Dicyclopentadiene (DCPD), which is usually considered inert, undergoes exothermic reactions at high temperatures. These reactions initially lower the pressure but ultimately can generate very high pressures. Adiabatic and nonadiabatic laboratory data are presented and characterized into a kinetic model. Strategies are described for safeguarding against potentially high temperatures in DCPD containing vessels and for relieving overpressures should runaway reactions occur.
{"title":"Exothermic reactions of DCPD and protection against them","authors":"M. Ahmed, M. Lavin","doi":"10.1002/PRSB.720100307","DOIUrl":"https://doi.org/10.1002/PRSB.720100307","url":null,"abstract":"Dicyclopentadiene (DCPD), which is usually considered inert, undergoes exothermic reactions at high temperatures. These reactions initially lower the pressure but ultimately can generate very high pressures. Adiabatic and nonadiabatic laboratory data are presented and characterized into a kinetic model. Strategies are described for safeguarding against potentially high temperatures in DCPD containing vessels and for relieving overpressures should runaway reactions occur.","PeriodicalId":364732,"journal":{"name":"Plant\\/operations Progress","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129748784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effects of oxygen concentration on the stability of methacrylic acid (MAA) have been examined using HQ, MeHQ and PTZ as inhibitors. The O2 has been found to have a dual effect so that an optimum concentration confers very high stability but increased [O2]s give significantly reduced induction periods, especially at higher temperatures. This behavior has been explained in terms of radical scavanging competing with peroxide formation and cleavage. The main parameters controlling the system have been examined. The rate of stabilizer consumption was found to be controlled mainly by temperature and [O2]. The rate of energy release on polymerization is dependent on temperature, [stabilizer] and O2 supply to the system and is rapid (violent in extreme cases) only when all three factors are favorable for efficient peroxide formation and cleavage. Preliminary experiments with n-butyl methacrylate indicate that the same principles and mechanism operate for the simple methacrylate esters.
{"title":"The effect of O2 concentration on methacrylic acid stability","authors":"A. Nicolson","doi":"10.1002/PRSB.720100311","DOIUrl":"https://doi.org/10.1002/PRSB.720100311","url":null,"abstract":"The effects of oxygen concentration on the stability of methacrylic acid (MAA) have been examined using HQ, MeHQ and PTZ as inhibitors. The O2 has been found to have a dual effect so that an optimum concentration confers very high stability but increased [O2]s give significantly reduced induction periods, especially at higher temperatures. This behavior has been explained in terms of radical scavanging competing with peroxide formation and cleavage. The main parameters controlling the system have been examined. The rate of stabilizer consumption was found to be controlled mainly by temperature and [O2]. The rate of energy release on polymerization is dependent on temperature, [stabilizer] and O2 supply to the system and is rapid (violent in extreme cases) only when all three factors are favorable for efficient peroxide formation and cleavage. Preliminary experiments with n-butyl methacrylate indicate that the same principles and mechanism operate for the simple methacrylate esters.","PeriodicalId":364732,"journal":{"name":"Plant\\/operations Progress","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121109813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The certification test standards that presently exist for flame arresters are highly inadequate for inline applications. A proper flame arrester test method should ensure that a unit will work with any flame front conditions that it could be exposed to in actual use. When evaluating flame arrester performance, it is just as dangerous to neglect deflagration testing as detonation testing. The comprehensive inline flame arrester test method outlined here involves exposing a unit to the entire flame propagation pressure spectrum. This includes low, medium and high pressure deflagrations as well as overdriven and stable detonations. The test method also takes into account the following factors: flow restriction on the protected side of the flame arrester, flame propagation through a flowing gas, initial system pressure and temperature, and specified gas mixture. Flow restriction on the protected side of the flame arrester has a very significant effect on performance and has not previously been given consideration in flame arrester testing. Besides moving flame front tests, endurance burn testing and hydrostatic pressure testing are also discussed here. Major regulatory organizations have recently adopted these findings as the basis for new standards proposed to cover an inline flame arrester test method.
{"title":"A comprehensive test method for inline flame arresters","authors":"N. Roussakis, K. Lapp","doi":"10.1002/PRSB.720100207","DOIUrl":"https://doi.org/10.1002/PRSB.720100207","url":null,"abstract":"The certification test standards that presently exist for flame arresters are highly inadequate for inline applications. A proper flame arrester test method should ensure that a unit will work with any flame front conditions that it could be exposed to in actual use. When evaluating flame arrester performance, it is just as dangerous to neglect deflagration testing as detonation testing. The comprehensive inline flame arrester test method outlined here involves exposing a unit to the entire flame propagation pressure spectrum. This includes low, medium and high pressure deflagrations as well as overdriven and stable detonations. The test method also takes into account the following factors: flow restriction on the protected side of the flame arrester, flame propagation through a flowing gas, initial system pressure and temperature, and specified gas mixture. Flow restriction on the protected side of the flame arrester has a very significant effect on performance and has not previously been given consideration in flame arrester testing. Besides moving flame front tests, endurance burn testing and hydrostatic pressure testing are also discussed here. Major regulatory organizations have recently adopted these findings as the basis for new standards proposed to cover an inline flame arrester test method.","PeriodicalId":364732,"journal":{"name":"Plant\\/operations Progress","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116394284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Michel Desjardin, D. Gustafson, R. Helling, M. Ladd, K. Steele, Danae Vanderhoof
The Western Division of Dow Chemical, USA, started a program in the late 1970's to review early stage research projects prior to operation. The name Pre-op (Pre-operational Review) was given to describe the series of steps or process of reviewing projects for safety concerns. In recent years, the process has been examined and improved by a committee of research chemists and engineers. Some of the changes have been dictated by regulatory considerations, but primarily the focus of the continuous improvement effort has been directed at the customers: the users of the system and the research management who are ultimately responsible for the safety of their area. Pre-op reviews are a thorough review of the safety aspects of a new project along with the information necessary to meet current OSHA, EPA, Safety and Loss Prevention Principles, industrial hygiene, and other environmental regulatory concerns. The end result of the Pre-op review process is a document that contains the information needed to understand and review the proposed project. The document is reviewed at a meeting with two to eight reviewers that are not directly involved with the project. The review committee is appointed by a Pre-op Coordinator, a person who administers the system.more » The committee should include research management, research safety management, a site reactive chemicals committee representative, the pilot plant supervisor, operators, an unaffiliated chemist and engineer, and the project supervisor. The committee reviews the document package and then conducts a field inspection of the facility so that a list of recommendations can be generated. The committee recommendations must be completed by the person responsible for the project prior to start-up.« less
{"title":"Dow Chemical Western Division Research pre-operational review for new projects","authors":"Michel Desjardin, D. Gustafson, R. Helling, M. Ladd, K. Steele, Danae Vanderhoof","doi":"10.1002/PRSB.720100205","DOIUrl":"https://doi.org/10.1002/PRSB.720100205","url":null,"abstract":"The Western Division of Dow Chemical, USA, started a program in the late 1970's to review early stage research projects prior to operation. The name Pre-op (Pre-operational Review) was given to describe the series of steps or process of reviewing projects for safety concerns. In recent years, the process has been examined and improved by a committee of research chemists and engineers. Some of the changes have been dictated by regulatory considerations, but primarily the focus of the continuous improvement effort has been directed at the customers: the users of the system and the research management who are ultimately responsible for the safety of their area. Pre-op reviews are a thorough review of the safety aspects of a new project along with the information necessary to meet current OSHA, EPA, Safety and Loss Prevention Principles, industrial hygiene, and other environmental regulatory concerns. The end result of the Pre-op review process is a document that contains the information needed to understand and review the proposed project. The document is reviewed at a meeting with two to eight reviewers that are not directly involved with the project. The review committee is appointed by a Pre-op Coordinator, a person who administers the system.more » The committee should include research management, research safety management, a site reactive chemicals committee representative, the pilot plant supervisor, operators, an unaffiliated chemist and engineer, and the project supervisor. The committee reviews the document package and then conducts a field inspection of the facility so that a list of recommendations can be generated. The committee recommendations must be completed by the person responsible for the project prior to start-up.« less","PeriodicalId":364732,"journal":{"name":"Plant\\/operations Progress","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123972555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents the results of a generic reliability analysis of fault-tolerant digital control systems (F-T DCS). This analysis differs from previous efforts at estimating the reliability performance of F-T DCS in the sense that this analysis relies extensively on actual experience with redundant computer systems rather than on theoretical evaluations. The dominant contributors to the frequency of failure of F-T DCS are (1) failures within common or shared equipment, (2) software failures, and (3) inadvertent operator actions. Other contributors include loss of electric power, spurious signals that originate from within the DCS, lack of coverage, common cause failure (CCF) of redundant hardware, CCF of instrument channels, and physical damage from externally initiated events (e.g., high temperature). Much variation is expected in the reliability performance of F-T DCSs. Although some systems may operate for 10 or 15 years without experiencing system failures, other systems may fail several times during the same time interval. This variation is expected among systems of different architectures as well as among systems of the same architecture. Because most failures of DCSs can be traced to some kind of CCD, particularly software failures and inadvertent operator actions, CCFs should probably receive more attention than they aremore » presently given when selecting an F-T DCS.« less
{"title":"Reliability performance of fault‐tolerant digital control systems","authors":"H. M. Paula, M. W. Roberts, R. E. Battle","doi":"10.1002/PRSB.720100212","DOIUrl":"https://doi.org/10.1002/PRSB.720100212","url":null,"abstract":"This paper presents the results of a generic reliability analysis of fault-tolerant digital control systems (F-T DCS). This analysis differs from previous efforts at estimating the reliability performance of F-T DCS in the sense that this analysis relies extensively on actual experience with redundant computer systems rather than on theoretical evaluations. The dominant contributors to the frequency of failure of F-T DCS are (1) failures within common or shared equipment, (2) software failures, and (3) inadvertent operator actions. Other contributors include loss of electric power, spurious signals that originate from within the DCS, lack of coverage, common cause failure (CCF) of redundant hardware, CCF of instrument channels, and physical damage from externally initiated events (e.g., high temperature). Much variation is expected in the reliability performance of F-T DCSs. Although some systems may operate for 10 or 15 years without experiencing system failures, other systems may fail several times during the same time interval. This variation is expected among systems of different architectures as well as among systems of the same architecture. Because most failures of DCSs can be traced to some kind of CCD, particularly software failures and inadvertent operator actions, CCFs should probably receive more attention than they aremore » presently given when selecting an F-T DCS.« less","PeriodicalId":364732,"journal":{"name":"Plant\\/operations Progress","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128741070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The current regulations and accepted recommended practices relating to the use of mechanical flame arresting devices on low pressure, flammable liquid storage tanks will be reviewed. The applicability of these recommendations to typical manifolded tank and closed piping vapor recovery systems, as opposed to the more common stand alone, venting to atmosphere storage tanks, will be examined with particular emphasis on the widely varying service conditions that mechanical flame arresting devices may encounter. The limitations placed on the use of commercially available Factory Mutual Approved and Underwriters Laboratories Listed flame arresters will be explained.
{"title":"Specification of flame arresting devices for manifolded low pressure storage tanks","authors":"T. Piotrowski","doi":"10.1002/PRSB.720100210","DOIUrl":"https://doi.org/10.1002/PRSB.720100210","url":null,"abstract":"The current regulations and accepted recommended practices relating to the use of mechanical flame arresting devices on low pressure, flammable liquid storage tanks will be reviewed. The applicability of these recommendations to typical manifolded tank and closed piping vapor recovery systems, as opposed to the more common stand alone, venting to atmosphere storage tanks, will be examined with particular emphasis on the widely varying service conditions that mechanical flame arresting devices may encounter. The limitations placed on the use of commercially available Factory Mutual Approved and Underwriters Laboratories Listed flame arresters will be explained.","PeriodicalId":364732,"journal":{"name":"Plant\\/operations Progress","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127849366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nine depressurization experiments for vessels containing water, freon-114 and high viscosity fluids have been analyzed. These experiments were carried out at different plants and provide information about the dependence of the depressurization process on the size of the vessel, the type of vent installed, and the initial conditions. The differences of venting into the atmosphere or venting into a catch tank have been also examined. The accuracy of the two-phase flow model used for the analysis of these experiments has been demonstrated by comparisons with steady state data referring to co-current liquid/vapor flow as well as to batch type of flows, where the liquid phase is stagnant.
{"title":"Hydrodynamic aspects of venting for vessels containing viscous fluids","authors":"A. Skouloudis, H. Kottowski","doi":"10.1002/PRSB.720100211","DOIUrl":"https://doi.org/10.1002/PRSB.720100211","url":null,"abstract":"Nine depressurization experiments for vessels containing water, freon-114 and high viscosity fluids have been analyzed. These experiments were carried out at different plants and provide information about the dependence of the depressurization process on the size of the vessel, the type of vent installed, and the initial conditions. The differences of venting into the atmosphere or venting into a catch tank have been also examined. The accuracy of the two-phase flow model used for the analysis of these experiments has been demonstrated by comparisons with steady state data referring to co-current liquid/vapor flow as well as to batch type of flows, where the liquid phase is stagnant.","PeriodicalId":364732,"journal":{"name":"Plant\\/operations Progress","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121822355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Two low-level dust fires and explosions occurred in rotary dryers in one of E.I. du Pont de Nemours and Co.'s east Texas plants. Although there was no significant damage, the potential for safety or loss incidents initiated a concerted effort to determine the cause. The analytical and explosive hazards efforts showed an iron-adipic compound most probably autooxidized and caused the problem.
E.I. du Pont de Nemours and Co.位于德克萨斯州东部的一家工厂的旋转式干燥机发生了两起低粉尘火灾和爆炸。虽然没有造成重大损失，但安全或损失事故的可能性促使各方共同努力确定原因。分析和爆炸危害表明，铁己二酸化合物很可能是自氧化引起的。
{"title":"Forestalling a serious incident: A detective story","authors":"M. Kaiser","doi":"10.1002/PRSB.720100209","DOIUrl":"https://doi.org/10.1002/PRSB.720100209","url":null,"abstract":"Two low-level dust fires and explosions occurred in rotary dryers in one of E.I. du Pont de Nemours and Co.'s east Texas plants. Although there was no significant damage, the potential for safety or loss incidents initiated a concerted effort to determine the cause. The analytical and explosive hazards efforts showed an iron-adipic compound most probably autooxidized and caused the problem.","PeriodicalId":364732,"journal":{"name":"Plant\\/operations Progress","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130894009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Experience has shown that a Distributed Control System (DCS) can provide enhanced process monitoring and control capabilities, as well as system self-diagnostics, that permit increased safety of process operations. However, this enhanced safety does not come about automatically with the installation of a DCS. The complexity and versatility of the DCS can introduce new failure scenarios leading to process upset and potential relization of process hazards. This paper reviews some novel considerations that should be taken into account when conducting process hazards reviews on facilities controlled by a DCS.
{"title":"The process safety impact of distributed control systems","authors":"Walter L. Franke, O. M. Zodeh","doi":"10.1002/PRSB.720100208","DOIUrl":"https://doi.org/10.1002/PRSB.720100208","url":null,"abstract":"Experience has shown that a Distributed Control System (DCS) can provide enhanced process monitoring and control capabilities, as well as system self-diagnostics, that permit increased safety of process operations. However, this enhanced safety does not come about automatically with the installation of a DCS. The complexity and versatility of the DCS can introduce new failure scenarios leading to process upset and potential relization of process hazards. This paper reviews some novel considerations that should be taken into account when conducting process hazards reviews on facilities controlled by a DCS.","PeriodicalId":364732,"journal":{"name":"Plant\\/operations Progress","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113958802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Center for Chemical Process Safety (CCPS) was formed to provide leadership and coordination to engineering approaches to safety in the chemical process industry. the center focuses its' activities on safety in the manufacturing, handling and storage of toxic flammable or explosive and reactive materials and those scientific and engineering practices that can prevent or mitigate episodic events involving the release of potentially hazardous materials. CCPS recognized, however, that enhancements in chemical process technologies alone would not be good enough to prevent catastrophic events such as Bhopal. Therefore, with the support of its advisory and managing boards, a multifaceted program was established to address the need for management commitment to the technical elements of chemical process safety. Commitment in any company must start at the top level. This paper, therefore, focuses on the importance of leadership, and how management demonstrates importance of leadership, and how management demonstrates leadership through creating a vision of the future and aggressively converts that vision into reality. The paper also discusses efforts within CCPS directed at engineering visions of process safety management. These efforts have been directed by the technical management subcommittee of CCPS who collectively represent centuries of experience in process safety.
{"title":"Guidelines for technical management of chemical process safety","authors":"Sanford Schreiber","doi":"10.1002/PRSB.720100204","DOIUrl":"https://doi.org/10.1002/PRSB.720100204","url":null,"abstract":"The Center for Chemical Process Safety (CCPS) was formed to provide leadership and coordination to engineering approaches to safety in the chemical process industry. the center focuses its' activities on safety in the manufacturing, handling and storage of toxic flammable or explosive and reactive materials and those scientific and engineering practices that can prevent or mitigate episodic events involving the release of potentially hazardous materials. CCPS recognized, however, that enhancements in chemical process technologies alone would not be good enough to prevent catastrophic events such as Bhopal. Therefore, with the support of its advisory and managing boards, a multifaceted program was established to address the need for management commitment to the technical elements of chemical process safety. Commitment in any company must start at the top level. This paper, therefore, focuses on the importance of leadership, and how management demonstrates importance of leadership, and how management demonstrates leadership through creating a vision of the future and aggressively converts that vision into reality. The paper also discusses efforts within CCPS directed at engineering visions of process safety management. These efforts have been directed by the technical management subcommittee of CCPS who collectively represent centuries of experience in process safety.","PeriodicalId":364732,"journal":{"name":"Plant\\/operations Progress","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125383933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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