A phase model for the gas–liquid equilibria in the ammonia–carbon dioxide–water–urea system in chemical equilibrium at urea synthesis conditions. II. Experimental verification

Bubble- and critical-points in the ammonia–carbon dioxide plane and ammonia–urea system are presented as well as bubble-points in the carbon dioxide–urea system. In order to confirm the form of a previously presented phase model a large number of bubble- and dew-points were measured at various ammonia–carbon dioxide–water–urea compositions (including those most important to the urea industry) in the range of 140 ⩽ T ⩽ 200°C and 15 < P < 400 atm. All of the measurements were carried out under conditions of complete chemical equilibrium. The results are in agreement with the ternary phase model presented in a previous article.