基于H_(2)S生成简化动力学模型的富燃料煤粉燃烧数值模拟研究(英文)

Numerical Simulation of Fuel-rich Combustion of Pulverized Coal With Reduced Kinetic Model of H_(2)S Formation

富燃料燃烧过程中,燃煤锅炉的水冷壁附近容易形成高浓度的H_(2)S,引发高温腐蚀。为准确计算炉膛中H_(2)S的浓度分布,并且尽量少占用计算资源,有必要发展H_(2)S生成的简化动力学模型。因此,提出H_(2)S生成的简化动力学模型,包括10种含硫组分和30个基元反应,并将该模型与计算流体动力学模型耦合,利用Ansys Fluent软件开展了富燃料煤粉燃烧的数值模拟研究。结果显示,SO_(2)、H_(2)S和COS浓度较高,在CO和H_(2)的作用下,SO_(2)可被还原为H_(2)S和COS;CS_(2)浓度虽然较低,但是对于H_(2)S的生成有重要影响。对比发现,由该模型计算得到的煤粉燃烧炉中主要组分(CO、H_(2)、CO_(2)和O_(2)等)的浓度与实验结果吻合较好,最大误差不超过10%;含硫组分(SO_(2)、H_(2)S、COS和CS_(2))浓度的计算值与实验值的最大误差小于13%。所以,该简化模型可用于富燃料燃烧过程中H_(2)S浓度的计算。

In the fuel-rich combustion,high concentration of H_(2)S is easily produced and thus leads to high-temperature corrosion in coal-fired power plants.In order to accurately predict the H_(2)S distribution while greatly reduce the computing time,it is necessary to develop a reduced mechanism of H_(2)S formation during pulverized coal combustion.In this work,a reduced kinetic model,consisting of 10 sulfur species and 30 elementary reactions,was proposed on the basis of our previous detailed kinetic model.After that,a numerical simulation of fuel-rich combustion of pulverized coal was performed in Ansys Fluent by coupling the reduced kinetic model with computational fluid dynamics(CFD).The results show that SO_(2),H_(2)S and COS are released in large amounts.H_(2)S and COS are further formed from SO_(2) in the presence of H2 and CO.CS_(2) is produced only no more than 100μL·L^(-1),but significant for H_(2)S formation.It is found that the predicted concentrations of the major species,namely,CO,H_(2),CO_(2),and O_(2),are overall consistent with the experimental values with the maximum error of less than 10%,and that the peak error is within 13%between the calculated and measured results for the sulfur species.Thus,the reduced kinetics model is acceptable in actual engineering application to predict the H_(2)S production.