常压塔顶部挥发线露点腐蚀与多相流模拟

Study on Dew Point Corrosion with Multiphase Flow Simulation at The Overhead Vapor Line of the Atmospheric Tower

运用CFD仿真软件Fluent,参考国内某炼厂常压塔挥发线管道结构和运行工况,对注水后管道内的多相多组分状态进行了模拟,编写了相应的传热传质模型,对其中的腐蚀性介质参数进行了计算分析,结果表明:在注入中性水后,挥发线管道内气相腐蚀性介质HCl和H_2S在水相中快速溶解,导致水相pH值呈酸性,注水点下游附近出现了液相跌落区,此处的pH值最低。对不同的注水流量和液滴粒径的注水工况进行模拟后,发现注水参数对跌落区的位置、最低pH值产生了影响,其中液滴粒径的影响更加显著。据此,预测了不同注水工艺对塔顶露点腐蚀状态的影响,以期指导腐蚀监测和工艺防腐。

In order to study the dew point corrosion of the overhead pipeline,a CFD simulation software,Fluent,was used to simulate the multiphase and multi-component state in the pipeline after water injection based on the actual pipeline structure and operation conditions of a domestic refinery.The models of heat and mass transform were compiled and the parameters of corrosivesin the pipeline were calculated and analyzed.The results showed that after fresh neutral water was injected,the corrosivessuch as hydrochloric and hydrogen sulfide gas rapidly dissolved into the water phase and turned the solution to acidic in the pipeline.The initial condensation zone was locatednearthe downstream from the injection point,where the pH value was the lowest.It was also found that theposition of the initial condensing area lowest pH value changed with water flow rate and droplet size,with a bigger impact from the latter.Based on this,the influence of different technologies of water injection on the dew point corrosion state of the overhead system wasstudied,which couldguide thedesign of effective anti-corrosion methods.