Techno-Economic Analysis of Carbon Dioxide Separation from Different Flue Gases

Kurzfassung

In response to increasing environmental concerns and globally growing energy demand, CO2 capture, re-use and storage technologies have been proposed to reduce the emissions of carbon dioxide resulting from fossil fuel combustion and use it again to produce new synthetic fuels. In the present thesis, the post-combustion CO2 capture with amine solvents is studied. It is the most mature CO2 capture technology especially for large scale applications like cement or natural coal-fired power plants. The main originality of this work is to simultaneously consider both aspects within a global model of the CO2 capture process applicable for three different flue gases assessing energy demand and cost estimation. An Equilibrium and Rate-Based Aspen Plus model was built in order to remove the CO2 from different flue gases using the MEA as a solvent with a concentration of 30-40 wt%. This model was used to analyze the effects of process variables such as the MEA mass fraction, the theoretical number of stages and the reflux ratio on the CO2 purity which vary in this process between 97-99.9% and the energy requirements. Finally, heat integration was performed using the pinch point analysis to reduce the energy consumption as well as the operating cost of about 50% and the total annualized cost of 2%. However, different drawbacks still limit the development of this model. At the operational level the two main drawbacks are the high energy requirement for desorbing the CO2 and the solvent losses.