Special Joint ChBE/ME Seminar: Cor J. Peters
Friday, March 12, 2010
DeWALT Seminar Room, 2164 Glenn L. Martin Hall
Professor F. Joseph Schork
Carbon Dioxide, a Nuisance or a Blessing?
Presented by Cor Peters
Department of Chemical Engineering
The Petroleum Institute
Abu Dhabi, United Arab Emirates
By now the content of carbon dioxide (CO2) in our environment has reached a level that drastic measures are required to control and even to reduce further depletion of CO2. Industrial and societal activities like power generating by burning fossil fuels, cement and steel-making and, last but not least, the transportation sector, are the major sources of CO2 depletion. Worldwide extensive programs are in progress to study the various long term effects of the excessive amounts of CO2 in our environment and to develop methods for carbon capture and storage (CCS). One of the possible approaches to reduce the CO2 content is to store it as clathrate hydrate in sediments on the ocean floor.
Alternatively, the characteristic behavior of CO2 in mixtures makes this species a prominent chemical in all kind of industrial applications. For instance, when a mixture of an organic solvent and a solute is compressed with CO2, at low concentrations of CO2 (i.e., at lower pressures) it acts as a co-solvent towards the solute, while at higher concentrations (i.e., at higher pressures) it changes nature and becomes an anti-solvent towards the solute. In the latter case, precipitation of the solute may occur. This phenomenon plays an important role in designing controllable micronization processes of all kind of materials like, for instance, pharmaceuticals.
Another example where CO2 is most useful is in combining reactions and separations. The basis of this application is the observation in phase behavior that CO2 always is able to force an heterogeneous fluid phase system into an homogeneous phase. This generally applicable principle in phase behavior allows the CO2-pressure to control the number of phases in the system. This phenomenon, called miscibility windows, can be applied in all kind of reacting systems, where the homogeneous phase (high pressure) is most suitable for the reaction whereas the heterogeneous phase (lower pressure) gives the proper conditions to perform the separation of the reaction product. This approach has been successfully applied in reacting systems with ionic liquids as the solvent.
This presentation aims to discuss some issues related to carbon capture and storage CCS), while on the other hand it will be demonstrated how CO2 can be applied successfully in modern industrial applications. In particular, the special thermodynamic features behind the application of CO2 in mixtures will be highlighted.