Gray Cast Iron Gas Pipeline Risk Assessment And Simulation Of Gas Leakage

At the beginning of the fuel gas development in China, due to the limited to the use of pipeline technology and pipe, gray cast iron pipe is widely used. As town gas displacement for gas as well as the rapid development of urban construction, the gray cast iron pipe due to poor tensile strength, bending capacity, has a brittle defects, pipes are caused by the continuous casting tube technology, its defects such as trachoma, skin, not round caused problem is becoming more and more prominent, and the construction quality and safety management does not reach the designated position, in recent years, frequent gray cast iron tube leakage, such as fracture phenomenon. Therefore, gray cast iron gas pipeline risk assessment has become one of focus in the study of domestic city gas pipeline safety.This article will combine comprehensive risk management theory and modern evaluation theory of gray cast iron gas pipeline risk assessment. Through the statistical analysis of gray cast iron pipeline characteristics, accident, risk of gray cast iron pipe failure are identified, determine the risk factors affecting pipeline; Selects the expert evaluation method and pipe index evaluation method to establish the failure possibility of index system; Using analytic hierarchy process (ahp) to index weight is calculated; In the analysis of pipeline failure consequence seriousness, could spread to the scope and level of analysis, to determine the pipeline from various indicators of the severity of accident consequence. Thus, the establishment of a complete gas semi-quantitative risk assessment system of the gray cast iron pipe.By using Fluent software for gas leakage diffusion process are simulated. Spill mouth diameter, pipe pressure is studied, the influence of wind speed and direction of leak the consequences. Results show that with the increase of equivalent diameter, pipe pressure increases, the release amount and explosion danger area all increased; The size of the change of the external wind direction and wind speed are directly affect the methane concentration distribution, reverse the most adverse wind, wind will enhance methane diffusion to other directions, and wind speed, the greater the spread.This paper not only for gray cast iron gas pipeline risk assessment, and through the Fluent software to simulate numerical effect on gray cast iron gas pipe leakage problem carried on the thorough research, gray cast iron gas pipe leakage accident consequences of impact factors affect specific, more intuitive for gray cast iron gas pipe leakage accident emergency rescue to provide the scientific basis.