The Allam Cycle is an oxy-fuel power generation process which uses hydrocarbon fuels, with nearly all atmospheric emissions including the generated carbon dioxide (CO2) being captured. In designing the compressors/pumps of the Allam Cycle, it is required that the vapour-liquid equilibrium (VLE) phase behaviour of the working fluid can be predicted.
The Objectives
The objective of this project was to investigate the reliability of two widely used models for predicting phase equilibrium, by experimentally studying mixtures of sCO2 with different impurities. The measurements were conducted using custom-built microwave resonators to perform dew-and bubble-point measurements over a range of compositions and conditions.
Project Findings and Recommendations
The apparatus designed and assembled for this project was successful in providing relevant phase behaviour measurements, along isochoric, isobaric, and isothermal pathways. A unique methodology was developed for preparing mixtures with low water content as an impurity, to access aqueous dew points, and handling of the mixtures to avoid phase separation during sample loading. The results obtained in this work reveal that the two thermodynamic models investigated can both be reliably used to predict VLE phase envelops for the CO2 streams used in the Allam cycled. However, the selection of preferred model is dependent on the stream composition and stage of the Allam cycle, according to the inlet/outlet conditions of the compressors and pumps.
Project Reseachers
- Prof. Eric F. May
- A/Prof. Paul L. Stanwix
- Dr Liam Tenardi
- Dr Ehsan Sadeghi Pouya
Project Status
Complete
Partners
