温度对煤化工废焦积灰特性的影响

Effect of Temperature on Ash Deposition Characteristics of Waste Coke from Coal Chemical Industry

为了得到温度对煤化工废焦燃用过程积灰特性的影响机制,在高温沉降炉实验系统上研究了烟气温度和壁面温度对热解废焦初始层及烧结层沉积灰理化特性的影响。结果表明:烟气温度主要影响烧结层沉积灰的理化特性,对初始层沉积灰理化特性的影响较小,而壁面温度对沉积灰理化特性的影响与之相反;随着烟气温度的降低,沉积灰的熔融粘连情况逐渐减弱,通过吹灰或振打方式较易被清除,随着壁面温度的降低,初始层沉积灰的熔融程度降低,对大颗粒的捕捉行为减弱,也在一定程度上减轻了飞灰沉积;碱金属多以异相凝结的方式存在于初始层沉积灰中,烧结层沉积灰中碱金属含量较少;高钙和高铁特性是导致该燃料在燃烧利用过程中受热面积灰严重的主要原因。

To find the influence mechanism of flue gas temperature and wall temperature on the ash deposition characteristics in the process burning pyrolysis waste coke,experiments were carried out in a high-temperature drop-tube furnace to analyze the physicochemical properties of the deposited ash respectively in the initial and sintered layer.Results show that flue gas temperature has a greater effect on the property of the deposited ash in sintered layer than in initial layer,while wall temperature has an opposite effect.With the decrease of flue gas temperature,the fusion and adhesion degree of deposited ash reduce gradually,resulting in easy removal of the deposited ash;whereas,the decrease in wall temperature could alleviate the fusion of deposited ash in initial layer,thus weakening the capture of large ash particles,thereby reducing the ash deposition to some extent.In addition,alkali metal elements mainly exist in the initial layer rather than in sintered layer by the way of heterogeneous condensation.The existence of high contents of calcium and iron is the main causes leading to severer ash deposition on the heating surface during waste coke combustion.