Introduction – The solar two-step Zn/ZnO redox cycle [5] consists of: (1) the endothermic dissociation of ZnO to Zn and O2 at 2000 K using concentrated solar energy; and (2) the exothermic reaction of Zn with H2O/CO2 to H2/CO (mixture known as syngas, the precursor of liquid hydrocarbon fuels) and the initial ZnO; the latter is recycled to the first step, thus closing the material cycle. Following the technical demonstration with a 10 kWth solar reactor prototype, a 100 kWth solar pilot plant has been designed, fabricated, and experimentally tested at the large-scale solar concentrating facility of PROMES-CNRS in Odeillo, France. The operational experience of two previous experimental campaigns in 2011 and 2012 points out to further R&D needs and guides the development of an industrial solar chemical plant for the production of H2, syngas, and liquid hydrocarbon fuels.
Research purpose – The main purpose of the current research project is to optimize the solar reactor technology for the thermal dissociation of ZnO and to successfully demonstrate the fully integrated reactor at pilot scale (solar power input of 100 kWth). An advanced numerical heat transfer model of the 100 kWth solar reactor will be developed and validated with experimental data from the test cam-paigns at the 1 MW Solar Furnace (MWSF) in Odeillo, France. Towards the end of this P&D project, conceptual designs and preliminary economics for commercial solar Zn production and storage facili-ties will be developed based on large-scale concentrating solar power (CSP) tower technology.
The results from this research program will advance our ability to store solar energy as a fuel, such as Zn, H2, or syngas in a manner that increases our chances of having a sustainable solution to the cur-rent world problem of being dependent on a limited supply of fossil fuels