A comparative analysis between temperature and pressure measurements for early detection of runaway initiation

In this work, we have analysed the use of pressure instead of temperature measurements for the early warning detection of runaway initiation. This is possible due to the fact that our runaway criterion, i.e. div>0, does not depend specifically on which state space variable we are using for divergence calculation. A series of runaway experiments, carried out in a 250 l pilot-scale reactor, has been used to compare the results. In accordance with previous analysis, we show that by using temperature, early detection of runaway initiation is achieved. Analogously to temperature, pressure may be also used for runaway detection. By comparing the different types of reactive systems analysed (vapour and gassy), it can be observed that temperature works better, in terms of earlier detection, than pressure but the differences are more pronounced for vapour than for gassy systems.     

系统安全性与可靠性分析的故障树方法

探讨了大型复杂系统安全性与可靠性分析的故障树技术。阐述了国外具有代表性的几种建树方法。针对实际应用情况,提出了将建树过程划分为5个阶段,应遵循的8条基本准則。导出了典型系统可靠度与故障率等可靠性参数计算的通用公式。论述了故障树分析方法的特点及发展动向。     

浅层物探在监测城市地质灾害中的应用

我国约有160多个城市发生不同程度的地质灾害,迫切需要查明其成因,估计其发展趋势,并提出减小灾害的方法。本文以铜陵市长江路大面积出现的地裂缝及塌陷为例,对比使用了电法、磁法、地质钻探、人工地震等方法。认为人工地震方法在喀斯特地区可以用来确定此类地质灾害的范围、趋势和找出其成因。     

NEW ZEALAND'S NATIONAL WATER QUALITY MONITORING NETWORK - DESIGN AND FIRST YEAR'S OPERATION1

ABSTRACT: The design and implementation of a national surface water quality monitoring network for New Zealand are described. Some of the lessons learned from the first year of operation are also addressed. Underpinning the design, and specified in advance, are the goal and objectives, the data quality assurance system, and the mechanism for data interpretation and reporting. Because of the difficulties associated with the use of a multitude of different agencies, only one agency is involved in field work and one laboratory undertakes the analysis. Staff training has been given a high priority. The network has been designed to give good trend detectability for regular sampling over a 5–10 year period.     

Automated diagnosis of malfunctions based on object orientated programming

The diagnostic event analyser (DEA) is a system for automated diagnosis of malfunction in continuous processes. DEA interprets real-time sequences of abnormal events such as measurements out of normal ranges and violation of quantitative algebraic constraints. DEA can be used to supplement an existing alarm system, providing a higher-level interpretation of patterns of abnormal events for the process operator. To use DEA, the user must supply only standard ‘form’ inputs of the root causes and relationships between abnormal events. DEA is implemented using object- oriented programming, a technique which allows general rules and procedures to be applied to process-specific objects. This architecture facilities treatment of multiple malfunctions and robustness to variation in event sequences.     

Modelling Complex Pipeline Network Leak Detection Systems

A novel model for detecting leaks in complex pipeline network systems has been developed. The model derives from the theory of Liapunov stability criteria. A leak is detected if the resulting eigenvalues from the deviation flow matrix have values less than a predetermined value. An advanced mesh network algorithm was used to decompose the complex pipeline network system into sub-networks. The flow model (equations of motion and continuity) which incorporates a leaking factor, k_L, is solved by a numerical technique that uses the method of characteristics and an implicit finite function. The unsteady state flow matrix of the complex pipeline network system was analysed using a modified Hardy Cross algorithm, where the velocity and pressure were computed for each node and pipeline loop in the complex network. The plots for the characteristic pressure and velocity eigenvalues show that pressure measurements are faster parameters for leak detection than volume measurements. Volume measurements appear to be suitable for larger leak systems and longer response time.     

浮头式换热器故障树的建立

通过现场调研，运用故障树对浮头式换热器常见故障进行分析，得出浮头式换热器系统的主要故障为腐蚀导致的泄漏。从而，从设计、焊接制造、安装、操作维护等几个环节提出改进措施，为浮头式换热器的可靠性分析提供指导。     

隧道含水断层破碎带的探测

以泉三高速公路某隧道含水断层为例,对比瑞利波和地质雷达两种探测技术,论述其优缺点,阐明瑞利波探测技术探测公路施工隧道含水断层破碎带的优点。     

提速条件下小唐河大桥运营性能的安全性评价

针对提速后的小唐河大桥,运用动力检测方法,对其梁跨中的动挠度、横向振幅、横向及竖向加速度、振动频率,梁端横向振幅,墩顶横向振幅、加速度、振动频率,桥墩基础顶(承台顶)横向振幅等进行了测量。根据测量的结果对其进行安全性评价,评价结果表明:提速条件下各跨梁体的最大横向振幅均不满足规范的要求,墩顶、桥墩横向振幅值较大,承台顶的横向振幅也偏大,梁墩体系横向自振频率低,而各墩墩顶和梁体跨中的横向加速度值、梁体跨中竖向振动加速度值仍能满足规范的要求;梁跨具有足够的竖向刚度。根据评价的结果对小唐河大桥的加固提出了建议。     

乙炔干燥变温吸附装置安全性分析与燃爆事故预防对策

针对乙炔变温吸附装置的燃爆事故问题,采用HAZOP方法对该装置进行安全性分析,找出存在的安全隐患,提出整改措施,指出装置发生燃爆事故的可能性;又将该装置可能发生的燃爆事故作为顶上事件,利用FTA方法进行分析,得到了装置发生燃爆事故的可能原因,制定了预防发生燃爆事故的对策。通过将HAZOP和FTA分析方法结合使用,有效地识别出乙炔装置存在的隐患,降低了装置操作的危险性,预防了燃爆事故的发生,值得推广应用。