Abstract: Coal gasification technology has played an important role in coal development and utilization approaches of coal. Texaco gasifier, as a representative of the mature gasifier, is purchased by most of the enterprises to carry out industrial production. In order to improve the gasification process, detailed numerical simulation is necessary. Based on Fluent software, numerical simulation of the coal gasification process for a Texaco gasifier was investigated with a comprehensive model. Previous geometric model of gasifier payed more attention to simple two-dimensional rectangle shape, and ignored the effect of nozzle and spherical head on the flow field of the gasifier. In addition, previous researches mainly focused on the method of probability density function, while it was hard to use non-premixed combustion model to simulate the heterogeneous reactions of coke with CO₂, H₂O and other substances. Therefore, the distribution of the components in the gasifier can't be well reflected. In this paper, Finite Rate/Eddy-Dissipation model was adopted to simulate the coal gasification process and DPM(Discrete Phase Model) was adopted to solve the multiple-surface-reactions of coal combustion. Compared with the non-premixed probability density function method, the results were more accurate. Standard k-ε turbulent model was adopted to close the momentum equation. P-1 radiation model was adopted to simulate the internal radiation characteristics of gasifier. The validity of the model was confirmed by comparing the model prediction data with industrial data. On the basis of this model, the coupling relationship of the three factors, including the coal slurry flow rate, oxygen flow rate and coal slurry concentration was investigated. The effect of the center oxygen ratio defining as the proportion of center oxygen to total oxygen on the gas components of gasifier outlet, the efficiency of effective components, the outlet temperature and the carbon conversion ratio were investigated; A reference was provided to improve the efficiency of effective components and the carbon conversion ratio, and to ensure industry production safety.