8 replies to this topic

[Andree]

My question is very general, please tell me what you recon, even if these are thoughts and guesses only

Mercury has to be removed from 3-phase G/L/L mixture (gas is mixture of natural gas with some higher mol. weight hydrocarbons -> Mw about 23-24 g/mol; light liquid phase are mostly hydrocarbons C6-C12; heavy liquid phase is water + MEG). Is it possible, reasonable and efficient to purify this mixture as a whole on a carbon bed (e.g. Mersorb) OR it has to be separated upstream the adsorbtion and each phase treated separately (probably optimum selection of adsorbent will differ for each phase).

[Zauberberg]

Andre, if you are thinking to put 3-phase mixture through an adsorber bed, forget about it.
Usually, mercury is the contaminant in gas processing; however I'm not sure about what levels of mercury we are speaking here, and what your flowsheet looks like. Some technologies (for condensate processing) may pose concerns with regard to feed mercury levels, but you have to do the legwork and do some more research on the topic.

[JoeWong]

When we deal with mercury, first far most important things is understand species of mercury in your feed. Mercury can be in elementary, ionic and organic form. With my limited experiences, i still have not heard from mercury specialist company like JMC that a single bed can take all types of mercury. With today technology, i tends to believe that they need to be removed separately in each phase.

Second thing you may need to understand is the behavior of elementary mercury. It tends to stay in liquid under pressure, however it is sensitive to temperature. This will assist you in mercury removal strategy.

Adsorption bed may possible remove elementary mercury. Ionic and organic type may need different method i.e. reaction.

Few years back, we have doubt on effectiveness of mercury adsorption in liquid phase. Hope Chem Jedies can update me with new effective technology for removal of mercury in liquid (organic phase and/or aqueous phase).

[mido]

From my little experience in gas processing,
in my company we remove mercury from gas only because i think that dangerous of mercury come from its corrosion effect on aluminum heat exchanger used for NGL extraction so we remove mercury upstream these exchangers.
why we need to remove it from liquid (condensate or water)?

[Qalander (Chem)]

From my little experience in gas processing,
in my company we remove mercury from gas only because i think that dangerous of mercury come from its corrosion effect on aluminum heat exchanger used for NGL extraction so we remove mercury upstream these exchangers.
why we need to remove it from liquid (condensate or water)?

Dears,

I understand that mercury is considered 'highly poisonous' to many catalysts and even considered highly dangerous to eco systems/animals via water route; thus undesirable. Requires removal from liquid stream as well.

Best Regards
Qalander

[Mehrdad]

Andree

i have not any experiences about mercury in oil industries but as joe wong mentioned , mercury may be find in elemental, organometallic or ionic forms.
i think the separation process is depend on forms of mercury in the feed.
the ionic mercury probably find in aquaes phase and organo metal mercury may find in gas,liquid and aquaes phases .
the preferable method of ionic mercury separation isn't like the separation of organometallic mercury.
you can use carbon bed for adsorption of organometallic mercury and not for ionic mercury in aquaes solution.
regards

[BrianEJensen]

An Internet search of "mercury removal" produced many sites. This one looks appropriate.
http://www.uop.com/o...curyRemoval.pdf
regards,
Brian E. Jensen

My question is very general, please tell me what you recon, even if these are thoughts and guesses only

Mercury has to be removed from 3-phase G/L/L mixture (gas is mixture of natural gas with some higher mol. weight hydrocarbons -> Mw about 23-24 g/mol; light liquid phase are mostly hydrocarbons C6-C12; heavy liquid phase is water + MEG). Is it possible, reasonable and efficient to purify this mixture as a whole on a carbon bed (e.g. Mersorb) OR it has to be separated upstream the adsorbtion and each phase treated separately (probably optimum selection of adsorbent will differ for each phase).

First of all based on my modest experience I did not see Hg removal from liquid, if some one encountered it, please inform about it and the purpose.

Thanks

[siretb]

It is possible to capture the mercury in liquids, and specially in water. Mercury, unless in an organic compound specie, should not be much soluble in organic layer.

We do this removal on an industrial basis either (we do not offer this, as a process)
adsorbing the mercury on a solid (activated cabon, as a slurry in water, or other adsorbent (zeolithe like , fly ash , ..) ; Once it is bound the solids are separated and extracted. the partition coefficient is good and we remove most of the total mercury frol aqueous solutions. In what we do the adsorbant is dispersed in an agitated vessel, this is not a static bed.
You may also chelate the mercury (only ionic form). This will drag the equilibrium and render the mercury "inactive". Eventually it will be discharged out of the sysr=tem through a purge and the purge treated by a waste water treatment unit

Sulzer, to name them, manufactures (manufactured?) structured packings made of carbon. You can find carbon loaded rings, as special packing, for the adsorbtion of dioxins in flue gas from incineration. Should work too. If the amount if mercury is low, or if you are ready to "regenerate" by heating the packing, this could be a solution. Laboratory experiments would be needed in your case.

Back to your original problem if you have two liquid phases I would be careful about solids staying at the interface. Could be that granular activated carbon does the job. What could happen also is saturation of the carbon with the organic; Since I would expect that most of the mercury is present in the aqueous phase , why not treat, separately, the aqeous layer?

As said do not think of just percolating a L/L 2-phase into a static bed.