油水分离系统密度测量误差分析

Error Analysis for the Density Measurement in Oil-Water Separation System

某核化项目的油水分离系统采用吹气法测量油水分离槽中的液位、界面和密度。其密度测量误差会影响油水分离槽的界面测量,不利于有机相和水相的准确分离。针对密度测量误差大这一问题,从吹气测量管线、信号转换和信号传输等三方面进行分析,确定长期运行过程中测量管线内壁油膜吸附杂质是造成压力损失现象和就地强电磁干扰的关键因素。为解决管线内部杂质聚集问题,在测量管线中增加一套酸洗装置溶解油膜;在信号传输通道中增加隔离模块,以减小环境设备的电磁干扰。试验结果表明,密度测量误差满足设计要求,油水分离槽的水相和有机相分离效果好,能满足运行要求。实际运行证明,吹气测量变送器的改进方案简单、经济,具有一定的实用价值。

In a certain nuclear-chemical project,air blowing method is used to measure the level,interface and density of the oil-water separation tank. It is found that the error of density measurement affects the interface measurement,and also not good for the accurate separation between organic phase and water phase. For the large error of density measurement,the reasons are analyzed from the three aspects,i. e.,the air blowing pipeline,signal conversion and signal transmission. Two key factors have been found. One is the pressure drop phenomenon caused by oil slick in the pipeline which adsorb the impurities after long-term operation. The other is the local strong electromagnetic interference environment. A new acid cleaning device is added in the pipeline to dissolve the oil slick and solve the impurities problem inside the pipeline. A isolation module is used in the signal transmission path to decrease the electromagnetic interference. The test results prove that the density measurement error meets design requirement,and the separation effect of water phase and organic phase in the oil-water separation tank is good. The practical operation verifies that the improvement method for air purge transmitter is economical,simple and has a certain practical value.