Phase equilibrium for Industrially Important Processes

Phase equilibrium description underlies the design and optimization of many industrially important processes. Our group works on experimental measurement, thermodynamic modeling, and algorithm development in the phase equilibrium area for various industrial processes. We currently offer an MSc project in collaboration with Haldor-Topsøe on Phase Equilibrium Modeling of the Ammonia-Carbon Dioxide-Water system. We can also offer projects on

• Thermodynamic modeling of complex mixtures
• Robust and efficient algorithms for phase equilibrium/chemical equilibrium calculation
• Modeling and simulation of CO₂ geological storage
• Measurement of phase equilibrium and thermophysical properties
• Estimation of thermodynamic properties

You can find more details about our research profile through the link

https://www.kemi.dtu.dk/english/research/physicalchemistry/cere/weiyan

MSc project in collaboration with Haldor-Topsøe

Phase Equilibrium Modeling of the Ammonia-Carbon Dioxide-Water System

The ammonia-carbon dioxide-water system is of great industrial importance and it is crucial to describe accurately its phase equilibrium, sometimes in the presence of other components, for reliable process analysis or simulation. The existing models available in commercial software are not satisfactory in many aspects. There is a lack of consensus on the modeling approach. Different models have been recommended but there is no systematic comparison. It is not always clear how the model parameters are obtained, resulting large uncertainties in the prediction results, in particular, at extreme temperature and pressure conditions. In addition, many existing codes are not sufficiently robust to handle simultaneous chemical and phase equilibrium (CPE) required in this system.

This project intends to improve the phase equilibrium modeling of the ammonia-carbon dioxide-water system using the advanced thermodynamic models and the state-of-the-art CPE calculation algorithm. The project will be in collaboration with Haldor-Topsøe and it consists of the following aspects:

1. Literature study of the aqueous system with weak electrolytes (ammonia and carbon dioxide), including a systematic compilation of related reaction equilibrium constants and equilibrium constants.
2. Modeling of the system using the non-stoichiometric CPE algorithms in a wide temperature and pressure range.
3. Application of a more accurate electrolyte model, like the extended UNIQUAC, to modeling the phase equilibrium of the ammonia-carbon dioxide-water system.
4. Comparison of modeling results with the literature data and improvement of model performance through parameter tuning.