孔隙结构对燃煤脱硫反应最大转化率的影响

Effect of Pore Structure on Maximum Conversion of Desulfurization Reaction of Coal Combustion

为研究燃煤脱硫反应中氧化钙孔隙结构对最大转化率的影响，采用随机行走法模拟氧化钙颗粒，基于分子运动论建立多孔颗粒中气体扩散模型，应用简单碰撞理论和Fick扩散定律分别描述脱硫反应的两个阶段．模拟了15种不同孔结构的氧化钙在700～900℃和1500×10～3500×10^-6二氧化硫条件下的脱硫反应，通过引入一个表征孔内扩散特性的模数来研究孔隙结构对最大转化率的影响．结果表明，氧化钙最大转化率随反应温度和二氧化硫浓度的升高而增大；最大转化率随着该模数的增大呈某一指数函数增大．

To study the effect of pore structure on the maximum conversion of desulfurization reaction of coal com- bustion, CaO particles were modeled with a random walk method, gas diffusion in pores was modeled with the clas- sic kinetic theory of gases, and two-stage desulfurization reactions were described by simple collision （SCT）and Fick＇s law, respectively. The maximum conversions were predicted for 15 kinds of CaO with different pore structure under 700～900℃ and 1500×10～3500×10^-6 SO2. A module that characterizes the pore diffusion was introduced to study the effect of pore structure on the maximum conversion. The results show that the maximum conversion in- creases with temperature and S02 concentration, and increases exponentially with the module.