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dc.contributor.advisorJackson, Gregory
dc.contributor.authorImponenti, Luca
dc.date.accessioned2018-12-12T23:07:47Z
dc.date.accessioned2022-02-03T13:11:06Z
dc.date.available2018-12-12T23:07:47Z
dc.date.available2022-02-03T13:11:06Z
dc.date.issued2018
dc.identifierImponenti_mines_0052E_11632.pdf
dc.identifierT 8625
dc.identifier.urihttps://hdl.handle.net/11124/172807
dc.descriptionIncludes bibliographical references.
dc.description2018 Fall.
dc.description.abstractRedox cycles with reducible perovskite oxides of the form ABO$_3$ can provide thermochemical energy storage (TCES) with higher energy density and storage temperatures than molten-salt systems for large-scale energy storage in concentrating solar power (CSP). Perovskites from earth abundant cations are desirable for cost-effective solutions, but such materials must demonstrate appropriate thermodynamics for high specific TCES and favorable kinetics for heat-driven reduction and exothermic re-oxidation. This dissertation explores the thermodynamics and kinetics of doped CaMnO$_{3-\delta}$ particles for TCES redox cycles where particles are heated and reduced in N$_2$ ($P_{\text{O2}} \approx 10^{-4}$ bar) to high temperatures (700 to $1000^{\circ}$C) in a solid-particle solar receiver. Chemical and sensible energy stored in the reduced perovskite particles is released as needed to a supercritical CO$_2$ power cycle via re-oxidation and cooling of the material. Thermodynamics of Ca$_{1-x}$Sr$_x$MnO$_{3-\delta}$ ($x=0.05$ and $0.1$) and CaCr$_y$Mn$_{1-y}$O$_{3-\delta}$ ($y=0.05$ and $0.1$) are characterized through thermogravimetric analysis and calorimetry. Results indicate Ca$_{1-x}$Sr$_x$MnO$_{3-\delta}$ compositions can store over 200 kJ kg$^{-1}$ more specific energy storage compared to inert particulate TES media for $T \ge 900^\circ$C; the specific energy storage potential of Ca$_{0.9}$Sr$_{0.1}$MnO$_{3-\delta}$ at $T=900^\circ$C and $P_\text{O2}=10^{-4}$ bar is 706 kJ kg$^{-1}$. Challenges are expected achieving these high values of energy storage in a transport-limited receiver with low residence time for CSP. Redox kinetics are explored in a packed bed reactor with rapid heating capabilities. Results in isothermal tests show that oxidation is significantly faster than reduction. Modeling of packed bed experiments indicate that reduction at $T \ge 800^\circ$C is limited by build-up of oxygen in the gas phase and equilibrium thermodynamics between the solid and gas phases. Long-term redox cycling tests, which simulate a nominal TCES cycle, demonstrate excellent chemical stability for all materials. A standard deviation of 1.9\% on the extent of reduction over 1000 cycles was observed for Ca$_{0.9}$Sr$_{0.1}$MnO$_{3-\delta}$. Modeling efforts of the packed bed experiments allow for characterization of redox kinetics, to be implemented in computational models for system component design. One of the most promising compositions, Ca$_{0.9}$Sr$_{0.1}$MnO$_{3-\delta}$, is implemented in a 1-D receiver model to explore designs and operating conditions for perovskite-based energy storage systems.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.relation.ispartof2010-2019 - Mines Theses & Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.subjectconcentrated solar power
dc.subjectredox cycles
dc.subjectcalcium manganite
dc.subjectthermochemical energy storage
dc.subjectperovskite
dc.titleRedox cycles with doped calcium manganites for high-temperature thermochemical energy storage in concentrating solar power
dc.typeText
dc.contributor.committeememberO'Hayre, Ryan P.
dc.contributor.committeememberKee, R. J.
dc.contributor.committeememberBraun, Robert J.
thesis.degree.nameDoctor of Philosophy (Ph.D.)
thesis.degree.levelDoctoral
thesis.degree.disciplineMechanical Engineering
thesis.degree.grantorColorado School of Mines


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