Research On Risk Analysis Of Large LPG Spherical Tank Failure Mode And Method

In recent years, with the rapid development of China’s petrochemical industry and thewide application of liquefied petroleum gas（LPG） and liquefied natural gas, the numberof the spherical tanks, as a common storage devices, increases dramatically.Once thefailure of large LPG spherical tank occurs, it may lead to project delay and economic loss,or casualties and equipment being seriously damaged. With the expanding of LPG marketscale, the use of large LPG spherical tank has seriously affected the social construction ofindustrial safety and public security. Therefore, the studies on the risk assessment of largeLPG spherical tank can effectively prevent and control the occurrence of major accidents,guide the implementation of the LPG spherical tank, and ensure the safe operation.Meanwhile, it has a good theoretical significance and application value.After systematically researching for a long time, large LPG spherical tank riskevaluation model is established. By means of the Internet of things, combined with thelatest RFID radio frequency identification technology, we have preliminarily designed anddeveloped a portable large risk of LPG spherical tank analyzer and large LPG sphericaltank of the risk management system. The complete system can realize the organiccombination among the large LPG spherical tank intelligent identification, risk assessmentand management.Combined with the design, manufacturing, installation, testing and otherspecifications, this article is to analyze the statistics of spherical defects and defect causes,and sum up the spherical tank failure of various factors. Then, the research constructs aspherical tank failure fault tree, which is calculated by the minimal cut sets, to identify themain factors of the cause of the spherical tank failure. By the calculation and sorting ofstructural importance, the largest sources of danger are identified. Thus, the sphericalmajor hazard evaluation is completed, and some reasonable recommendations are putforward. By major danger sources evaluation, the possibility of factors are divided into technical factors, management factors, operational factors and damage factors; theconsequences influence factors are divided into casualties, property loss, environmentalinfluence and social opinion influence. Thus, the large spherical tank risk assessmentsystem is established. The quantitative and qualitative indicators are used to establishscoring rules. And the method of the fuzzy Analytic Hierarchy Process is used for the fuzzycomprehensive evaluation to calculate the risk evaluation of the total score (the likelihoodof failure score). By the Pareto’s law (Best matching principle regulation efficiency)，ittakes high risk score of20%as risk class, low risk score of20%as Ⅲ risk class, and therest of the risk score as Ⅱ risk class. Those unqualified large LPG spherical tanks screenedon technology levels can be executed for the safety evaluation, and the load reductionmeasures will be taken; as those on operation levels, the tanks with longer durable yearscan be filtered out to determine which ones should be repaired; as those on managementlevels, high-risk large LPG spherical tanks resulting from mismanagement are selected tonotify their use units to strengthen the management.