The Numerical Simulation of Opposed-multi-burner Pulverized Coal Gasifier

摘要

The gas-solid flow and multiphase turbulent reaction flow in opposed-multi-burner pulverized coal gasifier were numerically simulated respectively. The comprehensive coal gasification model included Realizable k-ε turbulent model, particle random trajectory model, the two competing rates coal devolatilization model, homogeneous and heterogeneous reaction models and Eddy-dissipation-concept (EDC) turbulent reaction flow model. For gas-solid flow simulation,the particles are enriched in impinging zone, and the dispersion of the particles is increased with increasing gas velocity of the burner. The numerical result of particle residence time distribution agreed well with the experiment data. For multiphase turbulent reaction flow simulation, the numerical results of opposed-multi-burner pulverized coal gasifier agreed well with the pilot plant experiment data, including gasification temperature and syngas composition. In the operation range of oxygen-coal ratio, the maximum temperature of the impinging flow is 1800～2000K, and the gasification temperature is increasing 30～40 ℃when oxygen-coal ratio per increasing 0.01Nm 3 /kg coal. When the height-diameter ratio (above the burner) is decreased form 1.67 to 1.11, the temperature of gasifier arch is increased form 1511K to 1573K and the velocity in gasifier head is increased by 50%.