关键词： process safety   artificial intelligence   process hazards analysis   expert system   chemical industry  

摘要： A framework for representing the HAZOP knowledge for batch chemical plants was proposed in Part I of this paper. In Part II, we present a knowledge-based system, called Batch HAZOPExpert, which is an implementation of the framework proposed in Part I. The important features of Batch HAZOPExpert and its performance on an industrial case study are described. (C) 1998 Elsevier Science Ltd. All rights reserved.

摘要： The prototype of an integrated hazard analysis system IHAS has been developed in this study. Essentially any process can be analyzed with this software if the system topology is correctly supplied by user. Three widely accepted hazard assessment procedures, i.e. FTA, ETA and HAZOP, can be performed automatically. From the results obtained in practical applications, one can see that the quality of hazard analysis can be improved if IHAS is used as an aid to the human experts.

关键词： Process control  

摘要： Hazard and Operability (HAZOP) analysis is the study of systematically identifying every conceivable deviation, all the possible abnormal causes for such deviation, and the adverse hazardous consequences of that deviation in a chemical plant. HAZOP analysis is often carried out by a group of experts poring over the process flowsheets for weeks or months. Thus, it is a labor- and time-intensive process that would gain by automation. Previous work has addressed the issue of automating HAZOP analysis for continuous chemical plants. However, the HAZOP methodology of continuous processes cannot be applied to batch and semi-continuous plants as such because they have two additional sources of complexity. One is the role of operating procedures and operator actions in plant operation, and the other is the discrete-event character of batch processes. To represent these characteristics of batch operation, high-level Petri nets with timed transitions and colored tokens are used. The causal relationships between process variables are represented using subtask digraphs. This Petri net-Digraph model based framework has been implemented in G2 for a pharmaceutical batch process case study. The salient aspects of this framework are discussed with the aid of this case-study.

关键词： Expert systems  

摘要： Hazard and operability (HAZOP) analysis is the study of systematically, identifying every conceivable deviation from the design intent, and all possible abnormal causes, and adverse hazardous consequences that can occur in a chemical plant. This is a difficult, labor- and knowledge-intensive, and time-consuming analysis. HAZOP analysis is typically performed by a group of experts poring over the process P&IDs for week. An intelligent system for automating this analysis can reduce the time and effort involved make the analysis more thorough and detailed, and minimize or eliminate possible human errors. Towards that goal, a model-based which the knowledge required to perform HAZOP analysis is divided into and process-general components. The consists of the process material properties and the process P&ID. The process-general knowledge consists of the HAZOP-Digraph models of the process units which are qualitative causal models developed specifically for hazard identification. These models are developed in a context independent manner so that they can be used in a wide variety of processes. An inference mechanism is developed for appropriate interaction between these components in order to identify process-specific abnormal causes and adverse consequences. Based on this framework, an expert system called HAZOPExpert has been developed in an object-oriented architecture using the expert system shell G2. The salient features of the HAZOPExpert system and its performance on an industrial-scale sour water stripper plant case study are presented.

关键词： Accident prevention  

摘要： Hazard and Operability (HAZOP) analysis is the most widely used and recognized as the pre ferred safety analysis approach in the chemical process industry. A model-based framework and an expert system called HAZOPExpert has been developed recently for automating this analysis. The performance of HAZOPExpert was evaluated on a sour water stripper plant and a hydrotreator plant case studies. The expert system was found to successfully emulate the human experts reasoning and identify the hazards similar to the HAZOP team. But, it generated a large number of unrealizable hazardous consequences compared to the team, due to the strict qualitative seasoning approach implemented. In order to filter and rank the results from HAZOPExpert using additional quantitative knowledge similar to the team, a semi-quantitative reasoning methodology is developed using the quantitative design and operating specifications of the process units, and process material property values. Significant reduction in the number of consequences was obtained using this approach on an ethylene plant case study.

关键词： Accident prevention  

摘要： Hazard and operability (HAZOP) analysis is a systematic hazard identification procedure for predicting the various adverse consequences that might arise in a chemical plant due to abnormal causes. HAZOP analysis is typically performed by a group of experts by systematically considering all possible deviations from normal behavior of a process plant. This is a labor- and knowledge-intensive problem that can benefit from automation. Towards that goal, a framework using digraph-based models is described in this paper. The HAZOP-digraph models of the process units are developed in a process independent manner so that they can be used in a wide variety of process flowsheets. Based on this framework, an expert system for performing HAZOP analysis has been implemented in an object-oriented architecture using the expert system shell G2. A graphical HAZOP-Digraph model building tool is provided to let the user develop new models or add more knowledge to the existing models of the process units. The performance of this system was evaluated on an industrial HAZOP case study of a sour water stripping plant. The salient features of the expert system and its performance for this case study are described.

关键词： 加热炉   安全分析   安全系统工程   安全评价  

摘要： 本文采用危险性可操作研究(HAZOP)方法对运行中的道生油加热炉进行系统安全分析,并对该法进行了扩展,既考虑工艺操作参数的偏差又考虑设备结构参数的变化对系统安全运行的影响,使其安全分析更全面、更切合生产实际。

关键词： Knowledge based systems  

摘要： Hazard and operability (HAZOP) analysis is the study of systematically identifying every conceivable abnormal process deviation, its abnormal causes and adverse hazardous consequences in a chemical plant. HAZOP analysis is a difficult, time-consuming, and labor-intensive activity. An automated HAZOP system can reduce the time and effort involved in a HAZOP review, make the review more thorough and detailed, and minimize or eliminate human errors. Towards that goal a knowledge-based system, called HAZOPExpert, has been proposed in this article. In this approach, HAZOP knowledge is divided into process-specific and process-independent components in a model-based manner. The framework allows for these two components to interact during the analysis to address the process-specific aspects of HAZOP analysis while maintaining the generality of the system. Process-general knowledge is represented as HAZOP models that are developed in a process-independent manner and are applicable to a wide variety of process flowsheets. The important features of HAZOPExpert and its performance on an industrial case study are described.

关键词： Hazards  

摘要： When a new industrial system is designed, lots of information about it is collected in various documents. The use of modem CAD technology makes it possible to create an object-oriented description of the system with its physical structure and characteristics. Safety and reliability analyses are carried out during the design using various methods, typically HAZOP. Later, when the system has been constructed and taken into use, new information is created when malfunctions are diagnosed and controlled. The information sources mentioned here contain such information that could prove very useful to the operating personnel at a plant with the aid of an appropriate information system. A Nordic project to develop an information system to support process risk management is described. The safety analysis module is a HAZOP documentation tool which stores the information in a structured database. The idea of the disturbance analysis module is to make those safety analysis results which are relevant in the monitored situation available to operating personnel and to provide a tool for the recording of operating experiences. The discharge monitoring module aims to extend the number of the top-level process operation goals to include the minimizing of environmental discharges and pollution by using intelligent process models.