(754g) Thermodynamic Modelling of FeCO3 Solubility Using the Extended Uniquac Model | AIChE

(754g) Thermodynamic Modelling of FeCO3 Solubility Using the Extended Uniquac Model


Appelquist, I. - Presenter, Technical University of Denmark
Thomsen, K., Technical University of Denmark
CO2 corrosion is receiving more attention these days, as we need to reduce the emission of greenhouse gases. CO2 is present in many processes including biogas, carbon capture and storage, the cement-, and in the oil and gas industries, and their presence result in corrosion of the equipment and pipelines, which over time will lead to significant production losses and costly shutdowns.

One way to reduce corrosion is to engineer/manipulate/tailor the precipitation of the protective layer formed by FeCO3. Detailed knowledge of the FeCO3 solubility is important in the prediction on CO2 corrosion as studies suggest that the protective layer is not forming below 60 °C[1]–[5].

This study focus on the thermodynamic modelling of FeCO3 solubility in water, salt solutions, and under the influence of CO2 partial pressure. The purpose is to create a thermodynamic model, which describes these systems. It is important that the model is able to accurately predict phase equilibria and physical/chemical properties of this system. The Extended UNIQUAC model is applied as it has previously been shown to be able to model these kind of systems [6]. Parameters in the thermodynamic model are determined based on the obtained experimental data.

The interaction parameters, u0 and uT, the surface, and volume parameters, r and q used in the Extended UNIQUAC model are fitted using experimental SLE data. The parameters in the model are optimized by minimizing the sum of squared residuals of each data point.

Through comparing the obtained experimental SLE data with the model, the validity/ability of the Extended UNIQUAC is corroborated.

This work is relevant for future understanding, and process simulation of systems dealing with CO2 corrosion.


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[6] K. Thomsen, “Aqueous electrolytes : model parameters and process simulation,” Ph.D thesis, DTU, 1997. https://doi.org/10.11581/dtu:00000074