During the process of water electrolysis,the "bubble effect" will significantly reduce the overall performance of the system.The classical nucleation theory (CNT model） fails to reveal the regulatory mechanism of the electrical double layer (EDL),surface microstructure,and mass transfer synergy on nucleation kinetics in actual electrochemical systems.This study develops an electrode interface bubble nucleation model with the synergistic effect of electrical double layer?mass transfer?surface microstructure,considering the synergistic regulation mechanism of ion migration diffusion behavior,electrode surface nano microstructure,and concentration boundary layer on the nucleation process.The research results show that the synergistic effect of EDL and microporous structurel generates significant potential gradients at the surface micropores,leading to an increase in local supersaturation and prioritizing bubble nucleation.At high overpotentials,the effect of the concentration boundary layer on nucleation energy barrier exhibits a nonlinear relationship.The thinner the concentration boundary layer is,the more significant the decreasing trend of the nucleation rate at high potential will be.The growth of bubbles is dominated by the net concentration flux near the three?phase contact line (TPCL),exhibiting a two?stage growth characteristic.The study provides a theoretical basis for optimizing the surface design of gas evolution electrodes.
CeO2?X (X is the hydrothermal synthesis time, X=3, 6, 12, 24 h) carriers were prepared by varying the hydrothermal synthesis time using Ce(NO3)3·6H2O and urea as raw materials, and CuO/CeO2?X catalysts were obtained by isovolumetric impregnation with active component Cu, which were applied to methanol steam reforming (MSR) reaction. The effects of hydrothermal synthesis time on the structure and physicochemical properties of the prepared CeO2?X carriers and CuO/CeO2?X catalysts were explored by XRD, BET, H2?TPR.The performances of the CuO/CeO2?X catalyst samples were evaluated in methanol steam reforming(MSR) reaction.The results show that the CuO/CeO2?6 has good catalytic activity. At the reaction temperature of 280 °C, when the molar ratio of water to methanol was 1.2, and the space velocity of methanol vapor (GHSV) was 800 h-1, the methanol conversion rate could reach 92.8%.
Some strategies for improvement of the key technology of testing?adjusting integrated separate injection technology have been investigated, due to much lower efficiency of conventional testing?adjusting integrated separate injection technology, which cannot accomplish layered static pressure testing. Through optimizing the string structure to improve the pressure balance during water injection, the creep of the string caused by the large displacement water injection is reduced. Design of the bridge channel of the water distributor greatly increases the flow area,reduces the interlayer interference, and further improves the testing?adjusting efficiency. Meanwhile, the pressure hole is added in the water distributor body to establish stratum?tubing pressure transfer channel, and the static pressure testing instrument is equipped for further testing of the layered static pressure. The improved technology works well in application, the deployment efficiency has been significantly improved, which takes only 5 hours to complete the deployment of 6 layers. The overpressure layer can be successfully picked out during the layered static pressure test, which provides a basis for the layered injection allocation adjustment. The adaptability of the improved technology in Bohai oilfield is significantly enhanced.
