfurization:
CH3-S-CH3 + H2 goes to CH3-CH3 + H2S