Solar-Driven Reduction of Iron Oxydes with Methane for Chemical Looping Application

In the present work the chemical looping process driven by the high heat temperature provided by a solar dish concentrator was assessed. This process aims at using water or carbon dioxide (or a mixture of the two) to produce hydrogen or carbon monoxide; starting from the mixture it’s possible to obtain high value chemicals with further processes. Since Global Warming has become one of the most challenging issues of our era, finding new pathways for the decarbonization of the energy sector has become a vital issue. Thanks to thermochemical processes such as chemical looping it is possible to produce high value chemicals (hydrogen and syngas) but also to collect and reuse 〖CO〗_2 with CCS (Carbon Capture and Storage) and CCU (Carbon Capture and Utilization) processes. In order for the process to be sustainable and non-polluting, it requires the exploitation of renewable resources; in the case here analyzed the solar dish positioned on the rooftop of the Energy Center will be used to drive the high temperature heat reaction. Both the experimental and numerical approach took place to analyze the reduction process of hematite (〖Fe〗_2 O_3) reduction using methane (〖CH〗_4) as a reducing agent. During the experimental part of the work the attention was focused on the process happening inside the reactor, where the hematite was inserted, and on the choice of the reactor itself. The main aim was to understand the feasibility of the process and its effectiveness in non-artificial environment (laboratory). During our five main experiments the main issue was the high temperature reached on the focus of the solar dish concentrator, which didn’t allow for long standing measurements, as the reactors’ materials couldn’t endure for extended duration the high heat of the concentrated solar radiation. Indeed, all the experiments had destructive effects on the reactors. For what concerns the numerical analysis, COMSOL Multiphysics was used. The focus of the simulation is the validation of the result of the data collected during the experiment and also of the data found in literature. The main goal was to recreate the chemical reaction happening inside the reactor, through a chemically focused simulation. The main quantities related to the kinetic of the reaction were taken from literature, according to the boundary conditions of our experimental work. The numerical analysis allowed to obtain the evolution of the reduction reaction.