THERMAL COUPLING OF METHANE, EXPERIMENTAL INVESTIGATIONS ON COKE DEPOSITS

We have studied the formation of coke during the thermal coupling of a n equimolecular methanehydrogen mixture at 1230 degrees C and under a one-atmosphere pressure. Coke samples are recovered in rectangular boa ts placed along the pyrolysis reactor. The deposits show a non-homogen eousness of coke along the reactor in terms of deposition rate and in terms of structure. We observed al least two kinds of coke that settle at different rates along the pyrolysis reactor: (a) a silver-grey, un iform film and (b) a black powder. Transmission electron microscopy an d oxidative pyroanalysis showed that the former is a well crystallized graphite-type coke with a highly refractory character, while the latt er corresponds to amorphous powder carbon.