Decarbonisation of methane - directions of post-pyrolytic coal management

The presented literature review concerns possible directions of coal management, which is a by-product of the methane pyrolysis process (methane decarbonization). Methane pyrolysis is more and more often considered as an alternative technology for the production of hydrogen without CO2 emission - the so-called blue hydrogen. Pyrolysis/decarbonization has been used in the production of carbon black since the 1930s (e.g. the well-known Huels process). Methane pyrolysis is an endothermic process that requires, in order to obtain high efficiency, the use of temperatures of 1000 degrees C and more, which makes it a highly energy-consuming and expensive process compared to the currently used methods of hydrogen production, e.g. steam reforming. However, the greatest advantage of the methane/natural gas pyrolysis/decarbonization method is the lack of the need to capture and store CO2 (sequestration), which significantly simplifies the process and brings the economic cost of hydrogen production by this method closer to the cost of its production to the previously mentioned "classic" methods. Moreover, the production of hydrogen by this method is not only characterized by lower CO2 emissions, but also allows to obtain hydrogen of high purity, similar to that suitable for use in fuel cells. A major limitation of the process, in addition to the aforementioned high process temperature, is the formation of a carbon by-product. If hydrogen is obtained from this process on an industrial scale in the future, large amounts of this by-product will be produced, therefore the development of new coal applications is a key factor in the development of this technology as a viable method of hydrogen production. The possibilities of using coal will depend on its nature and properties. The available scientific and specialist articles were analyzed in terms of the types of produced coal, with particular emphasis on its structure. An attempt was made to collect information on the correlation between the applied methane decarbonisation method and the structure of the generated coal.