Natural Gas Distribution Station Risk Assessment

With the rapid development of oil and natural gas industry, China has ccelerated the laying of pipelines, which has now become the major means of overland transportation of oil and gas. And as a result, gas is taking an increasingly larger proportion in the country’s primary energy consumption. Within the country, there are four large gas fields-Tarim, Chongqing, Sichuan and Qinghai----their output of gas being increasing steadily. At the same time, gas is imported from abroad through the China-Central Asia pipeline, Sino-Russia Pipeline, and the Sin-Burma pipeline that is still under construction, thus formed the gas supplying system which covers the whole country and reaches to overseas gas fields, and so is able to provide multiple resources and to centralize control. In this system, what plays the core role is the gas transporting stations, including gas gathering stations, gas filling stations, and urban gas distribution stations, where the safety of the complex facilities is especially important and deserves our attention.This thesis establishes a gas station risk management model following the method of pipeline index evaluation, and makes both quantitative and qualitative analysis of the risks adopting such methods as analytic hierarchy process, Delphi method, and expert panels; thereby the risk proportion can be decided.The thesis includes the following parts:The first part briefly introduces the background, development, survey of research on the technology of gas station risk evaluation and its scientific basis.The second part briefly introduces the recent technology of risk evaluation. Also, several related risk evaluation methods (i.e. index evaluation, analytic hierarchy process, Delphi method and expert panels) and their procedures and operation are explained. Besides, YAAHP is introduced in this part.The third part focuses on the risk evaluation model. A model of station failure is established which includes ten risk indexes-the station location and environment, the underground pipes, the ground pressure facilities, motion facilities, switches、instruments, process flow, methane leak, fire control system and security contingency plan; MUHLBAUER’s index evaluation is adopted to evaluate the ten indexes. The fourth part is about the standards of xrisk evaluation. Station risks (including sub-risks) and the evaluation standards are stated in detail.The fifth part is the decision of risk proportion. This part explains how to make both quantitative and qualitative analysis of the risks by the method of analytic hierarchy process and Delphi method; how to decide the risk proportion, and how to calculate the highest grades of risks and all the sub-risks at the failure pointso as to help the practical operation.The sixth part is about risk acceptability. A risk matrix will be made on the basis of the relationship between risk and cost and the principle of ALARP to decide the risk acceptability.The seventh part is about the practice of the risk evaluation plans mentioned above. Risks will be discovered and relevant solution will be worked out.In this thesis, not only is the popular method of risk control is adopted, but various principles and methods used in the field of risk control are also adopted, considering, at the same time, the reality of China’s gas stations, so as to the make the research scientific and the conclusion reliable.At the beginning stage of writing this thesis, the focus was put on the latest tendencies and results about the relevant subject. Relevant literature was also consulted to get better understanding of risk control theory. Then the major work was to establish the risk management model on the basis of the reality of China’s gas stations, make quantitative and qualitative analysis of the risks in the model, evaluate the data, and work out corresponding resolution. At the later stage, major effort was made to study the problems about the gas stations according to the results of previous research and work out effective and scientific solution.