Analysis of operation economy with the optimization search space and station spacing for hot oil pipeline

Influence factor in the scope of optimum temperature and length of station spacing in operation economy for hot oil pipeline is studied by nonlinear optimization method. Results show that the influence of optimum scopes on optimal throughput of pipeline and the trend that economic transport costs decrease with the increase of oil throughput is slight. However, the transport costs will increase as the lower limit of the search space is set higher, which is very distinct in the case of lower throughput. So it is possible to obtain a more economical plan by decreasing the low limit of the search space, but it would be impracticable due to the limit in actual pipeline. The variation in the length of station spacing is related to the influence of throttle loss accompanied throughput, and it is slight in lower and medium throughput scopes, but as the throughput increases, the throttle loss for the pipeline with shorter station spacing will increase rapidly and go dramatically. Further the climax of the throttle lost will be lagged. The effect of different station spacings on throttle loss is also related to the optimization search scope. As the low limit of the search space is going up, the throttle loss for shorter station spacing will increase at most of the throughput points. Therefore its economy decreases. Rational station spacing length should be determined by considering all of the following parameters, that is, throughput, the pipe diameter, pump types and maximum allowable operation pressure and so on.