600 MW机组锅炉低温省煤器磨损机理研究与治理

Research and treatment on abrasion mechanism of low temperature economizer of 600 MW unit boiler

针对某600 MW机组锅炉低温省煤器频繁出现磨损泄漏问题,结合飞灰颗粒对管道表面的磨损机理,采用数值模拟仿真分析导流板最优布置方案。数值模拟仿计算结果表明:采用最优导流板布置方案,第一、二级低省入口截面速度相对均方根分别由原始工况的0.65、0.86降至0.40、0.33;颗粒浓度相对均方根分别由原始工况下的0.78、1.14降至0.68、0.75;左侧第二级低省的磨损率最大值由原始工况下的30降至10;最小值由原始工况下的0.001升至0.200。最优导流板布置方案下,低温省煤器入口烟气流速、飞灰浓度分布均匀性显著提高,有效减轻低温省煤器的飞灰侵蚀。

In view of the frequent abrasion and leakage of low temperature economizer in a 600 MW unit, combined with the abrasion mechanism of fly ash particles’ erodetion on the pipe surface, numerical simulation is used to analysis the optimal layout of the deflector. The results of numerical simulation shows that: the application of the optimal scheme makes the relative root-mean-square of velocity from 0.65 to 0.40 at the entrance of the first stage low temperature economizer, and from 0.86 to 0.33 at the entrance of the second stage low temperature economizer. The relative root-mean-square of the fly ash concentration is decreased from 0.78 to 0.68 at the entrance of the first stage low temperature economizer, and from 1.14 to 0.75 at the entrance of the second stage low temperature economizer. The maxium abrasion rate of the left second stage low temperature economizer is dropped from 30 to 10, and the minimum is increased from 0.001 to 0.200. The uniformity of the velocity, fly ash concentration and abrasion rate’s distribution at the low temperature economizer entrance are improved, the abrasion of the low temperature economizer is significantly improved.