A Heterogeneous Multiscale Dynamic Model for Simulation of Catalytic Reforming Reactors

Abstract

The present work aims to establish a generic reforming reaction scheme to evaluate the performance of catalytic reforming systems with the aid of a one‐dimensional heterogeneous dynamic model. The novelty of the numerical model stems from the direct inclusion of interphase (fluid‐to‐particle surface), intraparticle (within particle), and intrareactor heat and mass transport resistances under transient conditions. The developed model accounts for the multicomponent gas mixture physicochemical properties and correlations for calculating mass and heat transfer coefficients. Effective macroscopic properties within the particle are calculated by incorporating diffusivities and conductivities of the porous network characteristics accounting for Knudsen and molecular transport as well as tortuosity and porosity of the overall porous path. The industrial case of a steam‐methane reforming multitubular reactor was studied as the most representative case of the generic reaction scheme, with all mass/energy resistances present under severe pressure and temperature conditions. It was shown that there are notable diffusional limitations within the particle, whereas there are also temperature and partial pressure gradients due to the heat and mass transport resistances in the particle film layer. It is further demonstrated that the proposed model can be utilized as a versatile design tool for catalytic reactor development and optimization.

Advanced Operation of the Steam Methane Reformer by Using Gain-Scheduled Model Predictive Control

“…wtt rgo (7) where V m is the volume of reformer tube in m 3 , ρ m is the density of the reformer tube material in kg/m 3 , C m denotes the heat capacity of the reformer tube material in kJ/kg•K, T wg is the temperature of the waste gas in K, T wtt stands for reformer tube wall temperature, T rgo is the outlet temperature of the reformed syngas in K, h i is the heat transfer coeffcient of the catalyst in kJ/kg, and A j is the internal heat transfer area in m 3 .…”

“…Continuous operation over the design temperature for the reforming tube can result in a decrease in their lifetime. A prolonged increase of the tube wall temperature of 20 °C over the design temperature decreases the reforming tube’s lifetime by half. , The average conversion rate of hydrogen from hydrocarbons and water in standard steam-to-methane reformers within ammonia production are in the range from 60% to 70%, which means that the methane slip of the reformer is in the range from 10% to 11% . The term methane slip is commonly used in industrial practice to describe the methane molar concentration per dry basis at the outlet of reformer tubes.…”

Diagnostics and Prognostics‐Oriented Modeling of an NGSR Fuel Processor for Application in SOFC Systems

“…It is widely accepted , that this is accompanied by the water gas shift (WGS) reaction: …”

Modeling of Laboratory Steam Methane Reforming and CO2 Methanation Reactors

“…Indeed, from a review of the models developed in the literature for methanation reactors [6] and for SMR reactors [7][8][9], it emerges that pseudo-homogeneous models with isothermal temperature profiles are often employed for the simulation of laboratory reactors, with the purpose of identifying the correct kinetic model and/or the kinetic parameters of the selected kinetic model. On the other hand, more detailed heterogeneous models with thorough evaluation of 1D or 2D concentration and temperature profiles inside the individual catalyst particles, and in the solid and gas phase along the full-size reactor, are employed for a large scale industrial reactor design and deployment [6,[10][11][12][13][14][15][16]. In this work, a model is proposed for a laboratory scale reactor, where the hypothesis of pseudo-homogeneous behavior is retained (due to the small size of the catalyst particles), but thermal effects along the reactor are analyzed in more detail by including the local energy balance.…”

“…In this work, a model is proposed for a laboratory scale reactor, where the hypothesis of pseudo-homogeneous behavior is retained (due to the small size of the catalyst particles), but thermal effects along the reactor are analyzed in more detail by including the local energy balance. In this way, 1D temperature profiles along the laboratory reactor are evaluated, and it is found that, under relevant experimental conditions, temperature profiles Energies 2020, 13, 2624 3 of 19 can easily deviate from uniformity, due to the high enthalpy change of the reaction. Furthermore, possible development of the WGS reaction in the discharge piping is investigated, which often takes place [17][18][19].…”