Dense membrane with the composition of SrFe0.6Cu0.3Ti0.1O3-δ （SFCTO） was prepared by solid state reaction method. Oxygen permeation flux through this membrane was investigated at operating temperature ranging from ...Dense membrane with the composition of SrFe0.6Cu0.3Ti0.1O3-δ （SFCTO） was prepared by solid state reaction method. Oxygen permeation flux through this membrane was investigated at operating temperature ranging from 750℃ to 950℃ and different oxygen partial pressure. XRD measurements indicated that the compound was able to form single-phased perovskite structure in which part of Fe was replaced by Cu and Ti. The oxygen desorption and the reducibility of SFCTO powder were characterized by thermogravimetric analysis and temperature programmed reduction analysis, respectively. It was found that SFCTO had good structure stability under low oxygen pressure at high temperature. The addition of Ti increased the reduction temperature of Cu and Fe. Performance tests showed that the oxygen permeation flux through a 1.5 mm thick SFCTO membrane was 0.35-0.96 ml·min ^-1·cm^-2 under air/helium oxygen partial pressure gradient with activation energy of 53.2 kJ·mol^-1. The methane conversion of 85%, CO selectivity of 90% and comparatively higher oxygen permeation flux of 5 ml·min^-1·cm^- 2 were achieved at 850℃, when a SFCTO membrane reactor loaded with Ni-Ce/Al2O3 catalyst was applied for the partial oxidation of methane to syngas.展开更多
A release model for diffusion-controlled monolithic matrix coated with outer membrane system is proposed and solved by using the refined double integral method. The calculated results are in satisfactory agreement wit...A release model for diffusion-controlled monolithic matrix coated with outer membrane system is proposed and solved by using the refined double integral method. The calculated results are in satisfactory agreement with the experimental release data. The present model can be well used to describe the release process for all cd/cs values. In addition, the release effects of the monolithic matrix coated with outer membrane system are discussed theoretically.展开更多
The paper presents a simplified numerical model of evaporation processes inside vertical tubes.In this model only the temperature fields in the fluid domain(the liquid or two-phase mixture) and solid domain(a tube wal...The paper presents a simplified numerical model of evaporation processes inside vertical tubes.In this model only the temperature fields in the fluid domain(the liquid or two-phase mixture) and solid domain(a tube wall) are determined.Therefore its performance and efficiency is high.The analytical formulas,which allow calculating the pressure drop and the distribution of heat transfer coefficient along the tube length,are used in this model.The energy equation for the fluid domain is solved with the Control Volume Method and for the solid domain with the Finite Element Method in order to determine the temperature field for the fluid and solid domains.展开更多
基金Supported by the Natural Science Foundation of Guangdong Province （030514） and the Science and Technology Program of Guangdong Province （2004B33401006）.
文摘Dense membrane with the composition of SrFe0.6Cu0.3Ti0.1O3-δ （SFCTO） was prepared by solid state reaction method. Oxygen permeation flux through this membrane was investigated at operating temperature ranging from 750℃ to 950℃ and different oxygen partial pressure. XRD measurements indicated that the compound was able to form single-phased perovskite structure in which part of Fe was replaced by Cu and Ti. The oxygen desorption and the reducibility of SFCTO powder were characterized by thermogravimetric analysis and temperature programmed reduction analysis, respectively. It was found that SFCTO had good structure stability under low oxygen pressure at high temperature. The addition of Ti increased the reduction temperature of Cu and Fe. Performance tests showed that the oxygen permeation flux through a 1.5 mm thick SFCTO membrane was 0.35-0.96 ml·min ^-1·cm^-2 under air/helium oxygen partial pressure gradient with activation energy of 53.2 kJ·mol^-1. The methane conversion of 85%, CO selectivity of 90% and comparatively higher oxygen permeation flux of 5 ml·min^-1·cm^- 2 were achieved at 850℃, when a SFCTO membrane reactor loaded with Ni-Ce/Al2O3 catalyst was applied for the partial oxidation of methane to syngas.
文摘A release model for diffusion-controlled monolithic matrix coated with outer membrane system is proposed and solved by using the refined double integral method. The calculated results are in satisfactory agreement with the experimental release data. The present model can be well used to describe the release process for all cd/cs values. In addition, the release effects of the monolithic matrix coated with outer membrane system are discussed theoretically.
文摘The paper presents a simplified numerical model of evaporation processes inside vertical tubes.In this model only the temperature fields in the fluid domain(the liquid or two-phase mixture) and solid domain(a tube wall) are determined.Therefore its performance and efficiency is high.The analytical formulas,which allow calculating the pressure drop and the distribution of heat transfer coefficient along the tube length,are used in this model.The energy equation for the fluid domain is solved with the Control Volume Method and for the solid domain with the Finite Element Method in order to determine the temperature field for the fluid and solid domains.
