Study On Quantitative Risk Assessment Of Buried Crude Oil Long - Distance Pipeline

As the artery of national economy and energy, oil pipelines play an important role in the national development. However, crude oil is flammable, explosive and toxic. Once a pipeline leakage happen, it’s easy to lead to a malignant accident such as fire and explosion. A correct and reasonable risk assessment of crude oil pipeline can greatly improve the forecast ability of hidden accident danger, provide scientific evidence for making reasonable maintenance schemes, solve the increasingly prominent problem of pipeline safety, reduce the risk of pipeline operation to the greatest extent and reduce the economic loss, casualties and environmental pollutions caused by leakage accident. Therefore, a research on the quantitative risk evaluation of the buried crude oil long-distance pipeline technology has a great significance.Started from the characteristics of buried crude oil long-distance pipeline in China, on the basis of relevant researches at home and abroad, the article builds a quantitative risk assessment method which adapts to our country’s pipes. Its main research contents are as follows:(1) Based on the accident statistics of oil pipeline carried out by CONCAWE, this paper analyzes the cause of leakage accident abroad. We found that general corrosion was the main cause of hot pipeline accidents, accounted for about81%. The third party damage was the main cause of cold pipeline accidents, about42%.Most of leaks were caused by the third party damage and corrosion, respectively44.9%and27.7%of the total number of accidents. Mechanical failures and wrong operation followed. Based on the research of the accident at home and abroad, this paper considers the third party damage, the corrosion risk, the design risk and the operation risk as the main risk factors of crude oil long-distance pipeline.(2) On the basis of foreign leakage rate, we study the leakage rate adapted to our country. First, according to the method of Kent score, we evaluate the value-at-risk number of divided pipeline section. Then, using the rule generator and reverse cloud generator of cloud model, we achieve the transformation from qualitative language to quantitative language. The assessment process can ensure its fuzziness and randomness. Next, by using the entropy value method to determine the weight value of each risk factor of buried oil pipeline in our country, we obtain a total score of every evaluated pipeline section. At last, we use a modified model to revise the total scores and get the leak frequency of each pipeline section.(3) There are pressure energy and heat energy loss in the process of buried hot oil pipeline delivery, and they interact with each other. We set up pipe temperature drop model and pressure drop model to get the operational parameters of buried oil pipeline with the change of distance, so as to determine the oil leakage rate at the starting point. Then, the pool fire model is also used to simulate the accident consequences. Finally, determine three influence scopes by the thermal radiation damage criteria after a crude oil leakage.(4) Establish a calculation model for buried crude oil pipeline risk assessment, concretely including pipeline leakage risk frequency analysis and consequence analysis. As for personal risk, we use the designated point risk analysis method to calculate a personal risk distribution of a selected pipeline. In addition, acceptable levels of individual risk and social risk are studied to put forward a calculation model of individual risk and social risk, solving a quantitative calculating problem of risk acceptable level.