Maximizing fuel production rates in isothermal solar thermochemical fuel production
Timothy C. Davenport,
Chih-Kai Yang,
Christopher J. Kucharczyk,
Michael J. Ignatowich and
Sossina M. Haile
Applied Energy, 2016, vol. 183, issue C, 1098-1111
Abstract:
Production of chemical fuels by isothermal pressure-swing cycles has recently generated significant interest. In this process a reactive oxide is cyclically exposed to an inert gas, which induces partial reduction of the oxide, and to an oxidizing gas of either H2O or CO2, which reoxidizes the oxide, releasing H2 or CO. At sufficiently high temperatures and sufficiently low gas flow rates, both the reduction and oxidation steps become limited only by the flow of gas across the material and not by material kinetic factors. In this contribution, we develop a numerical model describing fuel production rates in this gas-phase limited regime. The implications of this behavior are explored under all possible isothermal pressure-swing cycling conditions, and the outcome is optimized in terms of fuel production rate as well as fuel conversion and utilization of input gas of all types. Fuel production rate is maximized at infinitesimally small cycle times and attains a value that is independent of material thermodynamics. Gas utilization is maximized at infinitesimally small gas inputs, but the values can be made independent of cycle time, depending on manipulation of flow conditions. Gas-phase conditions (temperature, oxidant and reductant gas partial pressures, and CO2 vs H2O as oxidant) have a strong impact on fuel production metrics. Under realistic, finite cycle times, material thermodynamics play a measurable role in establishing fuel production rates.
Keywords: Solar fuels; Thermochemical cycle; Kinetics; Thermodynamics; Ceria (search for similar items in EconPapers)
Date: 2016
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (8) Track citations by RSS feed
Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0306261916313162
Full text for ScienceDirect subscribers only
Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.
Export reference: BibTeX
RIS (EndNote, ProCite, RefMan)
HTML/Text
Persistent link: https://EconPapers.repec.org/RePEc:eee:appene:v:183:y:2016:i:c:p:1098-1111
Ordering information: This journal article can be ordered from
http://www.elsevier.com/wps/find/journaldescription.cws_home/405891/bibliographic
http://www.elsevier. ... 405891/bibliographic
DOI: 10.1016/j.apenergy.2016.09.012
Access Statistics for this article
Applied Energy is currently edited by J. Yan
More articles in Applied Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu (repec@elsevier.com).