Assessing the Viability of GeO 2 /GeO Redox Thermochemical Cycle for Converting CO 2 into Solar Fuels

Rahul R. Bhosale (), Shelby Adams, Zachary Allen, Gabrielle Bennett, Edvinas Berezniovas, Taylor Bishop, Michael Bonnema, Sequoia Clutter, Ryan Fagan, Jordan Halabrin, Mason Hobbs, Daniel Hunt, Miguel Ivarra, Mattigan Jordan, Pooja Karunanithi, Julianna Mcreynolds, Valerie Ring, Samuel Smith and Jonathan West
Additional contact information
Rahul R. Bhosale: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Shelby Adams: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Zachary Allen: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Gabrielle Bennett: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Edvinas Berezniovas: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Taylor Bishop: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Michael Bonnema: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Sequoia Clutter: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Ryan Fagan: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Jordan Halabrin: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Mason Hobbs: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Daniel Hunt: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Miguel Ivarra: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Mattigan Jordan: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Pooja Karunanithi: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Julianna Mcreynolds: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Valerie Ring: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Samuel Smith: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA
Jonathan West: Department of Chemical Engineering, University of Tennessee, 615 Mccallie Ave, Chattanooga, TN 37403, USA

Sustainability, 2024, vol. 16, issue 6, 1-20

Abstract: The solar thermochemical process of splitting CO 2 , known as CDS, is studied here using a redox cycle involving GeO 2 /GeO. The required thermodynamic data for a second-law-efficiency analysis is obtained from the HSC Chemistry software. The goal of this study is to investigate how different parameters, such as the operating temperatures and molar flow rate of the inert sweep gas, as well as the inclusion of separation units, heat exchangers, heaters, and coolers, can affect the solar-to-fuel energy conversion efficiency of the GeO 2 /GeO cycle. All calculations assume a constant gas-to-gas heat recovery effectiveness of 0.5. The analysis shows that the solar-to-fuel energy conversion efficiency is lower at a thermal reduction temperature of 1600 K (11.9%) compared to 2000 K. This is because high energy duties are required for heater-2, heater-3, and separator-1 due to the need for a higher inert gas flow rate. After conducting a comparative analysis of the three CDS cycles, it can be inferred that the GeO 2 /GeO cycle exhibits a significantly higher solar-to-fuel energy conversion efficiency in comparison to the ZnO/Zn and SnO 2 /SnO cycles across all thermal reduction temperatures. According to the comparison, it is confirmed that the GeO 2 /GeO CDS cycle can achieve a reasonably high solar-to-fuel energy conversion efficiency of 10% at less than 1600 K. On the other hand, ZnO/Zn and SnO 2 /SnO CDS cycles require a thermal reduction temperature of more than 1850 K to achieve a solar-to-fuel energy conversion efficiency of 10%.

Keywords: GeO 2 /GeO cycle; CO 2 splitting; solar fuels; thermodynamic model; efficiency (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2024
References: View references in EconPapers View complete reference list from CitEc
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