常压塔塔顶压降升高的原因分析

某常压蒸馏装置掺炼轻质原油或回炼轻污油时常压塔负荷变大，当常压塔塔顶（简称常顶）回流量大于22 t/h时，常顶和进料段压差由20 kPa增加到40 kPa以上，常顶油和常一线油出现馏程重叠。现场调研发现，常压塔上数第9~16层塔盘、浮阀有大量结垢沉积物，几乎堵塞整块塔盘。对现场堵塞位置垢样进行采样，元素分析、XRD、XRF表征结果表明，常压塔一中段处垢样的主要成分是NH4FeP2O7。通过高温缓蚀剂模拟结垢试验确定了塔顶结垢堵塞的原因，并针对性提出优化解决措施。

CAUSE ANALYSIS OF PRESSURE DROP INCREASE AT TOP OF ATMOSPHERIC DISTILLATION COLUMN

The load of atmospheric distillation unit is greatly increased when the feed blends with the light crude oil or the light sump oil recycled. When the reflux of the tower is greater than or equals to 22t/h, the pressure drop between the top of the tower and the feed entering position increases from 20kPa to 40kPa with the overlap of boiling range of the top oil and the first side line oil. It is found that there are a lot of fouling deposits at the 9-16 layer trays, almost blocking the whole tray. The deposits were characterized by the elemental analysis, XRD and XRF. The results indicate that the main component of the deposit is NH4FeP2O7, confirmed by the simulation test of high temperature corrosion inhibitor. Finally, the optimization solutions for the problem are proposed.