Effect of Carbon Dioxide on Hydrogen Permeation Through Palladium Membrane

• Main Authors: You-Ting Chung, 鍾侑庭
• Other Authors: Jan-Chen Hong
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/9dq72a

碩士 === 大同大學 === 化學工程學系(所) === 95 === In this study a semi-batch device has been set up with a new high- hydrogen-permeation palladium membrane tube to study the hydrogen permeation through palladium membrane tube. The device is made of a stainless steel cylinder with a hydrogen-permeable palladium membrane tube. The signals of pressure and temperature of the device and volume signal of permeated hydrogen have been acquired and recorded in a personal computer. The device can be used to test the hydrogen permeation in a wide range of pressure by a single experimental run for a given temperature. The first palladium membrane tube (Pd-1) was used to run study the pure hydrogen permeation through palladium membrane, while the second palladium membrane tube (Pd-2) was used to study the permeation of hydrogen with pure hydrogen or mixed gas (H2+CO2). Two simplified mathematical models developed previously in this laboratory were used for data regression. The results show that the average relative error for Mathematical Model 1 is less than 2%, and that for Mathematical Model 2 is less then 1%. The results of data regression with Mathematical Model 2 are as follow. The flux of pure hydrogen permeation through palladium membrane: J=4.002•exp[(-11250/R)(1/T-1/613.15)]•(Ph^(0.635)-Pl^(0.635)) The flux of hydrogen that permeats through palladium membrane in a gas mixture of hydrogen and carbon dioxide: J=2.903•exp[(-14670/R)(1/T-1/613.15)]•(Ph^(0.718)-(Pl+Pr)^(0.718)) where the relationship between Pr and temperature is: Pr=-6.252•10^(-6)•T^2+1.815•10^(-2)•T-8.449 The unit for J is mol/m2-min, for R is J/mol-K, for Ph, Pl and Pr is bar, and for T is K. The applicable range is 2 bar≦Ph≦12.8 bar and 573 K ≦ T ≦ 633 K. Experiment results show that at the end of experiment, for pure hydrogen permeation, the hydrogen pressure at the high pressure side is the same as that at the low pressure side. However, for hydrogen permeation in a gas mixture of H2 and CO2, the hydrogen partial pressure at the high pressure side is higher than that at the low pressure side. Furthermore, this pressure difference increases with increasing temperature or increasing initial partial pressure of CO2.