Numerical Simulation Of Coal Gasifier

In this paper,the simulation model of GE coal-water slurry gasifier was established by STAR-CCM+ software;the flow fields of nozzle and combustion chamber and nozzle heat exchange system were calculated.The calculated results of the CWS nozzle showed the fast and the flow effect along the wall led to the flow rate of the external oxygen changed,the flow rate of the outer oxygen inlet side of the lower part of the nozzle was obviously low;the results also revealed that without changing the height of the nozzle,the local transformation to achieve the nozzle below the basic flow rate uniformity,the flow rate was at the range of 2.5 to 1.3m/s.The results of simulating the heat transfer system of the nozzle showed that the heat transfer effect was not suitable,the temperature of the nozzle wall was around 600 oC.The temperature of the wall of the nozzle should be lowered to about 300 oC when the coil heat exchanger to change the heat transferThe simulation results of the flow field of the combustion chamber showed that the speed in the axial direction was too large and the refracted flow appeared;which were corresponded to the short residence time of the gasifier and the short life of the refractory bricks.Three kinds of improvement schemes were proposed and simulated.In the Scheme I,the percentage of the oxygen in the central oxygen was adjust at the range from 13% to 16%;In the Scheme II,the outer ring of the main oxygen contraction angle was changed from 60 o to 50o;In the Scheme III,the oxygen channel were installed four to eight oblique baffle.In the Scheme I,it was found that refracted flow increased with the proportion of oxygen in the center.It was found that the effect of the shrinkage angle on the flow rate was not obvious.In the Scheme III,the results showed that the refracted flow of the flow field and the velocity of the axis decreased obviously,but the coal slurry concentration was not well;By adjusting the position and the number of leaves and leaf angle,the concentration of coal water slurry can become uniform.A strong theoretical support was provided to The gasification furnace optimization design from the gasification furnace flow field,and at the same time the risk was reduced of improving the gasifier.