Study On The Freezing Point And Viscosity Of Lancheng Line Mixed Crude Oil And Its Application

With the development of economy in our country, more and more crude oil needs to be imported, which increases the burden of oil transporting capacity in our country. Making use of pipelines that have been built, adding light imported crude oil into local crude oil with bad fluidity can not only accomplish the task to transport imported crude oil, but also improve fluidity of local crude oil at some extent. Therefore, transporting the mixture of local crude oil and imported crude oil with pipelines is an easily operational, safe and economical transportation approach. Due to the complex fluidity of crude oil, most of application studies focused on exploring the feasibility of blending crude oil in specific proportion, which leads to the lack of solution that can respond flexibly to the changes. Aiming to make a plan for blending crude oil transportation at normal temperature in Lancheng crude oil pipeline, the paper launches studies in several following fields:Taking oil from KZ, Talimu, Tuha and Changqing as the basic samples, mixed crude oil rheology experiments has been lauched. Taking condensation point and viscosity as the main index, the paper discussed the mixing proportion, heat treatment and flow shear influent on mixed crude oil.Using 118 groups of measured condensation point of mixed crude oil, the paper checked accuracy of four condensation point cultulation models, which include Lichuangwen model, Liutianyou model ?, Liutianyou model ? and Chenjun model. Besides, the paper checked six mixed crude oil viscosity calculation models by 617 groups of measured viscosity of mixed blending crude oil. The six models include Arrhenius modified model ?, double log modified model ?, double log modified model ?, Bingham modified model ?, Cragoe modified model ? and Cragoe modified model ?.Futhermore, the paper accomplished a comprehensive evaluation to calculation models based on average deviation, the biggest deviation and the distribution of deviation. The result indicated that Liutianyou modified model ? shew the strongest applicability to calculate condensation point for mixed crude oil in Lancheng pipeline, and Arrhenius modified model ? shew the strongest applicability to calculate viscosity of mixed crude oil.Applicating the evaluation results of the models, combining with LanCheng cloth station along the line and ground temperature conditions, considering constraints of oil transportation task, mixed crude oil condensation point and viscosity, the paper compiled program with MTLAB to calculate the blending ratio of LanCheng crude oil that can be transported under normal temperature. The culculated result of the program can provide technical support for making plan of transportating blending crude oil in Lancheng line.The studies above demonstrate a proposal of making scheme to transport mixed oil at normal temperature, and provide reference to other pipeline.