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The paper reports the results of a kinetic and thermodynamic analysis of non-catalytic partial oxidation of methane and C2–C4 hydrocarbon/hydrogen mixtures (C/H = 1 : 4) at 1400–1700 K. The hydrocarbon conversion sequence and the time periods of the major process stages were identified for isothermal conditions. The initial stage of the oxidative conversion of C2+ hydrocarbons consists of their pyrolysis, primarily into ethylene and propylene, followed by oxidation of the pyrolysis products. In this respect, the kinetics of C2+ hydrocarbon oxidative conversion are different from those of methane conversion, marked by the almost simultaneous and significantly slower occurrence of pyrolysis and oxidation. The subsequent stages involve steam and dry reforming of the oxidation products, namely acetylene and methane; these stages continue until the main products (H2, CO, CO2, and H2O) reach an equilibrium distribution for the given temperature. The study findings are important for the optimization of various techniques for high-temperature syngas production via partial oxidation of C2+ hydrocarbons, as well as Moderate or Intense Low-Oxygen Dilution (MILD) combustion processes. [ABSTRACT FROM AUTHOR]

The possibility of using coalbed methane to produce methanol is assessed. Methanol can be obtained from methane both by direct partial oxidation and from synthesis gas formed through the oxidative conversion of methane. Thermodynamic analysis of coalbed methane conversion was carried out to determine the conditions for obtaining synthesis gas with the ratio [H2]/[CO] = 2, which is optimal for methanol production. The system consisting of methane, nitrogen, and oxygen, with different contents of oxygen and water vapor, was considered. The fuel-air equivalence ratio varied in the range from 2 to 4. The optimal conditions for obtaining synthesis gas for the production of methanol is the use of a mixture with an equivalence ratio of at least 4. It has also been shown that the addition of water vapor leads to an increase in the [H2]/[CO] ratio. Direct gas-phase oxidation of methane to methanol opens up the possibility of complex use of coal mining waste, including not only coalbed methane but also a large amount of coal waste accumulated during coal mining and beneficiation. [ABSTRACT FROM AUTHOR]