Multiphysics Studies of 3D Plate Fin Heat Exchanger Filled with Ortho-Para-Hydrogen Conversion Catalyst for Hydrogen Liquefaction

A comprehensive 3D Multiphysics model was developed to simulate a plate fin heat exchanger designed for hydrogen liquefaction, incorporating an ortho-para hydrogen conversion catalyst in the hot fin channel. The model encompassed the 3D serrate fin structure, turbulent flow within the cold fin channel, and porous flow through the catalytic hot fin channel. Species transportation within the hot fin channel is coupled with ortho-para hydrogen conversion kinetics, while heat transfer mechanisms between the hot and cold fin channels are rigorously accounted for. Additionally, the state-of-the-art equation of state is employed to accurately describe the thermodynamic properties of ortho- and para-hydrogen within the model. Numerous operational parameters, including the gas hourly space velocity, cold gas velocity, ortho-para hydrogen conversion kinetics, and operating pressure, were systematically varied to identify the kinetic and heat transfer constraints during the heat exchanger operation. The findings revealed that the ortho-para hydrogen conversion kinetic parameter predominantly governs operations requiring high gas hourly space velocity, particularly in large-scale hydrogen liquefaction processes. Furthermore, a significant pressure drop within the catalytic filled channel was observed; however, operating at higher pressure mitigates this issue while mildly enhancing ortho-para hydrogen conversion kinetics.