Virtually Accessible Laser Heated Stagnation Flow Reactor for Characterizing Redox Chemistry of Materials Under Extreme Conditions
LaboratorySandia National Laboratories (SNL)
Capability ExpertAnthony McDaniel
Node Readiness Category1: Solar Thermochemical (STCH)
High temperature flow system equipped with an optically-accessible stagnation flow reactor (SFR), automated mass flow and pressure control systems, mass spectrometer, and 500W CW near-IR diode laser for sample heating during thermal reduction. In stagnation flow, the gas-phase region above the sample is an ideal one-dimensional stagnation plane governed by diffusive transport. An idealized flow field is key to the numerical approach used for data analysis. Model-based data reduction extracts the intrinsic kinetic behavior of the material by accounting for: 1) kinetic processes occurring in the solid state based on proposed reaction mechanisms; 2) the transient nature of the experimental information; 3) detector time lag; and 4) dispersion/mixing of the H2 evolved from the solid as it is transported downstream of the reactor volume to the detector. Approximately 100mg of sample material is required. During thermal reduction, samples can be heated to 1600°C (or greater if desired) using a diode laser. The energy flux and heating rate(>>20°C/s) closely mimic the thermal environment expected in a concentrated solar power application. Gas composition of the reactor effluent is measured by a mass spectrometer. The Laser-heated SFR is fully automated and accessible through a remote desktop and internet connection.
System operates routinely at 1/10 atm pressure, and can cycle material several times per hour. SFR can only accommodate one sample at a time. In addition, heating furnace to the baseline operating temperature takes 90 min or longer. This limits sample throughput to one per a day.
The SFR facility is the only laser heated system in use by STCH community today, and likely the only one virtually accessible. Combined with staff expertise and codes developed for model-based data analysis, this facility is a unique capability within the National Labs system. It enables performance evaluation of reactive materials for solar‑thermochemical hydrogen production under real‑world conditions (namely high heat flux).
The reactor is located at Sandia National Laboratories in CA, and available for use with external collaborators. It is also a virtual laboratory that can be accessed by collaborators from their home institutions.
Performance evaluation and screening of reactive materials for solar‑thermochemical hydrogen production under real‑world conditions (namely high heat flux).
J. R. Scheffe, A. H. McDaniel, M. D. Allendorf, and A. W. Weimer, "Kinetics and Mechanism of Solar-Thermochemical H2 Production by Oxidation of a Cobalt Ferrite–Zirconia Composite," Energy Environ. Sci., vol. 6, no. 3, p. 963, 2013.
A. H. McDaniel, E. C. Miller, D. Arifin, A. Ambrosini, E. N. Coker, R. O'Hayre, W. C. Chueh, and J. Tong, "Sr- and Mn-doped LaAlO3-δ for Solar Thermochemical H2 and CO Production," Energy Environ. Sci., vol. 6, no. 8, pp. 2424–2428, 2013.
D. Arifin, V. J. Aston, X. Liang, A. H. McDaniel, and A. W. Weimer, "CoFe2O4 on a Porous Al2O3 Nanostructure for Solar Thermochemical CO2 Splitting," Energy Environ. Sci., vol. 5, no. 11, pp. 9438–9444, 2012.