Risk Analysis Of Loading And Unloading Process Of CNG Carrier And Comprehensive Risk Index Model Design

With the increasing demand for natural gas,the high transport costs of natural gas becoming a bottleneck witch restricted the use of natural gas.Currently,the way of widely maritime transport of natural gas is using liquefied natural gas(LNG)way.Because its expensive investment of LNG carriers and its related equipment,the new and higher efficiency transport way urgently need to explore in a smaller scale and short distance maritime transport.In this time,compressed natural gas(CNG)carrier crashed out.Due to the particularity of Natural gas as goods,once leakage occurs,it may cause the risk of fire and explosion,therefore the risk assessment for CNG carrier is particularly important.Taking Integrated Safety Assessment Act(FSA)as the theoretical framework,the risk of CNG carrier will be analyzed from three aspects,including CNG carrier loading and unloading process fault tree qualitative risk analysis,CNG carrier gas leak consequence analysis and CNG carrier comprehensive risk index analysis.The main research works are listed as follows:(1)In this paper,a comprehensive safety assessment(FSA)method to carry out a detailed analysis and presentation.It introduces the Safety Assessment(FSA)method outlined,Safety Assessment(FSA)method of evaluation process and procedures and this paper's structural framework.(2)The risk identification and qualitative analysis during the CNG carrier loading and unloading process are conducted with the method of fault tree analysis.Then corresponding measures are put forward according to the path for generating the risk.(3)This paper describes some of the basic functions of PHAST software,summed up the accident model CNG carriers may occur.And established the CNG carrier loading and unloading process gas leakage accident injury criteria.Using PHAST software first analysis the factors that may affect the conduct of a gas leak,summed up the influence of various factors,and ultimately determine the most dangerous,likely to occur,prone to accident three kinds conditions.Though the analysis of three conditions which combined with fire and explosion accident injury criteria,the Heat radiation range chart and Overpressure range chart of each conditions has simulated.(4)On the basis of CNG carrier comprehensive risk index design principles and it intended function analysis,combining risk assessment theory and index theory,this paper presents a mathematical model CNG carrier comprehensive risk index and determine the weight of the model determining method.From the human factor,the ship factors,environmental factors,management four factors established CNG carrier security Index System.