bluuebunny/crossref_metadata_2025 huggingface dataset:
Static hazards using flexible intermediate bulk containers for powder handling
Authors: Britton Laurence G.
Published: June 2004

FIBC use is increasing rapidly owing principally to improved handling efficiency and product quality improvement. However, selection of the proper FIBC has many aspects, of which safety is paramount. Numerous accidents have occurred when emptying flammable powders from FIBCs, both with and without flammable vapors additionally present. Owing to the mode of operation and speed of emptying, not only is there a high probability of static generation but also a high probability of one or more operators being in the flash fire zone should ignition occur. Apart from the flash fire produced by a dust cloud and/or flammable vapors displaced from a receiving vessel, a flame may in some cases propagate into the FIBC, which might then explode. This paper discusses the FIBC selection problem, a series of case histories, and available literature. Since no FIBC loading incidents are known, the paper will focus on emptying. In particular it should be appeciated that the potential for operator grounding error and sudden nemesis can be very high.
Dispersion of instantaneous jets
Authors: Landis John G. , Linney Robert E. , Hanley Brian F.
Published: June 2004

When a gas under pressure is released, the momentum imparted to it causes the gas to mix with the surrounding air. A series of tests was carried out, and a model was used to determine the dynamics of the gas and air mixing for releases of a very short time duration. The amount of mixing that occurs when a pressurized fluid is released was determined by filling a container with varying mixtures of fumed silica and nitrogen, by bursting the container's rupture disks at fixed pressures, and by measuring the cloud velocity, location, and size at successive time intervals. A two‐stage model was developed to predict the location, size, and fluid concentration (i.e., degree of dilution) of the cloud resulting from the release of a two‐phase fluid composed of a non‐flashing or non‐evaporating dense phase. The dimensionless form of the model (ρ0u0t/ρ0r0) was found to correlate the cloud properties over initial pressures ranging from 3.1 to 70.7 barg (46 to 1025 psig), and gas quality ranging from 0.2 to 0.7 (gas mass fraction). Both the model and the data showed that the initial fluid concentration was reduced by factor of 300 to 1000 as a result of the momentum imparted mixing. This dilution is in addition to that resulting from atmospheric dispersion. Combining the predicted dilution effect from the instantaneous release with atmospheric dispersion to predict both near field and far‐field concentration is an important application of this two stage model.
Safety and chemical engineering education
Authors: Louvar J. F. , Kubias F. O.
Published: June 2004

SACHE, or Safety and Chemical Engineering Education, is a project under the auspices of AIChE's Center for Chemical Process Safety (CCPS). SACHE's mission is to assist universities to add an element of process safety to their undergraduate curriculum.

This project is funded by university members ($300/year/school) and CCPS ($30,000 annually). With the current membership of 72 universities, this gives SACHE an annual budget of $52,000 to produce teaching aids for universities. The teaching aids which have been produced and distributed to member universities include slide packages with scripts, videos, problems for use in class, and instructional modules covering technical subjects or case histories.

The SACHE products are primarily developed for universities; therefore, they contain (a) the fundamentals, (b) good illustrations, and (c) text to assist the professors develop effective educational exercises. Industry is also discovering that these products are valuable training aids; products are available via CCPS publications.
Static electricity hazards of flexible intermediate bulk container (FIBC)
Authors: Dahn C. James , Kashani A. , Reyes B.
Published: June 2004

Flexible intermediate bulk containers are being widely used. Much concern has been expressed regarding the electrostatic discharge hazards around flammable vapor/air mixtures and some very sensitive dust clouds. Methods were developed to analyze and test powders with FIBC materials to predict full scale electrostatic charging characteristics. Comparison with full scale FIBC operations shows very good correlation. Operations using FIBCs, including grounded versions are not recommended in flammable vapor environments. When dusty powders with low dust cloud ignition energies are used for FIBC systems, engineering analysis and testing is required to assure ESD safety.
Investigation of a thermal runaway hazard‐drum storage of thionyl chloride/ethyl acetate mixture
Authors: Wang Steve S. Y. , Kiang San , Merkl William
Published: June 2004

Thionyl chlorie is routinely shipped in galvanized drums. The compatibility of this drum for the storage of a mixture of thionyl chloride and ethyl acetate was investigated by thermochemical studies, condensed phase and off gas analysis. The chemical incompatibility of the ternary mixtures (thionyl chloride/ethyl acetate/zinc) resulted in an exothermic runaway reaction with extensive gas evolution, which has not been heretofore described in the literature. Storage in a drum was simulated in a half‐liter, high pressure containment vessel. Adiabatic calorimeter data are also presented to illustrate the mass transfer process involved in the induction period and the runaway reaction characteristics. Ethyl acetate is inert with thionyl chloride. However, in the presence of metallic zinc, an equimolar amount of each component are consumed by the reaction to generate ethyl chloride (g), sulfur dioxide (g), acetyl chloride (l) and sulfur (s). It was also found that the rate of gas evolution is highly dependent on the molar ratio of the thionyl chloride or ethyl acetate to metallic zinc in the solution. Based on the semi‐batch process experiments, the reaction mechanism is proposed. A potential hazard indication based on the oxygen balance for the reaction mixture is also discussed. Data on similar ternary mixtures are presented.
Loss prevention in a modern ethylene plant
Authors: Olivo John
Published: June 2004

Quantum's Deer Park Ethylene Plant was built with a philosophy of risk management which was based on loss prevention. To this end, the plant incorporates a number of concepts designed to effect early detection containment and dispersion of hydrocarbon releases. Features include a gas detection grid system, water curtain in the furnace/boiler area with open path IR detector, extensive deluge systems on equipment and in pipe racks, remote television monitoring, large portable monitors (as well as the more standard plant safety systems such as hydrants), fixed monitors, and foam generators.

The systems described are monitored by means of a graphic panel and alarm console located in the Central Control Room. This centralized facility enables the operator to monitor and activate the proper subsystems and provide a visual interface between the operator and the physical plant.
An accurate methodology for modeling the characteristics of explosion effects
Authors: Madsen Warren W. , Wagner Robert C.
Published: June 2004

A new means for modeling blast effects of all types of reactants including vapor cloud explosions has been developed and verified against empirical data. Methods such as the TNT‐equivalency model are still being widely used to simulate vapor cloud explosions and blast effects. However, many limitations exist in the accuracy of those models. Use of such flawed models could potentially provide for deleterious results from an explosion such as loss of property and/or life as well as the ramifications of liability. This should be of extreme interest to not only the chemical process industry, but also to insurerers who must understand the nature of the risk that is being under written, government safety compliance organizations and the legal profession which must either defend or litigate liability cases resulting from explosions.

The computer code, CMBWAT, models the physics of detonations and deflagrations occurring in the reaction zone and the resulting shock wave which attenuates with distance. It computes static and stagnation pressure, velocity and the shock wave impulse delivered to target surfaces within the flow field, all as a function of time, both for the incident and reflected waves. Data resulting from these analyses are used to examine the structural response of the object due to the resulting shock and to determine proper risk mitigation solutions to minimize damage effects. The model can also examine the physics of solid or vapor reactants including nuclear explosions.

Systems Integration Corporation has developed this code which was independently verified against actual test data by Sandia National Laboratory. The Nuclear Regulatory Agency is currently revising its REG GUIDE 131 as a result of this work.
Improved fire and explosion index hazard classification
Authors: Scheffler Norman E.
Published: June 2004

The Fire and Explosion Index (F&EI) is one of the most widely used hazard indices for chemical process plants. It was developed by The Dow Chemical Company in 1964 and has been improved, enhanced and simplified through the publishing of six editions. This paper describes the latest 7th edition and the improvements it contains. The F&EI is to serve as a guide for evaluating the hazard potential for separate major units of chemical process plants, is to aid in determining the consequences of a fire or an explosion and is to help determine appropriate loss prevention features to be used.

Efforts have been made to make the task of completing the F&EI form easier and the results more consistent based on the most current and accurate material property data. Some of the major features of the revised F&EI are:

Improvement of readability and corrections to previous edition.

Addition of F&EI versus Degree of Hazard table.

Major upgrading of data table which gives key chemical properties and materials factors.

Revised, streamlined F&EI forms available in computer spreadsheet form.

Improvement in data plots with equations developed for ease of calculations.

Adjustments and updating of credit factors and check lists.

The main purpose for creating the 7th edition is to update information, procedures and data to make the F&EI and auxiliary calculations more accurate and easier to perform. There are no fundamental changes in the methodology. Use of the new Fire & Explosion Index Hazard Classification Guide should lead to better determination of this important hazard index which is a valuable tool for analyzing risks for chemical process plants and selection of appropriate measures. The revised F&EI guideline will be made available as an AIChE publication as it has been since 1966.
Emergency relief system (ERS) design: An integrated approach using DIERS methodology
Authors: Biocourt Gerald W.
Published: June 2004

The Design Institute for Emergency Relief Systems (DIERS) has developed methodologies for sizing relief devices for two‐phase flow. Good engineering practices which account for two‐phase flow will ensure against undersized relief devices and potentially catastrophic vessel overpressurization. Application of the DIERS tools and methodologies for two‐phase flow can be a formidable undertaking for the uninitiated. This paper attempts to mitigate some of the complexities by a discussion of tempered systems in an integrated form. Tempered, gassy and hybrid systems are identified. Both reactive and non‐reactive systems will be considered. The integrated relief system consists of the reactor, relief device, and vent line. The design equations are presented with their underlying assumptions and application limitations. The importance of experimental design data is stressed. The “omega” methodology is discussed with examples.
Take chemistry and physics into consideration in all phases of chemical plant design
Authors: Lutz William K.
Published: June 2004

Accurate description of chemical and physical properties form the basis of chemical research, development, and commercialization of chemistry into products. The operating conditions for the chemical process are usually quite specific and are the focus of the entire commercialization activity. With the commitment to protect the worker, the public, and the environment, new or refined methods may be needed to control chemical and physical phenomena that can occur at the extreme bounds of the processing conditions. This control is accomplished in a variety of ways, but is usually done by providing a mix of passive, active and procedural controls.

Those with safety and risk assessment responsibilities in the Chemical Process Industry (CPI) identify hazards and assess risks inside these operating conditions and work diligently with their respective chemical development Teams to define the phenomena that can occur at the full operating capability of the commercial equipment. Phenomena like loss of thermal stability, and side reactions that do not occur within the desired operating conditions, may be enabled when the chemical processing conditions proceed toward the design limits of the equipment once control is lost.
Method used to estimate screening‐level total failure probability for human error events
Authors: Burns R. S. , Turner J. H.
Published: June 2004

This document briefly describes the method used to estimate a screening value for the Total Failure Probability (FT) of human error events that are identified in the fault trees which describe potential liquid UF6 release accidents at two U.S. Gaseous Diffusion Plants. A discussion is provided of the assumptions, limitations, and overall logic of the FT assignment method, and a description is presented of how the method is employed. The description herein, and more completely in Burns and Turner [1], presents the screening technique* used to quantify human errors in the accident analysis portion of the Gaseous Diffusion Plant Safety Analysis Report Upgrade Program.
Some thoughts on the difference between inherent safety and safety
Authors: Hendershot Dennis C.
Published: June 2004

Inherently safer processes represent the most desirable way to manage risk. However, we must not forget that other approaches can be used effectively, and the inherently hazardous processes can be operated safely. The overall benefits of a hazardous technology can justify the use of that technology, with appropriate resources devoted to risk management, as we continue to search for viable inherently safety alternatives.
Inherently safer design: The growth of an idea
Authors: Kletz Trevor A.
Published: June 2004

Inherently safer design, that is, avoiding hazards rather than controlling them, has advocated since the explosion at Flixborough in 1974. Progress has been real but nevertheless the concept has not been adopted nearly as rapidly as quantitative risk assessment, introduced into the chemical industry only a few years earlier. The present position is reviewed and the constraints that have to be overcome are outlined.

A man takes a mustard seed and sows it in his field. It is the smallest of all seeds, but when it grows up, it is the biggest of all plants. It becomes a tree…—Matthew 13:31–32

It takes longer to familiarize oneself with a region of the mind than with a country…—Graham Greene (Introduction to Brighton Rock)
Inherently safer latex plants
Authors: Scheffler Norman E.
Published: June 2004

Major improvements have occurred in the technology for making latex. Latex plants represent good examples of the application of inherently safer plant features. Early plants had Fire & Explosion Indexes (F&EIs) in a range of 159‐171 (Severe) whereas recent plants are in a range of 97–127 (Intermediate). A key design feature is adequate spacing. Minimum inventories of hazardous materials are maintained. Containment of hazardous materials minimizes exposure to facilities and people and provides adequate volume.

Process structures are open to avoid accumulation of flammable gases. Containment in vessels uses high design pressures. Safe emergency relief venting is provided. The ability to make discrete batches is maintained, but some semi‐continuous feeding is used. Appropriate redundancy of instrument and control systems is used with sophisticated process control systems. Emergency block valves and fire tested valves are used. Inherently unsafe equipment is avoided. Good operating practices are employed with documentation of operation procedures, testing, maintenance and training. Fire protection systems and emergency planning are provided.

The final result in applying inherently safer design practices is major improvement in safety and minimization of the risk potential for losses that could affect people, plant equipment, business loss and the environment.
The effects of downsizing on safety in the CPI/HPI
Authors: Perron Mlchael J. , Friedlander Randal H.
Published: June 2004

A number of incidents including observations that underline the dangers of “starving” a safety program are discussed. While accurate data on the impact of substantial staff reductions remains scarce, many people in industry fear that excessive cutbacks could create conditions leading to a catastrophic accident. Guidelines are provided to assist management in evaluating manpower needs for successful management systems for Process Safety Management (PSM).
Hazopexpert: An expert system for automating HAZOP analysis
Authors: Vaidhyanathan Ramesh , Venkatasubramanian Venkat , Dyke Frederick T.
Published: June 2004

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 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 case study are presented.
A team‐based approach to mechanical integrity implementation
Authors: Herrington Edwin F.
Published: June 2004

The U.S. Occupational Safety and Health Administration (OSHA) promulgated the Process Safety Management of Highly Hazardous Chemicals standard (29CFR 1910.119) in 1992. One key provision of the regulation calls for a Mechanical Integrity (MI) program to ensure that process equipment containing and controlling highly hazardous chemicals is maintained to high standards, standards which minimize the chances of accidental release and subsequent injuries or incidents. This article addresses the approach taken by Tennessee Eastman Division in the implementation of the OSHA MI requirements.
Testing the suitability of FIBCs for use in flammable atmospheres
Authors: Ebadat Vahid , Mulligan James C.
Published: June 2004

Flexible intermediate bulk containers are used in several industries, including the chemical, pharmaceutical, and food processing industries, for convenient handling of bulk solids and powders. While the electrostatic hazard posed by FIBCs is well known, little full‐scale experimental work has been performed to quantify this hazard.

In this paper, experimental work conducted to evaluate the suitability of a new type of FIBC for use in common industrial flammable atmospheres is described. As a part of this work, two other FIBC types were evaluated for comparative purposes. Testing included determination of electrostatic discharge incendivity and measurement of charge transfer, surface potential, and charge density.

The primary outcome of this work has been to establish the viability of a new type of FIBC for use in flammable atmospheres without the need for electrical grounding. However, consequent outcomes include a move towards a quantification of the electrostatic hazard posed by FIBC use and a better understanding of the mechanism characteristic of discharges from charged FIBC surfaces.
Carbon‐initiated effluent tank overpressure incident
Authors: Sherman R. E. , Crawford K. C. , Cusick T. M. , Csengery L. V.
Published: June 2004

This report provides, for information purposes, a description of an unusual event and the corrective actions undertaken by the Shell facility involved. Shell and the authors hope that this information will help personnel associated with other facilities understand a non‐obvious failure mechanism and take action to prevent their experienceing similar incidents.

While drawn from actual experience, the information provided should be considered illustrative. Each company should review their own facilities, materials or processes to determine the appropriate equipment and procedures for their own specific circumstances.
Procedure for determining the distribution ranking index
Authors: Latino Michael A.
Published: June 2004

The Distribution Ranking Index (DRI) has been developed as a simple but effective means to indicate the inherent, acute hazards of a material that might be released in a transportation accident. Utilizing existing Dow resources and procedures, it is one of the methods used for prioritization of chemicals in Dow's distribution related process risk management effort.

Seven individual hazard indexes are considered for a material. The values range from 1 to 4 with 4 representing the most severe hazard. The highest value from any hazard index determines the overall DRI.
Management of chemical plants using chemical compatibility information
Authors: Leggett David J.
Published: June 2004

OSHA's Process Safety Management Standard, 29 CFR 1910.119 (September, 1992) requires that process hazard evaluations be performed on covered processes. The regulations contain 14 areas for consideration, six of which are related to the need to provide comprehensive information of all process materials, including the consequences of inadvertent mixing of process materials. This information can be made available to those involved in the manufacturing process through the development of an Interaction Matrix. A brief overview of the subject is given in a publication by the Center for Chemical Process Safety (CCPS) [1].

In 1996 AIChE announced the availability of the computer package CHEMPAT that provides a straight‐forward method of generating and documenting the interaction matrix, or Compatibility Chart, and accompanying database. CHEMPAT was developed, and used internally, by the Dow Chemical Company since 1987. It was donated by Dow to AIChE in 1995 for use by the chemical process industries.

This paper outlines the approach used to develop chemical compatibility information and briefly describes the use of CHEMPAT in that process.
Severe pressure surges in a simple pump‐pipeline‐valve system (and what to do about it)
Authors: Anderson A. , Simpson A. R. , McPheat J. G.
Published: June 2004

A Simple case study of a relatively high‐friction pipeline with pump‐assisted gravity flow (e.g., for high viscosity fluids such as hydrocarbon products) illustrates three features which lead to unexpectedly high transient pressure surges for which conventional alleviation practices (such as extended value‐closure times or surge‐relief devices at the pump discharge) are ineffective:

the use of a value to control flow in a long or high‐friction pipeline;

a system with a value closure a significant distance downstream of a pump; and

a system where surge protection is located a significant distance away from a control value.
Improved safety through distributed manufacturing of hazardous chemicals
Authors: Koch T. A. , Krause K. R. , Mehdizadeh M.
Published: June 2004

Large scale centralized manufacture of chemicals coupled with distribution to remote customers has obvious economic advantages derived from economy of scale. In some cases, however, concern for safety and environment can drive a search for competitive small scale processes for production of toxic chemicals at the end‐use site, thereby eliminating the potential hazards associated with transportation. We will present a case study in which novel technology is being explored to develop a safe, economically attractive process with minimal waste for the synthesis of hydrogen cyanide.
The use of slam shut valves on LCA plants
Authors: McConnell R. A.
Published: June 2004

One of the many novel features on ICI's leading Concept Ammonia Plants is the use of Slam Shut Valves instead of safety relief valves for certain important relief duties. The design intention was to reduce the environmental impact of gas releases to the vent and flare systems, to allow a smaller vent and flare system to be installed, and to contain gas within the plant systems to allow rapid re‐start following a plant upset giving considerable savings in flaring and plant re‐start time. As the design proceeded throughout 1984–86, various implications of the design were revealed, and these are discussed in this paper. Nearly 15 years of operating and maintenance experience on the 2 plants at ICI's Severnside factory have justified the decision to use Slam Shut Valves.
Out‐of‐the‐loop performance problems and the use of intermediate levels of automation for improved control system functioning and safety
Authors: Kaber David B. , Endsley Mica R.
Published: June 2004

Human supervisory control and monitoring of automated systems, as well as, passive system(s) information processing can all be classified as forms of out‐of‐the‐loop (OOTL) performance. Whether the operator's task is to decide if process control intervention is necessary, detect a critical system event, or accept or reject the actions of a computer controller, he or she is removed from direct, real‐time control of the system. OOTL performance is a critical issue in overall automated systems functioning because it is associated with numerous negative consequences including: (a) operator failure to observe system parameter changes and intervene when necessary (vigilance decrements); (b) human over‐trust in computer controllers (complacency); (c) operator loss of system or situation awareness; and (d) operator direct/manual control skill decay. These consequences have been found to impact human performance under both normal operating conditions and system failure modes, with a greater effect on the latter [15] leading to serious problems in operator ability to perform their assigned tasks when working with automated systems.

Level of automation (LOA) has been put forth as an approach to ameliorating OOTL performance problems. It is intended to determine the optimal assignment of control between a human operator and computer in order to keep both involved in system operations. LOA considers the capabilities and capacities of both the human and computer controller in determining their optimal coupling. It constitutes a systems approach to resolving OOTL performance problems by minimizing the negative consequences associated with the removal of the operator from active system control, and allows for the strengths of both human decision making and computer processing to be realized. When compared to a technological approach that assesses only the capabilities of the computer in allocating as much responsibility to the machine as possible, and assigning the remaining tasks to the human operator, the advantages can be considerable.

A LOA taxonomy will be presented along with research examining its utility in a dynamic control task. Using LOA to identify optimal combinations of human and computer control was found to produce improvements in system performance under intermediate levels. These levels involve joint human and computer control of various system functions, such as monitoring, planning, and option selection and implementation. Results indicated decreases in the number of system processes/tasks overlooked by operators. These improvements may translate into cost reductions due to improved operational safety and are anticipated to be applicable to process control operations.
An overview of SuperChems for DIERS: A program for emergency relief system and effluent handling designs
Authors: Melhem G. A. , Fisher H. G.
Published: June 2004

The Design Institute for Emergency Relief Systems (DIERS) Users Group awarded Arthur D. Little, Inc., a contract to provide the next generation computer program for emergency relief system and effluent handling designs.

The new computer program, SuperChems for DIERS, is a dynamic simulator, capable of performing emergency relief system and effluent handling designs for complex geometries and multiphase reaction systems. In addition, SuperChems for DIERS is an equation‐of‐state based program which provides several benefits over existing non‐equation‐of‐state based methods for systems involving supercritical reactions like polymerizationsof butadiene and acrylonitrile, solution effects such as HCl/Water, and a priori determination of phase splitting.

This new computer program allows the user to dynamically simulate several common configurations for vent containment design. For example, the user is able to simulate a vessel discharging a two‐phase mixture into a quench/vent where the catch/vent tank will vent to a stack or a scrubber. Unit operations available include separators (horizontal and vertical), cyclones, etc. The impact of back pressure and continuing reaction in the vent containment system is accounted for in the dynamic simulations.
Decomposition of thermally unstable chemicals in solvents
Authors: Chervin Sima , Evon Skip E. , Bodman Glenn T.
Published: June 2004

Knowledge of the decomposition reactions of chemicals when tested neat versus in mixtures with various solvents is essential for process safety studies. The decomposition of several mercaptotetrazole derivatives was studied by differential scanning calorimetry, both neat and in seven different solvents. Most mixtures exhibited destabilization of the chemical in the solvent compared with the neat material, resulting in a lower decomposition onset temperature in the mixture. It was demonstrated that the decomposition mechanism and kinetics changed significantly when these chemicals were mixed with solvents. The highly variable effects on thermal stability from mixing thermally unstable chemicals with solvents demonstrates the value of thermal stability testing of reaction mixtures as integral part of process hazard identification.
Toxic hazard reduction with passive mitigation systems
Authors: Myers Philip M. , Morgan Richard S. , Flamberg Stephanie A.
Published: June 2004

A major component of the United States Environmental Protection Agency's 112(r) Risk Management Program Rule is the evaluation and control of potential public exposures to toxic chemicals. The rule requires identification and evaluation of a worst case accidental toxic release scenario, but provides for the inclusion of passive mitigation systems in modeling the dispersion hazard zones that are to be communicated to the public. These passive mitigation systems can be taken into account in the consequence modeling if they will withstand the initiating event that causes the accidental release and function as intended.

This paper discusses several passive mitigation systems that can be designed as an integral part of storage or processing of highly toxic chemicals. These include, but are not limited to, optimizing storage conditions, design of secondary containment, toxic vapor generation control, and enclosure design. The effectiveness of various passive mitigation systems is evaluated using consequence modeling for case studies involving highly toxic chemicals such as phosgene, chlorine, and ethylene oxide.
The influence of the geometry of the hot surfaces on the autoignition of vapor/air mixture: Some experimental and theoretical results
Authors: Duarte Dayse , Rohatgi Janardan , Judice Raul
Published: June 2004

Two major accidents in the 80's: the summit Tunnel Fire, England and Piper Alpha disaster, an offshore platform in the North Sea; and very recently, possible explosion of the Boeing, TWA flight 800 at New York, makes it imperative that further research into the mechonisms of the ignition of flammable vapor/air mixture in contact with hot surfaces needs to be done. There have been a number of studies of ignition by hot surfaces, but in all these studies the ignition sources were wire, sphere or strip, i.e., most of them were flat surfaces. But to the authors' knowledge, other variables which affect the ignition mechanism such as irregular geometrical shapes have not been studied. The purpose of this paper is to examine how the degree of confinement (or, configuration), size and orientation, of the heated surface affects the ignition temperature of the flammable vapors. The results were obtained by experimentnal and by computational fluid dynamics.
Short communication: Estimating the minimum ignition energy of hybrid mixtures
Authors: Britton Laurence G.
Published: June 2004

A simple analytical method is presented for estimating the hybrid minimum ignition energy (HMIE) of dust–gas mixtures, based on the assumed generality of Bartknecht's well‐known test data for mixtures of propane with a series of dusts in air. Since the HMIE equation requires input data which might be unavailable, the use of conservative default methods is discussed.
Investigation of an explosion and flash fire in a fixed bed reactor
Authors: Ogle Russell A. , Schumacher John L.
Published: June 2004

An explosion and flash fire in a fixed bed reactor occurred at a municipal wastewater treatment plant (WWTP). Two employees were injured in the accident. The accident occurred in an ozone treatment building where ozone was used to treat odors from the offgas of the sludge concentration units. Excess ozone manually was routed to the fixed bed reactor (ozone destruct unit) where the ozone is catalytically transformed into oxygen before being discharged to the atmosphere.

An investigation of the accident was conducted to determine the root cause of the explosion and flash fire and identify corrective actions which the WWTP management could undertake to prevent a recurrence. This investigation included site inspections, interview with the injured employees, sampling and analysis of various materials, an explosion dynamics analysis, and a root cause analysis.

It was concluded that cooling oil from one of the ozone generation units entered the main ozone gas line due to a crack in one of the reactor's dielectric tubes. The cooling oil was vented into the ozone destruct unit when an employee opened a ball valve on the main ozone gas line. The cooling oil, essentially a saturated hydrocarbon mixture, reacted exothermically when it contacted the manganese dioxide catalyst. The exothermic reaction resulted in an explosion which propelled the access panel outwards and dispersed the catalyst pellets. A flash fire followed the explosion. The flash fire burned two employees and caused thermal damage to a nearby control panel.

Although this accident was the first of its kind at this facility, this was not the first time that the ozone generator had experienced a failure of a dielectric tube. Thus, there was a significant probability that a dielectric tube failure could leak cooling oil into the main ozone gas line. This failure event could, in turn, result in another explosion and flash fire. The WWTP staff neither designed nor fabricated the ozone generator‐destructor system. Therefore, it did not seem appropriate for the WWTP staff to modify the ozone system. Instead, it was recommended that the ozone destruct unit be taken out of service. The WWTP management acted on this recommendation.
Investigation of a steam explosion in a petroleum product storage tank
Authors: Ogle Russell A. , Schumacher John L.
Published: June 2004

An explosion occurred in a petroleum product storage tank at a refinery. The liquid petroleum product was a heavy oil used as an asphalt extender. There were no injuries, but the cleanup was costly. The storage tank was one of several which received the product stream from a dehydration unit. The accident occurred shortly after the refinery was brought back on‐line following a shutdown for schduled maintenance.

This was the first incident of this kind to occur at this facility. Analysis of the process data and eyewitness observations indicated that the dehydration tower, which was supposed to be maintained at a minimum of 100°C during the shutdown, was allowed to drift below 100°C for an unknown period of time. This deviation enabled liquid water to enter the storage tank. Three operational factors contributed to the accident. Corrective actions were recommended to prevent a recurrence of a similar incident.
Suppression of class a fires with HFC‐227ea
Authors: Robin Mark L.
Published: June 2004

HFC‐227ea (CF3CHFCF3;1, 1, 1, 2, 3, 3, 3‐heptafluoropropane) is an effective replacement for Halon 1301 in fire suppression systems, providing rapid extinguishment of flames through a combination of physical and chemical mechanisms. The vast majority of applications for HFC‐227ea involve the protection of Class A hazards, which are characterized by low fuel loadings and low energy output, with fire sizes often in the range of 5–10 kW. Mid‐ and large‐scale testing has demonstrated that HFC‐227ea, at its minimum design concentration of 7.0% v/v, is effective at extinguishing fires typical of those expected to occur in electronic data processing (EDP) facilities, telecommunication facilities and anechoic chambers. The levels of HF produced following extinguishment of typical Class a fires with HFC–227ea were well below the estimated mammalian LC50 and the human Dangerous Toxic Load (DTL), and do not appear to present a threat to electronic equipment.
A thematic approach to system safety
Authors: Ekman Mark E. , Werner Paul W. , Covan John M. , D'Antonio Perry E.
Published: June 2004

Sandia National Laboratories (Sandia) has refined a process for developing inherently safer system designs based on methods used by Sandia to design detonation safety into nuclear weapons. The process was created when Sandia realized that standard engineering practices did not provide the level of safety assurance necessary for nuclear weapon operations, with their potential for catastrophic accidents. A systematic approach, which relies on mutually supportive design principles integrated through fundamental physical principles, was developed to ensure a predictably safe system response under a variety of operational and accident‐based stesses. Robust, safe system designs result from this thematic approach to safety, minimizing the number of safety critical features. This safety assurance process has two profound benefits: the process avoids the need to understand or limit the ultimate intensity of off‐normal environments and it avoids the requirement to analyze and test a large array of accident environment scenarios (e.g., directional threats, sequencing of environments, time races, etc) to demonstrate conformance to all safety requirements.
Analysis of diers venting tests: Validation of a tool for sizing emergency relief systems for runaway chemical reactions
Authors: Klein H. H.
Published: June 2004

A one‐dimensional computer model of multiphase, chemically reacting flow has been used to analyze a number of DIERS Phase III venting tests.
Safety evaluation of chemicals: The regulatory framework
Authors: West A. S.
Published: June 2004

Major industrial countries have relatively recent new laws regulating the manufacture, distribution and use of industrial chemical products. The resultant regulations in the United States (under TSCA), European countries, Japan, and Australia, with emphasis on the testing requirements, are summarized.
Design and use of containers for cryogenic liquids
Authors: Shattes Walter
Published: June 2004

Cryogenic liquid containers of a nominal 165 liter (43.6 gal.) capacity from three domestic manufacturers were tested and compared.
Practical and economic benefits of falling film evaporation
Authors: Murray A. J.
Published: June 2004

Particular emphasis is given to the flexibility, potential steam savings, and ease of cleaning falling film units.
Explosion of a benfield solution storage tank
Authors: McDaniel J. T.
Published: June 2004

After a plant shutdown, a 100,000 gallon Benfield solution storage tank exploded causing extensive damage to the plant.
The behavior of denser than air ammonia in the presence of obstacles—wind tunnel experiments
Authors: Guldemond C. P.
Published: June 2004

In case of the release of pressurized liquid ammonia, a heavier than air gas cloud can be formed. It was found that the dispersion is very strongly influenced by the presence of obstacles.
For energy savings—look at your boiler blowdown
Authors: Kelly Thomas J.
Published: June 2004

The cost of boiler blowdown is frequently overlooked in efforts to diminish costs of production.
Modification chains
Authors: Kletz Trevor A.
Published: June 2004

Typical instances and concepts on prevention.
Transportation of Hazardous substances: The UK scene
Authors: Kletz Trevor A.
Published: June 2004

The good record seems to be due to high standards rather than good luck, but there are some loopholes in the UK procedures.
Loss prevention through machinery vibration surveillance and analysis
Authors: LeBlanc Ronald W.
Published: June 2004

The benefits and the necessary elements of a successful machinery vibration surveillance and analysis program in a petrochemical complex.
Boiler and machinery protection through control of piping reactions
Authors: Hansen D. E.
Published: June 2004

The effect of the three main classes of mechanical piping reactions (sustained, displacement, and dynamic), and the significant problems of accurate calculation, proper construction, operation, and maintenance.
Lessons in hazardous material transportation based on case histories
Authors: Gallagher Gerard A. , McCone Scott W.
Published: June 2004

Reducing human error as a cause of accidents.
Pressure venting of dust explosions in large vessels
Authors: Bartknecht W.
Published: June 2004

The validity of the dust explosion venting nomograph D in NFPA 68 was examined in tests with vessels having volumes from 2.4 to 250 cubic meters and with dusts of classes St 1 and St 2.
Inerting for safety
Authors: Wrenn Christopher
Published: June 2004

Instrumentation replaces estimation and assures safety in closed vessel fire prevention.
Determining heater retrofits through risk assessment
Authors: Arendt J. S.
Published: June 2004

Large damage and business losses can result from heater fires and explosions and these occur fairly often. An economic risk analysis using fault tree/event techniques can efficiently determine heater protection system retrofit priorities— and show where money does not need to be spent.
Emergency preparedness and response
Authors: Kalnins Ruta V.
Published: June 2004

In order to select routes that minimize risk, government officials need information about the material being transported and its sources and destinations, the risks involved, shipping patterns, and emergency response capabilities.
An assessment of burning waste fuel in circulating fluidized bed boilers
Authors: Gendreau R. J. , Raymond D. L.
Published: June 2004

An objective evaluation of the performance and capabilities of operating CFB units. This evaluation is based on observations and discussions with plant management and operations personnel, and representatives from the companies that supplied the CFB units to the six sites visited.
Hazard analysis and safety considerations in refrigerated ammonia storage tanks
Authors: Al‐Abdulally Falah , Al‐Shuwaib Saad , Gupta B. L.
Published: June 2004

A systematic approach to find out the probability of Ammonia tank failure was adopted and a consequence analysis in case of accidental Ammonia release from refrigerated ammonia storage tanks was made. The study revealed that construction of a concrete bund wall around the tanks is not justified. Instead, it would be adequate to upgrade the safety in the common dyke around the tanks by adopting additional conventional methods.
Commissioning of CIL's ammonia II plant
Authors: Taylor W. K. , Pinto A.
Published: June 2004

Special features of this process design contributed to fast start‐up, including the role of the computer simulator for training purposes and the concept of commissioning by process test system.
Looking back and wishing
Authors: Phillips Ailene G.
Published: June 2004

Most chemical engineers discover soon after they enter the workplace that their preparation is lacking in one or more areas. They find themselves looking back and wishing that their education had been more complete. This article provides feedback to help students and faculty minimize the gaps in the chemical engineer's education.
Damage to and replacement of an ammonia storage tank foundation
Authors: Martinez O. A. , Madhavan S. , Kellett D. J. , Hamrouni H.
Published: June 2004

An ammonia tank foundation suffered structural damage and was replaced. While foundation damage, soil freezing and tank movement were apparent, the failure‐triggering event remains inconclusive though theorized to have been of seismic origin.
Unusual operating histories of gas processing and olefins plant columns
Authors: Kister Henry Z. , Hower Tom C.
Published: June 2004

A description of several cases of columns that did not perform satisfactorily. The causes range from very complex; such as unique features of multicomponent distillation, to very simple, such as a mislocated control valve.
Fire at semi‐lean pump by reverse motion
Authors: Fromm Dieter , Rall Wolfgang
Published: June 2004

The fire developed in an MDEA CO2 removal system because of switching from one semi‐lean pump to another.
Gas plant problems and the insurance industry
Authors: Spiegelman Arthur
Published: June 2004

The methodology used by insurance companies in evaluating risk covers both property and casualty insurance. Topics of discussion include: Total Loss Control (How to achieve it, and its relationship to Governmental Regulations), and the importance of equipment design and maintenance in preventing catastrophic losses. This discussion is based on studies of hundreds of large losses over the past twenty‐five years.
Effect of fireproofing design on thermal performance of horizontal members with top flange exposed
Authors: Castle G. K. , Castle G. G.
Published: June 2004

It is common practice in the industrial sector to leave the top flanges of fireproofed beams bare. The main reason for this is to permit placement of pipes and grating on the beams without interference from fireproofing materials. To the authors' knowledge, tests of such configurations have not been conducted to determine actual resistance to fire. However, structures fireproofed in this manner have survived actual fire exposures. The purpose of this paper is to examine theoretically the effect of various fireproofing designs on the performance of these members and point out which practices can lead to premature failure of fireproofed beams where top surfaces are left bare. An approximate but practical analytical model is used to evaluate bare steel, encased (concrete/contour) and box (hollow) constructions. The need for reinforcements is demonstrated by examining the effect of bond loss in decomposable systems. Thermal performance is related to load carrying capability of the member.