基于热风险理论对道化学评价中物质系数的研究

随着本质安全研究的深入,道化学评价方法中物质系数MF的计算已不能准确描述反应物本身的热风险大小。在道化学评价方法中引入热风险概念,比较热危险性评价方法和道化学评价方法间相异点;以六甲基磷酰三胺工艺为研究对象,用DSC量热仪对反应物进行分析得出放热速率q、反应波峰峰值、单位质量的反应焓Hr,对采集的工艺参数用热力学理论外推法、基因贡献法得出活化能E、比热容CP并以此求出最大反应失效时间TMRad、绝热温升Qad、物质系数MF值以及工艺单元中物料量。得出最大反应失效时间与物质系数MF间具有相关性,道化学评价方法对因失效反应引发二次反应的热风险评估也适用。     

概率统计在矿井通风系统可靠性评估中的应用

构建一个随机非稳定地下矿山通风系统,此通风系统有三个机组,机组的随机运行状态构成了一个完整的“系统的概率结构”。对此通风系统的运行状态进行概率统计分析,探讨了该随机系统的特征。由此推导出了通风系统故障的平均时间是一个显式的概率表达式。同时,假设系统失效时间和更换时间符合指数分布的情况下,得出计算系统故障平均时间的一个五阶多项式公式。通过验证,证明了系统故障平均时间的大小依赖于系统维修和更换的比率,而且是检验系统可靠性的重要指标,有利于提高矿山安全水平。     

软岩大变形巷道支护技术及应用

针对三门峡铝土矿软岩巷道大变形难支护的问题,综合现场工程地质调查、软岩水理作用测试、现场测试等手段和方法,对该地区巷道破坏模式和失稳机理进行详细分析,提出了锚喷-砌碹相结合的互补支护技术。按照互补支护参数建立数值模型并进行稳定性分析,数值计算结果表明在此支护方式下巷道各部位围岩收敛变形控制良好,且支护后围岩安全系数较之前明显提高。将新支护方案进行工程试验,巷道变形监测数据表明,支护后的巷道变形得到了良好的控制,混凝土喷层未出现裂缝,围岩变形速度迅速减小;锚喷10天后围岩变形基本稳定,此时进行二次砌碹支护效果最好,可以保证巷道的长期稳定。     

API Standard 521 new alternative method to evaluate fire relief for pressure relief device sizing and depressuring system design

Since the 1950's, API Standards have provided guidance on determining relief loads for equipment exposed to pool fires. The API method is empirical based on tests performed in the 1940's. There is increasingly widespread interest in analytical methods based on heat transfer principles to model fire heat input. The API committee agreed to include an analytical method in the 6th edition of API Standard 521 to establish relief loads for pressure relief devices and to design depressuring systems for the fire scenario. The analytical method provides more flexibility than the empirical method but has limitations (e.g., too many permutations are possible leading to potential under-sizing of the pressure relief device).This paper discusses the basis for the empirical method in API Standard 521 and provides comparisons of the empirical and analytical method with two more recent large-scale pool fire tests. This pool fire test data indicates that the empirical method will provide a conservative estimate of pool fire heat input for most applications and is still the method of choice when designing pressure relief systems. However, these recent tests indicate the empirical method needs to be modified when a vessel or equipment is partially confined by adjacent embankments or walls equal or greater than the vessel height. In such cases, the wetted area exponent should be 1.0 instead of 0.82.The analytical method is useful in determining time-versus-temperature profiles for heating unwetted vessels of varying wall thicknesses and materials of construction. These profiles, which depend upon the type of fire (e.g., unconfined pool fire, jet fire, etc.), can be combined with tensile strength and stress-rupture data to specify a depressuring system's pressure-versus-time profile. This will minimize failure and/or mitigate the effects of failure due to overheating from fire exposure.     

基于FTA的尿素热解脱硝系统可靠性分析

为提高尿素热解脱硝系统可靠性水平,通过分析系统组成和各种可能的失效情况,以尿素热解脱硝系统不能正常工作为顶事件建立了故障树,对其进行定性分析,求取了故障树的最小割集。同时在此基础上分析了各个基本事件的结构重要度,明确了导致尿素热解脱硝系统失效的主要影响因素,并对其相应的解决措施进行了探讨。     

细尾矿砂破坏准则的测试与安全影响

为研究细尾矿砂破坏准则的具体形式和安全影响,利用HCA试验的方法测试了子午平面和π平面的破坏曲线;采用数值模拟的方法分析了所获破坏准则引起的尾矿坝安全系数变化。结果表明:子午平面的破坏曲线为单调递增;π平面破坏曲线在静水压力较小状态与Mohr-Coulomb准则一致,静水压力较大状态与Drucker-Prager准则一致,针对试验对象静水压力分界点可确定为200 kPa;若基于分界点在坝体内设置双重破坏准则,安全系数介于单独准则所得值之间,且Drucker-Prager准则单元所占比重介于31.33%～60.67%时,滑面区内Drucker-Prager准则单元数量变化,安全系数变化较明显,比重取其余值滑面区内Drucker-Prager准则单元数量不变,安全系数变化不明显。细尾矿砂破坏准则应为Mohr-Coulomb与Drucker-Prager组合而成的双重准则,组合过程需考虑静水压力的影响。     

高速气固两相流作用下的煤化工管材冲蚀磨损行为研究

为解决煤化工业中节流阀突扩口高速气固两相流对管壁材质的冲蚀磨损问题,利用基于激波管原理驱动的气固两相流冲蚀实验装置,试验研究冲击角度、温度对煤化工管材(10#、AISI304)的冲蚀磨损规律。研究结果表明:10#、AISI304管材的冲蚀率将随着冲击角度的增加而先增大后减小;室温下,10#、AISI 304钢的最大冲蚀率均出现在15°~30°区间;随着温度的升高,10#的最大冲蚀率出现在30°~45°区间,AISI304最大冲蚀率出现在30°。10#在30°,45°冲击角度下冲蚀磨损率会随温度上升显著上升,在15°冲击角度下冲蚀磨损率反而会随温度上升而下降。AISI 304在15°,30°,45°冲击角度下,冲蚀磨损率均会随温度上升而上升;在特定条件下,10#管材的冲蚀性能将优于AISI304。     

Occupational Cognitive Failures and Safety Performance in the Workplace

Introduction. The majority of industrial accidents occur because of human errors. Human error has different causes, however, in all cases cognitive abilities and limitations of human play an important role. Occupational cognitive failures are cognitively-based human errors that occur at work. The aim of this study was to examine the relationship between occupational cognitive failures and safety consequences. Method. Personnel of a large industrial company in Iran filled out an occupational cognitive failure questionnaire (OCFQ) and answered questions on accidents. Univariate and multiple logistic regression analysis were used to determine the relationship between cognitive failures and safety consequences. Results. According to developed regression models, personnel with a high rate of cognitive failure, in comparison to low rate, have a high risk of minor injury involvement (OR 5.1, 95% CI [2.62, 10.3]); similar results were for major injury and near miss. Discussion. The results of this study revealed usefulness of the OCFQ as a tool of predicting safety-related consequences and planning preventive actions.     

高速铁路信号系统的安全管理评价研究

高速铁路信号系统要通过安全管理来保障其开发与运行中的安全相关活动符合系统安全计划的要求。为了评估安全管理活动的可信性,提出基于系统安全分析技术的安全管理评价方法。通过建立安全管理流程与系统安全功能相关联的概念模型,使用安全文化危险与可操作性研究(SCHAZOP)辨识出安全管理流程中的行为偏差,基于失效传导转换符号(FPTN)建立管理角色的安全文化失效模型,最终将管理行为失效模式转换成组件故障树作为安全管理评价证据。研究结果表明,安全管理行为偏差体现了信号系统开发与运营过程中的安全文化特征;辨识与分析安全文化失效,为信号系统安全管理活动的可信性提供了评价依据。