bluuebunny/crossref_metadata_2025 huggingface dataset:
Emergency relief adequacy for acrylic polymerization processes
Authors: Balchan A. S. , Paquet D. A. , Klein J. A.
Published: April 2004

Acrylic polymerizations are highly exothermic processes which must be carefully evaluated to ensure safe manufacture. In particular, failure to remove the heat of reaction can lead to runaway polymerizations, characterized by sudden and rapid increases in reaction rate, temperature, and pressure. If not adequately vented, runaway polymerizations can quickly lead to reactor overpressure, possible vessel rupture, and release of flammable or toxic materials.

Because of complex polymerization kinetics and the large number of industrial acrylic polymer processes, practical application of DIERS two‐phase flow methodology for sizing reactor emergency vents required development of a computer model to simulate specific commercial polymerizations. This model is currently used to determine the emergency vent adequacy of reactors prior to manufacture of new resins in existing equipment, as well as to assist in design of new reactor systems. The purpose of this paper is to discuss practical application of DIERS technology for ensuring safe acrylic resin manufacture through use of computer simulation.
Experiments on the propagation of vented dust explosions to connected equipment
Authors: Valiulis John V. , Tamanini Francesco , Zalosh Robert G.
Published: April 2004

Some air streams within closed, pneumatic dust handling systems are essentially free of dust. Such is the case within the clean air duct downstream of dust collectors. In the event of a dust explosion in the equipment connected to the dust‐free air ducts, some of the explosion products (dust and flame) will be ejected into the duct. However, because the interior of the duct has no dust to act as fuel prior to the explosion, the distance of explosion propagation (as defined by a flame front) will necessarily be limited.

An experimental project is being conducted to study the distance of flame front propagation into a clean duct for dust explosions occurring in a primary volume which is provided with explosion venting. A near‐cubical primary explosion chamber measuring 23 ft3 (0.64 m3) is used. The effect of the most significant process variables on propagation distance is being studied. The process parameters whose effects are being studied are: dust reactivity, vented explosion pressure, explosion vent relief pressure, in‐duct air velocity, and dust concentration. Tests conducted to date in an 8 in. (200 mm) diameter, 89 ft (27 m) long duct have resulted in flame propagation distances in the range of 22‐89ft (7‐27 m).
Pressure refief valve piping failures and fire: Ammonia synthesis loop
Authors: Sutherland Lester E. , Holman Michael , Hansen Don
Published: April 2004

This paper describes a piping failure and fire resulting from inadequate support of an ammonia synthesis loop pressure relief valve, the non‐destructive testing and evaluation of fire‐impinged equipment, and the pipe failure mode. It also addresses support criteria for relief valves and other piping systems illustrating the importance of evaluating both static and dynamic loads.
Safety instrumented system design: Lessons learned
Authors: Gruhn Paul
Published: April 2004

Engineering is a bold discipline. Engineers are constantly reaching for new heights, searching for new materials and greater efficiency. Unfortunately, part of that process means we occasionally exceed known boundaries. It is regrettable, but it would appear that human nature requires that we learn the hard way. While this is an obviously painful process, we can learn more from our few mistakes than from our many successes. Our many successes may contain flaws that are never revealed under normal conditions, and we may go on repeating them over and over. It is only when expected conditions are exceeded, and failure is the result, that we learn where we went wrong [12].

Valuable lessons can be learned from failures, and there are plenty of examples from industry in general as well as specific details regarding failures of safety control system. For example, the UKHSE (Health and safety Executive) issued a publication in 1995 [2] that reviewed 34 accidents that were directly caused by control and safety system failures. The HSE published the reviews so that engineers could learn from and hopefully not repeat the mistakes discussed in the book. The IEC and ISA standards on this subject, as well as the CCPS Guidelines, are based upon a “Safety Life Cycle” which is a set of steps one should go through in the overall design process in an effort to ensure that nothing falls through the cracks.

As responsible engineers, we should not have to learn the hard way. Plants have become too large and the risks have become too great for us to learn by mere trial and error. Because we cannot do a recall on all refineries we need to get things right the first time. We can, however, learn from the mistakes of otherts without re‐inventing the wheel or operating in isolation.
Hazard identification analysis of a hydrogen plant
Authors: Brown A. E. P. , Buchier P. M.
Published: April 2004

Process risk analysis is used in industrial activities to diminish accident potential by the application of prevention or protection techniques to improve process safety. For this purpose, Preliminary Hazard Analysis and HAZOP have been applied to a hydrogen gaseous effluent treatment and purification plant. This plant recovers contaminated gaseous effluent hydrogen from a metallurgical iron powder reduction furnace. Purified hydrogen is recycled to the process. The process safety studies included hazard identification and consequences to materials, equipment and people. The study proposed specific process safety measures and future additional process safety studies.
Explosion hazard analysis for an enclosure partially filled with a flammable gas
Authors: Ogle Russell A.
Published: April 2004

The constant volume explosion of a flammable gas is one of the more common accidental explosions. The explosion pressure at the stoichiometric condition is approximately 50 times greater than the failure pressure of most industrial structures. Observations from accident scenes suggest that some explosions are caused by a quantity of fuel significantly less than the stoichiometric amount required to fill an enclosure.

This paper presents a method for analyzing the explosion hazard in an enclosure which is only partially filled with a flammable gas. The method, called the adiabatic mixing model, is based on thermodynamics and can be used to calculate the minimum fuel quantity which will yield a specified explosion pressure. Results are presented for a set of representative fuels and are compared with alternative explosion models.

The results demonstrate that catastrophic structural damage can be achieved with a volume of flammable gas which is less than one percent of the enclosure volume. The method can be a useful tool for both hazard analysis and accident investigations.
Avoiding exposure to mercury during inspection and maintenance operations in oil and gas processing
Authors: Mark Wilhelm S.
Published: April 2004

Exposure to mercury and its compounds poses a potential health risk to workers involved with inspection and maintenance activities in facilities that process hydrocarbons containing significant amounts. The risks of exposure to mercury are often underestimated for a variety of reasons. Foremost is the fact that the exact amount of mercury present in processed petroleum often is not known with certainty. Secondly, the specific quantities of mercury compounds that may be present in hydrocarbon liquids seldom are known at all. Thirdly, monitoring for mercury vapor in work environments is not a routine procedure for many processing facilities. Lastly, mercury toxicity is gradual and produces no immediately apparent impairment that can easily be associated with occupational exposure. Superimposed on the risk issues are several aspects of the chemistry of mercury that make it illusive both to quantitative analysis and to detection in work environments. Tbe combination of the cited factors increases the likelihood that workers who are inadvertently exposed to occupational environments that contain mercury will be adversely affected.
A new set of blast curves from vapor cloud explosion
Authors: Tang M. J. , Baker Q. A.
Published: April 2004

Past accidents have demonstrated that vapor cloud explosions (VCEs) are the most severe threat to refining and petrochemical industries. In order to estimate the air blast parameters at any given distance from a possible explosion source, a variety of prediction methods have been developed. A brief description of these prediction methods is first presented. Then, the focus of this paper is on an engineering method based on blast curves, which is the most frequently used prediction method.

Knowledge of blast effects from vapor cloud explosions has greatly improved due to the efforts of investigators in many countries during the last three decades; however, blast curves have not been reexamined. One of the aims of this paper is to present a new set of blast curves which have been validated with available experimental results and analytical solutions. Another aim is to present a comprehensive set of blast curves including blast parameters for both positive and negative phases.

The new blast curves, which are a modification of the Baker‐Strehlow curves, improve the prediction for detonations and supersonic deflagrations as well as for subsonic flames. By changing the slope of the blast pressure versus distance curve, the overly consserative blast pressure predictions by the previous Baker‐Strehlow curves at large standoff distances for detonations and supersonic deflagrations are reduced. By clarifying the labeling of the flame. Mach number for each blast curve, the overly conservative pressure and impulse preditions for subsonic flames are also avoided.

The new blast curves have been validated against VCE experiments including detonations, fast deflagrations, and slow deflagrations. Particular attention was given to large scale deflagration experiments, which became available only recently. Good agreement is shown between the new blast curves and the experimental blast data for vapor cloud detonations and subsonic deflagrations. For supersonic deflagrations, the blast curve predictions are overly conservative in that blast pressure decays more rapidly with distance in experiments than the calculated curves.
Conduct of operations: A control system for your most important safety component
Authors: Haas Paul , Hager Guy
Published: April 2004

Instrumentation and control engineers go to great lengths to ensure availability and operability of control and information display systems for process system operation, especially for safety systems. It is critically important to maintain equipment performance within the bounds of safe operation. The most crucial safety components in your facility are the human beings controlling, maintaining, monitoring, and managing the process and equipment. Have you ever given much thought to the control systems operated by humans in your facility?
Human factors: Preventing catastrophic human error in 24‐hour operations
Authors: Westfall‐Lake Peggy
Published: April 2004

Human factors can play havoc with quality of task performance in safety‐sensitive operations, especially those that run 24‐hours, 7‐days a week. Research across multiple industries indicates common threads of observable and preventable behaviors that can lead to catastrophic events. Fatigue, monotony, overwork and a multitude of other cultural factors and organizational policies can trigger these mental and physical human errors. With recent extensive capital investments in hardware and software to automate continuous operations, the human operating the controls may become complacent and fail to perform as anticipated.

Since the chemical plant, maritime, aviation and space disasters of the mid‐1980's, there has been an increased focus on operational procedures. Operational fatigue has been on the National Transportation Safety Board's list of Most Wanted Transportation Safety Improvements since the list's inception in 1990 [1]. Today, it may be time to re‐visit human factors and focus on the human in operational settings in all modes of 24hour operations. The key is to first understand two strategies to prevent shiftwork‐related human error. The first strategy is at the organizational level where we can align human resource and safety policies, address aging needs through better shift scheduling, develop work/rest guidelines and design wellness objectives to enhance 24‐hour safety performance. The second strategy is at the operational level where employees recognize personal set‐ups for human error and take the appropriate measures. These skills are learned through “fatigue counter‐measure training.” Both strategies will be discussed throughout this article.
Safety hazards associated with air‐emission controls
Authors: Ozog Henry , Erny William J.
Published: April 2004

Air‐emission controls have been installed in refineries since 1990 to comply with environmental regulations such as Benzene NESHAP and the Clean Air Act. Companies have experienced incidents associated with these air‐emission controls, but the extent of the problem could not be quantified. In this paper, we present the results of a survey of the member companies of API's Safety and Fire Protection Subcommittee (SFPS) to determine the number and type of air‐emission controls which have been installed, and the types of incidents which they have experienced. The survey was completed in February 1998.

We obtained responses from eight SFPS member companies, including 16 refineries, 1 gas plant, 2 chemical plants and 1 marketing terminal.

A total of 2,110 air‐emission controls have been installed at these facilities and 70 incidents associated with these controls have been reported. Of the 70 incidents a number involved recurring events associated with the same air‐emission control, so when these events are deleted, only 32 unique incidents remain. 15 of these unique incidents resulted in injury or significant property damage.

Carbon canisters are the most common air‐emission control installed (769) and there have been 10 unique incidents associated with carbon canisters/beds, of which 5 resulted in injury or significant property damage. Given the prevalence of carbon canister installations and the associated incidents, the SFPS Emission Control Safety Work groups decided to focus mitigation/prevention efforts on carbon canisters.

If carbon beds are overloaded with volatile organic compounds (VOCs) or highly reactive materials, they can overheat and catch fire, which can then provide an ignition source for VOC vapors.

The industry however does not appear to be fully aware of the hazards associated with the use of carbon canisters and the limitations on their use. In many installations safeguards to prevent fires or explosions may be necessary. Typical safeguards include:

pre‐wet new canisters to prevent excessive heat buildup.

avoid applications where adsorption of highly reactive chemicals such as ketones, aldehydes and organic acids may occur.

avoid VOC concentrations in excess of 10,000 ppmv.

provide flame arrestors to pre vent flashback to VOC sources.

provide vacuum breakers directly on process equipment to prevent air ingress into hot carbon canisters.

We believe that the widespread use of carbon canisters presents the need to develop appropriate guidelines to prevent further incidents.

The objective of this project was to research and evaluate the safety hazards associated with certain air‐emission control systems used in the petroleum industry and to develop recommendations to address these hazards.
Studies on the probabilities and likely impacts of chains of accident (domino effect) in a fertilizer industry
Authors: Khan Falsal I. , Abbasi S. A.
Published: April 2004

Fertilizer industries are among the chemical process industries where hazardous chemicals are handled and accidents involving heat/mass/momentum transfer can result in explosions, fires, and toxic releases. Based on experience gained from past incidents in the fertilizer industries risk assessment tools and techniques are often employed in order to identify hazards and to forecast potential disasters. These efforts have almost always focused on single events or “stand alone” accidents.

The interaction of an accident with other hazardous units with the potential to cause secondary, tertiary, or higher order accidents is seldom studied. Yet, chain of accidents have been occurring in the past and the probability of a repetition in the future constantly increases because of the proximity of industrial plants and the increasing population pressure in most countries. Consequently we have developed models and computer‐automated tools to study chain of accidents or “domino effects.” In this paper we discuss the concept of domino effect in the context of our methodologies, and present an illustrative case study of a major fertilizer industry situated near the city of Chennai(Madras, India).
A methodology to evaluate industrial vapor and dust explosion hazards
Authors: Dahn C. James , Reyes Bernadette N. , Kusmierz Andrew
Published: April 2004

A methodology was developed to evaluate the potential of vapor, dust and hybrid mixtures (combustible dusts and flammable gas in air) explosions in small to medium size industrial operations. Also, a protocol to conduct analysis and evaluation of explosion potential for industrial operations is presented.

Elements for thorough site inspections are defined based on uncovering potential failures and hazards. The best ways to review applicable standards and codes pertaining to the specific operations and occupancies are also covered.

The engineering hazard analysis (HA) method selection is critical to achieve the most complete evaluation of hazards in the operations. Methods and guidelines for their use will be discussed. Guidelines will also be presented for best selection of tests to evaluate the hazards. Extensive investigation to identify hazardous materials present in the industrial operations will be conducted.

Criteria for successful fire and explosion hazards analysis are also identified.
Fire protection in telecommunication facilities
Authors: Robin Mark L.
Published: April 2004

The telecommunications industry is one of the fastest growing industries on the planet, with some analysts estimating the current annual world market to be approximately $750 billion. Telecommunications companies worldwide have spent billions of dollars to ensure that voice, data and video routes operate reliably, and of primary concern to these providers is the minimization of service disruptions. Fire is one of several possible causes of service interruption in telecommunication facilities. This paper describes the telecommunications network, its associated fire hazards, and the application of clean agent fire suppression agents, specifically HFC‐227ea, in the protection of such facilities.
Deflagration and detonation of ethylene oxide vapor in pipelines
Authors: Thibault Paul , Britton Laurence G. , Zhang Fan
Published: April 2004

Pure ethylene oxide (EO) vapor may propagate decomposition flames through pipe above certain minimum conditions of temperature, pressure and pipe diameter. Flame propagation was studied in both closed and vented 5 cm (2‐inch) pipe and closed 30 cm (12‐inch) pipe. Flame progression in closed pipe was irregular and proceeded in pulsed stages. A possible mechanism involves preferential flame propagation at the pipe roof accompanied by periodic autodecomposition of EO accumulated in hot products behind the flame front, such accumulation probably being augmented by liquid EO condensed on the pipe walls ahead of the expanding flame system. Flames propagated 15 m (50 ft) through horizontal 5 cm pipe at 70°C and initial pressures ≥ 4.3 bar (62 psia). In a series of 30 cm pipe tests employing low‐energy ignition and otherwise increasingly severe conditions, a deflagration‐to‐detonation transition (DDT) occurred, partially destroying the test equipment. A new test facility was set up to confirm the ability of EO to propagate detonations in 30 cm pipe and to further investigate the phenomenon. Two EO detonations at 2.9 bar and one at 3.5 bar were directly initiated via the strong shocks from hydrogen‐oxygen detonations. Based on a spectrum analysis of the pressure histories, the two detonations at 2.9 bar were probably marginal and propagated in a single spin detonation mode. At 3.5 bar, the pressure history suggests that the detonation propagated in a two‐head detonation mode near the end of the 24 m test section.
Dust deflagration extinction
Authors: Chatrathi Kris , Going John
Published: April 2004

Two basic phenomenological models for deflagration propagation in dust clouds are discussed as the basis for interpreting explosion suppression results. The first model is based on oxygen diffusion to fuel dust particles as the controlling step in explosion propagation through a dust cloud. The second model assumes explosion propagation is controlled through fuel particle volatilization followed by combustion in the gas phase.

With this scientific framework as the basis, the inhibition aspects of explosion suppression are discussed to provide guidelines for industrial dust explosion mitigation. As part of the analysis, experimental results are presented for organic, inorganic and hybrid high Kmax dust explosions and dust explosion suppression.

Inorganic dusts fuels included aluminum, and silicon. Organic fuels in the experiments were Pittsburgh coal, cornstarch, polyethylene, anthraquinone, calcium stearate, cadmium stearate, and cornstarch w/propane. Extinguishing agents used in the experiments were sodium bicarbonate, potassium bicarbonate, mono‐ammonium phosphate and calcium carbonate.
Safety aspects during transient and steady‐state operation of a pilot‐scale distillation column
Authors: Stark Douglas E. , Shonnard David R. , Crowl Daniel A.
Published: April 2004

In distillation involving flammable liquids, inert gases are used to prevent the formation of flammable or combustible gas mixtures by precluding oxygen from the equipment vapor space. In this study, a pilot‐scale distillation column for the separation of ethanol and water was used to directly measure pressure changes within the isolated column and within the inerting system during start‐up, steady‐state, and transient operation. Our results show the following:

Distillation column vacuum relief rates due to reboiler shutdown, as predicted by current literature sources, are conservative by a factor of 50 compared to measurements.

During steady‐state operation, the difference in solubility of the inert gas (N2) between the feed and distillate streams accounts for pressure changes in an isolated column. For ethanol and water, the nitrogen is more soluble in the distillate, resulting in a column vacuum. For an open system, this effect could result in air being drawn into the system, resulting in potential formation of combustible vapor mixtures.

A nitrogen balance model is presented to calculate the changes in column pressure during steady‐state column operation. The predictions are conservative by a factor of 2 to 5.

For transient operation, a simple model based on fraction‐al utilization of the condenser over‐predicts pressure changes resulting from reboiler steam duty changes to within about 30% of the measurements.
Use of propylene oxide versus nitrogen as an ethylene oxide diluent
Authors: Britton Laurence G.
Published: April 2004

Decomposition flame propagation limits of ethylene oxide (EO) diluted either with nitrogen or propylene oxide were measured under initial conditions enveloping those commonly used in simple stirred ethoxylation reactors. Tests conducted in a 600 liter vessel at 6.5 bar (95 psia) and 165°C verified that “energetic ignition” decreases the EO propagation limit relative to the predictions of “weak ignition” models. The limit in nitrogen found using “energetic ignition” (1 gm gunpowder squib or EO decomposition flame fired into the test mixture) was about 38 mol% EO while the limit found using hot coil igniters was about 46% EO, similar to the predictions of “weak ignition” models. The rates of pressure rise due to decomposition of near‐limit mixtures were highly sensitive to low levels of turbulence but much less than values previously reported for mixtures containing 90% EO.

Propylene oxide (PO) has been reported to be a more effective EO diluent than nitrogen. However, tests using “energetic ignition” in the large vessel revealed a potentially hazardous feature of PO dilution. Although the EO decomposition limit was raised from 38% in nitrogen to about 48% in PO, the latter started to decompose at greater EO concentrations, becoming a hazardous reactant rather than a diluent. Decomposition of near‐limit EO + PO mixtures generates much greater pressures than can be achieved by decomposing near‐limit EO + nitrogen mixtures. At the test conditions used in this study, decomposition of 55% EO in nitrogen produces a maximum pressure of about 34.5 bar (500 psia) while 55% EO in PO produces about 51.7 bar (750 psia). The PO decomposition phenomenon has not been previously reported. A plausible explanation involves the fate of ethylene formed during PO decomposition. In diluent mode, PO decomposes endothermically producing ethylene, CO, and hydrogen. The large heat losses and short duration of decomposition events in small test vessels allows ethylene to persist as a stable product and PO therefore appears to be an effective diluent. However, in large test vessels, the greater temperature and pressure transients developed during EO decomposition cause ethylene to decompose and the net decomposition reaction of PO becomes exothermic.
Mixture reactivity in explosions of stratified fuel/air layers
Authors: Tamanini Francesco , Chaffee Jeffrey L.
Published: April 2004

The paper addresses one aspect of the definition of the explosion hazard from flammable liquid spills or slow heavy vapor releases in enclosures. In this type of accidents, the explosive mixture is typically confined to a layer near the floor. No methods are currently available for the sizing of explosion vents in these partial‐volume deflagrations. Resolution of the issue was sought through tests carried out in a 63.7 m3 (2250 ft3) chamber with stratified mixtures of propane in air. The layers were formed by slowly injecting propane at the chamber floor through diffusers, at a rate of the order of the estimated rate of vaporization of a typical solvent such as acetone. The layer composition was carefully characterized through gas concentration measurements at twelve locations, using a single continuous analyzer connected to a multiplexed sampling system. Following ignition of the layers, data were obtained on the propagation velocity of the flame and on the pressure developed by the explosion in the room both with and without venting.

The results of the experiments have been correlated using an existing model, modified to account for the cylindrical geometry of the system and for the dual‐mode character of the combustion process (a premixed flame is typically followed by diffusive/ convective burning of the rich portion of the fuel/air layer). While confirming the conservatism of current design recommendations, which are based on the assumption of a full‐volume explosion, the work has brought out the fact that the contributions to pressure development from the different portions of the layer must be properly taken into account.

Work is currently in progress to predict the fuel distribution in the explosive layer as a function of the parameters that define the spill (or fuel release) scenario. This step is being done through modeling of the rate of vaporization of a liquid pool and the subsequent dispersion of the vapors in the surrounding area. The model, when combined with the already‐developed treatment of the explosion problem, will provide an integrated tool for predicting the protection requirements of flammable liquid process/dispensing areas.
A blasting cap test for evaluating self‐reactivity hazards
Authors: Meyers S. , Singh S. K. , Shanley E. S.
Published: April 2004

This paper describes a simple blasting cap test that furnishes information on sensitivity to initiation as well as rudimentary information on propagation. The design of the test provides containment of most condensed‐phase residues and explosion reaction products while minimizing noise pollution. We include comparison between test results and thermochemical hazard predictions determined by calculation of the adiabatic reaction temperature (CART).
Ignition of combustible fluids by heated surfaces
Authors: Michael Bennett J.
Published: April 2004

Industrial machinery fires are commonly caused by flammable operating fluids leaking onto hot machinery surfaces. This paper discusses doctoral research currently underway to identify the dominant fundamental mechanisms controlling the overall ignition process of combustible liquid stream‐fed pools impinging on heated surfaces. Experiments are now underway to characterize these processes, via modeling and the use of dimensional analysis, to be able to predict the minimum surface ignition temperature for a given set of fluid and surface properties, more accurately define safe operating boundaries of equipment to mitigate fire events, and suggest optimal designs to widen the safe operating envelope. As a result of recent analyses, a surface modification technique has been proposed to use a pattern of micro‐cavities, sized to prevent fluid seepage, on the exterior of the heated surface to reduce the heat transfer from surface to liquid (due to reduced direct contact), and inhibit the formation of superheated vapor films. This behavior could increase the temperatures necessary for ignition, permit‐ting a wider range of safe operating conditions.
Investigation of an acid spill caused by the failure of an air‐operated diaphragm pump
Authors: Ogle R. A. , Morrison D. T.
Published: April 2004

A spill of concentrated hydrochloric acid caused considerable damage at an ion exchange resin regeneration plant. The release was caused by two independent failures: the failure of a diaphragm pump and a containment dike. An accident investigation determined the root causes of the accident and evaluated the system safety of the process. The root cause of the diaphragm pump failure was environmental stress cracking of the PTFE diaphragm in 33% HCl service. The root cause of the dike failure was insufficient steel reinforcement.

Based on the accident investigation, additional safeguards were implemented to prevent a recurrence of the accident.
Multilayer protection analysis for photovoltaic manufacturing facilities
Authors: Fthenakis Vasilis M.
Published: April 2004

This paper gives an overview of environmental health and safety (EHS) issues related to photovoltaic (PV) technologies, and strategies for reducing EHS risks. These strategies include layers of prevention and mitigation in six sequential steps. Prevention layers are related to safer technologies, processes, and materials; safer use of materials; preventing accident‐initiating events; preventing or minimizing releases, and preventing human exposures. The mitigation options include secondary confinement, emergency scrubbers, and adsorption units. As the PV industry approaches these issues and mitigation strategies in a vigilant, systematic way, the risk to industry, workers, and the public will be minimized.
Risk analysis of a petrochemical industry using ORA (optimal risk analysis) procedure
Authors: Khan Faisal I. , Iqbal Asad , Abbasi S. A.
Published: April 2004

Risk assessment is an essential prelude to the development of accident prevention strategies in any chemical process industry. But, the high costs and time involved in conducting risk assessment by conventional techniques often becomes a deterrent. In order to circumvent this problem, the authors have developed a risk analysis methodology based on a set of reliable rapid techniques and tools. The suitability of the methodology, named by us ORA (Optimal Risk Analysis), has been demonstrated by applying it to a real‐life situation.
A simplified development of a unified dust explosion vent sizing formula
Authors: Ural Erdem A.
Published: April 2004

Traditionally, different formulae have been used to size the explosion vents for strong (Pred > 0.1 bar‐g or 1.5 psig) and weak (Pred < 0.1 bar‐g or 1.5 psig) enclosures. Recently, the National Fire Protection Association (NFPA) 68 Committee has developed a simplified equation for strong and weak structures that may be subjected to full volume or partial volume internal explosions.

This paper presents a simplified analysis which was used to develop the unified formula. The analysis provides insight into the form of the correlating parameters, as well as into the validity of the key hypotheses used in vented dust explosion data analysis.
Establishing a data farm to harvest quality reliability information
Authors: Thomas Harold (Hal) W , Moosemiller Mike
Published: April 2004

Obtaining useful reliability information from collected maintenance and inspection data requires effort. In the past, this has been referred to as data “mining,” as if the data can be extracted in its desired form if only it can be found. In contrast, this paper proposes data “farming,” and describes the “seeds” that are necessary to harvest the best possible crop of reliability information. The CCPS Equipment Reliability Database project provides valuable lessons on how to “farm” rather than merely “mine” data. The CCPS work processes for establishing failure modes, populations to track, event data to collect, and implementation are all reviewed. Attention is given to knowing up front the data objectives and the quality of information desired. Also, the treatment of equipment surveillance periods turns out to be a critical variable for data quantity and quality. Reasons for this and approaches to take are discussed. It will be seen that the quality and continuity of derived information is much greater when the data sources can be “farmed” rather than “mined”.
Selection and design of cost‐effective risk reduction systems
Authors: Antes Matthew K. , Miri Mahdi F. , Flamberg Stephanie A.
Published: April 2004

With the need to juggle design requirements, recommendations, personal opinions, and company preferences, how does one determine a safe, cost‐effective risk reduction design? A quick solution may be to incorporate all potential safeguards, but that is neither practical nor cost‐effective. Companies have turned to various methods to evaluate their mitigation options for fire, explosion, and reactivity hazards. Most methods simply identify the high‐risk issues; they do not determine the most cost‐effective risk reduction options.

Whether it is for a capital project, regulatory compliance, or to define standards, cost‐benefit analysis (CBA) is a proven method for cost‐effective risk management. Three case studies are presented in this paper to illustrate the flexibility and benefits of this approach.
The effect of additives on the detonation hazard of some hydrocarbon‐air mixtures
Authors: Lizhong Yang , Xiaodong Zhou , Qing'an Wang , Weicheng Fan
Published: April 2004

Hazards caused by detonation of hydrocarbon‐air mixtures are a continuing problem. Of the factors affecting detonation hazards of hydrocarbon‐air mixtures, additives play an important role. In this paper, a series of experiments are described addressing the influence of chemical additives on the detonation of some hydrocarbon‐air mixtures under confined (rectangle shock tube tests) conditions. The experimental results show that NT (nitric ether or RONO2), PO (1,2‐epoxypropane), and BPO (benzoyl peroxide) have a clear sensitizing effect on the detonation hazards of these mixtures. The mechanistic influence of additives is simply described, according to the chain reaction theory of detonation.
Kinetics of the reactions of ethylene oxide with water and ethylene glycols
Authors: Melhem Georges A. , Gianetto Arturo , Levin Marc E. , Fisher Harold G. , Chippett Simon , Singh Surendra K. , Chipman Peter I.
Published: April 2004

This study of the water‐contamination reactions of ethylene oxide was conducted by Arthur D. Little, Inc. with funding from, and under the auspices of, the Ethylene Oxide Industry Council, part of the American Chemistry Council. Significant experimental and technical contributions were also made by staff from Shell Chemicals' Westhollow Technology Center in Houston, Texas, and Union Carbide Corporation's Research Center in South Charleston, West Virginia. Unique fourth‐order kinetics for the reactions of ethylene oxide with water, and ethylene oxide with ethylene glycols were derived and validated, as were kinetics for the reactions of neat ethylene oxide and the decomposition of ethylene glycols. The latter data was incorporated into a reaction model useful for the determination of ethylene oxide storage stability and pressure relief system design under water‐contamination scenarios.
Regulations: Build a system or add layers?
Authors: Dowell A. M.
Published: April 2004

Many government, industry, and self‐imposed regulations have been added to the chemical business, seemingly stacking massive three‐ring binders on top of our backpack of “making chemicals.” This paper proposes that we design work systems to include the needs of the various initiatives in the structure and fabric of our backpack. Examples will be given.
Safe design and operation of a cryogenic air separation unit
Authors: Schmidt William P. , Winegardner Karen S. , Dennehy Martin , Castle‐Smith Howard
Published: April 2004

Cryogenic Air Separation Units (ASUs) frequently supply oxygen and nitrogen to chemical, petroleum and manufacturing customers. Typically, the ASU is located remotely from the use point, and the products are supplied via a pipeline. This paper provides the basic design and operating methods to safely operate an ASU. The four primary hazards associated with these units are: (1) the potential for rapid oxidation, (2) interfaces between the ASU and the downstream systems, (3) pre s s u re excursions due to vaporizing liquids, and (4) oxygen enriched or deficient atmospheres. Requirements for safely handling oxygen within the air separation facility and at the product use point are also discussed in this paper.
Flame propagation in industrial scale piping
Authors: Chatrathi Kris , Going John E. , Grandestaff Bill
Published: April 2004

The use of pipelines to connect vessels and transport material is a common practice in the processing industry. Often, these pipelines carry potentially hazardous materials, such as flammable gases. The potential of fires and explosions in the process industry has been well recognized and is addressed in consensus guidelines such as N F PA 68 – Guide for Venting of Deflagrations and N F PA 69 – Explosion Prevention Systems. Both of these guides differentiate between vessels and piping systems by providing diff e rent rules to address the differences in explosion propagation behavior. Both NFPA 68 and NFPA 69 are based on an understanding of explosion propagation behavior developed from empirical or experimental evidence.

The purposes of this paper are to present experimental evidence and to further develop a detailed understanding of combustion propagation in industrial scale piping, primarily deflagration propagation in pipes. However, it is also the intent to understand the transition points between fires and deflagrations, and between deflagrations and detonations as related to piping systems. In order to study combustion propagation in industrial scale piping, three pipe diameters and three fuels were selected. Although, gaseous fuel mixtures are often transported in waste streams, only pure fuels were used in this study. The effect of bends was evaluated but other piping system components were not evaluated.
Case history: PTFE‐lined pipe failure
Authors: Schisla Robert M. , Ernst Steven C. , Lodal Peter N.
Published: April 2004

A recent incident at the Eastman Chemical Company's Kingsport site involved a 20‐foot section of PTFE‐lined pipe that failed at a flange joint, resulting in a leak, but no injuries. Initial scene observations indicated that a section of the liner had disintegrated, leaving an open space where the liner forms the flange gasket. More detailed analysis showed that the entire liner was intact, but had retracted approximately 2.5 inches into the pipe.

This paper will discuss the physical mechanisms (thermal cycling, viscoelastic properties of PTFE) that explain the liner retraction, as well as the installation factors (electrical tracing, liner length), which influenced the timing and nature of the failure mechanism.
Safety management in a hazardous experimental environment: The Borexino case
Authors: Caputo Antonio C. , Pelagagge Pacifico M. , Tartaglia Roberto
Published: April 2004

Applying a methodological approach for process plant safety improvement and management in a high risk underground experimental facility is described using as a reference case the Borexino experiment in the Gran Sasso National Laboratory, Italy. The adopted procedure involved utilization of both qualitative (HAZOP and FMEA) and quantitative techniques (FTA) in order to improve process safety in a high technology experimental setting where no previous experience on similar plants was available. In the paper, we describe a complete process characterization and detail the safety analysis phases that identify the main problem areas and suggested and adopted corrective actions.
Explosion and fire in a gas‐oil fixed roof storage tank: Case study and lessons learned
Authors: Riezel Yigal
Published: April 2004

On November 2, 1997, a fixed roof gas‐oil tank located in the tank farm of Ashdod Oil Refinery exploded, causing the death of one Sample Man, and a fire in two adjacent tanks located in the same dike. The fire lasted less than 3 hours, but there was significant public concern about the necessity for emergency evacuation from two neighboring settlements.

Emergency operations of the refinery and outside services were very effective, and fires in both tanks and the dike were put out without any additional damage to other equipment in the tank farm. The source fire was classified as a heavy top phase pool fire.

The investigation pointed out that hydrogen was the source of the explosive mixture in the tank. Hydrogen penetrated the tank as a result of non‐complete gas‐oil stripping at the exit of a hydro treating unit. The source of ignition was an electrostatic spark initiated by synthetic rope (instead of a cotton one) used with a device to obtain samples from the tank.

After the accident, it was found that a similar scenario was reported about 15 years earlier. However, it was not disseminated widely enough through accident databases.
Layers of protection analysis for human factors (LOPA‐HF)
Authors: Baybutt Paul
Published: April 2004

Process hazard analysis (PHA) performed to meet the requirements of OSHA and EPA regulations must address human factors. Both the human failures that can cause accidents and the human factors that can influence them must be addressed. This is important because it is generally believed that 50% to 90% of process accidents can be attributed to human failures. Human failures are usually identified in a PHA by simple brainstorming. However, PHA teams have a tendency to focus on equipment failures. A better approach is needed. Common approaches for identifying the human factors that influence human failures involve the use of checklists during the PHA. Unfortunately, these approaches have proven problematic. There is a need for an improved method that is both efficient and effective in helping to control process risk.

This paper describes improved approaches for identifying human failures in PHA and human factors issues that impact on the hazard scenarios identified by PHA. The former is accomplished using an approach that conceptually identifies human failures in a manner analogous to generating deviations in a hazard and operability study. The latter is achieved by the application of the framework and methods of Layers of Protection Analysis (LOPA), a simplified risk assessment method. These approaches are described and illustrative examples are provided.
Risk evaluation of decomposition of hydroxylamine/water solution at various concentrations
Authors: Iwata Yusaku , Koseki Hiroshi
Published: April 2004

The thermal property of HA/water solution was studied from the calorimetric data obtained using differential thermal analysis (DTA). The intensity of decomposition was studied from results of a mini closed pressure vessel test (MCPVT), and a pressure vessel test (PVT), in addition to the steel tube test.

The thermal analysis was conducted to evaluate the ease of thermal decomposition using DTA. The heat‐release onset temperatures using the no‐treated stainless steel cells were more than 70° C below those measured using the gold‐coated stainless steel cells. This result implies that the heat‐release onset temperature depends on the materials of the sample cell.

The intensity of the thermal decomposition was investigated using the MCPVT, the PVT, and the steel tube test. The intensity of the thermal decomposition increased as the HA concentration increased in the MCPVT. The intensity of the thermal decomposition increased greatly when the HA concentration was beyond 80% (wt.) in the MCPVT. It was determined that the thermal decomposit ion of HA 70%/water solutions was very violent in the PVT. In addition, HA/water solutions of more than 80% concentration could detonate in the steel tube test.
Potential impacts to process safety management from mergers, acquisitions, downsizing, and re‐engineering
Authors: Philley Jack
Published: April 2004

Corporate organizational mergers, acquisitions, downsizing, and re‐engineering can greatly impact Process Safety Management (PSM) programs and, ultimately, PSM performance. Almost every organization has experienced some degree of change in organizational staffing. A primary objective of this paper is to identify potential adverse impacts to PSM resulting from ineffectively managed organizational changes. Several process safety incidents are examined from an organizational change perspective. In addition, options and strategies are offered for preventing or mitigating adverse consequences associated with these changes.
Fire in secondary reformer outlet line to waste heat boiler
Authors: Singh Jagmohan , Basu P. , Rao B. M.
Published: April 2004

This paper describes the failure of the pressure shell of an interconnecting pipe between the secondary reformer and primary waste heat boiler that led to a fire in Ammonia Unit I after 13‐and‐a‐half years of operation. The fire incident resulted at KRIBHCO in a plant shutdown of 15 days. It also describes analysis, the repair work carried out to put the plant back in service in the least possible time, and the remedial measures taken.
An index‐based method for assessing exothermic runaway risk
Authors: Kao Chen‐Shen , Duh Yih‐Shing , Chen Thomas J. H. , Yu S. W.
Published: April 2004

This paper proposes a simplified mathematical and tabular method for assessing the risk of exothermic runaway reactions, based on the calculated hazard index. Intrinsic elements, such as reactivity, stability, exothermic enthalpy, etc., are presented as measures of severity of a potential runaway event. Similarly, extrinsic elements, such as risk and safety factors associated with operating conditions, are considered as measures of the likelihood of an event. All intrinsic and extrinsic parameters, with proper weightings, are converted into a runaway risk index (RRI). The chemical process risk can therefore be quantified and divided into six levels based on the normalized RRI: extremely high, high, moderate, mild, low, and very low. They can be further classified into tolerable and intolerable risks. Sample runs on methanol‐acetic anhydride esterification, cumenehydroperoxide decomposition, and decompositions of ammonium nitrate, are presented to illustrate the validity of the method.