ISSN:1066-8527    

DOI:10.1002/prs.680150202

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractSome distillation columns in the chemical industry are operated in batch mode with a fairly short operating cycle. At the end of each cycle the columns are cooled and recharged. During the cooling cycle, air will be drawn into the column by the action of a vacuum relief valve. Consequently, for a finite portion of the operating cycle a flammable mixture will exist in the column.Here we evaluate the risk posed by such an operation to see if a mitigation measure is justified. We develop a fault tree and estimate the frequency of ignition by all possible ignition sources. By comparing the risk reduction attainable by installing a lightning protection system with that attainable by using an inert blanketing system the lightning protection system is found to be the preferred solution. It provides about the same risk reduction at a lower overall cost.

ISSN:1066-8527    

DOI:10.1002/prs.680150203

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractPressure relief sizing for refrigeration equipment is considered in this paper. In particular the ASHRAE fire sizing formula [2] is critically examined and comparisons are made with methods employed in other engineering institutes. The traditional sizing approach based on vapor relief is re‐exmained in light of the recent findings from the DIERS (Design Institute for Emergency Relief Systems) work [11]. The occurrence of two‐phase discharges during relief may result in significant overpresurization of the refrigeration equipment. The purpose of this paper is to suggest a methodology adequate for most designs and which has been verified with available experimental d

ISSN:1066-8527    

DOI:10.1002/prs.680150204

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractProcess tanks and vessels can withstand internal pressures much larger than the vacuums needed to collapse them. Such tanks and vessels are often collapsed when they are emptied without proper venting, or when their vents are obstructed. It is also possible to collapse a vented tank, if it is filled with steam and cooled rapidly.

ISSN:1066-8527    

DOI:10.1002/prs.680150205

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractHazard 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 weeks. 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 framework has been developed in which the knowledge required to perform HAZOP analysis is divided into process‐specific and process‐general components. The process‐specific knowledge 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 c

ISSN:1066-8527    

DOI:10.1002/prs.680150206

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractKemira B.V. operates a 1200 metric tpd (100%) high pressure nitric acid plant in Rozenburg, the Netherlands since 1968. Until the incident described here occurred, operation had always been uneventful. In August 1993, however, the ammonia/air mixer suddenly burst open, releasing large amounts of air and ammonia to atmosphere. Two persons working in the plant miraculously missed being hit by the gas jet and flying debris. This paper describes the incident, its cause and measures taken to prevent reoccurrence.

ISSN:1066-8527    

DOI:10.1002/prs.680150207

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractThis AIChE/CCPS sponsored workshop brought together a panel of experts to discuss the development and communication of worst‐case scenarios for EPA's proposed Risk Management Program (RMP) Regulation. This paper presents specific issues raised during the Workshop, such as selecting release scenarios, performing hazard assessments, and communicating the results. However, the ultimate goal is chemical accident prevention and preparedness. Findings are not attributed to the individual experts but represent the view of the discussion chairma

ISSN:1066-8527    

DOI:10.1002/prs.680150208

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractI would like to begin with a little exercise—I would like you to transport yourself back to your plant. Now, as you're back in your office, imagine for a moment that the plant emergency alarms start to go off. You catch a faint hint of ammonia as you walk to your office window. What you see can easily be described as your worst nightmare. You feel as though your heart has stopped and you freeze as if you were paralyzed. The 40 million pound (18 million kilogram) capacity double‐walled ammonia storage tank located about 200 yards (182 meters) from your office has a massive leak. Ammonia is vaporizing and being carried downwind toward the city in which you and your family live.All right—enough of the nightmare. What went through your mind? How would you react? What would be the impact on you, your family, your community? It wouldn't be good, I can assure you.Why have I tried to ruin your day by asking you to live a nightmare? For one simple reason—to show you what the Environmental Protection Agency (EPA) is going to make us all do under its proposed Risk Management Program (RMP) regulation. In fact, the EPA goes a step further. It will ask us not only to create our nightmares for ourselves, but to share them with the communities around our plants that could be impacted by our nightmare r

ISSN:1066-8527    

DOI:10.1002/prs.680150209

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractSince the early 1980s, CMMS has been clearly defined as Computerized Maintenance Management Systems. By definition, CMMS has some huge short falls. I begin by breakage down the acronym and then, give you the path forward, that has been demonstrated to ensure success. For people that need the answer right away, skip directly to the “Systems,” Sect

ISSN:1066-8527    

DOI:10.1002/prs.680150210

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper introduces a new method (now commonly referred to as the Baker‐Strehlow Method) for estimating pressure and impulse generated by vapor cloud explosions. Strehlow's blast curves and concepts from the Multi‐Energy method for determination of explosion energy are applied in this technique. New correlations for maximum flame speed based on obstacle density, fuel reactivity, and cloud confinement allow selection of the appropriate blast curve. Application of these correlations removes much of the subjectivity present in existing explosion estima

ISSN:1066-8527    

DOI:10.1002/prs.680150211

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY