Paul Scherrer Institut | CH-5232 Villigen PSI | Phone +41 56 310 21 11 | Fax +41 56 310 21 99 Solar Technology Laboratory

SOLZINC: Solar carbothermic production of Zn from ZnO



Contact: Christian Wieckert
Start: 2001
Funding: Swiss Federal Office for Education and Science


We investigate the storage of solar energy by producing metallic Zinc: Concentrated solar light is used to drive the strongly endothermic chemical reaction

ZnO + C -> Zn + CO.


The use of carbon as a reductant allows operating at a temperature of around 1200 °C in contrast to the much higher temperatures required for the solar thermal ZnO decomposition. The "solar zinc" produced can be used as commodity zinc produced with only 20% CO2 -emissions compared to conventional Zn-production. Alternatively it can be used in cyclic processes to either produce electricity from the Zn in Zn-air fuel cells or hydrogen from reacting with steam (see diagram). In both cases ZnO is the major process product which can be recycled back into the solar reactor. In these processes Zn is only a means to produce electricity or hydrogen at times and/or locations independent of the current local solar irradiation. Image
Based on earlier laboratory scale work the SOLZINC-project primarily aims at scaling-up a technology for carbothermic solar zinc production to a pilot scale.

SOLZINC is a joint European research project partially funded by the European Community within its 5th framework programme. PSI's project partners are


A pilot plant for 300 kW concentrated solar energy has been erected, tested and operated at the Weizmann Institute of Science. The performance of the plant was very satisfactory and - based on the results - a conceptual design for a 5 MW demonstration plant has been performed. Details can be found in the papers listed below



related publications


Papers in Peer-Reviewed Journals
  • Towards the Industrial Solar Carbothermal Production of Zinc
    Epstein M., Olalde G., Santén S., Steinfeld A., Wieckert C.
    ASME Journal of Solar Energy Engineering, Vol. 130, No. 1, 014505, 2008. pdf file (0.4 MB)
  • A 300 kW solar chemical pilot plant for the carbothermic production of zinc
    Wieckert C., Frommherz U., Kräupl S., Guillot E., Olalde G., Epstein M., Santén S., Osinga T., Steinfeld A.
    ASME Journal of Solar Energy Engineering, Vol. 129, No. 2, pp. 190-196, 2007. pdf file (0.5 MB)
  • Economic evaluation of the solar carbothermic reduction of ZnO by using a single sensitivity analysis and a Monte-Carlo risk analysis
    Kräupl S., Wieckert C.
    Energy, Vol. 32, No. 7, pp. 1134-1147, 2007.
  • Solar Carbothermic Reduction of ZnO in a Two-Cavity Reactor: Laboratory Experiments for a Reactor Scale-Up
    Kräupl S., Frommherz U., Wieckert C.
    ASME Journal of Solar Energy Engineering, Vol. 128, No. 1, pp. 8-15, 2006.
  • Experimental Determination of the Extinction Coefficient for a Packed-Bed Particulate Medium
    Osinga T., Lipiński W., Guillot E., Olalde G., Steinfeld A.
    Experimental Heat Transfer, Vol. 19, No. 1, pp. 69-79, 2006
  • Design Studies for a Solar Reactor Based on a Simple Radiative Heat Exchange Model
    Wieckert, C.
    Journal of Solar Energy Engineering, Vol. 127, 425-429, 2005.
  • Simulation of Thermal and Chemical Processes in Annular Layer of ZnO–C Mixtures
    Vishnevetsky, I., Epstein, M., Rubin, R.
    Journal of Solar Energy Engineering, Vol. 127, 401-412, 2005.
  • The solar carbothermal reduction of ZnO - Shrinking packed-bed reactor modeling and experimental validation
    Osinga T., Olalde G., Steinfeld A.
    Industrial & Engineering Chemistry Research, Vol. 43, 7981-7988, 2004.
  • A two-cavity reactor for solar chemical processes: heat transfer model and application to carbothermic reduction of ZnO
    Wieckert, C. ,Palumbo, R. and Frommherz, U.
    Energy, The Int. Journal, Vol. 29, 771-787, 2004.
  • Experimental Investigation of the Solar Carbothermic Reduction of ZnO Using a Two-Cavity Solar Reactor
    Osinga, T., Frommherz, U., Steinfeld, A. and Wieckert, C.
    Journal of Solar Energy Engineering, Vol. 126, 633-637, 2004.
  • Indirectly Irradiated Solar Receiver Reactors for High-Temperature Thermochemical Processes
    Wieckert, C., Meier, A. and Steinfeld, A.
    Journal of Solar Energy Engineering, Vol. 125, 120-123, 2003.
  • Solar thermal reduction of ZnO using CH4:ZnO and C:ZnO molar ratios less than 1
    Wieckert, C., and Steinfeld, A.
    Journal of Solar Energy Engineering, Vol. 124, 55-62, 2002.

Proceedings
  • Pilot scale solar carbothermic reduction of ZnO to Zn
    Wieckert C., Epstein M., Olalde G., Santén S., Steinfeld A.
    Sohn International Symposium on Advanced Processing of Metals and Materials, TMS, San Diego, USA, August 27-31, 2006
  • Solar thermochemical production of hydrogen - the carbothermic ZnO/Zn cyclic process
    Epstein M., Olalde G., Santen S., Steinfeld A., Wieckert C.
    16th World Hydrogen Energy Conference, Lyon, France, June 13-16, 2006.
  • Solar Carbothermic Production of Zinc from Zinc oxide: SOLZINC
    Guillot, E., Epstein, M., Wieckert, C., Olalde, G., Steinfeld, A., Santén, S., Frommherz, U. Kräupl, S., Osinga, T.
    Proceedings of ISEC 2005 - ASME Int. Solar Energy Conference, Orlando, Florida, USA, August 6-12, 2005.
  • Design of a pilot scale solar reactor for the carbothermic reduction of ZnO
    Frommherz, U., Kräupl, S., Wieckert, C., Epstein, M., Guillot, E., Olalde, G., Osinga, T., Palumbo, R., Robert, J.F., Santen, S., Semrau, G., Steinfeld, A., Vishnevetsky, I.
    Proceedings 12th SolarPACES International Symposium, Oaxaca, Mexico, October 6-8, 2004.
  • Solar Carbothermic Production of Zinc and Power Production via a ZnO-Zn-Cyclic Process
    Wieckert, C., Frommherz, U., Kräupl, S., Palumbo, R., Osinga, T., Steinfeld, A. , Bruesewitz, M., Semrau, G., Epstein, M., Vishnevetsky, I., Olalde, G., Robert, J.-F., Santén, S.
    Proceedings ISES Solar World Congress, Göteborg, Sweden, June 14-19, 2003. pdf file 2 MB
  • The Solzinc-Project for solar carbothermic production of Zn from ZnO
    Wieckert, C., Epstein, M., Olalde, G., Palumbo, R., Pauling, H.J., Reichhardt, H.U., Robert, J.F., Santén, S., Steinfeld, A.
    Proceedings 11th SolarPACES International Symposium, Zurich, Switzerland, September 4-6, 2002.

Annual Reports
  • A Pilot Scale Solar Reactor for Carbothermic Reduction of ZnO
    Frommherz, U., Kräupl, S., Wieckert, C.
    PSI Scientific Report 2004 - Annex V, 43-44, 2004. pdf file 949 kB
  • Solzinc Reactor Modeling and Experimental Validation
    Osinga, T., Olalde, G., Steinfeld, A.
    PSI Scientific Report 2004 - Annex V, 45-46, 2004. pdf file 812 kB
  • Upscaling of a solar reactor for carbothermic reduction of ZnO: Design studies with a simple radiative heat exchange model
    Wieckert, C., Frommherz, U. and Kräupl, S.
    PSI Scientific Report 2003 - Annex V, 45-46, 2003. pdf file 484 kB
  • Experimental Investigation of the Solar Carbothermic Reduction of ZnO Using a Two-Cavity Solar Reactor
    Frommherz, U., Osinga, T., Steinfeld, A. and Wieckert
    PSI Scientific Report 2002 - Annex V, 24-25, 2002. pdf file 158 kB
  • On Indirectly Irradiated Solar Receiver-Reactors for High-Temperature Thermochemical Processes
    Wieckert, C., Meier, A. and Steinfeld, A.
    PSI Scientific Report 2002 - Annex V, 23, 2002. pdf file 466 kB
  • The Solzinc-Project for Up-Scaling the Solar Chemical Technology for Producing Zinc as a Solar Fuel
    Wieckert, C., Palumbo, R., Epstein, M., Olalde, G., Pauling, H.-J., Robert, J.-F., Santén, S. and Steinfeld, A.
    PSI Scientific Report 2001 - Annex V, 39-40, 2001. pdf file 381 kB

Others
  • Zink speichert Sonnenenergie
    Wieckert, C., Frommherz, U., Kräupl, S., Palumbo, R., Osinga, T. and Steinfeld, A.
    ENET-NEWS, 57, March 2004, 26-27.
  • Zink speichert Sonnenenergie - SOLZINC: PSI-Technologie für ein EU-Pilotprojekt
    Frommherz, U., Kräupl, S., Palumbo, R., Steinfeld, A. and Wieckert, C.
    PSI Spectrum 2/2003, 4-11. pdf file 726 kB