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Preparation Of Dielectric Barrie And Its Applicaton In Co2decomposition By Dielectric Barrier Discharge

Posted on:2013-09-09Degree:MasterType:Thesis
Country:ChinaCandidate:S WangFull Text:PDF
GTID:2231330374457514Subject:Chemical Engineering and Technology
Abstract/Summary:PDF Full Text Request
Three kinds of glass powder, CaO·B2O3·SiO2, CaO·B2O3·SrO andCaO·B2O3·Bi2O3, were prepared and added into Ca0.8Sr0.2TiO3(CST)powder at the adding level of0.5wt%,1wt%and5wt%, respectively, tofabricate CST ceramics by liquid phase sintering. The results indicate thatthe addition of glass successfully lowered the sintering temperature from1400°C to1180°C and improved the bulk density and dielectricproperties. The dielectric constant reached the values at the range of200to300. The dielectric loss reached10-3, the breakdown strength is high,all of which are good enough to meet the requirement of dielectric barrierdischarge applications.These ceramics have been used as dielectric barriers in a homemadereactor to perform CO2decomposition. The influence of differentdielectric barriers were researched while other influential factors such asfeeding gas ratio (N2:CO2=9:1), the flow rate (300ml/min), the gapdistance (1mm), the applied voltage (50kV) and the frequency (6.5kHz)were kept constant during the experiments. The results revealed that asuitable ceramic material for the barrier was found. And the conversion rate and the conversion efficiency reached beyond60%and5.7%/W,respectively. Moreover, there is no carbon deposition on the surface of thebarrier material. The barrier can be used continuously. At last, impedancespectra were used to analyze the mechanisms about how the dielectricbarrier influences the discharge behavior. It is believed that high capacityof grain boundaries is prone to catch charges and low resistivity canconduct and diffuse the charges swiftly. These behaviors will enhance thecharge density of the plasma and help generating homogenous discharges.Furthermore, the measurement results indicate that the oxygen vacanciesare the dominant charge carriers in the ceramics. These defects make thesurface resistivity of the barrier lower. Such low surface resistivity coulddiffuse the charge easily and improve the decomposition efficiency ofCO2.
Keywords/Search Tags:liquid phase sintering, CST ceramics, dielectric barrier, conversion rate, conversion efficiency
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