Combined Reaction System for NH3 Decomposition and CO2 Methanation Using Hydrogen Permeable Membrane Reactor in 1D Model Analysis

Abstract

In a previous study, we developed an integrated reaction system combining NH3 decomposition and CO2 methanation within a membrane reactor, significantly enhancing reactor performance through efficient H2 separation. Ru/Ba/γ-Al2O3 and Ru/ZrO2 were employed as catalysts for each reaction. To ensure the accuracy and reliability of our results, they were validated through 1D models using FlexPDE Professional Version 7.21/W64 software. Key parameters such as reactor arrangement, catalyst bed positioning, overall heat transfer coefficient, rate constants, and H2 permeance were investigated to optimize system efficiency. The study revealed that positioning the NH3 decomposition on the shell side and CO2 methanation on the tube side resulted in a better performance. Additionally, shifting the methanation catalyst bed downward by approximately one-eighth (10 mm from 80 mm) achieves the highest CO2 conversion. A sensitivity analysis identified the rate constant of the NH3 decomposition catalyst and the H2 permeance of the membrane as the most influential factors in enhancing CO2 conversion. This highlights the priority of improving membrane H2 permeance and catalytic activity for NH3 decomposition to maximize system efficiency.