Pressure swing adsorption for carbon dioxide sequestration

2nd Mercosur Congress on Chemical Engineering 4th Mercosur Congress on Process Systems Engineering

PRESSURE SWING ADSORPTION FOR CARBON DIOXIDE SEQUESTRATION
Carlos A. Grande *, Simone Cavenati, Alírio E. Rodrigues
Laboratory of Separation and Reaction Engineering (LSRE), Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias (4200-465), Porto, Portugal.

Abstract. The members of the MERCOSUR as well as the European Union have agreed in the Kyoto protocol to diminish 12% the emissions of carbon dioxide up to 2010. Carbon dioxide emissions are quite high in the entire European continent with many countries being in the top 20 larger polluting countries of the world. Co-generation of electricity and heat has proved to be one of the most efficient and less polluting technologies for power generation. Even though, these centrals are still based on the combustion of fossil fuels, requiring additional processes for carbon dioxide sequestration and concentration for further uses. Many alternatives are already available for CO capture from flue gases: cryogenic process, absorption with monoethanolamine, MEA and membranes. Up to 1995, Pressure Swing Adsorption (PSA) adsorption technologies were the ones having the higher capture efficiency, although was penalized by global economics. In this work we studied the feasibility of concentration and capture of carbon dioxide from flue gases of electric power centrals by Pressure Swing Adsorption (PSA) units. Two different adsorbents, zeolite 13X and activated carbon, were used as selective adsorbents for carbon dioxide. We used a four-step cycle comprising pressurization, feed, counter-current blowdown and purge at temperature around 373 K, conditions of a typical co-generation exhaust stream. Following, scale-up and process economics (installation and operational costs and its impact in energy price) were evaluated.
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Keywords: Carbon Dioxide, Sequestration and