加压喷动流化床煤快速热解的三维数值模拟

Three-dimensional numerical simulation of fast pyrolysis of coal in pressurized spout-fluid bed

对处理量为50 kg/h的中试尺度喷动流化床反应器内加压煤快速热解过程进行数值模拟。研究反应器高度、煤进料口位置等结构参数以及不同压力(0.1、0.3和0.5 MPa)、射流风与流化风比值(0.2、0.3和0.4)和粒径(0~3和0~6 mm)等操作参数的影响规律。结果表明:升高压力,煤与半焦混合程度降低,煤气产率提高;流化风量Qf不变,随射流风量Qs增加,气固流动更剧烈,颗粒温度分布更加均匀,顶部出口颗量增加;增大粒径虽可降低挥发分出口的颗粒量,但不利于煤与半焦混合。

Numerical simulation of pressurized fast pyrolysis process of coal in a pilot-scale reactor with the capacity of 50 kg/h was carried out.Characteristics of structural parameters,such as reactor height,coal feeding inlet position,pyrolysis pressures(0.1,0.3,and 0.5 MPa),ratios of spouted gas to fluidized gas(0.2,0.3,and 0.4),and particle size(0-3 and 0-6 mm),were investigated.The results are shown as follows.With the increase of pressure,the mixing of coal and semi-coke became worse while the gas yield increased.Keeping the fluidized gas Qf unchanged,with the increase of spouted gas Qs,the gas-solid flow became more intense,the particle temperature distribution became more uniform,and the particle outflow at the volatile outlet increased.Although increasing particle size reduced the particle outflow at the volatile outlet,it might weaken the mixing of coal and semi-coke.