Numerical Study of dehydrogenation of dodecahydro-N-ethylcarbazole in fixed bed reactor based on the porous medium approach

Liquid Organic Hydrogen Carriers (LOHC) technology shows promise for hydrogen storage and transportation technology. However, it encounters challenges in fixed bed reactors, especially the inefficient heat transfer during the dehydrogenation process. Computational Fluid Dynamics (CFD) can be used to analyze the interaction of multi-physical fields in the reactor. In this study, a two-dimensional axisymmetric porous medium model of the fixed bed reactor was established to explore the dehydrogenation reaction performance of the liquid organic hydrogen carrier system N-ethylcarbazole(NEC). We studied the effects of key parameters such as wall temperature, inlet LOHC velocity, inlet LOHC temperature, porosity, thermal conductivity of wall and length of reactor to optimize reactor performance. Meanwhile, the content changes of intermediate components and the axial and radial temperature distributions were studied. The results indicate that inlet LOHC temperature, bed porosity and thermal conductivity of wall have no significant influence on the degree of dehydrogenation. Under the condition of wall temperature of 473 K, inlet velocity of 0.026 mm/s and 0.125 m in length, the obtained degree of dehydrogenation is 0.9853, which facilitate both high heat transfer rate and good reactor performance. This study can provide a basis for researching the heat transfer mechanism and designing and optimizing the reactor.