(540a) CFD Modeling and Computation for an Industrial Steam Methane Reforming Furnace

Hydrogen is one of the most important raw materials for petroleum refineries that convert crude oil into a variety of products with higher economic value, and its unavailability can limit the production rates of petroleum products. Hydrogen is produced on commercial scale most commonly and economically by the steam methane reforming (SMR) process. Specifically, the steam reforming process is an overall endothermic process in which raw natural gas, e.g., methane, reacts with high-pressure, high-temperature steam (superheated steam) in the presence of a nickel-based catalyst to produce hydrogen, carbon dioxide and carbon monoxide. Due to large production rates of hydrogen (e.g., the largest North American plant in 2004 could produce up to 300, 000 Nm³/h of hydrogen [1]), the cost of raw materials can be on the order of millions of dollars [1]. Therefore, a small improvement in the process efficiency results in a great gain in profit margin of a plant. However, determining the optimal process parameters may be a time-consuming or risky process if performed experimentally, because it may require increasing the outer reforming tube wall temperature to improve efficiency, which can pose issues for the reactor material [1] [2]. To determine optimal processing parameters without experimental techniques, computational fluid dynamics (CFD) modeling is attractive because it can precisely capture all geometry characteristics of a given reformer through computer-aided design software, which in turn allows CFD models to generate simulation results that can be expected to serve as reasonable substitutes for experimental data, and the parametric effect can be visualized and quantified through CFD simulations.

This work develops a computational fluid dynamics (CFD) model of an industrial-scale steam methane reformer comprised of 336 industrial-scale reforming reactors, 96 industrial-scale burners and 8 industrial-scale flue gas tunnels. The industrial-scale reformer CFD model is developed by analyzing well-established physical phenomena, i.e., the transport of momentum, material, energy and turbulence, and chemical reactions, i.e., combustion and the SMR process, that take place inside the steam methane reformer. Specifically, the P â?? 1 radiation model, standard k â?? ϵ turbulence model, compressible ideal gas equation of state and finite rate/eddy dissipation (FR/ED) turbulence-chemistry interaction model are adopted to simulate the macroscopic and microscopic events in the reformer. The simulation results generated by the industrial-scale reformer CFD model are verified to be in agreement with the available typical plant data, and also data reported in literature. Furthermore, the CFD model of a reformer can provide insights into the system which cannot be captured by experimental data generated by on-site parametric study or by solution of a complete reformer mathematical model (e.g., the species distributions inside the combustion chamber.) Through this work, a converging strategy that allows one to quickly acquire the converged solution of complex CFD models is developed.

[1] Latham D. Masters Thesis: Mathematical Modeling of an Industrial Steam Methane Reformer. Queenâ??s University, 2008.

[2] Pantoleontos G, Kikkinides ES, Georgiadis MC. A heterogeneous dynamic model for the simulation and optimisation of the steam methane reforming reactor. International Journal of Hydrogen Energy. 2012;37:16346-16358.

[3] Lao L, Aguirre A, Tran A, Wu Z, Durand H, Christofides PD. CFD modeling and control of a steam methane reforming reactor. Chemical Engineering Science. 2016;148:78-92.

[4] Aguirre A, Tran A, Lao L, Durand H, Crose M, Christofides PD. CFD Modeling of a Pilot-Scale Steam Methane Reforming Furnace. Advances in Energy Systems Engineering, Kopanos G, Liu P and Georgiadis M (Eds.), Springer, in press.