燃烧工况对烘焙木球高温单颗粒燃烧特性的影响

Effect of Reactor Condition on High temperature Single Particle Combustion of Torrefied Wood

选择直径4mm的原生与260℃烘焙1h后的荷木球作为原料,在模拟工业锅炉实际燃烧条件的单颗粒燃烧器中进行不同工况下的燃烧实验,以研究烟气温度、流速和氧浓度对单颗粒荷木球着火、挥发分燃烧和焦燃烧时间的影响。此外,编写了图像识别程序对工业摄像机拍摄的焦燃烧视频进行识别。研究表明,随着烟气温度、流速及氧气浓度的增加,荷木球的着火、挥发分燃烧和焦燃烧时间都呈下降趋势。编写的MATLAB程序能够准确识别挥发分燃尽时间及焦燃尽时间,从而测出焦颗粒燃烧过程中,每一时刻的面积变化。此外,升高烟气温度和氧浓度均能显著消除烘焙后热解焦燃尽困难的问题,而气体流速的作用类似但不明显。

Wood spheres with 4mm schima and their torrefied counterparts(at 260℃ for 1h) were combusted in a single particle combustion reactor,which was designed to simulate the industrial conditions during pulverized combustion.The effects of various reactor conditions on the combustion behavior of wood spheres were investigated,including combustion temperature,flue gas flow velocity and oxygen concentration.Moreover,the char combustion videos are recognized by an image recognition program.The results show that the ignition,devolatilization and char burnout time were decreased by increasing flue gas temperature,flue gas flow velocity and oxygen concentration.The ending moment of devolatilization and char burnout time could be accurately measured by MTALAB program,thereby obtaining the area of char particle at any char burning moment.Morever,the effect of torrefaction on increased char burnout time could be eliminated mainly by increasing combustion temperature and increasing oxygen concentration,while the gas flow velocity can be proved to have the smallest effect.