多孔膜反应器中丙烷催化脱氢制丙烯的模拟研究

针对丙烷高效脱氢制丙烯的多孔膜反应器构建了无量纲数学模型并进行了模拟研究，考察了催化剂活性、透氢膜性能、操作条件对多孔膜反应器中丙烷脱氢的转化率、丙烯收率、氢气收率和纯度的影响。结果表明，移走产物氢气可以有效提升膜反应器的性能，其性能的提升程度由不同温压条件下催化剂和透氢膜性能共同决定。高活性催化剂是丙烷高效转化的基础，催化剂活性越高，膜反应器内的产氢速率越快；其次，膜的选择性和渗透通量越高，氢气的移除效率越高，可在最大程度上打破热力学平衡的限制，使反应向生成丙烯的方向移动。当多孔透氢膜的氢气渗透率在10^-7~10^-6 mol·m^-2·s^-1·Pa^-1，H₂/C₃H₈选择性达到100时，其丙烷转化率可以与Pd膜反应器内的转化率相当，但分离的氢气纯度低于Pd膜反应器。与传统的固定床反应器相比，膜反应器由于促进了化学平衡的移动，可以在较低的反应温度下获得相当高的丙烷转化率，且丙烷转化率随着反应压力的增加呈现出一个最大值。该模拟研究可为实际生产过程中膜反应器用于PDH反应的高效强化提供有益的技术指导。

A simulation study on propane dehydrogenation in porous membrane reactors for propylene production

A dimensionless mathematical model was formulated to theoretically study the behavior of propane dehydrogenation (PDH) in porous membrane reactors for propylene production. The effects of catalytic activities, membrane characteristics, and operating conditions on membrane reactor performance were investigated in detail in terms of propane conversion, propylene yield, and hydrogen yield and purity. The simulation results indicate that PDH can be significantly improved after the in-situ removal of the produced hydrogen during the reaction by using a hydrogen-permselective membrane, and the enhancement is largely affected by the catalyst, membrane, and operating conditions used in the reaction. A highly active catalyst plays a fundamental role in PDH in membrane reactors, which provides a high hydrogen production rate in the reactor. Furthermore, a highly permeable and selective membrane allows a highly efficient hydrogen extraction rate, which breaks the limit of thermodynamic equilibrium and significantly promotes PDH conversion in the membrane reactor due to the equilibrium shift effect. Compared with Pd-based membrane reactors, porous membrane reactors, which have a H₂/C₃H₈ selectivity larger than 100 and the same hydrogen permeance ranging from 10^-7 mol·m^-2·s^-1·Pa^-1 to 10^-6 mol·m^-2·s^-1·Pa^-1_, show a comparable PDH conversion but a lower hydrogen purity. The membrane reactor performance is much superior to that of conventional fixed-bed reactors due to the equilibrium shift effect, particularly under a low reaction temperature and a high feed pressure. A very high propane conversion and hydrogen yield can be obtained in the membrane reactor even at a relatively low reaction temperature, and both show a maximum with increasing the feed pressure. This simulation study can provide useful technical guidance for the efficient intensification of PDH reaction in a membrane reactor in practical applications.