天然气处理厂精馏塔堵塞成因及防治对策研究

Study on the causes of the blockage and countermeasures of distillation column in natural gas treatment plant

目的解决因精馏塔堵塞导致的甲醇产品回收效果差、设备频繁停运检修及水处理效率降低等一系列问题。方法在精馏塔内选取不同高度的试验点进行腐蚀监测,并结合室内含醇污水水质和堵塞物分析及X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能量色散谱(EDS)等手段,对比分析了该厂精馏塔堵塞的原因。结果与2017年相比,2019年含醇污水矿化度显著升高,成垢阳离子和氯离子含量也大幅提升,结垢预测结果为更易产生CaCO_(3)垢。结论精馏塔堵塞原因主要为结垢堵塞,且点蚀现象较为严重。2017年的堵塞物主要成分为Fe_(2)O_(3)、CaCO_(3)和CaMg(CO_(3))_(2),2019年的堵塞物主要成分为Fe_(3)O_(4)和CaCO_(3)。2019年,精馏塔堵塞的主要原因是高温下CaCO_(3)结垢和Fe_(3)O_(4)堵塞塔板。通过提高含醇污水pH值、优化药剂种类及加量解决精馏塔堵塞问题,现场运行效果良好。

Objective To solve a series of problems caused by blocked distillation column,such as poor recovery effect of methanol products,frequent equipment shutdown and maintenance,and reduced water treatment efficiency.Methods The test points of different heights were selected in the distillation column for corrosion monitoring,and the reasons for the blockage of the distillation column were compared and analyzed in combination with the analysis of the water quality of alcohol-containing sewage and the blockage in the laboratory and X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray energy dispersive spectroscopy(EDS),etc.Results Compared with 2017,the salinity of alcohol-containing sewage increased significantly in 2019,and the scaling cation and chloride content also increased greatly.The predicted result of scaling was more likely to produce CaCO_(3)scale.Conclusions The main reason of distillation column blockage is scaling,and pitting corrosion is serious.In 2017,the main components of the blockage material were Fe_(2)O_(3),CaCO_(3)and CaMg(CO_(3))_(2),and they were Fe_(3)O_(4)and CaCO_(3)in 2019.In 2019,the main cause of distillation column blockage was CaCO_(3)scale and Fe_(3)O_(4)blocking column plate at high temperatures.By increasing pH value of alcohol-containing sewage,optimizing the type and dosage of reagents,the blockage of distillation column have been solved,and the field operation effect is good.