Study On Alternative Transportation Technology Of Hot And Cold Crude Oil

With the rapid development of China’s national economy, the amount of import crude oil increased year by year in our country, and the research on the transport of crude oil gradually indepth. If different kinds of crude oil using blending transmission will make crude oil properties changed, increase the difficulty of the refining process, so we can adapt alternative transportation to transport different kinds of crude oil. There is a very big difference of physical property in Different kinds of crude oil, and it leads to the outbound oil and outbound temperature are changing. At the same time, heat is transferred between crude oil and soil, also between crude oil and The atmosphere. The alternative transportation is always in the process of hydraulic and thermal variation instability. The study of temperature field distribution of cold and hot alternative transportation pipeline to the design of crude oil pipeline, the succession of the crude oil pipeline safe and economic operation scheme maked and the crude oil alternative transportation pipeline’s transport and restart procedure has the important meaning. This paper taked cold and hot crude oil alternative transportation pipeline for example, studied from the following aspects:(1) Based on the researches at home and abroad, summarize the research methods for unstable coupled flow of hot oil pipeline, and to determine the calculation model of crude oil properties parameters, soil physical parameters, heat transfer coefficient and hydraulic friction factor.(2) In consideration of the unstable coupled flow of cold and hot alternative transportation, unstable heat transfer mathematical model is built, taking oil, pipeline, protective layer, insulating layer, semi-infinitely large temperature field of the soil and atmospheric as study subject. Unstable water power mathematical modal is built, taking oil alternating transportation as study sbuject. Adapted prediction correction method, characteristic line method and finite difference method in the numerical, the finite difference equation of oil temperature and pressure is inferred, taking unstable flow model as study subject. In solve the soil temperature distribution outside pipeline, through the bipolar coordinates conformal transformation, the complex partial differential equations into a ordinary equation.(3) This paper established a mathematical model of cold and hot crude oil alternative transportation transport and restart, and studied the numerical solution. Used the difference of hydraulic and thermal relaxation time, discussed the calculation steps of transfer interaction through first thermal calculation after hydraulic calculation.(4) According to the modular design method, make use of MATLAB to compile the program of cold and hot crude oil alternative transportation mathematical model, and verify the accuracy of the program by the field data of TangGu to TianJin pipeline.(5) As QingTie pipeline from Lin Yuan to TaiYangSheng for example, simulated the cold and hot crude oil alternative transportation by the program. Analyzed the oil and soil temperature field around the pipeline variation, analyzed the change of cold and hot crude oil outbound temperature impact on alternate pipeline operation. Through the optimized model of cold and hot crude oil alternative transportation, formulated the most economical operation scheme for cold and hot crude oil alternative transportation. Fitted out the calculation for the flow temperature at any time and any where, convenient for engineering application.