流化床煤气化炉内脱硫的研究　Ⅱ．脱硫剂焙烧反应动力学与脱硫反应动力学初步研究

INVESTIGATION INTO IN-SITU DESULFURIZATION OF COAL GASIFICATION IN FLUIDIZED BED Ⅱ.CALCINATION RATE OF CALCIUM BASED SORBENTS AND DESULFURIZATION REACTION KINETICS

钙质脱硫剂的焙烧反应是炉内脱硫的关键过程，本文研究了影响石灰石和白云石焙烧速率的因素。操作温度７５０℃以上时，焙烧速率很快。ＣＯ_２分压显著地影响焙烧过程，Ｐ_（ＣＯ）２高于平衡分压时，石灰几乎不分解。在本实验的粒度范围内，脱硫剂粒度对焙烧速率影响不大。采用未反应核收缩模型模拟焙烧过程的结果和实验结果基本一致。脱硫反应速率对气相Ｈ_２Ｓ浓度呈一级反应，操作温度特别在６００～７００℃的低温时显著地影响反应速率。

Shang le dolomite and Feng shan limestone particles are calcinated at temperature of 700～880℃ in a gas mixture of N2 and CO2.It is found that the reaction temperature and partial pressure of CO2 have significant effects on the calcination process.The calcination process can be described by the shrinking core model.Based on the model,conversion of limestone or dolomite can be expressed by X=1-(1-K·t)3,which fits experimental data fairly well.The activation energy are 184kJ/mol for dolomite and 176kJ/mol for limestone.The reaction rate between CaO and H2S is first order with respect to H2S concentration and can be increased rapidly by increase reaction temperature at temperatures below 700℃.