Dear Leo,
I have been using aspen plus for last 11 years successfully for more than 40 ammonia plants performance evaluation, bottleneck study, revamping,projects, checking licensor design or preparing basic engineer package. It has been wonderful so far with the updated property packages.
However, the CO2 removal unit is well suited in aspen Hysis where you can use amine property package and it gives very good results.
I do know there are other software which can be used, but aspen plus is quite user friendly and most commonly used by ammonia plant designers and manufacturers.
I would recommend for use of aspen plus for ammonia plant.
Kind regards,
Satyajit