Optimization on contaminated product cut of －35^# diesel/97^# gasoline in Jichang Product Pipeline

For long-distance product pipelines, it is of great significance to ensure the product quality, reduce contaminated volume and transport the product to the downstream tank farms safely. However, there is no mature experience at home for cutting the contaminated product of －35^# diesel/97^# gasoline in product pipelines. In this paper, the contaminated product cut of －35^# diesel/97^# gasoline in Jichang Product Pipeline was taken as an example. The effects of transportation rate on contaminated volume during the transportation were analyzed based on its actual operation data. It is indicated that when the Jichang Product Pipeline is operated at the transportation rate of 400 m³/h, the contaminated volume can be reduced to the utmost. The selection basis of density for the calculation of contaminated product cut was defined, and the asymmetric cut method was proposed. The empirical formula of contaminated product growth was established by analyzing the change trend of contaminated volume at each detection point along the pipeline. Based on this empirical formula, the contaminated volume at Changchun terminal can be predicted, and it is 1.15 times the contaminated volume at Jilin Initial station (or 1.02 times the contaminated volume at 8^# valve chamber). Finally, some suggestions were recommended to guide the contaminated product cut of －35^# diesel/97^# gasoline which are conducive to ensuring the safe operation of pipelines and improving the economic benefits.