Shell粉煤气化炉渣池内熔渣沉积的周向分布特性

摘要

The blockage of Shell coal gasifier caused by slag deposition is a challenging problem.Influence of operation loads, nozzle numbers on the gas flow field and circumferential distribution of slag deposited on the slag bath screen was investigated by cold mode experiments.Molten wax was used as the modeling slag.Results showed that when operated with 4 nozzles, gas flow rotated downwards and left the slag bath in the center, and the distribution of slag was uniform.When operated with 3 nozzles, rotational flow approached to the position near the closed nozzle, and left the slag bath from the opposite side.Slag tended to deposit at the rear of the rotational flow.At the position where axial gas velocity was the biggest, the amount of slag deposited was the least.The reason was that axial gas flow caused the redistribution of slag in the slag tap.Meanwhile, it formed an isolation layer near the slag bath screen which prevented the slag from depositing on it.This will lead to the accumulation of slag in a certain place and increase the risk of slag blockage.%针对渣池内熔渣沉积导致气化炉堵渣的问题,以石蜡为模拟介质,考察气化炉操作负荷、喷嘴数目等参数对渣池内流场和渣屏处熔渣沉积量周向分布的影响.研究结果表明,四喷嘴操作时,渣池空间内的气体旋流向下运动,并在中心处形成上升气流离开渣池空间,此时熔渣分布较均匀.关闭其中一个喷嘴后,渣池内的气体旋流向相邻喷嘴所处的壁面位置偏离,并从与该位置相对的另一侧离开渣池空间.熔渣倾向于在气体旋流的尾部沉积,在轴向速度最大的位置处熔渣沉积量最小.这是由于气体流场的改变一方面导致了熔渣在渣口处的重新分配,另一方面形成的气膜阻碍了熔渣的沉积.熔渣的不均匀分布将导致其在渣池壁面的局部累积,增大了堵渣的风险.