基于丙烷脱氢制丙烯的新型双功能膜催化反应器的构建与膜反应过程研究

Propane dehydrogenation to propylene, which is an important new way to alleviate the shortage of propylene in China, is great significant to improve the efficient utilization for oil and gas resources. In the project, firstly, a new bifunctional microporous membrane, which has composite structure with hydrogen permselective SiO2 layer (membrane) and Pt/γ-Al2O3/α-Al2O3 catalytic-support layer (catalyst), is prepared under the optimized conditions. The catalytic activity and stability of the membrane are enhanced according to the influence of the control of membrane microstructure on the membrane performance of catalytic-hydrogen separation and the mechanism of membrane formation. Secondly, the bifunctional catalytic membrane reactors (CMR) are designed by the two-dimensional mathematical model based on the parameters such as Damköhler number, Péclet number and membrane permselectivity, and constructed to be suitable for propane dehydrogenation reaction. The membrane performance of hydrogen permeation, reaction rate and feed rate are matched in CMR. Lastly, the effect of reaction conditions of CMR and the intrinsic properties of membrane materials and membrane reactors on the membrane processes are investigated in detail. Moreover, further research on the interaction between reaction process and membrane separation process, and the mutual influence between membrane layer and catalyst layer in the integrated membrane processes of bifunctional CMR will be studied with the aid of simulation. Thus, the related key problems of the chemical engineering foundation in this project would be resolved. The development of new bifunctional CMR would open up more opportunities for broadened application in theory and practice exploration.

丙烷脱氢制丙烯是缓解我国丙烯来源不足的重要新途径，对提高油气资源有效利用具有重要意义。通过系统考察膜微观结构的调控对膜“催化-氢分离”性能的影响和成膜机理，优化条件制备出具有透氢SiO2层（膜）和Pt/γ-Al2O3/α-Al2O3催化-载体层（催化剂）一体化复合结构的新型双功能微孔膜，提高膜的催化活性和稳定性能。以Damköhler数、Péclet数、膜分离系数等参数为基础，借助二维数学模型模拟设计并构建出适用于丙烷脱氢的双功能膜催化反应器，实现膜的透氢性能与进料速率、反应速率之间的良好匹配。通过深入研究膜催化反应条件、膜材料与膜反应器的本征特性对膜催化反应过程的影响等化工基础科学问题，借助过程模拟手段，进一步揭示膜催化过程中反应与氢分离过程的相互作用、膜和催化剂层之间的相互影响，解决其中关键的化学工程基础的科学技术问题，为新型双功能膜催化反应器的开拓应用进行理论与实践的探索。

丙烷脱氢制丙烯是缓解我国丙烯来源不足的重要新途径，对提高油气资源有效利用具有重要意义。以TPMS，NTEOS，BTESE、BTESM等有机硅烷为前驱体，采用CVD和sol-gel法，优化条件制备出了具有透氢SiO2层（膜）和金属M（M=Pt，La，Y等）/γ-Al2O3/α-Al2O3催化-载体层（催化剂）一体化复合结构的新型双功能微孔膜。该膜具有优异的透氢性能（H2渗透率>1.0*E-6molm-2s-1Pa-1），H2/C3H8和H2/C3H6的分离选择性，长时间稳定性。通过各种表征手段，建立了膜的“制备条件—微观结构（或表面性质）—催化/分离性能”之间的关联，明确了膜层中“Si−O−Si”和“M−O−Si”键的形成机理及其对膜性能的影响。以Damköhler数、Péclet数、膜分离系数等参数为基础，借助二维数学模型模拟设计并构建出适用于丙烷脱氢的双功能膜催化反应器。优化反应空速、氢气渗透率、H2/C3H8选择性等关键参数，双功能二氧化硅膜可明显提高C3H8转化率和C3H6选择性/收率，其数值远高于热力学平衡值，实现了膜的透氢性能与进料速率、反应速率之间的良好匹配。通过深入研究膜催化反应条件、膜材料与膜反应器的本征特性对膜催化反应过程的影响，初步揭示了膜催化过程中反应与氢分离过程的相互作用、膜和催化剂层之间的相互影响。孔径精确调控的双功能微孔二氧化硅膜将在气体分离、膜催化、脱盐等领域中具有潜在的应用前景。