Membrane Reactor for Sustainable Hydrogen Production: Modeling, Simulation, and Multiobjective Optimization Studies
Ayooluwa Tomiwa Akintola, Fernando V. Lima, Srinivas Palanki, Yuhe Tian
Abstract
High Resolution Image Download MS PowerPoint Slide Hydrogen is mostly produced through steam methane reforming (SMR), which is an endothermic process requiring high temperatures to overcome thermodynamic equilibrium limitations and utilizes different process units to improve methane conversion and the purity of hydrogen. Membrane reactors (MRs) have been poised to possess the capacity to overcome the enumerated challenges mentioned above. However, there still exists a lack of depth in understanding how the interaction of operating variables (especially temperature, pressure, and steam-to-carbon ratio) affects the performance of the SMR process in a palladium-silver membrane reactor, particularly when an environmental goal in terms of carbon dioxide purity is considered as a performance metric. This study aims to address this research gap. A one-dimensional pseudohomogeneous model of a Pd–Ag MR is developed, validated, and used to simulate SMR for hydrogen production. A sensitivity analysis is carried out to offer a detailed understanding of how the interaction of operating temperature, pressure, and steam-to-carbon (S/C) ratio influences the performance of the process. In addition, an MOO study is incorporated into this research under four different setups, especially with the integration of system performance metrics (methane conversion, permeation rate of hydrogen, and hydrogen recovery), economic metrics (membrane cost), and environmental metrics (carbon dioxide purity). From the MOO study, a Pareto curve that comprises a set of trade-off solutions for each setup is attained. For the conversion of methane against the cost of the membrane, the set of trade-off solutions is 70–100% and $3.1–8.3 × 10 4, respectively. For the recovery of hydrogen against the cost of the membrane, the set of trade-off solutions is 68–97% and $0.33–1.8 × 10 5, respectively. For carbon dioxide purity against the cost of the membrane, the set of trade-off solutions is 34–84% and $3.2–15.7 × 10 4, respectively. This study contributes to existing knowledge in the field of hydrogen research and offers clarity toward the sustainable production of hydrogen from SMR.