Methane pyrolysis - influence of selected parameters on the course of the process

Methane pyrolysis is a method of obtaining hydrogen from methane, which is increasingly gaining the interest of scientists and investors. This technology is an alternative to steam reforming - currently the most used method of hydrogen production. Despite its many advantages, steam reforming is a process that generates significant amounts of carbon dioxide. Therefore, the search for a new, efficient method of hydrogen production is underway. Apart from water electrolysis and biomass pyrolysis, methane pyrolysis is the most promising technology. It is method with many advantages; it is simple, fast and the hydrogen obtained by it is characterized by high purity, but its greatest advantage is the lack of carbon dioxide emission, which positively affects the assessment of the sustainability of this process. Methane decomposition is carried out in reactors at a temperature of 600-1200 degrees C, depending on the process type. In the pyrolysis process, in addition to hydrogen, proportional amounts of clean carbon, with various morphologies and levels of graphitisation, are produced. The paper presents the characteristics of the methane pyrolysis installation, built in 2022 at the Department of Sustainable Chemical Technologies INiG - PIB. The installation allows for methane pyrolysis tests at temperatures up to 1100 degrees C. The maximum theoretical capacity is 400 ml H-2/minute. A furnace equipped with a tubular quartz reactor with a capacity of 6.8 dm(3) was used. Methane decomposition, in the temperature range up to 1050 degrees C, has been described. Using chromatographic methods, the content of methane, hydrogen, nitrogen, oxygen and the C-2 + C-3 hydrocarbons in post-process gases was examined. Variables that may affect the pyrolysis results were selected. The influence of temperature, reaction time, raw material flow rate and the composition of the process gas mixture in selected ranges was checked. The dependencies between the temperature and flow rate of the substrate and the efficiency of the process were confirmed.