Study On The Oil Pipeline Optimization Design

Long-distance oil pipeline construction is related to the economic development of our country. Not only the construction is a huge investment, it is also a large cost on the annual operating after the completion. It is worth to make exploring and improving to decrease oil pipeline's building investment and operating fee by optimal design.This article made analyses and studies on the actuality of the long distance pipeline optimal design of worldwide firstly. Taking the long distance heated oil pipeline as study object, according to the long distance transportation theory and optimal design principle, a heated oil pipeline optimal design model was founded. In the model ,the variables including D (outside diameter of pipeline),? g(wall thickness of pipeline),? b (thickness of insult layer),n R (amount of the heating stations),n C (amount of the pump stations),t Z(the temperature at the inlet of every heating station) and H C(the lift of every pump stations). .Considering the time value of the investment, we choose the present value of the cost of the heated oil pipeline construction as the objective function. We roundly considered the thermal constraints, hydraulic constraints, strength constraints, and pump's performance constrains. In order to improve the calculate definition, we calculated the temperature drop along the line by discrete temperature in the heated oil pipeline calculation process. In each step, we have to judge the flow pattern from time to time, and calculate other parameters such as the physical parameter of oil,hydraulic landing along the way, the heat transfer coefficient of the pipeline.It is difficult to solve the optimization problem as the model we established for the optimization design of oil pipeline contains discrete variables and nonlinear constraints. By comparing the advantages and disadvantages of the optimization methods, we decided to solve the model of the optimization design of oil pipeline by GA (genetic algorithm). We expounded the thinking of the solution and designed a solving procedure.At last, taking a certain long distance heated pipeline as example, a module is programmed by using the computer language C++ Builder 6.0. Optimal design was made by using the computer algorithm language C++. The reliability and practicability of the mathematical model and solving method are approved by comparing the optimal results. From the result, we can see that the temperature of the out of stations have a great impact in the optimization. In the late of the optimization process, it is the optimization of the temperature of the stations. So, the optimization of the temperature of the stations is very important position in the optimal design.This article is also useful for the oil pipeline optimal operation to some extent.