10 replies to this topic

[Sherif Morsi]

Hi, I am building a model for Water/CO2 system using HYSYS. The main purpose is to produce Carbonated Water. Which equation of state should I use? Or should I use Peng Robinson?

 

Thank,

Sherif

[RockDock]

If I were doing this model in ProMax, I would use Electrolytic ELR. I don't think Hysys has that property package. I have no idea how accurate Hysys would be for this other than to compare it to sour water strippers. Hysys is not normally used for that process because of the reactions that ultimately take place. CO2 will form carbonic acid in the presence of water and then bicarbonate. ProMax is the only simulator I know of that would accurately model a water/CO2 system, including the ions which would surely form.

 

As a rule of thumb, I stay away from accepting Hysys results if there is water, H2S, CO2, SO2, COS, thiols or any ionic components in the process. Hysys is fantastic for modeling pure hydrocarbon systems, though.

[Zauberberg]

I'd suggest you go through the "Simulation basis" chapter in Hysys tutorials, an exhaustive information with regards to thermodynamic models is available therein. For pure H₂O/CO₂ systems (no additional components or catalysts) and at pressures up to 3.5 bara, Sour PR or Sour SRK generally yields good results.

[ahmadikh]

 Agree with Zauberberg, Sour packages work well for your system with the given pressure range. Also, you can try "Electrolyte NRTL" package..

 

Best,

Milad

[RockDock]

http://www.jmcampbel...phase-behavior/

 

This link shows Hysys has an average error of over 200%, while ProMax has about a 5% error for H2S/CO2/Water phase behavior.

[Sherif Morsi]

Thank you all for your reply.

 

However, the system will not be at low pressures all the time. Our facility consists of producing Carbonated Water required for Enhanced Oil Recovery, i.e. we will inject this carbonated water to improve oil production from the reservoirs. Some literature suggest operating at conditions higher than critical pressure and temperature of CO2 (75 barg and 30 C).

 

Would the same equations of state work? Also, could Aspen be a good choice for this?

 

Sherif

[Zauberberg]

What is that you actually want to simulate? Which properties or fluid behavior? I don't see how you can correlate Hysys with subsurface modeling or whatever is the target of this exercise. Please provide more information.

[Sherif Morsi]

It's a conceptual study for offshore topsides facility for the capture of CO2 from power generators and the production of carbonated water using seawater. The carbonated water will be used for enhanced oil recovery. I am not trying to simulate subsurface stuff using HYSYS this will be done using Petrell/Eclipse/....etc.

 

I am using HYSYS to simulate the facilities side, separation, adsorption/absorption, pumps/compressors and storage of carbonated water.

CO2 from the generators will be at very low pressure.  

 

Based on literature review, it's preferred to have the system at high pressure (higher than CO2 critical pressure) however, we are looking at reducing this pressure for weight, cost and footprint reasons given that it will be installed offshore.

 

I hope I made it clearer. Please let me know if you need more clarifications.

[RockDock]

That seems pretty clear now. I don't think Hysys or any Aspen product will model it very well, especially if you go above about 30 bar. Hysys would likely predict a much much larger system than needed. ProMax would be your best option.

[Zauberberg]

RockDock, are you a Sales Manager for ProMax? Each and every of your posts is advertising this software. I believe that product advertising is prohibited in ChE Forums.

[RockDock]

Zauberberg, I'm not a sales manager for ProMax. My area of expertise overlaps quite a bit with ProMax's capabilities. I've just been surprised by how little engineers know about it on this site. That's why I mention it as frequently as I do. I thought it would be helpful to point engineers in the right direction when I see them using the wrong tools. I believe engineers should think about the process itself before they choose a simulator, not the other way around. Of course, I don't want to come across as advertising anything. I've used plenty of other software, including Hysys. They are all good in their niche areas, which I try to point out when the opportunity comes up. I also think I have the unique experience of having used both Hysys and ProMax, knowing when to use one versus the other. The last thing I want to do is hurt ProMax's image by posting on here. I'm sure they would not appreciate that. I'll be sure to only mention it when I feel it is necessary. I'm sure you would agree that high pressure water/CO2 systems for EOR is not a Hysys strength, though.