Performance analysis of an autothermal membrane reactor for hydrogen production from methane

An autothermal reforming reactor in which the couple of steam reforming with partial oxidation reforming carried out is studied for the production of hydrogen from methane. In the autothermal reforming reactor, the endothermic heat and part of the steam required for steam reforming are balanced by an exothermic oxidation. The autothermal reforming reactor is generally an adiabatic fixed-bed reactor in the presence of mixture of two different catalysts for partial oxidation and steam reforming reactions. However, with such a reactor configuration, the management of the heat integration of the two reactions is difficult. In this work, the performance of three different methane autothermal reforming reactors, i.e., a conventional reactor, a dual-bed reactor and membrane reactor is investigated by using a one-dimensional homogeneous and non-isothermal model. For the membrane reactor, different type of membrane, i.e., H[subscript 2]-selective membrane, O[subscript 2]-selective membrane and H[subscript 2]-O[subscript 2] selective membrane, is applied. Effect of various operating parameters on the efficiency of each reactor is evaluated in terms of methane conversion, H[subscript 2]/CO of product, hydrogen recovery yield and separation factor. Simulation results show that the H[subscript 2]-O[subscript 2] selective membrane reactor provides the best performance in terms of the increased methane conversion and the reduced hot spot problem.

本研究针对甲烷制氢场景，对耦合了蒸汽重整与部分氧化重整的自热重整反应器（autothermal reforming reactor）展开探究。在该自热重整反应器中，蒸汽重整所需的吸热热量与部分进料蒸汽，可通过放热氧化反应实现热平衡。常规自热重整反应器通常为绝热固定床反应器，装填用于部分氧化与蒸汽重整反应的双组分催化剂混合物。然而该反应器构型下，双反应的热集成管控难度较高。本研究采用一维均相非等温模型，对三类甲烷自热重整反应器的性能进行探究，分别为常规反应器、双床层反应器与膜反应器（membrane reactor）。针对膜反应器，本研究采用三类不同的分离膜：氢气（H₂）选择性膜、氧气（O₂）选择性膜以及H₂-O₂双选择性膜。本研究以甲烷转化率、产物中H₂/CO比值、氢气回收产率与分离因子为评价指标，探究各类操作参数对各反应器性能的影响。仿真结果表明，H₂-O₂双选择性膜反应器可同时提升甲烷转化率并缓解热点问题，综合性能最优。