2 replies to this topic

[Propacket]

Hi,
I have performed a simulation of Dew point Control Unit for Natural Gas. I have used standard process scheme.i.e. Gas Gas Exchanger,Propane Chillar and Low Temperature Separator. I have injected Ethylene Glycol(EG) into the Gas Gas Exchanger & Propane Chillar for hydrate inhibitation. Problem is gas out from the Low Temperature Separator always shows hydrates formation. I have tried EG at different conditions but problem remains there. Is it a problem of hysys or wrong selection of inhibitor? Can anybody guide me how to select properties of EG?

[Zauberberg]

Hysys will not take into account the presence of hydrate inhibitor.

[daryon]

Hysys will not take into account the presence of hydrate inhibitor.

HYSYS does perform a inhibitor calculation if glycol or methanol is present in the gas stream. You can see this on the Hydrate Formation Utility page on the design tab, there is a field that says inhibtor calculation. If glycol/MeOH is present this will say included. - this is only for version 2005.6 onwards.

P.Eng.
Its hard to determine the answer to your problem from the information you have provided. What temperatures and pressures are we talking here? How much water is present? You may try using TEG or methanol to see if that makes a difference. Could you attach your simulation file so I can take a better look.

How are you adding the glycol? You need to have a glycol or MeOH stream combined with the gas stream via a mixer. I don't thing the inhibition calculations work if the glycol/MeOH is added by the composition tab of the process gas stream.

P.S. A warning from Aspentech: You need to be carefully using MeOH or Glycol with the PR EOS fluid package. The PR EOS was not orginally designed for these non-ideal components, so you need to double check the distribution of the components (MeOH/glycol) between phases is satisfactory, especially if 3-phases exsist.