Property package for NH3, CO2 in water 1

[Rajjil]

Can any one suggest which property package is good for simulation (HYSYS/ProII/VMGSIM) of NH3 & CO2 dissolved in water. I need to do a simulation of a distillation column which separates NH3/CO2 from water. I think Peng Robinson or SRK are not good for this mixture.
thanks
Rajesh

 

[BenThayer]

you can get fairly close by doing the following:

assume that all the CO2 will react with NH3 to form carbamate (pre-cursor to urea). so every molecule of CO2 will associate with 2 molecules of NH3.

then assume the excess NH3 will behave like a typical NH4OH ammonia/water compound.

you can get pretty close to estimating vapor pressure of the ammonia/water by doing this.

 

[unclesyd]

If the OP is trying to separate or recover the ammonia by distillation or other means he will have to prevent the formation of the Carbonate by adding enough NaOH to tie up the CO2 or he will have a system plugged with the Carbamate.

 

[BenThayer]

you might also want to contact Engineering firms that do Urea plants.

Many Urea plant process designs use a steam stripper (either live steam or via reboiler) to take water that is ~10% ammonia and 5% urea and get it down to ~10 PPM NH3 and ~10 PPM urea.

This stream typically contains a fair amount of CO2 as well and the relatively high bottom temperatures (~75 psig on the system and so >325°F) causes decomposition of the Urea to CO2 & NH3.

for this type of system, no NaOH was needed.