Kilic, Sevgi
(2004)
ENGINEERING OF POLYMERS TO THICKEN CARBON DIOXIDE: A SYSTEMATIC APPROACH.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Carbon dioxide (CO2) is one of the potential displacing fluids used in Enhanced Oil Recovery (EOR). However, the effective use of CO2 in EOR is hindered by its low viscosity, resulting in CO2 to "finger" towards production well and thus low sweep efficiency. The current research has aimed to bring the viscosity of CO2 to a level comparable to that of oil via dissolution of polymeric materials (thickeners) to suppress early breakthrough of CO2 in EOR. A series of fluoroacrylate-aromatic acrylate copolymers was designed and tested for their miscibility and viscosity enhancement in CO2 at 295 K. The change in the series was created by changing either the spacer length or the size of aromatic rings in the aromatic acrylate unit of the copolymer. Aforementioned copolymers were found to be highly miscible with CO2 and to impart enhancement in the viscosity of CO2, depending on the type and content of the aromatic acrylate unit in the copolymer. Increase in the viscosity was attributed to association of aromatic rings by stacking. Feasibility of EOR process depends also on the factors associated with economic and environmental issues. The current research, therefore, also aimed to explore the generation of low-cost, non-fluorous polymers to replace high cost fluoroacrylate moiety. The polymers were designed hypothesizing that a CO2-philic polymer should posses inherently low cohesive energy density, low glass transition temperature (i.e. high chain flexibility and free volume) and a number of Lewis base groups to promote cross interactions with CO2. Polymers were prepared, where possible, via modification of an existing polymer with a precursor containing Lewis base group to eliminate the effect of chain length on the phase behavior. Modifications were performed basically on silicone, polyether or hydrocarbon backbone (vinyl and allyl). The phase behavior results showed that there is a delicate balance between the forces working to increase the miscibility pressures (e.g. high cohesive energy density) or factors suppressing the entropy of mixing, and those working to lower miscibility pressures, such as enhanced specific interactions with CO2 and increased free volume or chain flexibility.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
2 February 2004 |
| Date Type: |
Completion |
| Defense Date: |
9 October 2003 |
| Approval Date: |
2 February 2004 |
| Submission Date: |
29 October 2003 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Chemical Engineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
CO2-thickener; CO2; CO2 philic polymers |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-10292003-135543/, etd-10292003-135543 |
| Date Deposited: |
10 Nov 2011 20:03 |
| Last Modified: |
15 Nov 2016 13:51 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/9535 |
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