The Oxygen Permeability Of Perovskite Materials And Ybco Membrane Reactor, Methane Conversion To Syngas

Dense mixed-conducting ceramic membranes with attractive oxygen permeability are of great interest for separating oxygen from air and improving the performance of catalytic partial oxidation of hydrocarbons in membrane reactor. Combining the mixed-conducting membranes with POM reaction could directly use air as the oxidant for POM reaction, which makes the separation of oxygen and catalytic oxidation in one process. Such combining simplifies the process of operation and reduces the production cost about 20-30%. That holds great promise for applications in the conversion of methane to syngas.In this paper, the oxygen permeation properties of mixed-conducting ceramics SFCO, BSCFO, LSCFO and BCCFO were studied by thermogravimetric method in the temperature range 600⁹00°C. The results show that the oxygen adsorption rate constants k_a of all material are larger than oxygen desorption rate constants k_d. Both k_a and k_d are not strongly dependent on temperature in the studied temperature range.The oxygen permeation flux relates to k_ak_d /(k_a+k_d) and Δδ/V_mol.But Δδ/V_molplays an important role in determining the temperature behavior of oxygen permeation flux.YBCO was studied by a transient thermogravimetric analysis (TGA) method. The equilibrium oxygen vacancy of YBCO sample increased with the decreasing of surrounding partial oxygen pressure and increasing of temperature. The temperature dependent of Δδ/ has different change rate below 600°C and above 600°C. That consisted with a phase transformation from orthorhombic to a tetragonal phase. Comparing with other perovskite-type materials YBCO has comparative oxygen absorption and desorption rate constant k_a and k_d, and oxygen permeation flux.The performance of YBCO membrane reactor in the process of partial oxidation of methane (POM) to syngas was investigated. When Ni/ZrO₂ catalyst was used the CH4 conversion and CO selectivity could reach almost 100% and 95% respectively...