Comparison of Equilibrium- Stage and Rate Based Model of an Absorption Column for a CO2-MEA system

Comparison of Equilibrium- Stage and Rate Based Model of an Absorption Column for a CO2-MEA system

Balvalli, P.

Vlugt, T.J.H. (mentor)
van Goethem, M.W.M. (mentor)

Mechanical, Maritime and Materials Engineering

Process and Energy

2017-03-27

The desorption step of the carbon dioxide absorption/desorption process is an extremely energy intensive process, which accounts for approximately 70% of operating cost according to Mofarahi et al. [2008]. Technip-ECN has proposed a solution of Heat integrated distillation column which will be adapted for the absorption process. In order to develop a model for this new column, an equation based model of the regular absorption column was required to be made where the equations are written in residual form so that the programmer has control over the parameters and equations. In this study, two models of CO2 absorption were developed in Python which represent the two different approaches that exist in literature, namely the rate based model and the equilibrium model. These models are then compared against each other on the basis of their ability to predict experimental data in four varying conditions. The key research question is to find out if the models can predict the temperature bulge inside the absorption column and what factors affect the position and shape of the temperature bulge. The results show that the rate based model gives better predictions as compared to the equilibrium model. The rate based model further reveals that competing absorption and evaporation processes produce the temperature bulge and that the position and shape of the bulge can be changed by changing the extent of absorption and evaporation. It is observed that the results of the rate based model are dependent on the model parameters such as mass transfer coefficient, enhancement factors, rate constants etc. This model is recommended to be used in the second stage of the project.

http://resolver.tudelft.nl/uuid:b843b27c-177b-4482-8e11-274c8b9d5ee8

Student theses

master thesis

(c) 2017 Balvalli. P.