<p>In order to enrich natural gas or other hydrocarbon gases with hydrogen, thus reducing the carbon content and thereby achieving a reduction or elimination of the discharge of carbon dioxide during combustion of the gases, a pyrolytic process is conducted in the feed stream for the natural gases or hydrocarbon gases which are to be burned. The gas is passed through a reactor in which it is decomposed at least partially into a carbon constituent and a hydrogen constituent. The carbon constituent is removed to a desired level. Any remaining constituent together with the hydrogen constituent is conveyed to the combustion process while the removed carbon constituent is conveyed out of the process for separate application. The pyrolytic process can be carried out on the entire stream or only on a partial stream.</p>