准东褐煤燃烧形成的颗粒在圆管上的沉积数值模拟  

Numerical Simulation of Particle Deposition Formed by Combustion in Zhundong Lignite on the Tube

作　　者：商月 穆林[1] SHANG Yue;MU Lin(School of Energy and Power Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学能源与动力学院,大连116024

出　　处：《应用能源技术》2020年第5期1-7,共7页Applied Energy Technology

基　　金：中央高校基本科研业务费专项资金资助项目(DUT20LAB134,DUT18JC25)。

摘　　要：准东煤中的碱性化合物在燃烧时会形成熔点低的灰烬,在锅炉的运行中容易引起传热表面的结垢,烟气通道的堵塞,传热速率的降低以及过热器管的腐蚀等问题。文中提出了一个模型用以描述和预测高碱金属成分烟气飞灰沉积的形成。在目前的工作中,建立的数学模型包括了从燃料床中释放出飞灰颗粒和碱蒸气向换热表面运输过程以及飞灰颗粒和碱蒸气的沉积行为。结果表明,烟气速度主要通过影响飞灰颗粒的碰撞效率对沉积产生影响,而在高烟气速度条件下,炉温通过改变积灰表面的熔融组分来影响飞灰颗粒的黏附效率。惯性碰撞和热泳引起的颗粒沉积决定了高炉温下灰分的形成,碱蒸气直接冷凝引起的沉积量主要存在于前期。Zhundong(ZD)lignite contain alkali compounds,which form ash with low melting temperatures upon combustion.This causes many problems in recovery boiler operation,including fouling of the heat transfer surfaces,plugging of the flue gas passages,reduction of the heat transfer rate and corrosion of the superheater tubes.A model was developed to describe and predict the formation of fly ash deposition in high alkali metal flue gas.At the present state of development the model covers the release of coarse ash particles and ash-forming vapours from the fuel bed,the transport to furnace and boiler surfaces and the deposition of particles and vapours.The results show that the velocity of flue gas affects the deposition mainly through the impact efficiency of fly ash particles.The temperature of furnace influences the predicted deposition formation by changing the melting degree of the deposit layer could greatly enhance the predicted deposition formation for the high furnace velocity condition.The deposition of particles caused by inertia collision and thermophoresis determine the formation of ash at high furnace temperature,and the deposition caused by direct alkali vapour condensation mainly exists in the early stage.

关 键 词：表面涂层颗粒 碱蒸气 灰分沉积 黏附机理 

分 类 号：TQ534[化学工程—煤化学工程]