Scrubber Sizing Paradox

[MatthewD]

So I got another problem that I could use some advice on. It has come time to create a datasheet on a conventional inlet scrubber for use in a typically sweet and dry compressor station (Horizontal with cyclone tubes) and I have to input conditions (density viscosity) for the liquids even though we never plan on having any. From talking with older engineers it apears I have 2 opitons

A) Assume someone dropped a couple of barrells of methanol in the pipeline up stream. Resulting in me using the density and viscosity of methanol. You could replace methanol with just about any other liquid typical to pipeline operation

B) Assume our upstream facillity is producing some off spec gas resulting in the formation of liquids somewhere downstream in the pipline as cooling occurs.

The popular answer seems to be A due to very tight time constraints but B seems to have more engineering merit. Im sure someone on here has come across this before. ANy help would be great

 

[vivbn]

Go with option B, this is the most likely scenario simply because there is a higher probablity of the upstream facility producing offspec gas than someone tipping a few barrels of methanol down the line. If you were to do a HAZOP on this you will be given the same advice.

 

[MortenA]

In my opinion you should startby check your operating pressure/temperatur and possible scenarios where liquids could occur. Have you considered start-up conditions?

Then:

If you cant find any special cases where liquids may occur the onsider you normal operating point: Is in the dense phase (typically oabve 80 barg)? Then liquid HC will not occur and you should consider only water and/or MEG/TEG/MeOH as suggested in A

If you are below then i would still go for A since while "tipping a few barrels" may not be very likely - malfunction of the dewatering equipment does seem more likely - or that MeOh is added in excess amounts by some other coincidense.

Best regards

Morten