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In this study 2D numerical simulation for two-stage entrained flow dry feed coal gasification performance was developed. The detailed operational characteristics of O/C distribution between the two stages of the gasifier were examined in standard CFD software FLUENT®14 to analyze their effects on the gasification performance. Furthermore the different reaction mechanisms were investigated for validation of the model with experimental results. The results show that H 2 and CO composition at the exit of gasifier are increased at O/C ratio 0.8 as compared to other simulation cases, and the temperature gradually decreases from 2nd injection level because of water-shift reaction. Maximum CO% was observed when 40% of oxygen injected at the lower level, overall range of H 2 % at the exit of gasifier was 10–45% but maximum H 2 % was found when 50% O 2 % and 30% of coal injected at a lower level. The maximum temperature about 2300 K when 40% O 2 and 40% of coal was injected at a lower level. Overall optimized results for CO, H 2 , and minimum CO 2 formation was observed when 60% O 2 and 40% of coal was injected at a lower level of the gasifier. The gasification performance can be controlled with the optimized coal/oxidant distribution between the stages.

A 3D CFD model for two-stage entrained flow dry feed coal gasifier with multi opposite burners (MOB) has been developed in this paper. At each stage two opposite nozzles are impinging whereas the two other opposite nozzles are slightly tangential. Various numerical simulations were carried out in standard CFD software to investigate the impacts of coal and oxidant distributions between the two stages of the gasifier. Chemical process was described by Finite Rate/Eddy Dissipation model. Heterogeneous and homogeneous reactions were defined using the published kinetic data and realizable k–e turbulent model was used to solve the turbulence equations. Gas–solid interaction was defined by Euler–Lagrangian frame work. Different reaction mechanism were investigated first for the validation of the model from published experimental results. Then further investigations were made through the validated model for important parameters like species concentrations in syngas, char conversion, maximum inside temperature and syngas exit temperature. The analysis of the results from various simulated cases shows that coal/oxidant distribution between the stages has great influence on the overall performance of gasifier. The maximum char conversion was found 99.79% with coal 60% and oxygen 50% of upper level of injection. The minimum char conversion was observed 95.45% at 30% coal with 40% oxygen at same level. In general with oxygen and coal above or equal to 50% of total at upper injection level has shown an optimized performance.