Initial Experimental and Theoretical Investigation of Solar Molten Media Methane Cracking for Hydrogen Production

Abstract

Previous work assessed the fundamental technical and market risks associated with the development and deployment of solar fuels technology in Alberta. It identified methane cracking in solar-molten media as the hydrogen production technology featuring the best combination of technical risk, market acceptance, and breakthrough potential of all the techniques covered in the study. Alberta Innovates – Technology Futures (AITF) plans to advance the technology from a conceptual stage to a proof-of concept over a span of 4 years. The ultimate goal is to design, build and test a prototype solar receiver/reactor in a suitable solar simulator. The paper outlines the activities to date concerning the initial bench-scale testing of methane cracking in molten media at temperatures ranging from 1023 to 1373 K. The design and construction of an experimental apparatus used to establish the fundamental thermo-chemical performance of the process is presented, along with preliminary results and lessons from the first testing campaign. A transient, non-isothermal, preliminary mathematical model of a reacting bubble within the molten metal has been developed using MATLAB. The model accounts for the chemical reactions, diffusion of the gases in the bubble and heat transfer from the molten metal to the reacting gases. The model can be used to predict the minimum bubble residence time needed to achieve a given hydrogen yield. The simulation tool will be used to numerically estimate methane conversions in the reactor at various conditions.