锅炉尾部烟道阻力诊断及粉尘浓度分布影响

Resistance Diagnosis of Boiler Tail Flue and Influence of Dust Concentration Distribution

为研究电厂锅炉尾部烟道阻力分布情况,文章同时使用了实验测量手段与两相流数值模拟仿真手段,进行了比对分析研究。研究表明,实验测量得到的空预器出口至除尘器入口的烟道阻力平均值约705 Pa,数值计算得到的结果含粉尘情况下约609 Pa,计算结果比实验测量结果低了约14%,而水平烟道至除尘器入口的烟道实验测量的阻力平均值约425 Pa,数值计算得到的相应结果含粉尘情况下约408 Pa,二者数值相差约17 Pa,计算结果比实验测量结果低了约4%,这些差异可能是由于烟道积灰的情况造成的;气体粉尘两相流动的数值模拟结果表明,对于空预器出口至除尘器入口区域不含粉尘粒子的情况下烟道阻力约564 Pa,含粉尘粒子的情况下烟道阻力约609 Pa,粉尘带来的阻力增加约45 Pa,该差异占比不超过8%,对于水平烟道至除尘器入口区域不含粉尘粒子的情况下烟道阻力约375 Pa,含粉尘粒子的情况下烟道阻力约408 Pa,粉尘带来的阻力增加约33 Pa,该差异占比不超过9%,含粉尘计算结果与实验数据更为接近;流场分析发现,在拐角附近、联箱中、爬升段有复杂的漩涡运动,是烟道阻力主要产生的地方,且这些地方气流发生偏转流动,造成粉尘粒子的浓度出现不均匀分布,可以使用导流板的方式减小阻力,或者采用优化的烟道布局与构型。

In order to study the resistance distribution of the tail flue of the boiler in power plant,the experimental measurement method and the two-phase flow numerical simulation method are used in this paper.The results show that the average resistance of the flue from the outlet of the air preheater to the inlet of the dust remover is about 705 Pa,and that of the numerical calculation is about 609 Pa with dust,which is about 14%lower than that of the experimental measurement.The average resistance of the flue from the horizontal flue to the inlet of the dust remover is about 425 Pa,and that of the numerical calculation is about 408 Pa with dust.The difference between the two values is about 17 Pa,which is about 4%lower than the experimental measurement results.These differences may be caused by the dust accumulation in the flue.The numerical simulation results of gas dust two-phase flow show that the flue resistance is about 564 Pa when there is no dust particles in the area from the air preheater outlet to the dust collector inlet,about 609 Pa when there are dust particles in the flue,the resistance caused by dust increases by about 45 Pa and the difference accounts for less than 8%.The resistance from the horizontal flue to the inlet area of the precipitator is about 375 Pa without dust particles,that from the flue with dust particles is about 408 Pa,the resistance caused by dust increases by about 33 Pa,accounting for less than 9%and the calculation results with dust are closer to the experimental data.The flow field analysis shows that,in the vicinity of corners,in the header and in the climbing section,there are complex vortex motion,which is the main place of flue resistance.In addition,the airflow deflects and flows occur in these places,resulting in the uneven distribution of dust particle concentration.Therefore,The way of deflector can be used to reduce the resistance,or the optimized flue layout and configuration can be used.