Research And Application Of Safety Risk And Life Prediction Method Of Urban Gas Steel Pipeline

City gas distribution system is a complex integrated facility.The natural gas is flammable and explosive,so the safety management of the natural gas pipe network is the most important part of daily management for the gas companies.This paper discussed the gas pipeline safety technology from the aspects of gas pipeline digitization,high consequence zone identification,risk assessment and residual life prediction of corrosion pipeline to strengthen the gas safety management level.With the rapid development of information technology,the traditional management methods and management modes of gas industry are no longer fit for today's information society and are no longer applicable to the development of the current gas industry.In order to strengthen the safe operation management of gas plant network,it is urgent to use the information system to provide new management and decision-making methods for gas safe operation management.As the upstream gas supply is diversified,there are many new sources like the multi-channel gas supply,LNG supply and other new sources.The rapid expansion of a variety of pressure level network and the construction of the key station like numerous gas distribution station,the high pressure natural gas station position,load and emergency gas storage facilities has gradually replaced gas supply model of single source plant in the past.Thus the dispatching center becomes the central control center of gas unified dispatching and safe operation.This article takes urban gas SCADA system as an example and introduces the important role of SCADA system in gas industry like the organization management,operation management,monitoring management supply and demand balance management,emergency management and the analysis of data management.This article introduced the function of SCADA system(real-time monitoring,remote control,automatic alarm,etc.),mobile application of SCADA system analysis on the application of SCADA in factory network security management.The function of GIS(tube,cross-sectional and longitudinal profile analysis,system analysis,etc.),mobile GIS system analysis on the application of SCADA in factory network security management.First,this paper introduced the regional classification principle,high consequence zone identification criteria and high consequence recognition scores of the gas pipeline.By collecting the relevant data required by the high consequence area of gas pipeline,and combining with the management practice of Chengdu Xindu Hong Kong and China Gas Co.Ltd.,the high consequence area of the pipe network was divided.The result was that 32 segments of the high-consequence pipe section of taixing town were identified,among which the high consequence score above 500 was 20 units and the high consequence score within 200?500 was 12 units.It also gives the specific management suggestion,which has good guiding significance to the identification and management of high consequence area of gas pipeline.Based on the characteristics of Kent method,the risk sources of gas pipeline were identified.The influential factors of the gas pipeline risk(the third party damage,corrosion,design,wrong operation,leakage effects)were analyzed,and the risk evaluation index system was established.As the complexity of the analysis of the result of pipeline leakage in high-consequence area,the leakage consequences of high consequence areas were analyzed from four aspects(medium harm,leakage index,leakage diffusion coefficient and high consequence area receptor model).Finally,through the definition of risk,the gas pipeline risk assessment model was established,and this model was applied to the Chengdu Xindu Hong Kong and China Gas co.Ltd.The result was that there were 7 segments with relatively high risk value of taixing to magnolia Longzhao Lu pipeline.Among them,3 segments were high consequence segments above 70 scores with relatively high risk.The scores of other 4 segments were between 50?70.The corresponding suggested measures of safety management of gas pipeline risk were suggested to make urban gas pipeline management more scientific.This paper analyzed the corrosion factors of corrosion pipeline in depth and discussed the main causes of corrosion.The geometrical forms of pipeline corrosion defects were determined by nondestructive testing of pipelines containing corrosion defects,and corresponding geometrical models were established.The corresponding corrosion rate model was established with the appropriate numerical analysis method.Based on the probability statistics and strength criterion,the prediction process of the residual life of corrosion pipeline was obtained,which was of great significance to the decision-making of pipeline operation,maintenance and replacement.In the end,the analysis of the residual life of the pipeline was carried out,and the prediction results were summarized and analyzed.By means of electrochemical analysis,semi-theoretical and semi-empirical calculation formula,the residual life can be predicted by uniform corrosion cylindrical model.The use of pitting corrosion cone model and the potential measurement on the field pipeline can predict the time of the pipeline due to corrosion and can predict the remaining life.It is necessary to assume that the cone angle of each pit is invariant in the process of corrosion.When the corrosion form of the component is uniform corrosion,the corrosion rate is not related to its corrosion form.When the corrosion shape of the component is the point corrosion,the corrosion rate will increase with the decrease of the taper top half angle.At the same time,the smaller the surface diameter of the corrosion defect,the faster the corrosion velocity,and the shorter the time of the perforation of the components.The results of this paper were applied to the gas pipeline of Chengdu Xindu Hong Kong and China Gas co.,Ltd.,and the results are in accordance with the objective reality of the pipe segment.