Features of non-catalytic conversion of light alkanes

Features of non-catalytic conversion

Abstract

The kinetics of non-catalytic gas-phase pyrolysis and oxidative conversion of light hydrocarbons in the temperature range of 1400-1800 K. has been analyzed. Their fundamental difference from the kinetics of the corresponding catalytic processes has been established. Unlike catalytic processes, at these temperatures the oxidative conversion of C₂+ hydrocarbons does not begin with the oxidative stages, but with their pyrolysis, which proceeds much faster than oxidation; and in the specified temperature range C₂+ hydrocarbons transform faster than oxygen. The thermal stage of conversion of C₂+ alkanes leads to the formation of ethylene, and then the oxidation process proceeds almost identically for all these hydrocarbons. Therefore, the additives of all C₂+ alkanes have the same effect on the oxidation and ignition of methane and, consequently, their impurities have the same effect on the knock characteristics of methane. Unlike its homologues, the oxidation of methane proceeds much more slowly and directly when interacting with oxygen, so the conversion of methane and oxygen proceeds similarly. When there is a lack of oxygen, after oxygen conversion is completed, thermal methane pyrolysis occurs at the reached temperature, mainly into acetylene. The subsequent conversion of latter into hydrogen and CO occurs as a result of its interaction with H₂O and CO₂ formed in the mixture.