Hydrolysis of evaporated Zn in a hot wall flow reactor

Hydrolysis of Zn is investigated as the second step in a ZnO/Zn redox solar water splitting process. Zinc is evaporated and hydrolyzed with steam in a hot wall flow tubular reactor. The influence of the reactor temperature distribution and residence time on hydrogen conversion was measured for furnace set point temperatures of 1023 K and 1073 K. The yield of ZnO aerosol was measured in situ using a scanning differential mobility sizer. The composition and morphology of the solid product were characterized with X-ray diffraction and microscopy. Hydrogen conversions of 87-96% at temperatures above zinc saturation are attributed primarily to hydrolysis of zinc(g) at the wall of the reactor at temperatures from 800 K to 1077 K.

[1]  Gilles Flamant,et al.  Screening of water-splitting thermochemical cycles potentially attractive for hydrogen production by concentrated solar energy , 2006 .

[2]  M. Zachariah,et al.  Size-resolved kinetic measurements of aluminum nanoparticle oxidation with single particle mass spectrometry. , 2005, The journal of physical chemistry. B.

[3]  A. Steinfeld,et al.  In situ formation and hydrolysis of Zn nanoparticles for H2 production by the 2-step ZnO/Zn water-splitting thermochemical cycle , 2006 .

[4]  T. Nakamura,et al.  Hydrogen production from water utilizing solar heat at high temperatures , 1977 .

[5]  Edward A. Fletcher,et al.  Solarthermal Processing: A Review , 2001 .

[6]  A. Steinfeld,et al.  Co‐synthesis of H2 and ZnO by in‐situ Zn aerosol formation and hydrolysis , 2006 .

[7]  A. Steinfeld,et al.  H2 production by Zn hydrolysis in a hot‐wall aerosol reactor , 2005 .

[8]  M. Zachariah,et al.  Understanding the mechanism of aluminium nanoparticle oxidation , 2006 .

[9]  Robert Palumbo,et al.  The production of Zn from ZnO in a high- temperature solar decomposition quench process—I. The scientific framework for the process , 1998 .

[10]  A. Weimer,et al.  Determination of aerosol kinetics of thermal ZnO dissociation by thermogravimetry , 2007 .

[11]  Robert Palumbo,et al.  The production of zinc by thermal dissociation of zinc oxide - Solar chemical reactor design , 1999 .

[12]  Michael Epstein,et al.  The kinetics of hydrogen production in the oxidation of liquid zinc with water vapor , 2000 .

[13]  Experimental Investigations on the Crystallization of Zinc by Direct Irradiation of Zinc Oxide in a Solar Furnace , 2000 .

[14]  M. Zachariah,et al.  Importance of Phase Change of Aluminum in Oxidation of Aluminum Nanoparticles , 2004 .

[15]  S. Möller,et al.  Solar thermal decomposition kinetics of ZnO in the temperature range 1950-2400 K , 2001 .

[16]  Direct thermal splitting of ZnO followed by a quench. Experimental measurement of mass balances , 1999 .

[17]  A. Steinfeld,et al.  Thermogravimetric analysis of the ZnO/Zn water splitting cycle , 2000 .

[18]  Alan W. Weimer,et al.  Likely near-term solar-thermal water splitting technologies , 2004 .

[19]  C. Yaws.  Chemical properties handbook , 1999 .

[20]  A. Steinfeld.  Solar hydrogen production via a two-step water-splitting thermochemical cycle based on Zn/ZnO redox reactions , 2002 .

[21]  A. Steinfeld.  Solar-processed metals as clean energy carriers and water-splitters , 1998 .

[22]  Irina Vishnevetsky,et al.  Production of hydrogen from solar zinc in steam atmosphere , 2007 .

[23]  Anton Meier,et al.  A Receiver-Reactor for the Solar Thermal Dissociation of Zinc , 2007 .

[24]  R. Flagan,et al.  Scanning Electrical Mobility Spectrometer , 1990 .

[25]  A. Steinfeld.  Solar thermochemical production of hydrogen--a review , 2005 .

[26]  C. Wagner.  Beitrag zur Theorie des Anlaufvorgangs , 1933 .