Solar Thermochemical Production of Syngas from H<sub>2</sub>O and CO<sub>2</sub>─Experimental Parametric Study, Control, and Automation
Remo Schäppi, Vivien Hüsler, Aldo Steinfeld
Abstract
High Resolution Image Download MS PowerPoint Slide We report on an experimental parametric study performed on a modular and fully automated solar fuel system for the solar-driven thermochemical splitting of CO 2 and H 2 O. Concentrated solar energy is used as the source of high-temperature process heat for effecting a ceria-based redox cycle, producing syngas with a tailored H 2 /CO ratio. We determine the influence of the main operational parameters (namely: pressure, reduction-end and oxidation-start temperatures, CO 2 and H 2 O mass flow rates) on the key performance indicators, such as the specific fuel yield, molar conversion, and solar-to-fuel energy efficiency. We show how the syngas product quality can be tailored for Fischer–Tropsch synthesis by selecting adequate oxidation conditions, eliminating the need for additional downstream refining of the syngas. The entire solar fuel system is fully automated based on real-time product gas analysis and feedback control loops, and can be further extended with an auto-optimization scheme that executes online mass and energy balances to guide performance improvement. An example of a solar run consisting of fully automated consecutive redox cycles is presented to show the implementation of this control scheme for the optimization of the solar fuel system.