两相流诱发低温省煤器磨损的分析与应用  

Analysis and application of low-temperature economizer erosion induced by two-phase flow

作　　者：叶兴联 YE Xinglian(National Environmental Protection Power Industry Dust Treatment Engineering Technology Center,Longyan 364000,China;Fujian Longking Co.,Ltd.,Longyan 364000,China;School of Metallurgy,Northeastern University,Shenyang 110819,China)

机构地区：[1]国家环境保护电力工业烟尘治理工程技术中心,福建龙岩364000 [2]福建龙净环保股份有限公司环境研究院,福建龙岩364000 [3]东北大学冶金学院,辽宁沈阳110819

出　　处：《中国粉体技术》2024年第5期47-56,共10页China Powder Science and Technology

基　　金：国家自然科学基金项目,编号:12072071;福建省自然科学基金杰出青年项目,编号:2020J06045。

摘　　要：【目的】为解决气-颗粒两相流诱发低低温电除尘器配套的低温省煤器磨损问题,诊断分析其磨损的主要影响因素和原因,进而提出优化措施。【方法】采用计算流体力学-离散相模型-冲蚀磨损预测模型(computational fluid dynamics-discrete phase mode-erosion prediction model,CFD-DPM-EPM)耦合的数值模拟方法,对低温省煤器进行数值模拟分析;构建低温省煤器的基准模型,分析烟气速度、粉尘浓度和烟气速度均匀性对磨损速率的影响;通过比较磨损速率和低温省煤器入口断面速度分布均匀性分别验证数值模型的可靠性和网格的敏感性。【结果】入口烟气速度过大、粉尘浓度过高和烟气速度分布不均都容易诱发省煤器磨损;某电厂2×660 MW机组低低温电除尘器低温省煤器改造后左、右两侧低温省煤器进口断面烟气最大速度分别从21.94、21.12 m/s降低到12.97、12.81 m/s,速度偏差系数分别从0.322、0.310降到0.201、0.210,最大磨损速率分别下降75.2%、87.8%。【结论】研究结果可为低温省煤器磨损现象的诊断分析以及磨损优化设计提供参考依据。Objective To enhance the dust removal efficiency of electrostatic precipitators,especially for the removal of fine particulate matter like PM2.5,a low-temperature economizer is often integrated into a sub-low-temperature electrostatic precipitator.It's worth noting that the sub-low-temperature electrostatic precipitator is often subjected to wear,ash accumulation,and corrosion during operation,leading to blockages and leaks in the heat exchange tubes.To address the wear problem of low temperature economizer within the low-temperature electrostatic precipitator induced by gas-particle two-phase flow,we diagnosed the causes and proposed optimization measures that can serve as a reference for the design and optimization of similar engineering projects.Methods Computational fluid dynamics and discrete phase model(CFD-DPM)method were employed to capture multi-phase flow details,and an erosion prediction model(EPM)was utilized for wear prediction.The realizable k-εturbulence model was applied to solve the continuous phase,employing the Lagrange method to track the dust particle trajectories and the rebound model for particle-wall collision.The reliability of the numerical model was verified by comparing the wear rates.The sensitivity of the grid was assessed by examining the uniformity of velocity distribution at the inlet section of low-temperature economizer.Results and Discussion In the benchmark model study,it was observed that lower flue gas velocities corresponded to reduced wear rates of the heat exchange tubes,indicating the necessity of a sufficiently large flue section area in the design of a lowtemperature economizer.Furthermore,a decrease in dust concentration upstream of the low-temperature economizer correlated with a slower wear rate of the heat exchange tubes,suggesting the importance of implementing pre-collection measures to mitigate high dust concentrations entering the economizer.The impact of dust particles on the heat exchange tubes and its fins led to decreased velocity and changed direction,res

关 键 词：两相流 低温省煤器 磨损 数值模拟 

分 类 号：TB773[一般工业技术—真空技术]