原油长输管道应用降凝剂研究

RESEARCH ON POUR POINT DEPRESSANT USED FORLONG-DISTANCE TRANSPORTATION OF CRUDE OIL

应用于输油管道的降凝剂,通过研究,在马惠宁输油管线进行了现场试验。结果表明:原油经过50ppm降凝剂处理,凝固点由16℃降至-2℃;5℃、11.5s^-1时粘度由1363mPa.s降至122.7mpa.s;反常点由24℃降至15℃;降凝剂处理原油与加热输送原油同期相比。油耗降低56％,电耗降低8％。处理温度、高速剪切、重复加热对改善原油低温流变性有一定的影响:原油理想的降凝剂处理温度应是最佳热处理温度;降凝剂的应用存在最佳始注入量,且遵循u=u0+Ae^-Bq规律;应用降凝剂长时间低温输油时,不宜用局部加热和大排量冲刷方法处理管线;采用热共处理和降凝剂综合技术,可改善原油低温的流变性。实现管道常温输送,产生良好的经济和社会效益。

The paper covers a technological research on pour point depressant used for long-distance transportation of crude oil and describes a field test on the Ma-Hui-Ning pipeline. The pour point of Maling crude oil is decreased from 16 degree to-2 degree C and 5 degree C after addition of 50 ppm depressant, the viscosity was decreased from 133 mPa·s to 122. 7 mPa. s at a shear rate 11. 5 s-1. The conversion point at which Newtonian behavior changed into non-Newtonian one is also decreased from 24 degree C to 15 degree C. In comparison with heated oil transportation at the same period, fuel consumption was reduced by 56%, the power consumption was reduced by 8％. The effect of treatment temperature, high shear rate and repeated heating on improving crude oil flowability at a low temperature was studied. The mixed transportation with the addition of Hongjing crude oil and restarting the pipeline in the case of shutdown were also observed and investigated. The ideal temperature of pour point depressant treatment should be the optimum temperature for heat treatment. The optimum amount for initial injection of pour point depressant can be determined from an aquation μ=μο+ Ae^(-Bq). Local heating and large pump rate flushing are not applicable for preconditioning the pipeline when pour point depressant is used for low temperature transportation of crude oil. The combination of addition of pour point depressant and heat treatment improve the low temperature flowability of crude oil to enable normal temperature transportation in Ma-Hui-Ning pipeline.