Air separation via two-step solar thermochemical cycles based on SrFeO3−δ and (Ba,La)0.15Sr0.85FeO3−δ perovskite reduction/oxidation reactions to produce N2: rate limiting mechanism(s) determination

2021 ◽  
Vol 23 (35) ◽  
pp. 19280-19288
Author(s):  
Nhu Pailes Nguyen ◽  
Tyler P. Farr ◽  
H. Evan Bush ◽  
Andrea Ambrosini ◽  
Peter G. Loutzenhiser
Keyword(s):  
Air Separation ◽  
Oxidation Reactions ◽  
Thermochemical Cycles ◽  
Reversible Reactions ◽  
Solar Thermochemical ◽  
Rate Limiting

Two-step solar thermochemical cycles based on reversible reactions of SrFeO3−δ and (Ba,La)0.15Sr0.85FeO3−δ perovskites were considered for air separation.

scholarly journals An A- and B-Site Substitutional Study of SrFeO3−δ Perovskites for Solar Thermochemical Air Separation

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5123
Author(s):  
Tyler P. Farr ◽  
Nhu Pailes Nguyen ◽  
H. Evan Bush ◽  
Andrea Ambrosini ◽  
Peter G. Loutzenhiser
Keyword(s):  
Pechini Method ◽  
Thermal Reduction ◽  
Air Separation ◽  
Solar Irradiation ◽  
X Ray ◽  
Modified Pechini Method ◽  
Solar Thermochemical ◽  
Pressure Swing ◽  
A Site

An A‑ and B‑site substitutional study of SrFeO3−δ perovskites (A’xA1−xB’yB1−yO3−δ, where A = Sr and B = Fe) was performed for a two‑step solar thermochemical air separation cycle. The cycle steps encompass (1) the thermal reduction of A’xSr1−xB’yFe1−yO3−δ driven by concentrated solar irradiation and (2) the oxidation of A’xSr1−xB’yFe1−yO3−δ in air to remove O2, leaving N2. The oxidized A’xSr1−xB’yFe1−yO3−δ is recycled back to the first step to complete the cycle, resulting in the separation of N2 from air and concentrated solar irradiation. A-site substitution fractions between 0 ≤ x ≤ 0.2 were examined for A’ = Ba, Ca, and La. B-site substitution fractions between 0 ≤ y ≤ 0.2 were examined for B’ = Cr, Cu, Co, and Mn. Samples were prepared with a modified Pechini method and characterized with X-ray diffractometry. The mass changes and deviations from stoichiometry were evaluated with thermogravimetry in three screenings with temperature- and O2 pressure-swings between 573 and 1473 K and 20% O2/Ar and 100% Ar at 1 bar, respectively. A’ = Ba or La and B’ = Co resulted in the most improved redox capacities amongst temperature- and O2 pressure-swing experiments.

Solar Thermochemical Production of Fuels

2010 ◽  
Vol 74 ◽  
pp. 303-312 ◽  
Author(s):  
Anton Meier ◽  
Aldo Steinfeld
Keyword(s):  
Fossil Fuels ◽  
Transition Period ◽  
Liquid Fuels ◽  
Thermochemical Cycles ◽  
Concentrated Solar Energy ◽  
Long Run ◽  
Decomposition Processes ◽  
Thermochemical Processes ◽  
Technological Developments ◽  
Solar Thermochemical

High-temperature thermochemical processes efficiently convert concentrated solar energy into storable and transportable fuels. In the long run, H2O/CO2-splitting thermochemical cycles based on metal oxide redox reactions are developed to produce H2 and CO, which can be further processed to synthetic liquid fuels. In a transition period, carbonaceous feedstocks (fossil fuels, biomass, C-containing wastes) are solar-upgraded and transformed into valuable fuels via reforming, gasification and decomposition processes. The most promising solar thermochemical processes are discussed and the latest technological developments are summarized.

Numerical Study of a Beam-Down Solar Thermochemical Reactor for Chemical Kinetics Analysis

2014 ◽  
Author(s):  
Selvan Bellan ◽  
Cristina Cerpa Saurez ◽  
Jose Gonzalez-Aguilar ◽  
Manuel Romero
Keyword(s):  
Fluid Flow ◽  
Numerical Study ◽  
Flow Distribution ◽  
Chemical Conversion ◽  
Chemical Reactor ◽  
Thermal Reduction ◽  
Operating Parameters ◽  
Thermochemical Cycles ◽  
Reactor Geometry ◽  
Solar Thermochemical

A lab-scale solar thermochemical reactor is designed and fabricated to study the thermal reduction of non-volatile metal oxides, which operates simultaneously as solar collector and as chemical reactor. The main purpose of this reactor is to achieve the first step in two-step thermochemical cycles. The chemical conversion rate strongly depends on the temperature and fluid flow distribution around the reactant, which are determined by the reactor geometry. The optimal design depends on the constraints of the problem and on the operating parameters. Hence, the objective of this investigation is to analyze the heat and mass transfer in the vertically-oriented chemical reactor by a CFD model and to optimize the reactor design. The developed numerical model is validated by comparing the simulation results with reported model. The influence of different technical and operating parameters on the temperature distribution and the fluid flow of the reactor are studied.

Metal oxide composites and structures for ultra-high temperature solar thermochemical cycles

2008 ◽  
Vol 43 (14) ◽  
pp. 4714-4728 ◽  
Author(s):  
James E. Miller ◽  
Mark D. Allendorf ◽  
Richard B. Diver ◽  
Lindsey R. Evans ◽  
Nathan P. Siegel ◽  
...  
Keyword(s):  
High Temperature ◽  
Metal Oxide ◽  
Thermochemical Cycles ◽  
Solar Thermochemical ◽  
Oxide Composites ◽  
Ultra High Temperature

scholarly journals Solar thermochemical splitting of water to generate hydrogen

2017 ◽  
Vol 114 (51) ◽  
pp. 13385-13393 ◽  
Author(s):  
C. N. R. Rao ◽  
Sunita Dey
Keyword(s):  
High Temperature ◽  
Oxide System ◽  
Experimental Conditions ◽  
Thermochemical Cycles ◽  
Step Process ◽  
Carbonate Formation ◽  
High Temperature Process ◽  
Multistep Process ◽  
Solar Thermochemical ◽  
Splitting Water

Solar photochemical means of splitting water (artificial photosynthesis) to generate hydrogen is emerging as a viable process. The solar thermochemical route also promises to be an attractive means of achieving this objective. In this paper we present different types of thermochemical cycles that one can use for the purpose. These include the low-temperature multistep process as well as the high-temperature two-step process. It is noteworthy that the multistep process based on the Mn(II)/Mn(III) oxide system can be carried out at 700 °C or 750 °C. The two-step process has been achieved at 1,300 °C/900 °C by using yttrium-based rare earth manganites. It seems possible to render this high-temperature process as an isothermal process. Thermodynamics and kinetics of H2O splitting are largely controlled by the inherent redox properties of the materials. Interestingly, under the conditions of H2O splitting in the high-temperature process CO2 can also be decomposed to CO, providing a feasible method for generating the industrially important syngas (CO+H2). Although carbonate formation can be addressed as a hurdle during CO2 splitting, the problem can be avoided by a suitable choice of experimental conditions. The choice of the solar reactor holds the key for the commercialization of thermochemical fuel production.

scholarly journals Investigation of long term reactive stability of ceria for use in solar thermochemical cycles

Energy ◽  
2015 ◽  
Vol 89 ◽  
pp. 924-931 ◽  
Author(s):  
Nathan R. Rhodes ◽  
Michael M. Bobek ◽  
Kyle M. Allen ◽  
David W. Hahn
Keyword(s):  
Thermochemical Cycles ◽  
Solar Thermochemical

Solar Thermochemical Water-Splitting Ferrite-Cycle Heat Engines

Solar Energy ◽  
2006 ◽  
Author(s):  
Richard B. Diver ◽  
James E. Miller ◽  
Mark D. Allendorf ◽  
Nathan P. Siegel ◽  
Roy E. Hogan
Keyword(s):  
Iron Oxide ◽  
High Efficiency ◽  
Heat Engine ◽  
High Concentration ◽  
Thermochemical Cycles ◽  
Design Concepts ◽  
Heat Engines ◽  
Close Proximity ◽  
Solar Thermochemical ◽  
Development Approach

Thermochemical cycles are a type of heat engine that utilize high-temperature heat to produce chemical work. Like their mechanical work-producing counterparts, their efficiency depends on operating temperature and on the irreversibilities of their internal processes. With this in mind, we have invented innovative design concepts for two-step solar-driven thermochemical heat engines based on iron oxide and iron oxide mixed with other metal oxides (ferrites). These concepts utilize two sets of moving beds of ferrite reactant material in close proximity and moving in opposite directions to overcome a major impediment to achieving high efficiency – thermal recuperation between solids in efficient counter-current arrangements. They also provide inherent separation of the product hydrogen and oxygen and are an excellent match with high-concentration solar flux. However, they also impose unique requirements on the ferrite reactants and materials of construction as well as an understanding of the chemical and cycle thermodynamics. In this paper, the Counter-Rotating-Ring Receiver/Reactor/Recuperator (CR5) solar thermochemical heat engine concept is introduced and its basic operating principals are described. Preliminary thermal efficiency estimates are presented and discussed. Our results and development approach are also outlined.

scholarly journals Solar Thermochemical Water-Splitting Ferrite-Cycle Heat Engines

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Richard B. Diver ◽  
James E. Miller ◽  
Mark D. Allendorf ◽  
Nathan P. Siegel ◽  
Roy E. Hogan
Keyword(s):  
Iron Oxide ◽  
High Efficiency ◽  
Heat Engine ◽  
High Concentration ◽  
Thermochemical Cycles ◽  
Design Concepts ◽  
Heat Engines ◽  
Close Proximity ◽  
Solar Thermochemical ◽  
Development Approach

Thermochemical cycles are a type of heat engine that utilize high-temperature heat to produce chemical work. Like their mechanical work producing counterparts, their efficiency depends on the operating temperature and on the irreversibility of their internal processes. With this in mind, we have invented innovative design concepts for two-step solar-driven thermochemical heat engines based on iron oxide and iron oxide mixed with other metal oxide (ferrites) working materials. The design concepts utilize two sets of moving beds of ferrite reactant materials in close proximity and moving in opposite directions to overcome a major impediment to achieving high efficiency—thermal recuperation between solids in efficient countercurrent arrangements. They also provide an inherent separation of the product hydrogen and oxygen and are an excellent match with a high-concentration solar flux. However, they also impose unique requirements on the ferrite reactants and materials of construction as well as an understanding of the chemical and cycle thermodynamics. In this paper, the counter-rotating-ring receiver∕reactor∕recuperator solar thermochemical heat engine concept is introduced, and its basic operating principles are described. Preliminary thermal efficiency estimates are presented and discussed. Our results and development approach are also outlined.

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