In this study, the separation of purl hydrogen gas from the combustible gases obtained from hazelnut shells was experimentally investigated. Pyrolysis of hazelnut shells was first carried out at temperatures between 500 and 700 degrees C in the quartz tube settled in the high temperature furnace. Pure hydrogen gas was, at the second stage, separated at the membrane temperatures between 180 and 250 degrees C in the solar assisted hydrogen separation system with palladium diaphragm. For each experiment, 400 g hazelnut shell was utilized. During the experimental studies, mass loss of hazelnut shells, combustible gas quantities, membrane temperatures in the solar reactor and the amounts of pure hydrogen gas were determined. The experimental results of hydrogen separation process were presented. It was concluded that pure hydrogen gas would be efficiently separated at the membrane temperatures between 180 and 250 degrees C, except the higher temperatures than 250 degrees C, and that its flow rate was between 2-3.3 1/h. (C) 2000 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.