Development Of Density And Temperature Analyzer For Sedimentation Tank In Longitudinal Direction

Oil-water separation in Jilin Oilfield mainly adopts thermochemical sedimentation method.The vertical distribution of water content and temperature parameters of crude oil in sedimentation tank in thermochemical sedimentation process is of great significance to the output of qualified crude oil,the control of sedimentation efficiency,energy saving and consumption reduction.Because the composition of crude oil produced liquid is complex,it contains not only oil and water,but also alkali,sand,salt,carbon black and other impurities.At the same time,there are poisonous and flammable gases such as H₂S and natural gas in the field of settling tank.It is required to prevent explosion in 0 area of settling tank mouth and explosion in 1 area of non-tank mouth,which makes it extremely difficult to measure the parameters of water content and temperature vertical distribution of crude oil in settling tank.At present,manual sampling is mainly used for water content detection of sedimentation tanks,which is characterized by heavy workload,poor real-time performance,frequent upstream and downstream sedimentation tanks,and no sampling in case of rain and snow.In order to realize the longitudinal density temperature monitoring of the settlement tank,the longitudinal density temperature analyzer of the settlement tank was developed.The instrument is mainly composed of two parts:the sensor detection mechanism and the sensor actuator.Under the condition of guaranteeing the intrinsic safety of the area,the sensor detection mechanism uses floating weight hydraulic balance method?custom?to detect the water content and temperature signals in its location,and the internal circuit of the detection mechanism realizes the signal conditioning and calculation,and transmits the signal to the sensor actuator by HART communication.The sensor actuator uses 86 stepper motors to install 20:1 worm gear and worm reducer with winch.Under the condition of guaranteeing regional flameproof,the sensor detection mechanism is dragged to move up and down in the tank,and the signal is transmitted to the upper computer through MODBUS communication.In order to realize the visualization of the signal,a PC monitoring system based on Siemens S7-300 PLC and WinCC is designed,and the XY curves of the water content,temperature and height of the crude oil in the tank are drawn.The instrument is applied in Fuyu Oil Production Plant of Jilin Oilfield.Through field test,the system can continuously detect oil-water distribution,temperature longitudinal variation and oil-water interface in tank.The accuracy of water content measurement is 0.5,temperature measurement is 0.2 and travel position is 1 mm,which meets the actual production needs.The instrument solves the problem that the vertical density and temperature of the settling tank in the oil field combined station can not be continuously and automatically monitored.According to the principle of detection,the instrument can also be applied to automatic monitoring of density and temperature in multi-component liquid mixing tank in petrochemical industry,which has broad application prospects.