Hydrate formation in refineries

I have never seen nor heard of any refineries that dehydrate the overhead gas product from their atmospheric distillations units. That gas joins the offgases from various other units within the refinery and the combined gases are then processed in the refinery "gas plant" (or gas plants) for removal and recovery of propane, butanes, and pentanes and heavier.

Nor have I ever heard of hydrates being formed in a refinery fuel gas.

Milton Beychok
(Visit me at www.air-dispersion.com)
.

The only refinery units where I've ever heard of drying fuel gas type streams or concerns about hydrate formation are cryogenic gas plants.

The Desalter is itself a dehydrator. Operating conditions and the applied electrical field are such that the quantity of water leaving the Desalter is minimized.
Doug

Crude oil atmospheric distillation units almost universally have two or three sidecut strippers into which live stripping steam is injected. So the distillation column itself (regardless of the oil feed desalter) has a good deal of water vapor traveling up to the overhead condenser.

Milton Beychok
(Visit me at www.air-dispersion.com)
.

The desalter doesn't remove all the water that is in solution with the oil. Water can stay with the lighter ends and if the gas is processed, there maybe the right combination of components to make hydrates. Methanol and ethylene glycol do not remove water, they keep any water that is in the liquid phase from forming hydrates or freezing. TEG and mol sieves (silica gels too) actually remove water from the gas phase.