【作者】 李强；

【导师】 宋健斐；

【作者基本信息】 中国石油大学(北京) ， 化工过程机械， 2020， 硕士

【摘要】 环栅式动力除尘器是一种惯性分离器,它体积小、分离性能佳、安装简便,可广泛应用于锅炉、烟草、水泥、冶金、电力、化工等领域。该型分离器布置灵活,可直接连接到除尘管道,理论上适于天然气管道的除尘。然而,环栅式动力除尘器的具体结构与尺寸并不明确,结构参数和流动参数对其性能的影响也缺乏系统的研究。本文在文献调研的基础上,采用数值模拟与实验研究相结合的方法对环栅式动力除尘器的分离性能进行研究。首先,采用ANSYS Fluent 18.0软件进行数值模拟,分析了环间距d、环错位b、环高h、环个数n、气速v、抽气流量比例φ、颗粒浓度c对分离器内部流场和分离性能的影响,得到最佳的结构参数;然后,以数值模拟得到的最佳结构参数为准加工环栅式动力除尘器,搭建了一套实验装置,采用称重法测得分离器分离效率,考察了不同气速、不同抽气流量比例、不同颗粒浓度条件下分离器的分离性能,并将实验结果与模拟结果进行了对比。结果表明,增大环间距d,分离效率先增大后减小,压降逐渐降低;增大环错位b,分离效率降低,对压降影响很小;增大环高h,分离效率先增大后减小,压降逐渐增大;增加环个数n,分离效率无提升,压降反而显著增大;增大气速v,分离效率提升,压降逐渐增大;增大抽气流量比例φ,可以显著提升分离效率,同时降低压降;增大颗粒浓度c,分离效率减小,压降几乎不变。分离器结构参数b=1mm、h=5mm、n=20为最佳结构参数,由于颗粒出口抽气与不抽气情况下,分离器的分离性能差别很大,导致环间距对分离器的影响也有所差别,所以综合来讲,最佳环间距d可取值3至8mm。实验得到的气速、抽气流量比例、颗粒浓度对分离器分离性能的影响规律与模拟的结果一致。最后,为了给后续的优化工作提供参考,本文通过数值模拟的方法对环间距进行了进一步的分析。结果表明,将环间距缩至3mm可以提高较大颗粒的粒级效率,但同时会增大分离器压降。更多还原

【Abstract】 Cascade-ring aerodynamic dust collector is a type of inertial separator,which can be widely used in boiler,tobacco,cement,metallurgy,electric power,chemical industry and other fields because of its small volume,good separation performance and convenient installation.Due to its flexible process layout,the separator can be linked with natural gas pipelines directly,which means it is theoretically appropriate to apply the separator to natural gas pipelines.Thus,this paper mainly studies the separation performance in the case of natural gas dedusting.However,the detailed structure and internal geometrical dimensions of the cascade-ring aerodynamic dust collector remain unclear yet,and the effects of structure parameters and flow parameters on its separation performance lack of systematic research so far.Studies on the separation performance of cascade-ring aerodynamic dust collector herein were conducted by means of numerical simulation and experiments.ANSYS Fluent 18.0 was utilized in numerical simulation to simulate the gas flow field and analyze the influence of seven factors(interval distance d,dislocation of rings b,loop height h,number of rings n,inlet gas velocity v,ratio of exhaust gas φ,particle concentration c)on separation performance of the separator.In that case,structure parameters for optimum separation performance can be deduced and determined.On the basis of these,a cascade-ring aerodynamic separation system was set up.The separation efficiency was measured by weighing method.Separation performance of the separator under different operating conditions was analyzed and the efficiency and pressure drop obtained by experiments and simulation were compared.The results show that increasing the interval distance d makes the separation efficiency increase at first and then decrease,and the pressure drop reduce;increasing the dislocation of rings b decreases the separation efficiency and hardly has effects on the pressure drop;increasing the loop height h makes the separation efficiency increase at first and then decrease,and the pressure drop reduce;increasing the number of rings n doesn’t improve the separation efficiency and brings about apparent increase of the pressure drop;with the increase of the inlet gas velocity,the separation efficiency increases and so does the pressure drop;increasing the ratio of exhaust gas is an effective way to improve the separation performance for the reason of higher separation efficiency with lower pressure drop;increasing the particle concentration decreases the separation efficiency and hardly has effects on the pressure drop.Structure with b=1mm,h=5 mm,n=20 comes with the best separation performance.In addition,interval distance corresponding to optimum separation performance depends on the ratio of exhaust gas,so,to consider comprehensively,3 to 8 mm shall be the best range.Effects of different operating conditions on separation performance deduced from experiments are consistent with simulation.Finally,the interval distance is further studied by means of numerical simulation in order to offer a reference for the follow-up optimization.The results show that decreasing the interval distance to 3mm can effectively improve the separation efficiency of particles with relatively larger diameters as well as the pressure drop.更多还原