Permeation of Hydrogen in a Gas Mixture of H2+Y through Palladium Membrane

摘要

In this study a semi-batch device has been used to study the hydrogen permeation through palladium membrane from a mixture of hydrogen and helium, nitrogen or carbon dioxide. The semi-batch device was 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 were 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 desired temperature.It has been found that, for the experiment of pure hydrogen, gas mixture of hydrogen and helium, and gas mixture of hydrogen and nitrogen the final hydrogen partial pressure of the semi-batch device is the same as the ambient pressure. However, for the experiment of gas mixture of hydrogen and carbon dioxide, the final partial pressure of the hydrogen in the semi-batch device is higher than the ambient pressure This different is denoted by Pr which can be determined from the experiment and correlated with temperature.The experimental results of hydrogen permeation through palladium membrane for temperature ranging from 603K to 663K and hydrogen partial pressure ranging from 2 bar to 12 bar can be regressed into the following three-parameter model:J=βref exp[-Eβ/RT(1/T-1/Tref)]·{Pnh-(Pl+Pr)n]where β ref,Eβand n are parameters in the model; J is the flux of hydrogen permeation;T and Tref are the temperature of the system and reference temperature, respectively; Ph and Pl are the hydrogen partial pressures at the high pressure and low pressure side, respectively. The model calculations agree well with the experimental results, indicating the model can be used to design a catalytic membrane reactor to produce pure hydrogen from methanol steam reforming.