Preparation Of Pd-Cu Alloy Composite Membranes And Study On Membrane Reactor For Hydrogenation Of Furfural To Furfuryl Alcohol

Pd-alloy composite membranes have recently received increasing interest fromtheir application research largely because they have many advantages such as highhydrogen permeace, excellent perm-selectivity for hydrogen and lower cost. It is aclassic example of how to design the membrane reactors through metallic compositemembranes. In fact, the concept of combining membranes and reactors has attractedmany researchers` attention for the past several decades, but the membrane reactorshave not been used in industry on a large scale so far. This is ascribed to the factthat the stability of the membranes has not been up to the industrial standards such asa good chemical and/or thermal stability and the better mechanical-strength for a longtime. Clearly, the stable membranes prepared is a prerequisite to development of themetal membrane reactors.In this dissertation, Thin (5~10 μm) Pd-Cu/ZrO2-PSS composite membraneswith the better performance were prepared by modified electroless plating techniqueon 0.2 μm graded 316L porous stainless steel (PSS) disks. The PSS support wascoated with a mesoporous palladium impregnated zirconia layer prior to the coatingof Pd-Cu film. The research results from gas permeation through the Pd-Cu alloycomposite membranes have shown that there are significant effects of the surfacecompositions and morphologies, thickness and structure of Pd-Cu alloy films, andpermeation temperatures on hydrogen transport behaviour. Furthermore, the values ofhydrogen pressure exponent and permeation energy to some extent indicate hydrogenpermeation properties. The information obtained by the correlation of the parametersmentioned above with hydrogen permeation behaviour can help us to gain a betterunderstanding of the mechanisms of hydrogen transport through Pd-Cu alloycomposite membranes, and enlighten us how to synthesis the alloy compositemembranes with the excellent functions.In addition, Pd-Cu alloy membrane reactor was designed and the performance ofthe membrane reactor for the catalytic hydrogenation reactions were investigated inthe present dissertation. Simulation results for both the membrane reactor mode andthe conventional packed bed reactor mode have been compared, and the conclusionsreached are as follows: (1) the membrane reactor has shown the higher yield, thebetter selectivity for the production and less side-productions compared to thetraditional reactor under the same operation conditions;(2) when H2 permeationfluxes are too large or small, the ideal yields are obtained for the membrane reactor.So it is necessary to optimize the operation conditions in order to gain more products;(3) a presence of the carrier gas in the membrane reaction system influences the yieldof product, therefore the quantity of the carrier gas should be as little as possible.At last, Pd-Cu membrane reactor with a Cu/MgO-K2O catalyst prepared by thecoprecipitation method for the hydrogenation of furfural to furfuryl alcohol has beenconstructed, and the hydrogenation reaction has been investigated. The experimentalresults are in good agreement with modeling predictions, which suggests that themathematical model of the hydrogenation membrane reactor is reasonable. Thetheoretical model will play a guidance role in further research on the hydrogenationmembrane reactors.