Study On Methane-Steam Conversion With Dielectric-Barrier Discharge

With the gradual decrease of petroleum resources, more and more attention has been paid to the exploitation and application of natural gas. The conversion of methane becomes the highlight of natural gas utilization because it is the major component of nature gas. It is well known that plasma is a very effective method to activate molecules. Furthermore, the low temperature plasma is predominantly utilized in methane conversion for its unique non-equilibrium character.The conversion of methane with steam was investigated via dielectric barrier discharge in this thesis. The effect of plasma generator parameters, reactor parameters and reactive technologic condition on methane/steam conversion was investigated without any catalyst. This offered academic elements in order to design and optimize the novel technology.A suit of equipment was established in order to measure and control the physical parameters, including voltage, current, and discharge power, in the process. The discharge powers in DBD reactor were measured by Voltage-Charge Lissajour trace diagram for CH4 discharge and CH4/H2O discharge. It was shown that it was the best for steam to react with methane in the state of vapor. The order of the activity of the background gas to convert steam was Ar〉N2〉He. The methane conversion was as high as 40%. The products contain large amount of hydrogen, ethane and less amount of carbon monoxide, ethene and propane.The conversion of methane, steam and oxygen was also investigated via dielectric barrier discharge. The effects of the composition of feed, discharge voltage and discharge frequency on methane/steam/oxygen reactions were studied. It was concluded that the addition of oxygen could improve the conversion of methane and eleminate the coke carbon. The product distribution, including syngas, carbon dioxide, ethene, ethane and propane, was analyzed. Under the experimental conditions, conversions of methane and oxygen were from 16.48% to 32.43% and from 60.27% to 99.03%, respectively. The maximal selectivities of hydrogen, carbon monoxide, and ethane were 25.74%, 66.29%, and 22.44%, respectively.In this paper, the qualitative analysis of liquid products was done through FT-IR and GC-MS. It was shown that liquid products were formaldehyde, methanol, ethanol, and water for methane/oxygen/steam reactions and were formaldehyde, methanol, ethanol, isopropyl alcohol, 1-propanol, 1-butanol, 2-butanol, and isobutyl alcohol for methane/steam reactions.