安全仪表功能的实现和验证

在IEC61511安全生命周期中的分析阶段要进行工厂或装置的危险和风险分析,安全保护层的设计和安全要求规范（SRS）的编制。根据安全要求规范中的安全仪表功能（SIF）要求合理地设计安全仪表系统（SIS）,     

故障树法在大型冗余结构失效率计算中的应用

安全仪表系统经常采用多个设备或子系统构成冗余结构来提高自身的可靠性。常见的冗余结构有1oo2,2oo2,2oo3等,在大型装置中还会遇到更为复杂的冗余结构。为定量分析大型冗余结构的可靠性,选择合适的方法对其进行建模至关重要。本文用故障树方法对大型冗余结构进行可靠性建模,并对假设参数条件下MooN结构的故障树模型进行简化分析,经过迭代计算,当M和N满足N-M+1≥4时,可以忽略系统的随机硬件失效,从而简化了计算模型。最后通过计算某大型乙烯装置安全仪表系统中大型冗余结构的危险失效概率,证明简化后的模型具有较高的精确度。     

基于FMEA的安全仪表系统安全完整性研究

安全仪表系统(SIS)的安全完整性是衡量安全相关系统在规定条件下、规定时间内成功实现所要求的安全功能概率的重要指标。笔者针对1oo2D冗余结构的SIS,采用FMEA(故障模式及影响分析)方法研究系统研发各个阶段的缺陷和薄弱环节,然后结合IEC61508中推荐的诊断技术和措施改进电路。通过该方法还可获得相关参数,得到系统的平均要求失效概率PFDAVG,确定SIS的安全完整性等级是否满足要求。目前该方法已成功应用在安全级DCS平台样机研制的安全完整性分析中,结果表明该系统满足要求的SIL3等级。     

石化装置的安全性设计探讨

针对石化装置在生产过程中可能出现的危险。如何设计安全仪表系统（SIS）。文章阐述了安全仪表系统的基本概念。介绍了安全仪表系统的选用以及相关元件的选型原则。对不同结构的SIS性能进行了比较。为自控设计人员提供了选型的依据。     

第三十五讲：人因可靠性对SIS整体可用性的影响分析

安全仪表系统SIS的联锁触发动作过程中往往需要人员的参与,本文为人因可靠性分析确定了恰当的方法,并将SIS按照功能的不同分为两类,并从两个方面详细分析了人因可靠性对SIS整体可用性的影响,最后提出了提高SIS整体可用性的有效方法.     

长输管道安全仪表系统设计

我国长输管道的快速发展,对其安全平稳运行提出了更高的要求,安全仪表系统（SIS）作为长输管道数据采集与监控系统（SCADA）的重要组成部分显得越来越重要。一个技术先进、性能可靠、应用灵活的安全仪表系统,是长输管道SCADA系统设计时考虑的重点。     

基于PHA-FMEA的石油炼化装置安全仪表系统设计与应用研究

石油炼化装置安全仪表系统关乎整个装置的安全可靠性,具有监测与预警功能。从石油炼化装置故障风险分析出发,采用基于PHA-FMEA的方法对石油炼化装置风险要素进行分析,并划定危险状态风险等级。在此基础上,分析影响石油炼化装置安全仪表系统设计的背景,并根据危险状态风险等级、SIS系统的控制要求、联锁控制要求等,提出石油炼化装置安全仪表系统设计。结合石油炼化工艺SIL3级的要求,设计石油炼化装置安全仪表系统,并开展实际应用。应用结果表明:该系统安全可靠,控制系统不发生误动作,能够满足实际生产中的工艺要求以及SIS系统的控制要求和各区的联锁控制要求。     

TRICON SIS系统在加热炉燃烧器管理系统上的应用

安全仪表系统(Safety Instrumented System,SIS)是一种独立于生产过程控制系统,能够独立完成安全联锁保护功能的系统。它可以避免由于工艺生产故障、现场仪表故障、系统供电故障等对生产装置造成的重大危害,保证生产装置能够安全运行。在石油化工装置中,配置一套安全可靠、动作及时的SIS系统是非常重要的。结合委内瑞拉PDVSA某炼油厂加热炉燃烧器管理系统(BMS)的应用,重点介绍了TRICON系统的硬件结构、系统组态、逻辑编程、人机界面组态和系统调试等方面的技术实现。实际应用表明,TRICON的SIS系统是一套功能全面、安全可靠、简单易学的安全仪表系统。     

在役大型石油储罐安全仪表系统改造方案

在石油化工行业的实际生产过程中,应用安全仪表系统(SIS)可以有效地避免和减少厂区或生产装置设施中存在的过程风险,该系统的合理设计以及运行情况可以对装置的安全状态产生直接影响.本文介绍了如何判断在役大型石油储罐罐区SIS设备等级,验证安全仪表功能(SIF)设计和安全完整性等级(SIL)确认,以对平均危险失效概率和可靠性...     

安全仪表系统安全完整性等级计算方法研究

介绍了安全仪表系统的作用、与基本控制系统的区别,以及安全完整性等级的评估过程,对比分析了常用的安全完整性等级验证计算方法,基于状态枚举法,得出了不同冗余结构的计算模型。     

结合模态区间分析和IARR的不确定性损伤识别

针对结构不确定性损伤识别中经典区间算法容易发生扩张的问题,提出将模态区间分析和改进解析冗余度(improved analytical redundancy reduction,简称IARR)相结合的损伤识别方法。首先,将结构静力平衡方程用约束条件方程组表示,通过改进解析冗余度使得方程组仅包含平动变量;其次,把与假定损伤单元相关的方程集中在同一子集,代入区间变量将方程扩展成区间形式,通过模态区间运算判断各约束条件的满足情况来实现损伤定位;最后,采用静载作用下的试验钢梁验证所提出的方法,结合刚度参数、挠度参数和外荷载3种随机变量,建立各梁段约束条件方程。结果表明:考虑测试误差、参数不确定性时,能通过约束条件的不满足有效定位梁的小损伤。     

Reliability analysis of the control system of large-scale vertical mixing equipment

The control system of vertical mixing equipment is a concentrate distributed monitoring system (CDMS). A reliability analysis model was built and its analysis was conducted based on reliability modeling theories such as the graph theory, Markov process, and redundancy theory. Analysis and operational results show that the control system can meet all technical requirements for high energy composite solid propellant manufacturing. The reliability performance of the control system can be considerably improved by adopting a control strategy combined with the hot spared redundancy of the primary system and the cold spared redundancy of the emergent one. The reliability performance of the control system can be also improved by adopting the redundancy strategy or improving the quality of each component and cable of the system.     

Safety instrumented functions and safety integrity levels (SIL)

This paper discusses two performance-based standards, ANSI/ISA S84.01 and IEC d61508, and the requirements they place upon user companies of electrical, electronic and programmable electronic safety related systems (E/E/PE SRS) or Safety Instrumented Systems (SIS). To comply to the requirements of the standards, a user company would have to: (a) identify the safety target level of the process; (b) evaluate the hazardous events that pose a risk higher than the safety target level; (c) determine the safety function(s) that must be implemented in an SIS to achieve the safety target level; (d) implement the safety functions in an SIS and evaluate its safety integrity level (SIL); (e) install, test and commission the SIS; and (f) verify that the installed SIS does in fact reduce the process risk to below the safety target level. Several risk analysis techniques that can be used to comply with the aforementioned requirements are discussed and a simple example is used to illustrate the use, advantages and disadvantages of the techniques. The evaluation of SIL of the SIS (probability to fail to respond to a process demand) is outside the scope of this paper.     

Reliability analysis of the control system of large-scale vertical mixing equipment

The control system of vertical mixing equipment is a concentrate distributed monitoring system (CDMS). A reliability analysis model was built and its analysis was conducted based on reliability modeling theories such as the graph theory, Markov process, and redundancy theory. Analysis and operational results show that the control system can meet all technical requirements for high energy composite solid propellant manufacturing. The reliability performance of the control system can be considerably improved by adopting a control strategy combined with the hot spared redundancy of the primary system and the cold spared redundancy of the emergent one. The reliability performance of the control system can be also improved by adopting the redundancy strategy or improving the quality of each component and cable of the system.     

继电器矩阵电路可靠性分析

根据继电器基本失效率模型和工作失效率模型，利用元器件基本失效率数据，分析了继电器可靠性的主要影响因素。在此基础上，分析了不同冗余结构对继电器矩阵电路可靠性的提高程度，得出了有设计和工程参考价值的结果。     

Closed-Form Modeling and Analysis of an XY Flexure-Based Nano-Manipulator

Flexure-based mechanisms are widely utilized in nano manipulations. The closed-form statics and dynamics modeling is difficult due to the complex topologies, the inevitable compliance of levers, the Hertzian contact interface, etc. This paper presents the closed-form modeling of an XY nano-manipulator consisting of statically indeterminate symmetric(SIS) structures using leaf and circular flexure hinges. Theoretical analysis reveals that the lever's compliance, the contact stiffness, and the load mass have significant influence on the static and dynamic performances of the system.Experiments are conducted to verify the effectiveness of the established models. If no piezoelectric actuator(PEA) is installed, the influence of the contact stiffness can be eliminated. Experimental results show that the estimation error on the output stiffness and first natural frequency can reach 2% and 1.7%, respectively. If PEAs are installed, the contact stiffness shows up in the models. As no effective method is currently available to measure or estimate the contact stiffness, it is impossible to precisely estimate the performance of the overall system. In this case, the established closed-form models can be utilized to calculate the bounds of the performance. The established closed-form models are widely applicable in the design and optimization of planar flexure-based mechanisms.     

一种新型重载三拐曲轴结构的研究及应用

对一种新型(专利)大行程、重载、组合式三拐曲轴进行了系统地阐述.采用有限元分析方法,将组合式三拐曲轴与整体三拐曲轴的各种支承结构进行了应力变化规律与最大应力值的分析、计算和对比.考虑整体三拐曲轴中支承结构的超静定因素,利用有限元分析方法中的弹性接触单元,分析了超静定因素对应力值的影响,比较了组合式三拐曲轴与整体三拐曲轴各种支承结构的动态特性差异.