Thermophysical Modeling: Why was UREA modified for the MSE model?
The Background
Circa 2009 OLI Systems was asked by one of its customers to model the decomposition of Urea in aqueous solutions. OLI undertook this modeling and created a model. The basic chemistry of urea decomposition is as follows:
Urea: (NH2)2CO
Water: H2O
Ammonium Carbamate: NH2COONH2
Ammonia: NH3
Carbon Dioxide: CO2
- (NH2)2CO + H2O = NH2COONH2
- NH2COONH2 = NH3 + CO2
There are several side reactions which OLI attempted to model as well. Two molecules of urea can combine to form a species called biuret with a loss of an ammonia molecule.
Biuret: (CONH2)2
The reaction is:
- 2(NH2)2CO = (CONH2)2 + NH3
In addtion, another side reaction is the formation of ammonium cyanate from urea.
Ammonium Cyanate: NH4OCN
- (NH2)2CO = NH4OCN
Finally Ammonia Cyanate decomposes to isocyanic acid and ammonia
Isocyanic Acid: HOCN
- NH4OCN = HOCN + NH3