0
Research Papers: Fuel Combustion

Reactivity of Iron/Zirconia Powder in Fluidized Bed Thermochemical Hydrogen Production Reactors

[+] Author and Article Information
F. Al-Raqom

Department of Mechanical and
Aerospace Engineering,
University of Florida,
Gainesville, FL 32611
e-mail: fragom@ufl.edu

J. F. Klausner

Department of Mechanical and
Aerospace Engineering,
University of Florida,
Gainesville, FL 32611
e-mail: klaus@ufl.edu

1Corresponding author.

Contributed by the Advanced Energy Systems Division of ASME for publication in the JOURNAL OF ENERGY RESOURCES TECHNOLOGY. Manuscript received August 23, 2012; final manuscript received April 3, 2013; published online September 12, 2013. Assoc. Editor: Mansour Zenouzi.

J. Energy Resour. Technol 136(1), 012201 (Sep 12, 2013) (8 pages) Paper No: JERT-12-1192; doi: 10.1115/1.4024856 History: Received August 23, 2012; Revised April 03, 2013

A fluidized bed reactor has been developed which uses a two-step thermochemical water splitting process with a peak hydrogen production rate of 47 Ncm3/min.gFe at an oxidation temperature of 850 °C. Of particular interest, is that a mixture of iron and zirconia powder is fluidized during the oxidation reaction using a steam mass flux of 58 g/min-cm2. The zirconia powder serves to virtually eliminate iron powder sintering while maintaining a high reaction rate. The iron/zirconia powder is mixed in a ratio of 1:2 by apparent volume and has a mass ratio of 1:1. Both iron and zirconia particles are sieved to sizes ranging from 125 μm to 355 μm. The efficacy of zirconia as a sintering inhibitor was found to be dependent on the iron and zirconia mean particle size, particle size distribution and iron/zirconia apparent volume ratio. At 650 °C, the oxidation of iron powder with a mean particle size of 100 μm and a wide particle size distribution (40–250 μm) mixed with 44 μm zirconia powder with an iron/zirconia apparent volume ratio of 1:1 results in 75–90% sintering. In all cases, when iron is mixed with zirconia, the hydrogen production rate is not affected when compared with the pure iron case assuming an equivalent mass of iron is in the mixture. When iron powder is mixed with zirconia, both with a narrow particle size distribution (125–355 μm), the first oxidation step results in 3–7% sintering when the reactions are carried out at temperatures ranging between 840 and 895 °C. The hydrogen fractional yield is high (94–97%). For subsequent redox reactions, the macroscopic sintering is totally eliminated at 867 and 895 °C, although the hydrogen fractional yield decreases to 27 and 33%, respectively. It is demonstrated that mixing iron with zirconia in an equivalent mass ratio and similar particle size range can eliminate macroscopic sintering in a fluidized bed reactor at elevated temperatures up to 895 °C.

FIGURES IN THIS ARTICLE
<>
Copyright © 2014 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Flow diagram of hydrogen production facility

Grahic Jump Location
Fig. 2

Variation of hydrogen yield per mass of material (Fe) during the oxidation step

Grahic Jump Location
Fig. 3

Hydrogen production rate per mass of reactive material (Fe) during the oxidation step

Grahic Jump Location
Fig. 4

Variation of hydrogen yield per mass of material (Fe) for three successive oxidation steps

Grahic Jump Location
Fig. 5

Hydrogen production rate per mass of reactive material (Fe) for three successive oxidation step

Grahic Jump Location
Fig. 6

Powder sample after, (a) experiment 1, (b) experiment 2, (c) experiment 3-1, (d) experiment 3-2, (e)

Grahic Jump Location
Fig. 7

SEM image for pure iron before reaction (125–355 μm)

Grahic Jump Location
Fig. 8

SEM image for pure iron and ZrO2 before reaction (125–355 μm)

Grahic Jump Location
Fig. 9

SEM image illustrating EDS points A and B for the single particle shown in Fig. 8 (right)

Grahic Jump Location
Fig. 10

EDS for the single particle; (a) point A in Fig. 9 and (b) point B in Fig. 9

Grahic Jump Location
Fig. 11

SEM image for the sample after first reduction step at different magnifications (850 °C reduction of the oxidized sample 3-Oxid-1)

Grahic Jump Location
Fig. 12

SEM image for the sample after third oxidation step at different magnifications (867  °C reduction of the oxidized sample 3-Oxid-3)

Grahic Jump Location
Fig. 13

SEM image for the fresh sample

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In