Syngas Production by Thermochemical Conversion of H2O and CO2 Mixtures Using a Novel Reactor Design

The proposed program will develop an innovative reactor to produce syngas (a mixture of hydrogen and carbon monoxide) using a steam and carbon dioxide mixture as input to a thermochemical cerium oxide cycle. Syngas is a particularly attractive fuel since it can be used to synthesize alternative fuels (notably, Fischer-Tropsch liquid fuels) or chemicals such as methanol and ammonia. It can also be used directly in high-temperature fuel cells. Today, syngas is primarily made from coal, methane or other hydrocarbon feedstocks using catalysts, whereas the proposed project aims to use solar energy to provide the heat required to drive the thermochemical cycle without the need for fossil fuels. The overall objective of the Phase I and Phase II programs is to develop and demonstrate the production of syngas using ceria-based materials in an innovative, isothermal packed-bed that is thermochemically cycled. A typical cycle works by heating the oxide (in this case, cerium oxide) to high-temperature, which generates oxygen gas leaving the oxide in a 'reduced' state. Steam and carbon dioxide are then introduced, react (oxidize) on the surface of the reduced material and produce fuel, in this case in the form of syngas. The proposed Phase I study will focus on a single reactor, while a concept for expanding the work in Phase II to enable efficient, continuous production of syngas with heat recovery is discussed. Advanced Cooling Technologies (ACT) will partner with Professor Sossina Haile at the California Institute of Technology on this project. Her research group will focus on the characterization and screening of new ceria-based materials that can cycle in a specified temperature range determined by reactor considerations. Specific targets for equilibrium fuel productivity are also discussed. The most promising candidate materials will be evaluated in the packed-bed reactor configuration developed at ACT and the selectivity and syngas productivity will then be experimentally evaluated. Dr. Diver at Sandia will also serve as an advisor on this project and has extensive experience with thermochemical cycles. Commercial Applications and Other Benefits: About 6,000 PJ/year (petajoule = 1015J) of syngas are currently produced worldwide (with a substantial increase in the anticipated market demand) from feedstocks that include coal, natural gas and oil/ residues. The syngas is then commercially used to synthesize alternative fuels and a variety of chemicals and plastics. The proposed technology does not require hydrocarbon feedstocks and can operate without catalysts. Also, if CO2 is sequestered from large-scale power plants, it can effectively be 'reused' to generate syngas in the proposed thermochemical reactor and then used to make liquid fuels.