Solar Reactor Demonstration of Efficient and Selective Syngas Production via Chemical‐Looping Dry Reforming of Methane over Ceria
Kent J. Warren, Richard J. Carrillo, Benjamin Greek, Caroline M. Hill, Jonathan R. Scheffe
Abstract
Technologies that facilitate the conversion of CH 4 and/or CO 2 with concentrated sunlight provide a viable strategy for storing solar energy in the form of liquid fuels and reducing anthropogenic greenhouse gas emissions. Herein, a scalable prototype receiver‐reactor is developed to experimentally demonstrate the chemical‐looping, dry reforming of methane over ceria with simulated concentrated solar radiation. Optimal operating conditions are identified by investigating wide ranges of parameters like temperature, gas flowrate, inlet CH 4 concentration, initial oxygen nonstoichiometry, and particle size. Ultimately, a selectivity to H 2 and CO of greater than 0.93 is observed at reactant conversions of 0.69 and 0.88 for CH 4 and CO 2 , respectively. As a result, the calorific value of the products relative to the reactants is upgraded, and a solar‐to‐fuel conversion efficiency of 10.06% is attained, higher than the previously reported record of 7%. Near‐perfect selectivity to syngas is achieved by operating with low reactant residence times, and if reactions were initiated over oxygen‐deficient ceria. Reactant conversion is enhanced through a reduction in particle size, which enables more rapid kinetics via an increase in surface oxygen availability. Stable performance is demonstrated over 10 consecutive redox cycles under conditions that maximized efficiency for the system presented herein.