Research And Optimization On Properties For Shanbei Crude Oil Blending

With the growth demand for oil refining in world and the decline in quality ofcrude oil, the use of the opportunity and low-quality crude oil is increasing. In orderto reduce the costs of operating and production, improve efficiency of the pipelinetransport and utilization of the tank, and to improve the efficiency of refineryenterprises, mixed transportation, mixed storage, mixed refining has becoming aninevitable situation. Therefore, the further research on the mixed crude system andoptimization of the system is needed for the actual production. This also attractedpetrochemical companies and researchers in relevant. The research in the areaincludes two aspects, the one is the direct impact on the production process and theproperties of mixed oils, such as the compatibility, viscosity, nitrogen content ofmixed crude oil(etc.). The other one is to optimize the mixing ratio and to improve thequality and profit of petroleum products. Based on previous studies, someinvestigation is done for the the optimization of mixed Shanbei crude oils properties,which came from six oil wells in Shaanbei different districts.First of all, six kinds of Shanbei crude oils and its blending oils were studied anddistilled. The basic properties of the oils were analyzed and characterized by measuretests, such as elemental analyzer means. The compatibilities of the five kinds of mixedsystems were measured by spot tests and compatibility index. The relations betweenthe yield of light fractions and the compatibility, density, viscosity of the oils werestudied, at same time, the relations between the compatibility and the tour componentsof the oils and its residue, specifically, the effect of the changing of the asphaltene andresins. The results showed that: the most kinds of the test crude oils were of highnitrogen, low acid value, low sulfur, light crude oil. If the lager the difference of theasphaltene content of the two single crude oils is, the greater incompatible of themixed oils is. In the experimental conditions, the actual light distillate yields of theoilswere greater than the theoretical calculations yields. If the viscosity of the mixedsystem is small, the total yield of the fraction of the system tends to become large, andthe effect of the density of the system has no obvious trend. To most kinds ofincompatible mixed oils, the asphaltene in its residual increased by a big margin,resins reduced amplitude was large, but the aromatic content decreased smaller. Tomost kinds of compatible mixed oils, the situations were just the opposite. The incompatible mixed crude oils more likely caused fouling or coking on the heatexchanger in the process of the production.Then, on the basis of the test and the distillation of twenty one kinds of mixedoils in the five mixed systems, a mixed crude oils optimization model was set up inthe form of non linear programming. The objectives consisted of maximum the salesrevenue of the fractions of the mixed oil and the total yield of the oil, and minimumthe compatibility and viscosity index of the oil. The main constrain conditions are thebalanced of the use of the six kinds of Shanbei crude oils. One advantage of thismodel was the use of information of the two mixed crude oils which make the modelmore fitting with the actual situation; another was that the compatibility and viscosityindex was introduced to the optimization model which can protect the wellperformance of the oil in the production and the processing. The model was solved byusing software lingo11, the optimal ratio of A: B:C:D:E: F=45:10:10:15:10:10. Withthe ratio, a kind of mixed crude oils was prepared and distilled, the results showedthat the model and method are valid.