Bypass of Silical Gel TSA, max. bypass determination

[dangnm]

Hello,

Due to extra nominiations, the ops department in my company has been asked to look at increasing throughput thru the plant by bypassing soem of the gas around teh TSA.

We want to run simulations to see how much gas can be bypassed from the TSA. Each TSA train is designed to process 312 MMscfd with a total export gas rate of 600 MMscfd to meet a hydrocarbon dewpoint of 5°C at the cricondentherm and a water dewpoint of 0°C at any pressure below 82 bar.

We have access to Hysys; but have absolutely no idea how to simulate a Silica Gel Adsorber in it. Some flow trials were done in the past, and we have Gas Chroatograaph compositions for inlet and outlet of the TSA unit. Can we use that data to tune some Hysys unit operation to simulate that?. How would we monitor Dew Points etc; I can't find the Dew Point property in ant of the hysys stream properties.

Would really appreicate all your help.

 

[zt2]

Not sure how to model silica Gel units in HYSYS either.

But you could use a standard refrigeration set up to achieve the same dew point as your plant gives.

then just add bypass gas until you hit either the water or hydrocarbon dew point limits.

Note that there is no stream property of dew point in Hysys the way I have found dew point in the past is via the envelope utility that gives a phase envelope for a stream in hysys. to set one up go to tools, utilities, envelope utility and attach a stream. This gives cricondentherm but not water dew point.

I've only worked on refrigeration dewpointing and the water dewponit is set by cold separator temperature so I didn't need to calc it.

Hope this gets you part of the way.

 

[Zoobie]

Just a comment regarind dew points & HYSYS. In version
3.2 & above you can append a number of different properties (dew points, heating values, Wobbe Index, etc.) to a stream from the 'property' ply of the worksheet tab for a stream. In version 3.1 the properties are also available but they are accessed via a macro (see Aspentech Support for details). For older versions there is the Gas Properties Extension which can be downloaded from the AspenTech Support sight.