Jeffrey Drese
Jeff Drese
Ph.D. Pre-Candidate
Georgia Institute of Technology
School of Chemical & Biomolecular Engineering
311 Ferst Drive NW
Atlanta, GA 30332-0100
Office: 2314 ES&T
Labs: 2315, 2350, 2385 ES&T
Telephone: 404-385-2371
Fax: 404-894-2866
jeffrey.drese@chbe.gatech.edu
University of Florida
B.S. Chemical Engineering, May 2004
Research Project: “Organic and Organometallic Surface Functionalization of Oxides for Catalytic and Adsorptive Applications”
Ph.D. Advisor: Christopher W. Jones
Research Summary:
The US Department of Energy has advocated Carbon Capture and Sequestration (CCS) as a temporary solution to reduce the US’s carbon footprint in order to slow or stop the rising atmospheric concentration of CO2. The National Energy Technology Laboratory (NETL) has estimated an 84% increase in the cost of electricity if the current benchmark, aqueous amine technology, is used. However, this does not meet their targeted goal of less than a 20% increase in the cost of electricity for advanced CO2 capture systems. It is believed that this reduction in the cost of capture is crucial for CCS to be fully deployed.
In a typical aqueous amine process, a large amount of energy is wasted on heating water in the stripping step required to regenerate the absorbent. Additionally, because both the amines and water are volatile, the solution composition must be adjusted as components evaporate. An alternative to using aqueous amines would be to use a solid CO2 adsorbent. A solid with a large capacity for CO2 should be much more energy efficient, because of the elimination of the need to heat water in the regeneration step. It is this type of adsorbent that is the focus of this research.
We have developed a solid, supported-amine adsorbent for this purpose called Hyperbranched-Aminosilica (HAS). This adsorbent consists of a hyperbranched aminopolymer covalently tethered to a mesoporous silica support. It is synthesized by the polymerization of aziridine from silanol functional groups on the support. Currently, efforts are focused on determining the effects of varied aminopolymer loading and capture temperature on the adsorptive properties of HAS. This information is vital if these adsorbents are ever to be used on the industrial scale.
Synthesized adsorbents are characterized by an array of techniques. Structural characteristics such as ordered mesoporosity, surface area, and pore diameter are measured by x-ray diffraction and N2 physisorption. The adsorbents’ aminopolymer loadings are determined by elemental analysis and thermogravimetric analysis. In order to be characterized, the aminopolymer must be cleaved from the silica support. Then the polymer’s molecular weight is measured by size exclusion chromatography and the ratio of 1°:2°:3° amines is found by inversely-gated 13C solution nuclear magnetic resonance spectroscopy.
The adsorptive properties of HAS are measured by three apparatuses. CO2 capture capacity is measured by a packed bed flow system analyzed by a mass spectrometer. The structural adducts formed during adsorption are determined by in situ infrared spectroscopy. Kinetics and adsorption isotherms are measured by a pressure decay cell. This information can then be used to determine the heat of adsorption of the materials. The measurement of these adsorptive properties is essential to understanding the effect of varied aminopolymer loading, capture temperature, and the presence of water during adsorption with the HAS adsorbent.