Application of Argon Plasma Jet for Methane Hydrate Decomposition by Radio Frequency Irradiation

In this study, decomposition of methane hydrate using argon plasma jet was investigated in the pressure range of 0.1MPa to 2.0MPa. The plasma was successfully generated under high-pressure condition, which is difficult to achieve when using radio frequency (RF) plasma in liquid method. Using emission spectrometer analysis, the excitation temperature is found to increase as the gas pressure increases, whereas, it decreases as the argon flow rate increases. During the process of plasma irradiation, the required basic reactions for methane hydrate decomposition i.e. methane hydrate dissociation (MHD), steam methane reforming (SMR), and methane cracking reaction (MCR) were not completely satisfied due to an insignificant amount of methane. The gas chromatograph analysis confirmed that the methane cracking reaction (MCR) was only occurred to generate hydrogen and the C(s), due to the absence of C2H2 and C2H4 as the byproducts. In comparison with the other basic reactions of methane hydrate decomposition, steam methane reforming reaction became dominant in converting methane into hydrogen. Although the hydrogen production efficiency is less than that of radio frequency plasma in liquid, the reduction of CO2 by the thermal decomposition of Teflon from CO making it possible to be considered as an advanced promising technique in the future.