Usage of reduced order models (ROMs) and reactor networks are becoming widely accepted tools for the modeling of complex reactors, such as entrained-flow gasifiers. The approximations made in a ROM reduce the required computational costs compared to computational fluid dynamic (CFD) models; however; the capabilities of the model in predicting the outputs for a range of operating conditions in the gasification unit face challenges. The following contribution presents a comparison between a ROM and the corresponding CFD model of a short-residence-time gasifier under different operating conditions and kinetic parameters. Although the framework of the proposed ROM was fixed and developed on the basis of CFD simulations generated at a base-case condition, the results showed reasonable agreement between the two models in predicting syngas composition, carbon conversion, and temperature profile in the gasification system. Sensitivity analysis of the inputs of the ROM (including test condition and reactor network parameters) has also been performed. This analysis has shown that the recirculation ratio and oxygen flow rate have a greater effect on the outputs compared to model geometry and kinetic parameters.