THERMAL COUPLING OF METHANE IN A TUBULAR FLOW REACTOR - PARAMETRIC STUDY

The thermal cracking of methane in the presence of hydrogen (H-2/CH4 r atio from 1 to 2), was investigated in a tubular flow reactor at 10(5) Pa, in the temperature range 1180-1230-degrees-C, at residence times ranging from 0.2 to 1.5 s. Reaction products were analyzed by gas-phas e chromatography: products in the gaseous samples were ethylene and ac etylene as major products and ethane, propene, propadiene, propane, bu tadiene, butenes, and cyclopentadiene as minor products. In the liquid samples (quenched) the products were benzene, toluene, xylenes, and n aphthalene. Formation of coke and tar was also observed. Hydrogen dilu tion increases yields and selectivities Of C2 hydrocarbons, avoid carb on formation, but reduces methane conversion. The experimental results show the large effect of short residence times associated with high-t emperature levels. The formation of the measured reaction products and the influence of H-2 dilution on methane conversion and on the produc t distribution are accounted for by a reaction model.