| Hydrogen has a high calorific value and is a clean energy,which is drawing more and more interest from researchers under the current environment of energy shortage and serious pollution from heavy industry.Palladium composite membrane has a wide application prospect in hydrogen-related membrane reactors such as hydrogen purification,hydrogenation,dehydrogenation and oxidation.Due to its high selectivity,chemical and thermal stability,the reaction efficiency can be improved while the reaction temperature can be reduced.In this thesis,we prepared porous stainless steel supported palladium composite membranes by electroless plating method and proposed a novel approach for defect-sealing of Pd composite membranes,i.e.,palladium chloride solution treatment.The surface morphology and composition of the palladium composite membrane were analyzed,and the hydrogen permeability of the membrane was investigated after modification,in order to explore the mechanism of defect repair.It was found that the N2 permeability can be reduced by 90%with increasing the H2/N2 selectivity by 10 times with this facile approach.In addition,water-gas shift（WGS）Pd membrane reactor experiments were performed by simulating biomass syngas.The important influencing factors of WGS reaction were explored:the effect of reaction temperature,H2O/CO ratio and feed gas space velocity on hydrogen production from biomass synthesis gas.The CO conversion was used as the main indicator to analyze the experiment results to obtain the optimal H2O/CO ratio,reaction temperature and reaction space velocity for hydrogen production from biomass synthesis gas.During the 550hours test of the experiment,the CO conversion was always higher than 98%,the purity of hydrogen was over 98%,the hydrogen selectivity was over 98%.This indicates that the activity of the catalyst and the performance of the palladium composite membranes remained almost unchanged during the stability test of up to 550 hours. |
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