Multi-dimensional modeling of non-catalytic partial oxidation of natural gas in a high pressure reformer

A three-dimensional simulation model for non-catalytic partial oxidation of natural gas in a high pressure reformer has been developed. In the model, the numerical methods and submodels conventionally used in turbulent reacting flows are used. The GRI-Mech 3.0 mechanism and a tabulated chemistry approach are applied to model the non-catalytic oxidation of natural gases under high pressures and temperatures. The reactions are assumed to be fast, hence only the equilibrium states of the multi-step reactions are read in an off-line generated chemistry table. This chemistry table has been created using the equilibrium solver EQUIL from the CHEMKIN II package, and the equilibrium values are functions of the initial mixture compositions and the temperatures at a constant pressure. A presumed PDF model is applied to simulate the interactions between turbulent mixing and the multi-step chemical reactions. Simulations have been performed for a commercial natural gas reformer at various O2/CH4 and O2/H2O ratios and pressures in order to investigate the effect of these parameters on the syngas yields. The results have provided some insights into the strategies of solving the hot-spot problem in industrial reformers.