### Abstract

A 45 kW concentrating solar furnace was used to study the thermal decomposition of ZnO at a nominal nitrogen pressure of 1 bar within the temperature range of 1950-2400 K. Flash assisted multi-wavelength pyrometry was used to establish both the hemispherical emissivity of the ZnO and its irradiated surface temperature for a given solar flux. We found that the decomposition rate is described well by the equation, m = 1.4 × 10^{9}exp(-328, 500/8.314 T) g m^{-2} s^{-1}. The uncertainty in the equation depends on temperature, but for temperatures near 2000 K it is ±70% at a 95% confidence interval. The emissivity is 0.9 for temperatures above 1900 K. Furthermore, a one-dimensional unsteady and steady-state heat transfer model that includes the physical processes radiation, conduction, and chemical decomposition was developed using the above expression for the reaction rate. The model predicts the measured steady-state ZnO surface temperatures and the time to reach steady state. For an average solar flux of 170 W cm^{-2} and after 400 s of transient conditions, the calculated temperature profiles within the ZnO solid as a function of time are within 100 K of measured profiles.

Original language | English (US) |
---|---|

Pages (from-to) | 4505-4515 |

Number of pages | 11 |

Journal | Chemical Engineering Science |

Volume | 56 |

Issue number | 15 |

DOIs | |

State | Published - Sep 7 2001 |

### Keywords

- Decomposition kinetics
- Solar thermal decomposition
- ZnO

## Fingerprint Dive into the research topics of 'Solar thermal decomposition kinetics of ZnO in the temperature range 1950-2400 K'. Together they form a unique fingerprint.

## Cite this

*Chemical Engineering Science*,

*56*(15), 4505-4515. https://doi.org/10.1016/S0009-2509(01)00113-0