Due to the increase in renewable energies and their fluctuating nature, hydrogen is to be generated from excess electricity using electrolysis. This can be fed into the natural gas grid either directly or as methane after methanation. However, due to the resulting change in calorific value, the direct fed of hydrogen is limited. The flow calorimeter, which was further developed is intended to determine the calorific value at natural gas crossroads. The focus of this work was placed on the cleavage of C-H molecules since a higher activation energy is required for the cleavage of C-H bonds than of C-C bonds, which makes the cleavage of methane molecules more difficult than long-chain hydrocarbons. By oxidizing propane, it was possible to create a calibration curve to determine the calorific value of the natural gas. Within this thesis, the residence time of the methane molecules on the catalysts and the ignition at different temperature levels were examined. However, based on the tests carried out an oxidation of methane with the installed heating system was never achieved. Therefore, the calorific value of the natural gas could not be determined within this work. However, the work provides a basis for further investigations.