This paper presents the results of an experimental investigation of natural gas pyrolysis at a hot matrix in a high temperature regenerative gas heater. It was demonstrated that formation of pyrocarbon during thermal decomposition of natural gas significantly influences upon the process efficiency. Burn out of the carbon deposits from the matrix during the matrix heating up stage produces components harmful to the environment. To make the pyrolysis process effective and environmentally benign it is necessary to provide special measures to exclude the possibility of pyrocarbon formation during the pyrolysis.