Analysis of thermally coupled chemical looping combustion-based power plants with carbon capture
Name
Ghoniem_Analysis of .pdf
Size
1.62 MB
Format
Adobe PDF
Checksum (MD5)
862aeab626b46aa8e2ee08b8c1aa4e2b
Author(s)
Ghoniem, Ahmed F
Iloeje, Chukwunwike Ogbonnia
Zhao, Zhenlong
Date Issued
February 2015
Journal
International Journal of Greenhouse Gas Control
Publisher
Elsevier
Citation
Iloeje, Chukwunwike; Zhao, Zhenlong and Ghoniem, Ahmed F. “Analysis of Thermally Coupled Chemical Looping Combustion-Based Power Plants with Carbon Capture.” International Journal of Greenhouse Gas Control 35 (April 2015): 56–70. © 2015 Elsevier Ltd
Version
Author's final manuscript
Abstract
A number of CO₂ capture-enabled power generation technologies have been proposed to address the negative environmental impact of CO₂ emission. One important barrier to adopting these technologies is the associated energy penalty. Chemical-looping Combustion (CLC) is an oxy-combustion technology that can significantly lower this penalty. It utilizes an oxygen carrier to transfer oxygen from air/oxidizing stream in an oxidation reactor to the fuel in a reduction reactor. Conventional CLC reactor designs employ two separate reactors, with metal/metal oxide particles circulating pneumatically in-between. One of the key limitations of these designs is the entropy generation due to reactor temperature difference, which lowers the cycle efficiency. Zhao et al. (Zhao et al., 2014 ; Zhao and Ghoniem, 2014) proposed a new CLC rotary reactor design, which overcomes this limitation. This reactor consists of a single rotating wheel with micro-channels designed to maintain thermal equilibrium between the fuel and air sides. This study uses three thermodynamic models of increasing fidelity to demonstrate that the internal thermal coupling in the rotary CLC reactor creates the potential for improved cycle efficiency. A theoretical availability model and an ideal thermodynamic cycle model are used to define the efficiency limits of CLC systems, illustrate the impact of reactor thermal coupling and discuss relevant criteria. An Aspen Plus® model of a regenerative CLC cycle is then used to show that this thermal coupling raises the cycle efficiency by up to 2% points. A parametric study shows that efficiency varies inversely with pressure, with a maximum of 51% at 3 bar, 1000 C and 60% at 4 bar, 1400 C. The efficiency increases with CO₂ fraction at high pressure ratios but exhibits a slight inverse dependence at low pressure ratios. The parametric study shows that for low purge steam demand, steam generation improves exhaust heat recovery and increases efficiency when an appropriate steam production strategy is adopted.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivs License
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1016/j.ijggc.2015.01.013
