Numerical Investigation of Contaminant Oil in the Batch Transportation of Crude Oil and Diesel Oil with Different Out-Station Temperatures

Batch transportation of crude oil and refined products maximizes pipeline utilization and prevents long-term operation below economic throughput with reduced economic benefits. In this study, a numerical method that couples heat transfer and oil mixing is proposed to investigate contaminant oil in the batch transportation of crude oil and diesel oil at varying out-station temperatures. A dynamic grid method is employed to significantly reduce the computational domain and enhance the calculation efficiency of the proposed method. The simulation results revealed that contaminant oil levels vary with the seasons due to changes in out-station and environmental temperatures. During winter, the lower oil temperature increases viscosity, especially for crude oil, resulting in higher contaminant oil levels. To address this, a local heating operation plan is suggested for the head and tail of the preceding and following batches, aiming to reduce contaminant oil and improve economic benefits. Through extensive simulation and operation optimization, the optimal operation plan for batch transportation of crude oil and diesel oil has been determined. The recommended heating lengths for the heads and tails of the following and preceding batches are 5 and 40 km, respectively, with an out-station temperature set at 20°C. For continuous pipeline operation in winter (90 days), with each batch running for 3 days, following this plan could theoretically increase economic benefits by 2.5 million RMB. The purpose of this study is to develop a safe and economically viable operation plan for the batch transportation of crude oil and refined products.