The Application Of Cold Plasma Jet On Carbon Dioxide Reforming Of Methane To Syngas

Since both methane and carbon dioxide are greenhouse gas, and carbon dioxide can beutilized as a source of carbon, more attention has been focused on the reforming of methane withcarbon dioxide to syngas as it is one of the promising ways to integrated utilization both naturegas and carbon dioxide. As the ratio of hydrogen to carbon monoxide in the syngas was around 1,it was the proper material for methanol synthesis and Fisher-Tropsch synthesis to liquid fuels. Thestudy of carbon dioxide reforming of methane by cold plasma is significative to resourceutilization and recurrent economy.Plasma is the forth state of matter, which consists of highly excited atoms and molecules,ions, electrons, radicals, neutral particles and so on. As a novel technology, more attentions havebeen focused on plasma chemical reactions and plasma assisted catalysts preparation. The majorwork in this thesis is .the application of cold plasma jet on carbon dioxide reforming of methaneto synthesis gas. This innovative work consists of three parts: the catalysts for carbon dioxidereforming of methane reduced by H₂ clod plasma jet, conversion of CH₄ and CO₂ to syngas byclod plasma jet and by the combined action of catalysts and clod plasma jet.In chapter 2, the catalysts reduced by H₂ clod plasma jet was studied in methane reformingcarbon dioxide reaction. The catalysts were characterized using BET, XRD and TGA techniques.The results indicated that bigger specific surface area, smaller crystallite size and higherdispersion of Ni were obtained in plasma reduction sample compared with that of the one reducedby thermal reduction. The plasma reduction sample has an enhanced anti-carbon deposit performance. The catalytic properties were tested with a continuous-flow fixed-bed quartz reactor.The plasma reduction sample 12%Ni/Al₂O₃(pl) was more activity at the low reaction temperaturecompared with the conventional reduction sample 12%Ni/AL₂O₃(c), and the conversion of CH₄and CO₂ were increased by 10.23% and 7.13% at 700℃. 12%Ni/Al₂OH(pl) catalyst showed highlystable activities at 800℃for 48h. The clod plasma jet is an effective and shortened time (10 min)catalysts reduction technology.In chapter 3, the conversion of CH₄ and CO₂ to syngas using the cold plasma jet chemicalapparatus was studied. For the total feed flow rate at 1.0 m³/h (CH₄=0.2m³/h, CO₂=0.3m³/h,N₂=0.5 m³/h) and the input power at 770 W, the conversions of CH₄ and CO₂ were 45.68% and34.03%, and the selectivity of CO and H₂ were 85.41% and 78.11%, respectively. Compared withother kinds of plasma (dielectric barrier discharge and corona discharge), the high selectivity ofH₂ and CO, large total feed flux(0.5m³/h) and high energy efficiency(2.94m mol/ld) wereobtained in cold plasma jet carbon dioxide reforming of methane reaction.In chapter 4, the role of catalyst in combination with the cold plasma jet in the conversion ofCH₄ and CO₂ to syngas has been studied. The 12%Ni/γ-Al₂O₃ put following the plasmadischarge zone, the conversions of CH₄ and CO₂ were increased by 14.38% and 6.32%, and theyield of H₂ and CO increased by 18.76%and 11.38%, respectively. The energy efficiencyincreased from 2.94 m mol/kJ to 3.67 m mol/kJ. The combined action of catalysts and clodplasma jet improve the reaction result.The clod plasma jet is an effective catalysts reduction method, with the advantages of highlystability and activity of catalysts and shortened catalysts preparation time. High energy efficiencyand large total feed flow rate were obtained in cold plasma jet methane reforming carbon dioxide.The reaction results and energy efficiency were improved by combined action of catalysts andcold plasma jet.