Plasma - Catalytic Activation Of The Carbon Dioxide System For Low-carbon Compounds

Carbon dioxide, the termination oxidation product of carbon and carbon?compounds, was significant in the comprehensive utilization of carbon resources and the control of environmental pollution. Therefore, it was extensively studied to convert carbon dioxide into more valuable chemicals (such as C2, high hydrocarbons, methanol, synthesis gas, etc.). The difficulty in the effective conversion is due to its thermodynamic property and the selective activation of C=O bonds. Generating hydrocarbon radicals and controlling their subsequent reactions are the key steps for the selective conversion of carbon dioxide. Various methods have been used for carbon dioxide conversion, such as chemical catalytic reforming, biosynthesis, coordination catalysis, photochemical radiation activation, electrochemical reduction activation, and plasma activation.In this paper, we studied activation and conversion of carbon dioxide by Plasma and catalyst firstly, and made very important progress. The contents are summarized as follows:1.Research and produce the reactor of synergistic plasma with catalyst;2.Research and produce the catalyst of activating carbon dioxide(prepare methods: chemical and plasma);3.Research process conditions and electric parameters of activation and conversion of carbon dioxide;4.Explore the mechanism of activation and conversion of carbon dioxide;5.Probe into the mechanism of preparing catalyst by cold plasma technology.The Results and conclusion are summarized as follows:1.Pure carbon dioxide could be activated partly under pulse coronaplasma, and be converted into carbon monoxide and oxygen, as well as a little carbon deposit and ozone;2.Under hydrogen plasma, the conversion of carbon dioxide and the selection of carbon monoxide were raised largely, and carbon deposit was put down;3.In the CH4ICO2, the addition of methane helped to convert carbon dioxide into carbon monoxide, but methane was oxidized into C2, carbon monoxide and carbon. As to methane, the addition of carbon dioxide was beneficial to the conversion of methane, however, conversion of C2 was dropped down and carbon deposit got worse;4.In the CH4/H2, the addition of hydrogen led to large enhancement of conversion of carbon dioxide and selection of C2, and carbon deposit was put down, which opened up a new technology route of hydrogenation coupling of methane;5.First, C02/H2 were converted into methane under synergism of plasma with catalyst, in which the conversion of carbon dioxide get to nearly 100%, and its yield to more than 90%. Its comprehensive index was much better than that of chemical catalytic techniques.6.Under synergism plasma with catalyst, the distribution of C2 was improved in the C02/CH4 system and CH4/H2 system;7.Plasma parameters(pulse voltage, repeated discharge frequency, power, discharge polar) are important in the conversion of carbon dioxide, as well as technological parameters (reactant gas抯 speed, charge gas抯 proportion, catalyst抯 load volume, air intake, space velocity);8.The synergism mechanism in the reaction system of plasma and catalyst is that the plasma can activate reactants, while the catalyst can selectively improved yield;9.The activity of catalyst prepared by cold plasma technology is higher than that of the catalyst prepared by conventionally chemical techniques. It suggests that plasma technique is significantly promising for preparing highly active catalysts, but the preparing mechanism need to be explored;10.In order to make a breakthrough in activating carbon dioxide by plasma and catalyst and to get more valuable chemical products, we must do further research in the preparation and selection of catalysts.