基于毕达哥拉斯模糊贝叶斯网络的海底管道泄漏风险分析*

为分析海底管道运行中存在的泄漏风险,提出1种基于毕达哥拉斯模糊数与贝叶斯网络的风险评估模型。首先,通过毕达哥拉斯模糊数转换专家定性评价,拓展专家意见模糊范围;然后,结合主客观组合赋权法,利用毕达哥拉斯梯形爱因斯坦混合几何算子（PTFEHG）实现专家意见的聚合;最后,通过贝叶斯网络的推理与敏感性分析,计算海底管道泄漏风险的失效概率,并辨识关键风险因素。研究结果表明:该方法可以结合专家意见对海底管道泄漏风险进行定量分析,并识别导致泄漏事故的关键风险因素,对海底管道安全管理具有指导意义。     

二阶模糊安全评估方法及其在油库安全评价中的应用

通过分析油库安全因素的层次关系,将影响油库安全的因素划分为人员、装备、管理以及环境因素等不同的层次,并对油库安全指标、各层次间的评估方法以及模糊运算方法进行研究,建立针对油库安全的二阶综合模糊评估模型,给出评估的整体流程。评估过程中以改进的层次分析法确定不同层次和因素的重要度,以加权平均方法为模糊运算准则。利用建立的评估体系对某油库的安全状况进行评估,并根据总体评估结果和各层次评估结果中的不足,提出了油库安全整改意见。评估实施过程表明:该二阶综合模糊评估模型避免了评估中的主观因素,并且可操作性好,评估过程易于实现。     

An integrated methodology to manage risk factors of aging urban oil and gas pipelines

Aging urban oil and gas pipelines have a high failure probability due to their structural degradation and external interference. The operational safety of the aging urban oil and gas pipeline is challenged by different hazards. This paper proposes a novel methodology by integrating an index-based risk evaluation system and fuzzy TOPSIS model for risk management of aging urban oil and gas pipelines, and it is carried out by evaluating the priority of hazards affecting pipeline safety. Firstly, the hazard factors of aging urban oil and gas pipelines are identified to establish an index-based risk evaluation system. Subsequently, the fuzzy TOPSIS model is employed to evaluate the importance of these hazard factors and to decide which factors should be managed with priority. This work measures the importance of a hazard factor from three aspects, i.e. occurrence (O), severity (S) and detectability (D), and the weights of these three parameters are determined by a combination weight method. Eventually, the proposed methodology is tested by an industrial case to illustrate its effectiveness, and some safety strategies to reduce the operational risk of the pipeline are presented. The proposed methodology is a useful tool to implement more efficient risk management of aging urban oil and gas pipelines.     

Application of a trapezoidal fuzzy AHP method for work safety evaluation and early warning rating of hot and humid environments

Hot and humid environments are prevalent in many industries. People working in hot and humid environments are at great risk of specific heat-related disorders, the productivity decrease and safety problems. In order to guarantee workers’ health and safety, safety evaluation and early warning rating of the hot and humid environments are studied in this paper. The fuzzy analytic hierarchy process (AHP) method is proposed to evaluate the work safety in hot and humid environments. Trapezoidal fuzzy numbers are adopted to handle inherent uncertainty and imprecision of the data involved in decision process. Within the proposed methodology, a decision group is firstly established. A safety evaluation framework containing three factors (work, environment, and workers) and ten sub-factors are established. The fuzzy weights of the factors and sub-factors are calculated based on the pair-wise comparisons. Then the fuzzy evaluating vectors of the sub-factors and factors can be calculated according to the initial evaluation data. Therefore, the comprehensive safety index, safety grade and early warning grade can be determined. An example is given to demonstrate the proposed method. The results demonstrate the engineering practicability and effectiveness of this method in extreme environment evaluation.     

An extension of the fuzzy improved risk graph and fuzzy analytical hierarchy process for determination of chemical complex safety integrity levels

The risk graph (RG) is widely used to evaluate the safety integrity level (SIL) of safety instrument systems (SIS). However, subjective opinion-based conventional RGs cannot provide successful results for the problems of risk parameters, such as shortages or lack of data; hence, the output of a conventional approach lacks sufficient reliability. We introduced the fuzzy improved risk graph (FIRG), an extension of fuzzy set theory, to deal with possible ambiguities during SIL study and increase the reliability of conventional RGs. In the present study, the levels of consequences defined as linguistic terms were converted into qualitative intervals; therefore, by correlating the proposed approach with experts’ opinions and attributing weight factors, a desired SIL value was obtained. The output of this new approach can be compared directly with quantitative risk assessment techniques to improve the safety performance of industrial systems.     

风险因子模糊评价法在钻机安全评价中的应用

钻机是石油与天然气钻井作业的重要设备,在使用过程中存在着极大风险,如果对其中的风险因素管理不善,风险转化为事故,将造成极大的损失,严重影响企业的形象与生产。为了预防石油与天然气钻井作业过程的事故发生,提高钻井队安全管理水平,论文采用通过对系统技术风险概率Pf和事故后果的严重程度Cf的估计和模糊评判的方法得到系统的风险状况Rf,为采取科学合理的风险消减措施提供了决策依据。论文以某型号电动钻机的电气控制系统为例进行风险分析,分析结果表明与实际情况比较符合。     

Improvement of integrity management for pressure vessels based on risk assessment - A natural gas separator case study

The process of oil and gas processing plant is complex, the types of pressure vessels are rich, and the functions are critical. However, the working medium is mostly untreated medium, and the hazard factors are complex, which poses a threat to the safe production of oil and gas processing plant. Based on PDCA cycle, this paper establishes a six-step links of integrity management for sustainable improvement of pressure vessels. The typical failure modes of pressure vessels are determined, and the fishbone diagram of risk factors under each failure mode is compiled. Risk quantification and classification of pressure vessels based on failure modes (RBFM) is innovatively proposed. Avoiding incalculable failure frequency index, the process quantification of failure possibility is formed according to the development of hazard factors. A failure consequence calculation model based on the leakage affected area was established. Combined with the failure probability level and risk level, the hierarchical inspection strategy for pressure vessels under different failure modes is established. Finally, the method is applied to the natural gas separator of H processing plant. The research results show that RBFM proposed in this paper can meet the requirements for rapid and accurate risk assessment of pressure vessels in oil and gas processing plant. This paper establishes a safe production barrier for the pressure vessel and improves the intrinsic safety of the equipment.     

Modeling and application of risk assessment considering veto factors using fuzzy Petri nets

Risk assessment is important for plant safety, and fuzzy set theory is useful for such assessment because many risk factors have fuzzy characteristics. In this study, veto factors for risk assessment are taken into account. Weighted fuzzy Petri nets (WFPN) with inhibitor arcs are proposed to model relationships between risk factors and establish the risk assessment structure considering veto factors. Definitions of WFPNs as well as the enabling rule and execution rule are provided. The modeling approach for the assessment combining normal factors with veto items is discussed. The proposed fuzzy risk assessment approach is illustrated by an example of the assessment of production installations and process technology of plants that deal with hazardous chemicals. Veto factors and non-veto factors are presented and the assessment structure based on WFPNs is established. Using the factor data of a plant, an assessment value is obtained through the operation of WFPNs and the verification of the approach is discussed.     

基于模糊数学的石化企业安全状况评估系统

针对石化企业安全信息存在模糊性和随机性的特点,提出了一个多因素多指标石化企业安全状况模糊综合评价算法,基于这种算法,设计了一个石化企业安全状况评估系统,以安全管理、工艺运行管理、设备运行管理、清洁生产、安全教育和人员素质等因素为系统的输入,运用模糊逻辑理论,结合专家评分,定量计算出石化企业的安全等级情况。系统充分考虑了多个安全因素对安全状况的影响,融合了主观判断和客观计算,解决了石化企业安全评价中多因素多指标带来的烦琐评价过程和复杂运算的问题,为石油化工企业的安全管理提供相关理论依据和实践支持。实际应用表明,其结果与实际情况较为符合,该方法可以较好的提高石化企业安全现状综合评价的客观性和准确性。     

Dynamic risk assessment for underground gas storage facilities based on Bayesian network

Loss of the underground gas storage process can have significant effects, and risk analysis is critical for maintaining the integrity of the underground gas storage process and reducing potential accidents. This paper focuses on the dynamic risk assessment method for the underground gas storage process. First, the underground gas storage process data is combined to create a database, and the fault tree of the underground gas storage facility is built by identifying the risk factors of the underground gas storage facility and mapping them into a Bayesian network. To eliminate the subjectivity in the process of determining the failure probability level of basic events, fuzzy numbers are introduced to determine the prior probability of the Bayesian network. Then, causal and diagnostic reasoning is performed on the Bayesian network to determine the failure level of the underground gas storage facilities. Based on the rate of change of prior and posterior probabilities, sensitivity and impact analysis are combined to determine the significant risk factors and possible failure paths. In addition, the time factor is introduced to build a dynamic Bayesian network to perform dynamic assessment and analysis of underground gas storage facilities. Finally, the dynamic risk assessment method is applied to underground gas storage facilities in depleted oil and gas reservoirs. A dynamic risk evaluation model for underground gas storage facilities is built to simulate and validate the dynamic risk evaluation method based on the Bayesian network. The results show that the proposed method has practical value for improving underground gas storage process safety.     

民航机务维修系统安全风险监测

从人的因素、飞机的因素、环境因素和管理因素4方面分析了民航机务维修系统安全风险影响因素,结合专家调查意见建立了机务维修系统安全风险监测指标体系,并给出各个指标的含义及其衡量方法。根据机务维修系统安全风险指标及其数据特点,建立了行业机务维修系统安全风险模糊综合评价模型,并进行实例分析。结果表明,采用笔者建立的指标体系和风险模型可以方便地进行机务维修系统的安全风险评价和预警,从而找出主要的安全风险影响因素,为采取安全风险管理措施提供依据。     

基于模糊综合评价的燃气管道第三方破坏失效研究

针对燃气管道第三方破坏事故复杂的特点,基于层次分析和模糊数学的理论,计 算燃气管道第三方破坏风险失效的可能性。全面识别城镇燃气管道第三方破坏事故的危 害因素,构建包含56个基本事件的燃气管道第三方破坏故障树。利用模糊集合隶属函数 ,计算燃气管道发生第三方破坏事故基本事件的模糊概率。利用改进的层次分析法,得 出各专家权重并修正各专家的评估意见,计算管道第三方破坏失效的可能性。以某大型 省会城市燃气管道为例进行验证分析,证明该方法的风险评价结果与实际情况相符,可 为燃气公司安全风险防控提供依据。     

基于模糊贴近度和熵权的航空装备维修安全综合评价

航空装备维修安全是确保装备飞行安全的重要因素,为提高航空装备飞行的安全性,需要对航空装备维修安全进行准确评价。根据航空装备维修安全评价涉及的不确定性问题,采用模糊数学和熵理论,提出一种基于模糊贴近度和熵权的航空装备维修安全综合评价方法。在建立航空装备维修安全评价指标体系的基础上,采用熵确定各指标的权重值、加权平均算子确定综合评价集,利用非对称贴近度进行决策分析。通过对某型飞机调查数据的算例分析,确定航空装备维修安全的主要影响因素,得出该型飞机维修安全水平的评价值。     

模糊综合评价在钻井队安全管理评价中的应用

钻井队的安全管理评价对于整个石油勘探与钻井工作的正常进行有着十分重要的意义,它也是油田进行日常管理的一项基本活动。为了研究与评价目前钻井队的安全现状,我们通过对钻井作业过程的分析,针对影响钻井队安全管理的因素,提出了钻井队安全管理中人员安全、安全钻井配套装备、安全制度与执行、危险识别与评价这四个方面的大指标,再细分成十二个方面的详细指标。在用层次分析法确定了各项指标的权重之后,设计了一个模糊综合评价体系,从而对目前钻井队的安全现状进行了定性与定量相结合的分析,并以某钻井队为例,进行了实证研究,根据模糊综合评价的最大隶属度原则,得出该钻井队安全管理现状处于很好的状态的结论。此方法从而为钻井队的安全管理工作提供了量化的借鉴依据。     

基于三角模糊理论的尾矿库风险评价研究

根据尾矿库的特点和我国现行的尾矿库安全生产监督管理法律法规及标准规范的要求,构建了尾矿库风险评价指标体系。综合考虑评价指标对风险发生可能性及后果严重程度的不同影响来确定指标权重,同时考虑到权重确定和指标赋值中的模糊性和不确定性等问题,选用三角模糊理论建立了尾矿库风险评价模型,并以本溪某尾矿库为例进行说明。理论分析和实例计算表明,该方法对尾矿库风险评价有很好的适用性。     

Allocation of performance shaping factors in the risk assessment of an offshore installation

Offshore oil production is one of the most important human productive activities. There are many risks associated with the process of constructing a subsea well, pumping oil to the platform, and transporting it to refineries via underwater pipes or oil tankers. All actions performed by workers in those operations are influenced by specific working conditions, involving the use of complex systems. Contextual factors such as high noise, low and high temperatures and hazardous chemicals are considered to be contributors to unsafe human actions in accident analysis and also give a basis for assessing human factors in safety analysis. Some failure modes are particularly dangerous and can result in severe accidents and damage to humans, the environment and material assets. Fires and explosions on oil rigs are some of the most devastating types of offshore accidents and can result in long-term consequences. The most typical root causes related to accidents include equipment failure, human error, environmental factors, work organization, training and, communication, among others. The principal objective of this study is to propose a methodological framework to identify the factors that affect the performance of operators of an offshore unit for oil processing and treatment. In this phase, an ergonomics approach based on operators' work analysis is used as a supporting tool. After identification of factors that affect the performance of operators, a decision-making model based on AHP (analytic hierarchy process) is applied to rank and weight the principal performance shaping factors (PSFs) that influence safe operations. The next step involves the use of the SHELLO model to group the main PSFs in elements named software, hardware, environment, liveware and organization. In the last phase, a relevant accident that occurred aboard a floating production storage and offloading (FPSO) vessel is analyzed. The allocation process of the factors that affect the operator's performance in risk assessment was developed through fuzzy logic and the ISO 17776 standard.     

Fuzzy risk modeling of process operations in the oil and gas refineries

Operating several assets has resulted in more complexity and so occurrence of some major accidents in the refining industries. The process operations risk factors including failure frequency and the consequence components like employees' safety and environment impacts, operation downtime, direct and indirect cost of operations and maintenance, and mean time to repair should be considered in the analysis of these major accidents in any refinery. Considering all of these factors, the risk based maintenance (RBM) as a proper risk assessment methodology minimizes the risk resulting from asset failures. But, one of the main engineering problems in risk modeling of the complex industries like refineries is uncertainty due to the lack of information. This paper proposes a model for the risk of the process operations in the oil and gas refineries. The fuzzy logic system (FLS) was proposed for risk modeling. The merit of using fuzzy model is to overcome the uncertainty of the RBM components. This approach also can be accounted as a benchmark for future failures. A unified risk number would be obtained to show how the criticality of units is. The case study of a gas plant in an oil refinery is performed to illustrate the application of the proposed model and a comparison between the results of both traditional RBM and fuzzy method is made.For the case study, 26 asset failures were identified. The fuzzy risk results show that 3 failures have semi-critical level and other 23 failures are non-critical. In both traditional and fuzzy RBM methods, some condenser failures had the highest risk number and some pumps were prioritized to have the lowest risk level. The unit with unified risk number less than 40 is in the non-critical conditions. Proposed methodology is also applicable to other industries dealing with process operations risks.     

特种设备模糊神经网络安全评价研究

根据特种设备的特点,提出了包含其各生命周期的安全评价指标体系,建立了模糊安全评价的评价因素及其权重,建立了评价模型.应用BP神经网络,建立了特种设备安全评价的模糊神经网络模型,通过神经网络的多次学习训练,评价因素权重得到优化.开发了特种设备模糊神经安全评价系统,以塔机为例对评价因素权重进行了优化.     

模糊聚类分析在安全工作状况综合评价中的应用

根据海因里希法则,在各项安全指标科学量化的基础上,运用模糊聚类分析,把厂二级单位完成的各项独立指标进行综合评价,从全局和总体上把握各单位的安全工作状况,从而科学地进行评优树先,分类指导、奖优罚劣。     

改进模糊Petri网在空管安全风险评估中的应用

科学、有效的空管安全风险评估是进行安全风险管理的重要环节,是保证航空事业健康发展的必要前提。遵循计划(P)—实施(I)—检查(C)—处理(A)的程序,建立了具有针对性的空管安全风险评价体系。在评估过程中采用模糊Petri网方法,同时针对其节点过多和变迁权值主观性强的缺点,引入风险等级阀值和层次分析法(Analytic Hierarchy Process,AHP),运用逆向搜索的方法简约复杂的模糊Petri网,在保证能够找出威胁安全的主要因素和准确评估空管系统安全状态的前提下,简化后续计算和推理过程,快速得到评价结果,实例验证该方法有效、可行。