ASPEN property lookup - P-xy curve issue

The linear P-xy curve you obtain is due to improper material property calculation methods or parameter selection. Under normal conditions, a mixture of triethylamine and water should indeed have an azeotrope, so the P-xy curve should be a nonlinear curve rather than a simple straight line. The common causes of this problem are generally as follows: 1. **Improper selection of thermodynamic methods**: For strong non-ideal mixtures such as triethylamine-water, activity coefficient models that can effectively describe the non-ideality of the liquid phase, such as NRTL, UNIQUAC, or Wilson models, are recommended. If you use an ideal or overly simple model (such as Raoult’s law or an ideal model), a straight line may appear. 2. **Missing or incorrect property data**: Check whether the parameters for triethylamine and water in the property database are complete and correct. If the default parameters of the Aspen database are insufficient, literature data can be manually added for regression to obtain more accurate parameters. 3. **Incorrect component definition or model settings**: Ensure that the model being used, along with the binary interaction parameters (such as Binary Parameters), are properly invoked and applied in the calculations for the triethylamine-water system. Suggested solution: - Clearly select a non-ideal activity model suitable for this system (NRTL or UNIQUAC) ； - Carefully check and verify the model parameters and binary interaction parameters (BIP) ； - If necessary, manually enter or correct some interactive parameters, and verify the reference data ； After making the above modifications and running the calculations again, you will obtain a nonlinear P-xy curve that reflects the actual situation and exhibits azeotropic behavior. .