Study On Operating Condition Analysis And Shutdown And Restart Process Of Dagang Crude Oil Pipeline

Based on collected survey and present operating status of Dagang crude oil pipeline, rheological properties of crude oil have been studied, the total heat transfer coefficient, equivalent diameter and paraffin thickness are calculated, and seasonal variation laws of the total heat transfer, equivalent diameter and paraffin thickness are analyzed. This paper does some researches on simulation computation of critical pipeline between Zaoda and Kongda station with the help of shutdown and restart simulation software. It also helps to determine allowable shutdown time under different oil temperature conditions in different months and minimum outlet oil temperature, and analyzes influences on different season, paraffin thickness and soil thermal conductivity.Research results shows that in summer environment temperature is relatively high, while the ratio of drop temperature is low, and vice versa in winter. It also shows that in process of shutdown the trend of incoming oil temperature is different from the trend of outlet oil temperature that reduces with increment of paraffin thickness. Incoming oil temperature is high in certain shutdown time in oil pipeline of heavy paraffin thickness owing to paraffin insulation. Because of paraffin existence, flowing heat quantity of oil is decreased, earth temperature is diminished and temperature range between oil and earth is enlarged. And then the ratio of temperature drop becomes fast in process of shutdown in some segments of oil pipeline. In addition, it points out that when soil thermal conductivity increases, oil temperature drops quickly and shutdown time shortens.According to simulation results of shutdown and restart process, the BP neural network algorithm is applied to calculate predictive value of shutdown time. Calculation results indicate that predictive values are similar to simulation values, and this proves that the BP neural network algorithm can be a supplementary theoretical means of determining shutdown time.This paper carries out technology optimization research on tight line transportation of each gathering station on the basis of safe outlet oil temperature results, and suggests that the pipeline between Guanda and Kongda station should be transformed firstly in summer. After a while, relevant technique and management experience are developed, and this transformation plan can be applied in the overall pipeline of Dagang Oil Field. This paper also analyzes economic effects on present and tight line transportation. It can be drawn a conclusion that energy consumption caused by present transportation is more than its caused by tight line transportation, and the latter transport mode can overcome drawbacks of the former mode and accomplish energy saving.