Grantee Research Project Results
Final Report: Capturing CO2 with MgO Aerogels
EPA Grant Number: SU835339Title: Capturing CO2 with MgO Aerogels
Investigators: Dong, Winny , Slackey, Cornelius , Kok, David , Li, Mingheng , Faltens, Tanya , Pan, Yu Hsin (Cindy)
Institution: California State Polytechnic University - Pomona
EPA Project Officer: Page, Angela
Phase: I
Project Period: August 15, 2012 through August 14, 2013
Project Amount: $14,644
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2012) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Air Quality , P3 Challenge Area - Chemical Safety , P3 Awards , Sustainable and Healthy Communities
Objective:
Carbon dioxide (CO2) capture on solid sorbents is an important technique in the context of greenhouse gas emission reduction as well as adsorption enhanced reaction processes. Traditional CO2 adsorbents such as hydrotalcite, alumina, and zeolites have been extensively investigated. This work focused on the study of sol-gel derived Magnesium Oxide (MgO) aerogels, which have a great potential for CO2 capture because of their large surface area and amorphous structure. MgO aerogels were also doped with sodium in an attempt to increase its absorbance capacity for CO2.
The objectives of this study were to determine and optimize MgO’s CO2 adsorption capacity in a simulated flue gas environment for implementation in various chemical and power plants, and to characterize the both the adsorption and desorption kinetics to determine the practicality and economic feasibility of using MgO aerogels as a CO2 capture medium for those industries. Some examples of industries that produce flue gases with a high concentration of CO2 are fossil fuel-fired power plants, industrial furnaces, amine plants, and cement plants.
This study had two components, the first was to synthesize and characterize the MgO aerogels and Na-doped MgO aerogels. This included optimizing the synthesis and testing procedures, surface area measurements, and CO2 adsorption capacity measurements under ideal conditions (through thermogravimetric analysis, TGA). The capacity of the aerogels after repeated cycling was also measured. The adsorption and desorption kinetics of the aerogels were modeled.
The second component of the study was to to simulate the flue gas capture environment and to study the CO2 adsorption characteristics of MgO aerogels and Na-doped MgO aerogels under such an environment. To accomplish this component, a bench-top size packed-bed reactor (PBR) was constructed, which can be fed a variety of gases at the appropriate flow rate and temperature. The aerogel data can then be compared to that of commercially available adsorbents.
The students, all undergraduates, were actively involved in the design of experiments, laboratory activities, and analysis of data, as well as presentation of results and seeing how their scientific endeavors can positively affect the society. The experiments designed for this research project will also be integrated into the upper-division laboratory courses in the Chemical and Materials Engineering department at Cal Poly Pomona.
Cal Poly Pomona has a campus-wide sustainability initiative. The students on this project will share their progress and results with the campus and the broader community through dissemination programs and conferences as part of this initiative.
Summary/Accomplishments (Outputs/Outcomes):
High surface area MgO aerogels and Na-doped MgO aerogels have been successfully synthesized. TGA characterization indicate that under ideal conditions, MgO aerogels have significant higher CO2 adsorption capacity compared to crystalline MgO and other commercially available adsorbents. Additionally, Na-doping further increases the adsorption capacity of MgO aerogels. The cyclic testing of MgO aerogels also show potential in maintaining a high CO2 adsorption capacity over multiple cycles.
In order to measure the CO2 adsorption capacity of MgO aerogels under conditions that simulate industrial settings, a PBR was designed, built, and calibrated by the team. The initial calibration was conducted with Na-doped alumina under both dry and wet conditions. By comparing the PBR results from the dry condition and the TGA data, it can be seen that the two tests are comparable. It was also shown that the presence of water promotes CO2 adsorption. Since flue gas has water vapor, MgO aerogels may perform better in the “realistic” conditions than the “ideal” conditions.
On-going experiments include testing MgO aerogels and Na-doped MgO aerogels in the PBR under both dry and wet conditions and over multiple cycles. Replicating the TGA data for Na-doped MgO aerogels and using those results to determine an optimum Na-doping concentration. Finally, the TGA and PBR results will be used to calculate the kinetics of adsorption and desorption for MgO aerogels.
Conclusions:
The Phase I project has shown the promise of MgO aerogels and Na-doped MgO aerogels as effective CO2 adsorbents for industrial applications. The project has demonstrated the significant improvement in CO2 adsorption capacity these aerogels have over commercially available adsorbents, especially at temperatures near 250 °C, typical for flue gases. The aerogels also show promise for good multi-cycle performance. By the end of the Phase I project (August 15, 2013), the team expects to have PBR cyclic performance data of MgO aerogels under both dry and wet conditions. The combination of small scale thermogravimetric analyzer testing and simulated industrial setting testing with the pack bed reactor will ultimately lead to real world application testing. This may result in MgO aerogels being used in industry as a high CO2 adsorbent material which may contribute to lower CO2 emissions from power station sources.
Journal Articles:
No journal articles submitted with this report: View all 1 publications for this projectSupplemental Keywords:
MgO, Aerogels, Carbon Dioxide CaptureThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.