Natural Gas Pyrolysis in a Liquid Metal Bubble Column Reaction System—Part II: Pyrolysis Experiments and Discussion

This contribution presents the results of continued investigations on the production of hydrogen by means of pyrolysis in a liquid metal bubble column reactor, as developed at the Karlsruhe Institute of Technology in recent years. Part I of this contribution described the motivation and the methodology of this study, as well as a significant scale-up, and discussed its results for pure methane pyrolysis. Here in part II, two additional experimental campaigns with methane–ethane mixtures (MEMs) and high-calorific natural gas (nGH) will be presented and discussed for the first time, using the up-scaled liquid metal bubble column reactor. It could be proven that an MEM as the feed gas led to an increase in methane conversion at low temperatures, which is consistent with the literature data. The nGH pyrolysis confirms this trend and also results in a significant rise in methane conversion compared to pure methane pyrolysis. Furthermore, the nGH pyrolysis leads to an increased methane conversion even at higher temperatures compared to MEM pyrolysis. Additionally, both MEM and nGH pyrolysis also showed a shift in the formation of by-products toward lower temperatures

Natural Gas Pyrolysis in a Liquid Metal Bubble Column Reaction System—Part I: Experimental Setup and Methods

Hydrogen is not only an important industrial chemical but also an energy carrier with increasing demand. However, the current production techniques are based on technologies that result in massive CO2 emissions. In contrast, the pyrolysis of alkanes in a liquid metal bubble column reactor does not lead to direct CO2 emissions. In order to transfer this technology from lab-scale to industrial applications, it has to be scaled up and the influences of the most common constituent of natural gas on the pyrolysis process have to be determined. For this study, the liquid metal bubble column technology developed at the KIT was scaled up by a factor of 3.75, referred to as the reactor volume. In this article, the experimental setup containing the reactor is described in detail. In addition, new methods for the evaluation of experimental data will be presented. The reactor, as well as the experimental results from pure methane pyrolysis (PM), will be compared to the previous generation of reactors in terms of methane conversion. It could be proven that scaling up the reactor volume did not result in a decrease in methane conversion. For part II of this publication, methane-ethane (MEM) gas mixtures and high calorific natural gas (nGH) were pyrolyzed, and the results were discussed on the basis of the present part I

Technological Pathways to produce compressed and highly pure hydrogen from solar power

Hydrogen (H2) produced from renewables has a growing impact on the global energy dynamics towards sustainable and carbon-neutral economy. The share of green H2 is still too low to meet the net-zero target, while the demand for high-quality hydrogen continues to rise. These factors amplify the need for economically viable H2 generation technologies. The present talk will make an overview of the existing technologies for high-quality H2 production based on solar energy. Technologies such as water electrolysis (PV coupled to electrolyzers), photoelectrochemical and solar thermochemical water splitting, liquid metal reactors and plasma conversion utilize solar power directly or indirectly (as carbon-neutral electrons) and will be reviewed from the perspective of their current development level, technical limitations and future potential for the generation of highly pure and compressed H2 [1].Key words: H2 generation, Water electrolysis, Water splitting, Methane pyrolysis, H2 purification and compressionAcknowledgements: The Helmholtz Association of German Research Centers (HGF) and the Federal Ministry of Education and Research (BMBF), Germany are acknowledged for supporting the development of solar powered H2 generation technologies within the frame of the Innovation Pool Project “Solar H2: highly pure and compressed“, HGF research program “Materials and Technologies for the Energy Transition” (MTET). Reference: [1] M. E. Ivanova et al., Angew. Chem. Int. Ed. 2023, e20221885

Technological Pathways to Produce Compressed and Highly Pure Hydrogen from Solar Power

Hydrogen (H2) produced from renewables has a growing impact on the global energy dynamics towards sustainable and carbon-neutral economy. The share of green H2 is still too low to meet the net-zero target, while the demand for high-quality hydrogen continues to rise. These factors amplify the need for economically viable H2 generation technologies. This presentation gives an overview of the existing technologies for high-quality H2 production based on solar energy. Technologies such as water electrolysis (PV coupled to electrolyzers), photo-electrochemical and solar thermochemical water splitting, liquid metal reactors and plasma conversion utilize solar power directly or indirectly (as carbon-neutral electrons) and are reviewed from the perspective of their current development level, technical limitations and future potential for the generation of highly pure and compressed H2 [Angew. Chem. Int. Ed., e202218850, 2023]; Acknowledgement: The Helmholtz Association of German Research Centers (HGF) and the German Federal Ministry of Education and Research (BMBF) are acknowledged for supporting the Innovation Pool Project “Solar H2: Highly Pure and Compressed“ under the Research Program “Materials and Technologies for the Energy Transition” (MTET) - Topic 3: Chemical Energy Carriers. The review paper in Angew. Chem. Int. Ed., e202218850 (2023) is a joint contribution of the HGF Centers FZJ GmbH, KIT, DLR, HZDR, HZB and MPI-IPP