Thanks you very much for the quick reply. The water in question is a condensed water that contains up to approximately 1,000 chlorides and a few millimoles of both CO2 and H2S. It is a system that produces bas and liquid hydrocarbons. I believe that I can get some of the dissociation/complexation data that I will need. Many thanks again. Regards, Al ----- Original Message ----- From: David L Parkhurst <dlpark@xxxxxxxx> Date: Tuesday, July 9, 2002 7:41 pm In-Reply-To: <001801c2272e$5708f960$763c090a@xxxxxxxxxx> Subject: Re: Fw: Question on PhreeqcI and glycol > > > Is there a way of using PhreeqcI to model the interaction of a > relativelylow solids brine containing both CO2 and H2S, plus some > glycol? I am > interested in modeling the behavior of such a brine vs. > temperature and > pressure, to determine the extent of degradation of the glycol. > > I'm not sure what you need. PHREEQC is not good with high ionic > strengthwaters, say 1 molal and greater. On the other hand, I'm > not sure what part > of the thermodynamics you need. If it is just solubility of gases, > it might > be adequate; it has a linear log activity coefficient expression for > uncharged species. Charged species will get more unreliable the > higher the > ionic strength. PHREEQC has no explicit pressure dependence in the > aqueousmodel, but it is possible to specify partial pressures of > ideal gases. I'd > be reluctant to push things past a few atmospheres total pressure. You > would have to define a new "Element" glycol and any > dissociation/complexation that are pertinent. If you are trying to > do all > this a priori, I suspect you can't do it. If you are trying to > model some > experiments, you may be able to use some of the features of PHREEQC. > > David > > David Parkhurst (dlpark@xxxxxxxx) > U.S. Geological Survey > Box 25046, MS 413 > Denver Federal Center > Denver, CO 80225 > > Project web page: http://wwwbrr.cr.usgs.gov/projects/GWC_coupled > > > >
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