## 2 Methodology  
Computational modeling is becoming more sophisticated in investigating the prohibitive syngas-fed reforming processes, and the demand for detailed descriptions of the flow, thermal, and chemical processes has increased in recent years. The presented study was carried out at the research laboratories of the Chair of Energy Systems at the Technical University of Munich (TUM). For the thorough investigation of the pre-reforming process, the current demonstration used an experimentally validated computational fluid dynamics (CFD) model of a planar-type pre-reformer component designed for both heated and adiabatic operation. The employed physical model is based on a previous study where the details of the full pre-reformer component and experimental measurements are given in references [31; 32]. Similarly, the governing equations describing the fluid flow, heat transfer, and the chemically reacting species transport are detailed. The component model consists of sub-components including metal plates with air channels, mesh structures, a catalyst, and metal frames. The operating principle is such that metal plates with air channels are used to separate the airflow and the fuel gas to avoid any gas mixing. Hot air is used as the major heating source and flows through the air channels. Two nickel mesh structures are placed between the air channel plates. The fuel gas side uses porous mesh structures to reduce the component manufacturing effort by avoiding an additional channel design on the fuel gas side. A nickel catalyst is sandwiched between the wire mesh structures to enable the chemical reactions to occur. The generated data considered the chemically reacting species transport simulation of the oxygen-containing syngas that involved \"mixed reforming\" or tri-reforming (TR) reactions [38]. Thus, the chemically reacting CH4, CO2, H2O, and O2 transport also encompasses the partial oxidation of methane in addition to the steam reforming, and the water-gas shift reactions, which can be expressed as  
\[\text{CH}_{4}+\text{H}_{2}\text{O}\rightleftharpoons\text{CO}+3\text{H}_{2} \text{ at }\Delta\text{RH}^{\circ}\text{ }298\text{ K}=206\frac{\text{ kJ}}{\text{mol}} \tag{1}\]  
\[\text{CO}+\text{H}_{2}\text{O}\rightleftharpoons\text{CO}_{2}+\text{H}_{2} \text{ at }\Delta\text{RH}^{\circ}\text{ }298\text{ K}=-41.2\frac{\text{ kJ}}{\text{mol}} \tag{2}\]  
\[\text{CH}_{4}+2\text{O}_{2}\rightleftharpoons\text{CO}_{2}+2\text{H}_{2} \text{O}\text{ at }\Delta\text{RH}^{\circ}\text{ }298\text{ K}=-191.7\frac{\text{ kJ}}{\text{mol}} \tag{3}\]  
Figure 2 illustrates the computational model showing the flow and geometrical symmetry while depicting its constituents, numerical grid, and boundaries. Details of the experimental measurements and deployment and the validation of the results of the CFD model are given in Ref. [32]. Using the counter-current flow principle, syngas-containing fuel is released into the pre-reformer. As the fuel comes into contact with the catalyst, chemical reactions start. The experimental measurement results from the reference study were used to approve the re-constructed model results to extend and enhance its thermochemistry modeling capability, incorporating oxygen-containing syngas compositions. This allows for a deeper understanding of the reforming processes operating on syngas. The partial oxidation reactions of methane were considered to assess the pre-reformer performance efficiently. Data sets were generated systematically in conjunction with the Design of Experiments (DoE) in the next two steps. In a recent research article [39], a cost-effective and sustainable artificial intelligence (AI)-based machine learning modeling approach was introduced to predict the syngas-fed pre-reforming process integrated with gasification and solid oxide fuel cell technology. This highlights the next step after the data are generated, as demonstrated in Figure 1 on the left section of the graphic.