Analysis of thermally coupled chemical looping combustion-based power plants with carbon capture

Handle URI:
http://hdl.handle.net/10754/597566
Title:
Analysis of thermally coupled chemical looping combustion-based power plants with carbon capture
Authors:
Iloeje, Chukwunwike; Zhao, Zhenlong; Ghoniem, Ahmed F.
Abstract:
© 2015 Elsevier Ltd. 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 3bar, 1000C and 60% at 4bar, 1400C. 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.
Citation:
Iloeje C, Zhao Z, Ghoniem AF (2015) Analysis of thermally coupled chemical looping combustion-based power plants with carbon capture. International Journal of Greenhouse Gas Control 35: 56–70. Available: http://dx.doi.org/10.1016/j.ijggc.2015.01.013.
Publisher:
Elsevier BV
Journal:
International Journal of Greenhouse Gas Control
Issue Date:
Apr-2015
DOI:
10.1016/j.ijggc.2015.01.013
Type:
Article
ISSN:
1750-5836
Sponsors:
This study is financially supported by a grant from the MAS-DAR Institute of Science and Technology and the King Abdullah University of Science and Technology (KAUST) Investigator Award.
Appears in Collections:
Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorIloeje, Chukwunwikeen
dc.contributor.authorZhao, Zhenlongen
dc.contributor.authorGhoniem, Ahmed F.en
dc.date.accessioned2016-02-25T12:42:11Zen
dc.date.available2016-02-25T12:42:11Zen
dc.date.issued2015-04en
dc.identifier.citationIloeje C, Zhao Z, Ghoniem AF (2015) Analysis of thermally coupled chemical looping combustion-based power plants with carbon capture. International Journal of Greenhouse Gas Control 35: 56–70. Available: http://dx.doi.org/10.1016/j.ijggc.2015.01.013.en
dc.identifier.issn1750-5836en
dc.identifier.doi10.1016/j.ijggc.2015.01.013en
dc.identifier.urihttp://hdl.handle.net/10754/597566en
dc.description.abstract© 2015 Elsevier Ltd. 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 3bar, 1000C and 60% at 4bar, 1400C. 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.en
dc.description.sponsorshipThis study is financially supported by a grant from the MAS-DAR Institute of Science and Technology and the King Abdullah University of Science and Technology (KAUST) Investigator Award.en
dc.publisherElsevier BVen
dc.subjectChemical looping combustion (CLC)en
dc.subjectPower generation process modelingen
dc.subjectRegenerative CLC cycleen
dc.subjectThermally balanced CLC reactoren
dc.subjectThermally coupled rotary reactoren
dc.subjectThermodynamic analysisen
dc.titleAnalysis of thermally coupled chemical looping combustion-based power plants with carbon captureen
dc.typeArticleen
dc.identifier.journalInternational Journal of Greenhouse Gas Controlen
dc.contributor.institutionMassachusetts Institute of Technology, Cambridge, United Statesen
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