Production of pure hydrogen and useful carbon materials by methane cracking in induction heated fluidised bed reactor

In the future, hydrogen will play an important role as an energy vector in the transition to a low-carbon society and a hydrogen economy. However, currently 96% of all hydrogen produced comes from fossil sources. The vast majority of hydrogen is currently produced by steam reforming of methane, which produces significant quantities of carbon dioxide. One emission-free alternative to this industrial process is methane cracking or pyrolysis. This involves the decomposition of methane at high temperatures (600-1100 °C) to produce hydrogen and carbon. An additional advantage of this approach is the ease with which hydrogen can be isolated, as the process does not produce any other gases, unlike steam reforming, which produces carbon monoxide and dioxide. By using a suitable catalyst, more useful forms of carbon materials can be obtained. Depending on the catalyst, for example, single-walled and multi-walled carbon nanotubes, graphite, amorphous carbon, etc. can be produced. Carbon nanomaterials can be useful in the for use in batteries, and graphite can be used in the manufacture of materials useful for the construction of high-temperature furnaces. In conventional heating, where the methane cracking reactor is heated from the outside, the heat must be transferred to the inside of the catalyst bed. Heating by electrical induction generates heat exactly where it is needed, i.e. on the catalyst particles. Active methane cracking catalysts often contain Fe and Co, which are ferromagnetic elements and can be heated by electromagnetic induction. The proposed project will use inductive heating to electrify the methane cracking process and increase its efficiency. For this purpose, suitable metal catalysts with sufficiently high Curie temperatures will be prepared to allow efficient inductive heating at methane decomposition temperatures. In fact, inductive heating is known to be more efficient in metals that have ferromagnetic properties in addition to electrical conductivity. Calculations using density functional theory (DFT) will be performed to identify potentially suitable materials for inductive heating that are also active for methane cracking. This method will also be used to investigate, on an atomic scale, the reaction mechanism of methane decomposition on selected catalysts. This will allow an understanding of all the elementary steps of the methane cracking reaction at the active sites of the catalyst. A multi-level mathematical model will be set up to understand the kinetics of the reactions at the atomic level and at the same time to describe all the chemical and physical processes at the reactor level. The prepared catalysts will be experimentally evaluated in a fluidised bed reactor, which will allow heating by electromagnetic induction. The results of the laboratory experiments will be used to validate the mathematical model. Furthermore, the model will be used to develop a new inductively heated fluidised bed reactor. Due to the fluidisation of the catalyst and the ideal mixing, the lubrication of the reactor due to carbon deposition between the catalyst particles will be prevented. Carbonaceous materials will be formed on the catalyst and will separate from the catalyst during operation due to fluidisation or collisions between the particles. The project will thus develop new catalysts suitable for electromagnetic induction heating and active for methane cracking. The understanding of the process will be enhanced by DFT and multi-scale modelling. A fluidised bed reactor will be designed and built which, using appropriate fluidised bed material and electromagnetic induction heating, will allow high temperatures to be achieved and methane to be efficiently converted to hydrogen and carbon nanomaterials.