bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermo‐kinetic analysis of reactions involved in the manufacture of o‐nitroaniline
Authors: Willey Ronald J. , Rodrigues Fausto , Chippett Simon , Melhem Georges , Singh Surendra K.
Published: April 2004

Exothermic reaction processing must be concerned with potential consequences when heat released by the reaction exceeds that removed by the reactor coolant system, a situation known commonly as a runaway reaction. We have investigated a complicated reaction process in which two exotherms can occur—the process of making the desired product, o‐nitroaniline (o‐NA), from ammonia and o‐chloronitrobenzene (T Onset around 140°C), and the decomposition of the product, o‐NA (T Onset around 225°C). A severe industrial loss occurred in 1971 at a plant producing o‐nitroaniline, an incident that has been the subject of several AIChE loss prevention presentations and papers. In this article, we take a closer look at the chemistry involved, and the ability to use thermo‐kinetic analyses to understand the reactions involved, and how these influenced the accident that occurred. Further, we present the progress we've made towards predictive models for the kinetics and the pressure‐time data. Several useful generalizations have evolved. First, is the need to include experiments that use stoichiometric mixtures when assessing exothermic reactions. Second, is the need to understand the role of reaction intermediates, and how they may influence the operation of the plant.
Computer‐aided planning for lockout/tagout program
Authors: Matsuoka Shinobu , Muraki Masaaki
Published: April 2004

Lockout/Tagout is an effective program to protect plant workers from exposure to hazardous energy sources. Because of the complexity of a process plant, it is a time‐consuming job for maintenance managers to achieve certain Lockout/Tagout plans for Turnaround Maintenance. Process flow and layout information are essential to this planning, so Computer‐Aided Design (CAD) systems are becoming very useful resources. In this study, we propose a computer‐aided method for planning Lockout/Tagout programs in process plants. To isolate certain equipment, minimum required operations are explored and reported automatically. Algorithms that investigate CAD data are shown in order to determine isolated areas. Data structures which mitigate limitation of calculation time are applied for large‐scale plants. We also consider the integration of isolated areas and the elimination of overlapping operations.
Process automation can advance loss prevention goals
Authors: Brandes David J.
Published: April 2004

Process automation can advance loss prevention goals even in today's pressure‐filled business environment of smaller workforces and subsequent needs to maximize production efficiency. The Dow Chemical Company has been totally automated for 30 years, and has seen substantial gains in process safety and reliability. Increased process control automation can benefit other areas as well. We have consistently seen a reduction of operating costs, faster startups and shutdowns, and improved product quality through the reduction of variability. You get your best operator 24‐hours per day.

As the level of automation increases and operator supervision decreases, more is demanded of the process control system. Significantly higher control system reliability in both hardware and software is needed. The control system must provide a platform that is fault tolerant in real‐time, and provide a graceful degradation of operations. This, in turn, leads to a need for process state‐based control, active redundancy, and deterministic operation.
Hazard identification using new logic diagrams and descriptors
Authors: Duarte Dayse , Pires Thiago
Published: April 2004

The motivation behind this work was the need to develop new logic diagrams for implementating risk management programs, taking into account the impact of the information revolution, and the globalization of business. These changes were not visualized some years ago. It is not logical to assume that the risk management strategies for a new millennium can be based on the assumptions of the past.

The new logic diagrams—continuous and single value network—presented in this article go beyond those recommended by the American Institute of Chemical Engineers' Center for Chemical Safety (CCPS), which are currently the most commonly used in the process industries. The new diagrams enable an engineer to evaluate the system mode of failures. One of the advantages of using these value networks is that they are flexible and provide a road map for logical thought. These logic diagrams and descriptors were used during the hazard identification analysis of the thermal dry area of Petroflex–Cabo Unit, the only synthetic rubber plant in Latin America.
Critical safe operating parameters: “Never exceed” limit and “never deviate” action
Authors: Dowell A. M.
Published: April 2004

Where does the human being fit in the normal operating system and where does he/she fit in the safety shutdown system? Planning ahead can make human interaction inherently safer. This paper offers the following suggestions for managing that interaction: (1) Use inherently safer principles in the design of the process and its layers of protection. (2) Define “Never Exceed” limits for critical safe operating parameters. (3) Define a mandatory action point and a “Never Deviate” action with enough response time to prevent exceeding the Never Exceed limit. (4) Train and drill.
Hazard investigation of reactive chemicals
Authors: Murphy John , Joseph Giby , Long Lisa , Mitchell Kevin , Poje Gerald V.
Published: April 2004

The U.S. Chemical Safety and Hazard Investigation Board (CSB) began operation as a new independent Federal agency in 1998. Its primary mission is to aid in the prevention of chemical related incidents (e.g., fires, explosions, or toxic releases) in fixed commercial or industrial facilities.

This paper discusses the organization and status of CSB's reactive chemical hazard investigation, which was initiated by a serious process incident at Morton International. The objectives of the reactive chemical hazard investigation are to: (1) determine the impact of reactive chemical incidents; (2) examine how industry, the Occupational Safety and Health Administration (OSHA) and the U.S. Environmental Protection Agency (EPA) address reactive chemical hazards; and (3) analyze the appropriateness of, and consider alternatives to, industry and OSHA use of the National Fire Protection Association (NFPA) reactivity rating system [1] for process safety management. The hazard investigation will make recommendations to promote the safe handling of reactive chemicals.
Getting from policy to practices: The pyramid model (or what is this standard really trying to do?)
Authors: Dowell A. M.
Published: April 2004

A major challenge in any organization is successfully getting from policies to practices. It is important that the acceptable risks envisioned by a company's safety and health policies be achieved in the actual practices of every worker. Frequently, standards and procedures are written to direct worker practices, but, over time, these standards may not be effective in meeting the organization's policies and values. When someone requests a variance from a standard, the organization may realize that no one knows exactly what it is trying to accomplish, making it almost impossible to rationally grant a variance. The criteria upon which the standard is based are rarely stated explicitly.

This paper presents a pyramid model showing the flow from values to policies to criteria/guidelines to standards/procedures to practices/behaviors. Actual examples from operating chemical plants and engineering groups illustrate the type of problems encountered when we leave out one or more steps. Cases in which all steps function are also presented.
Characteristics of fire and explosion in semiconductor fabrication processes
Authors: Chen Jenq Renn
Published: April 2004

The characteristics of fire and explosion in semiconductor fabrication processes differ from those in the chemical process industries. Case studies are given to illustrate the common, as well as peculiar features of fire and explosion in the fabrication processes. In particular, the process exhaust systems, usually involving flammable, pyrophoric and corrosive gases and vapors, were shown to be a major fire and explosion source. With some preliminary understanding of the semiconductor process, standard chemical process safety knowledge can be readily applied to semiconductor processes.
An update on the European explosion suppression and explosion venting standards
Authors: Moore Peter E. , Siwek Richard
Published: April 2004

This paper sets out the requirements for both explosion suppression and explosion venting according to the draft European Standards that are being prepared under the mandate given to CEN/TC305/WG3, the European Commission and the European Free Trade Association, and supports the essential requirements of EU Directive(s).
An example of a test method for vent sizing—OPPSD/SPI methodology
Authors: Poteet Charles S. , Banks Marvin L.
Published: April 2004

An alternative methodology to that of United Nations, Appendix 5, Sample Method, has been developed by the Organic Peroxides Producers Safety Division of the Society of the Plastics Industry (OPPSD/SPI) to assure the safe emergency venting of organic peroxides in an approved container. The methodology is applicable for designing a new container for an existing or new organic peroxide. Bench‐scale testing with a 10 liter vessel determined the maximum pressure pulse (spike) generated during a thermal decomposition/overpressurization vs. the ultimate, structural strength of the container measured and/or calculated. The methodology has been tested full scale with a United Nations 6(c) fuel fire. Container deformation, so long as there is no fragmentation, is permitted with the proviso that the container be retired from service following an incident. The methodology, as developed, reflects advances in technology while “harmonizing” to a maximum extent with the United Nations, Appendix 5, Sample Method.
Artificial intelligence advancements applied in off‐the‐shelf controllers
Authors: Marszal Edward M.
Published: April 2004

Since the earliest process units were built, CPI engineers have employed artificial intelligence to prevent losses. The expanding use of computer‐based systems for process control has allowed the amount of intelligence applied in these expert systems to drastically increase. Standard methods for performing Expert System tasks are being formalized by numerous researchers in industry and academia. Work products from these groups include designs that present process hazards knowledge in a structured, hierarchical, and modular manner.

Advancements in programmable logic controller (PLC) technology have created systems with substantial computing power that are robust and fault tolerant enough to be used in safety critical applications. In addition, IEC 1131‐3 standardized the programming languages available in virtually every new controller. The function block language defined in IEC 1131‐3 is particularly well suited to performing modular tasks, which makes it an ideal platform for representing knowledge.

This paper begins by describing some of the advancements in knowledge‐based systems for loss prevention applications. It then explores how standard IEC 1131‐3 programming techniques can be used to build function blocks that represent knowledge of the hazards posed by equipment items. The paper goes on to develop a sample function block that represents the hazards of a pressure vessel, using knowledge developed in the API 14‐C standard.
Benchmarking MOC practices in the process industries
Authors: Keren Nir , West Harry H. , Mannan M. Sam
Published: April 2004

Chemical, oil, and gas plants process many potentially hazardous chemicals. Historically, a variety of measures have been used for hazard reduction and risk management. However, a number of catastrophic chemical incidents can be attributed to incorrect handling of process changes. During the last decade, federal regulations have been promulgated in the United States mandating a well‐defined administrative procedure for “management of change” as a key element of a process safety management system. OSHA's Process Safety Management Program and EPA's Risk Management Program provide the baselines and framework for the development of Management of Change programs. Due to the performance‐based nature of these regulatory requirements, there is wide variation in management of change programs and practices. This paper summarizes the results of a benchmarking exercise aimed at identifying the diversity of implementation practices in industry.
Using operating and safety limits to create safety procedures
Authors: De La Cruz‐Guerra Cornelio , Cruz‐Gómez M. Javier
Published: April 2004

In this paper, the criteria for the development, implementation, and control of operating and safety limits of parameters like pressure, temperature, level, composition, etc., are described. Operating and safety limits are required by Elements 2 “process safety information” and 4 “operating procedures” of the information package for OSHA Process Safety Management (PSM). A brief description is also given of how these limits should be established and the information, with respect to consequences, safeguards, and corrective actions, that should be obtained during a detailed analysis of deviation from an operation or process parameter. This paper looks for an easier method of developing operating and safety limits within chemical and petrochemical plants to prevent and control undesirable events (human losses, material losses, economic losses, or environmental pollution) through adequate emergency plans and response programs.
Picture this! Incidents that could happen in your plant
Authors: Sanders Roy E.
Published: April 2004

Here is an opportunity to see misfortunes resulting from flaws in judgment on minor decisions. Observe these chemical plant case histories that involve relatively minor errors in design, operation, or maintenance. These incidents occurred within ordinary equipment found in most plants and refineries. Each minor error resulted in an unforgettable incident for the involved designers, operators, and maintenance crews, as well as their supervisors. You may have experienced similar memorable moments.

Note the fundamentals covered. Each can be shared in a technical review meeting or within control rooms. As our knowledgeable supervisors and veteran operators continue to move to other areas or retire, we are working with less people. We must share our past experiences with our leaner crews to avoid repeated incidents. Short, focused narratives with high‐impact, vivid illustrations can help us “Picture This!” It behooves us to share our costly information within our organizations and within technical meetings to help make us a better industry.
Common causes and corrections for explosions and fires in improperly inerted vessels
Authors: Morrison Delmar R. , Carpenter Andrew R. , Ogle Russell A.
Published: April 2004

In this article, causal factors and corrective actions surrounding improperly inerted vessel incidents are developed and compared based on several case studies of flash fires or explosions involving these process vessels. In industry, vessels that contain or have contained flammable vapors are commonly inerted for many reasons, but one of the most common is explosion prevention. Common inerting gases are carbon dioxide, nitrogen, steam, and air, depending upon the specific application. Incident causes ranged from procedures to design issues, but a general set has been produced for application to the problem of explosion prevention in process vessels. Each case study is compared to safety standards to show how safe work practices could have prevented the accidents. However, rigid adherence to safety standards may not be sufficient to prevent an accident. The application of a safety standard should be tempered by situation‐specific circumstances. Some specific recommendations for preventing explosions include methods for improved mixing of the inert gas, the use of blinds, filling the vessel with water, improved work procedures and improved monitoring procedures. A suggested design strategy for engineering an inerted system is presented.
Induced water atomization devices for gas explosion suppression
Authors: Ewan Bruce C. R. , Moatamedi M.
Published: April 2004

The work investigates the use of a new passive system for the mitigation of gas explosion overpressures in which a field of water droplets is generated continuously within the overpressure area. The system relies on the induced liquid flow from an aerodynamically shaped water container and the subsequent atomization in the convective cross flow.

A wind tunnel has been used to study the transient characteristics of the emerging liquid flow and atomization, by means of flash photography and laser diffraction sizing, for a range of generic devices. The sizes and spray concentrations produced are consistent with published values required for explosion mitigation. A 5.1m long explosion duct has been used to examine the effectiveness of one of the devices, and has demonstrated the possibilities for good explosion suppression. The practical areas of application of the system are for onshore and offshore process plant.
Establishing ignition conditions for the tank manifold fire at the Powell Duffryn tank terminal
Authors: Woodward John L. , Lygate James
Published: April 2004

A fire destroyed three tanks containing crude sulfate turpentine (CST) at a storage facility in Savannah, Georgia, on April 10, 1995, prompting an evacuation, and resulting in some environmental damage. The events of this fire have been documented an a U.S. EPA report [1]. The investigators determined the most likely cause of ignition was overheating in a newly‐installed activated‐carbon drum as air was drawn in during evening cooling. One aspect not entirely explained in the EPA report is that the tanks were connected by a vapor manifold and were not protected by detonation arresters, yet the flames initially propagated to only one tank.

This paper discusses the development of a model to quantify the likely sequence of events that is consistent with observations. Tank inflows and outflows forced by the diurnal temperature cycle were modeled to calculate hydrocarbon concentrations in the vapor space. This establishes that the combination of vapor concentrations above the lower flammable limit, and oxygen concentrations above the lower limit to support combustion, occur for only a few hours during the day. Further estimates of the ignition, flame acceleration, and run‐up distance indicate that an explosion probably occurred inside the polyvinyl chloride (PVC) pipe. The forces from such an explosion would be sufficient to open the PVC pipe, thereby slowing the flame front propagation and contributing to the failure to initially ignite more than one tank.

This paper illustrates how modeling strengthens an accident investigation and helps distinguish between alternative postulated ignition sequences.
Charge generation during filling of insulated tanks
Authors: Vidal Migvia , Wagner John P. , Rogers William J. , Mannan M. Sam
Published: April 2004

This research involves charge generation measurements for various flammable fluids during filling of insulated tanks and relating static charging with flow rate and physicochemical parameters, especially changes in electrical conductivity. The objective is to correlate static charge measured inside baffled metal and polyethylene tanks as a function of impeller, Reynolds number, and the electrical conductivity of both the hydrocarbon and the dispersed water phase for a variety of flammable liquids.

A product of the research is a correlation for polyethylene and other plastic insulated tanks for transfers of low conductivity liquid fuels. Also, a universal (dimensionless) correlation that relates the charging data to the colloidal nature of the mixture will be developed for static charge generation during impeller mixing of light hydrocarbons containing various concentrations of water in cylindrical tanks. The correlation of electrostatic data from this research will help make it possible to control electrostatic charges, and, as a result, greatly improve safety of operations involving flammable fluids in industry.
Retrofit experiences with a 32‐year‐old ammonia plant
Authors: Gupta Ved , Borserio Brennan
Published: April 2004

The Incitec Kooragang Island ammonia plant, built in 1969 by Kellogg, needed to replace, refurbish, or redesign both equipment and process in order to stay competitive. After an extensive plant assessment in the areas of safety, EPA compliance, reliability, efficiency, and capacity, a number of changes were implemented that have resulted in higher ammonia production and improved efficiency.
Bimetallic and alloy welds in HP hydrogen and nitrogen service
Authors: Sievert James B.
Published: April 2004

In 1999 and 2000, three bimetallic welded joints failed in our Kellogg Brown & Root, Inc., (KBR) ammonia processing plant designs. One was at an inlet and others were in the shells of Ammonia Converter Effluent Heat Exchangers (identified as 123Cs). These failures were in high‐pressure hydrogen services at two plant locations and occurred within about 5 and 10 years of operation. The exchanger operates with ammonia converter effluent on the shellside and boiler feed water on the tubeside. This paper presents a portion of the metallurgical failure investigation completed for one of the failures. In addition, failure avoidance of the dissimilar weldment (for repairs) and within current designs is noted. The particular failed weld joints were bimetallic, where nickel alloy filler metal “buttering” was applied to low chrome alloy base material. The “buttered” low alloy material had subsequently been postweld heat‐treated. The weld connecting the parts together was then completed using common nickel alloy filler materials without additional treatment in order to provide safe repairs for return to service. From these failures, the owners have learned what action steps are required. KBR also issued an “Advisory” to other operators in order to avoid failures of similar weld joints in other plants.
Fire tests to study the effect of pressure relief valve blowdown on the survivability of propane tanks in fires
Authors: Birk A. Michael , Vandersteen Jonathan D. J. , Cunningham M. H. , Davison C. R. , Mirzazadeh I.
Published: April 2004

There is a significant variation in the blowdown behavior of the pressure relief valves (PRV) commonly supplied on certain commercial propane tanks. Determining how different pressure relief valve characteristics affect the survivability of a propane tank in a fire and the associated hazards, was the goal of these tests.

To determine the effect of PRV blowdown, six 1890 L (500 gallon) propane tanks were exposed to an array of torch fires and thermally ruptured. A computer controlled valve was used to simulate the desired characteristics of a commercial PRV. In all cases the simulated PRV was set to open at 1.9 MPag, and blowdown was varied from 5% to 45%.

The impact of the blowdown was determined by observing the nature of the failure, the time to failure, and the energy stored in the liquid and vapor phases at failure. Blast, radiation, and projectile hazards were also observed and recorded in order to determine the impact blowdown has on these pressure vessel failure hazards.

An important finding of this testing is that the blowdown setting does impact the tank's survivability. It was consistently observed that large blowdown resulted in delayed failure. As a result, the PRV was open for a longer time, with a resulting reduction in hazards because of the lower fill at failure. This is believed to happen because of the lower average stress state in the tank with increased blowdown.
Study of major accidents and lessons learned
Authors: Balasubramanian S. G. , Louvar Joseph F.
Published: April 2004

Government and private sector safety‐related databases and other published safety resources were studied to determine their relevance and to identify the major lessons learned from each product. Information sources studied include the National Response Center (NRC), the Accidental Release Information Program (ARIP), the Bureau of Labor Statistics (BLS), Census of Fatal Occupational Injuries (CFOI), Major Accident Reporting System (MARS), the Marsh & McLennan Annual Reviews (Marsh), and Safety and Loss Prevention Symposia (LPS). This paper appropriately references these sources of information to facilitate similar studies.

We identified that: (a) there are some problems with the government databases, (b) even with these problems, some important information can be extracted, and (c) descriptions of accidents are especially useful and educational. Some surprising and useful conclusions have also been developed; e.g., (a) major accident performance is continuing to degrade, (b) although PSM may be making a mark, something else is needed to improve industry's accident performance, and (c) runaway reactions continue to be a significant cause of major accidents. Two case histories are summarized to support the conclusions and recommendations of this study.

Recommendations concerning PSM and runaway reactions are included in this paper; that is: (a) add “administrative controls” to PSM, and (b) initiate more fundamental research in the area of short stopping runaway reactions.
Assessing risks from threats to process plants: Threat and vulnerability analysis
Authors: Baybutt Paul
Published: April 2004

Process security management addresses threats from terrorist and criminal acts against plants that may result in the release of hazardous materials. The risk of such threats must be assessed to determine if existing security measures and safeguards are adequate or need improvement. Risk assessment is the heart of a process security program. Process plants need straight forward and easily applied methods to assess security risks using techniques that can be employed in a variety of situations and at varying levels of detail. This paper describes an approach that accomplishes these objectives.

Threat analysis is the first step. It is used to identify the sources and types of threats and their likelihood. The approach described in this paper involves the consideration of motivations and capabilities of adversaries and the rating of facility security factors to develop a threat profile. Once specific threats have been identified, process vulnerability analysis is used to identify threat scenarios, i.e., how threats could be realized. Plants and processes are divided into sectors, and each credible threat within each sector is considered. Vulnerabilities are identified by brainstorming the ways barriers can be penetrated and process containment breached. Checklists are used to guide the brainstorming, and scenario consequences are recorded. Existing security measures and safeguards are listed, and any recommendations for improvements to reduce the likelihood and severity of terrorist and criminal acts are made for consideration by management based on the nature of the threat, process vulnerabilities, possible consequences, and existing security measures and safeguards. Risk rankings are performed as part of the analyses.
Legionella pneumophila in an ammonia plant cooling tower
Authors: Verduijn Wim D.
Published: April 2004

In 1999, 30 people died from infection by Legionella pneumophila bacteria after visiting a flower exhibition in Bovenkarspel, The Netherlands. This event prompted Kemira Agro Rozenburg to sample its cooling tower water at regular intervals for the presence of the Legionella bacteria.

The results were consistently negative until the spring of 2000 when a sudden outbreak of the bacteria was detected. Safety measures were implemented immediately, the cause of the outbreak was discovered, and measures were subsequently taken to prevent a reoccurrence.
Natural gas line failure: Agrium Fort Saskatchewan Nitrogen Operations
Authors: McConnell Mark , Timbres Donald H.
Published: April 2004

While restarting an ammonia plant after a shutdown, the pipe line supplying natural gas to the sulfur removal section preheat coil in the primary reformer convection section ruptured. High‐pressure natural gas from the rupture ignited causing significant fire damage. The gas line rupture was determined to have been caused by corrosion. This paper examines the cause of the gas line failure and the corrective actions taken to prevent a reoccurrence.
Explosion protection with metal dust fuels
Authors: Going John E. , Snoeys Jef
Published: April 2004

Metal dust explosions have unique deflagration characteristics in comparison to organic fuels, and that can make them more difficult to control. The flame temperature of some metals dusts can exceed 3,500° K, more than 1,000° K higher than an organic flame. This can result in high explosion pressures, Pmax. Also, the pressure rate of rise, Kmax, as well as the flame speed, can greatly exceed that found with organic fuels. All of these contribute to making explosion protection more difficult.

Successful explosion protection lies in the speed of the system as well as its effectiveness. Detection and activation processes, as well as the mechanical response of the components, determine the overall speed. The effectiveness, for example, of suppression lies in the ability of the agent to stop the flame from propagating.

This paper reviews the potential effectiveness of explosion protection techniques (containment, suppression, venting and isolation) in metal dust explosions, and the limits associated with each technique. Experimental results will show that metal dust explosions can be controlled when the explosion protection techniques are properly applied.
Evaluation of reaction hazards for a wiped‐film evaporator
Authors: Johnstone Harold
Published: April 2004

To increase its capacity, a production plant investigated raising the operating temperature of a wiped‐film evaporator (WFE) unit. The WFE separates a high‐boiling product (taken overhead) from a heavy tar stream (taken out the bottom). Both product and tars begin to decompose at temperatures near the operating temperature of the WFE. The plant's Management of Change procedure required that all potential reactivity hazards be considered before making the proposed change. This paper describes the experimental work done on plant samples with ARC and Setaram C‐80 instruments, and how decomposition kinetic parameters were estimated using thermal safety software from Cheminform St. Petersburg, Ltd. The results of this hazard evaluation allowed the plant personnel to make an informed decision about the proposed operating change.
Understanding the role of process chemistry in fires and explosions
Authors: Mannan M. Sam , Aldeeb Abdulrehman A. , Rogers William J.
Published: April 2004

Chemical incidents involving fires and explosions cannot be prevented just through command and control regulatory requirements. Prevention requires understanding the fundamental root causes of safety incidents. When heat generated by an exothermic reaction exceeds the heat removal capability of the system, the exothermic reaction will accelerate and may lead to a thermal runaway reaction, explosion, and fire.

Understanding the role of process chemistry as a root cause of fires and explosions in the chemical process industry requires knowledge of the maximum quantities of both energy and gas generated by the primary and secondary exothermic reactions. Also, rates of energy and gas production are of utmost importance. This data is usually gathered by experimental methods. Experimental thermal analyses can provide an overall reactivity evaluation, but are often unable to explain the reaction mechanisms needed for safe process chemistry. Moreover, experimental analyses of all reaction pathways are expensive and sometimes impractical.

This paper provides a structured approach to chemical reactivity hazard evaluation using computational methods coupled with experimental techniques. This systematic approach helps to minimize experimental work, identifies the most important parameters in evaluating process fire and explosion hazards, and provides a more comprehensive understanding of process chemistry.

A reactive system involved in selected industrial fires and explosions is analyzed to test the validity of this systematic approach. Providing a better understanding of the reactive system chemistry, and reducing the experimental work were among the main objectives of this study.
Managing risk of electrostatic hazards in coating and printing on moving webs
Authors: Blitshteyn Mark
Published: April 2004

When static charges accumulate in flammable or explosive atmospheres, it can lead to an electrostatic discharge (ESD) known to cause fires. This paper will identify hazards attributed to electrostatic charges on moving webs in a flammable‐vapor environment, such as in coating and printing processes. Among the reviewed ignition sources are discharges of isolated conductors and insulating webs, as well as human operators as ignition sources. Grounding of conductors and operators, and air ionization for prevention of static buildup on insulators will be examined. This paper also reviews the safety and performance of various static neutralizers, including the importance of computer‐generated data to provide information on static conditions and neutralizing equipment status. It will be shown that diagnostic and performance data from static neutralizing equipment can provide valuable input to internal safety evaluations and post‐fire investigations. The paper will outline the key elements of a thorough electrostatic hazard risk management program in coating and printing.
Risk‐based assessment of a 25,000 ton ammonia storage tank
Authors: Daly D. , Deis Gregory J. , Frishmuth Ronald E. , McIntyre D. , Paneitz Doug , Smallwood Robert E.
Published: April 2004

Cytec's ammonia storage tank was last inspected in 1989, and based on internal requirements, would have been due for an internal inspection in 1999. Cytec has only one atmospheric ammonia storage tank. Inspecting this single tank would require solving significant logistical problems to avoid major business disruptions to the downstream operating units. Additionally, we wished to avoid the cost to decommission and clean, dispose of the wastes generated, inspect, and re‐commission the tank.

Based on prior inspection reports and a risk‐based inspection documented by Capstone Engineering, the tank has been approved for at least five more years of service without an internal inspection. Within five years, an acoustic emission study will be conducted to insure that no audible defects can be found.
Ammonia venting study to reduce environmental risks
Authors: McConnell Rod , McGrath Peter
Published: April 2004

Following closure of a substantial part of the BHP Steelworks at Newcastle, New South Wales, the smell of ammonia from occasional accidental emissions had become more apparent to people living and working around the plant. Incitec, therefore, conducted a review of all potential emission points where accidental releases of ammonia could occur. A detailed study was then carried out to quantify the frequency of each emission, the amount released, and the downwind concentration in populated areas. A risk grid was devised to help decision‐making for the various releases, and, for those emissions that did not meet the required frequency‐consequence standards, improvements were devised to reduce either the frequency or the consequences, or both. For the ammonia plant, this has led to several significant modifications. This paper describes the study and some of the resulting environmental improvements implemented on the ammonia plant, the ammonia storage area, and downstream nitrates plants.
Major hazards analysis: An improved method for process hazard analysis
Authors: Baybutt Paul
Published: April 2004

Process hazard analyses (PHAs) usually focus on major hazards—fires, explosions, and toxic releases. Traditional PHA methods, such as the Hazard and Operability (HAZOP) study and What‐If analysis, often include scenarios for other hazard types, such as operability problems. Sometimes, this may be desired, but not always. There is a need for a PHA technique that directly and exclusively addresses major process hazards. Such hazards are realized when process containment is lost. Therefore, the method proposed here uses a categorization scheme to guide brainstorming of initiating events that can result in fires, explosions, or toxic releases. It provides a more efficient and, likely, more complete, identification of major hazard scenarios than current PHA methods.
Requirements for a minimum ignition energy standard
Authors: Dahn C. James , Dastidar Ashok G.
Published: April 2004

Fires and explosions are serious hazards in the process industries. Mitigation methods, such as suppression and venting, can be expensive. Ideally, the best option would be to avoid fire or explosion, which may be accomplished by either removing the explosible fuel/oxidant mixture, or the ignition source.

One of the most overlooked and preventable ignition sources is electrostatic discharge (ESD). To evaluate the potential for ignition of a fuel/oxidant mixture, one must determine its minimum ESD ignition energy. Once the initiation thresholds have been identified, one can evaluate the likelihood of electrostatic charging and storage, which could result in an electrostatic discharge.

Identifying this threshold level can be problematic. An ASTM standard has been developed but, for this test standard to be effective, it must reflect the true hazard potentials observed in industry. Some important questions that need to be addressed to increase the utility of any minimum ignition energy standard are: (1) discharge geometry, (2) duration of the discharge and (3) calculation of the energy of the discharge. This paper will discuss the importance of these factors when evaluating the least amount of energy required to initiate an explosion.
Toxic gas release caused by the thermal decomposition of a bulk powder blend containing sodium dichloroisocyanurate
Authors: Carpenter Andrew R. , Ogle Russell A.
Published: April 2004

A thermal runaway reaction occurred during the mixing of a batch of a bulk powder that resulted in the production and release of toxic gases. The mixture consisted of an oxidizer (sodium dichloroisocyanurate), some organic compounds, and inert compounds. This toxic release led to the evacuation of the building and resulted in extensive damage to the facility. This was only the fourth time an 1,100‐pound batch of this material had been mixed in this equipment. Prior to this production run, the material had been prepared in small batches of 2 to 50 kilograms. Accelerated Rate Calorimetry (ARC) testing had been performed prior to the scale‐up to production batches.

This paper looks into the root causes of this particular accident and demonstrates how proper analysis of the testing data and other warning signs observed during the bench testing could have revealed the likelihood of this accident. Further, this paper will consider how simple design changes to the manufacturing process resulted in an inherently safer design.
Detection of hazardous reaction products during a thermal runaway
Authors: Kersten Ronald J. A. , Boers Marco N. , Opschoor Gerard , Cortes M.
Published: April 2004

The control of major accident hazards linked with the storage and processing of dangerous substances in chemical and petrochemical installations is regulated in the European Union by the so‐called “Seveso II Directive.” One of the requirements in this Directive is the declaration of not only the hazardous substances as present onsite, but also any hazardous products that could form during a loss of control situation.

This study focused on the development of an experimental technique to determine the substances that might be formed during an uncontrolled chemical reaction or runaway reaction. The decomposition reaction of a diazo compound was studied with the technique to assess its applicability.

The results show that, apart from its applicability in relation to the Seveso II Directive, the same technique can be used to obtain data for the design of gas treatment systems or to study the mechanism behind runway reactions. Understanding this mechanism, in turn, helps to identify conditions that might favor the occurrence of, or might temper the course of, the runaway reaction.
Using neural networks to monitor piping systems
Authors: Caputo Antonio C. , Pelagagge Pacifico M.
Published: April 2004

The paper proposes a state estimation technique, which uses Artificial Neural Networks (ANN) to monitor the status of piping networks carrying hazardous fluids, in order to identify and locate spills and leakages. A Multilayer Perceptron ANN is used to process pressure and flow rate information coming from a limited number of sensors distributed across the network. The ANN is trained on different sets of input data, which characterize several states of the fluid network under normal and abnormal operating conditions. During the running phase, it acts as a classifier in order to estimate the actual system status and pinpoint leaks, based on available information, thereby solving the stated inverse problem. A two‐level architecture is selected, composed of a main ANN at the first level, to identify the branch in which the leakage occurs, and several branch‐specific ANNs at the second‐level to accurately estimate the magnitude and location of the leaks. After describing the proposed methodology and the system architecture, we present a realistic application example in order to show the technique's potential.
Performance analysis of small size pilot plant and laboratory relief valves
Authors: Palluzi Richard P.
Published: April 2004

Spring‐loaded relief valves are one of the most common safety devices installed in pilot plants and laboratory bench‐top units. They are typically used in sizes much smaller than those in process units, but their performance is assumed to be equivalent. Most organizations provide only limited preventive maintenance and re‐inspection for these valves under the assumption that they are very reliable devices and operation is fairly assured.

Our experience and detailed test data with small size (1/2‐inch and less) spring‐loaded relief devices indicates that most will not perform as reliably as expected due to adhesion of the elastomer seal over time. This leads to initial relief pressures well over the 10% overpressure considered routine, with 30% overpressure being fairly common among certain sizes and conditions. Failing to recognize this problem can lead to otherwise preventable accidents, and even injuries.

Data on more than 1,000 relief devices in actual research service for several years was analyzed and the performance measured over time. The data clearly indicate the problem is endemic across all manufacturers and not easily solved. Results are presented in summary form to allow evaluation of the risk inherent in the use of these devices. It indicates a lower level of confidence in actual valve performance, as well as a need for more detailed hazard analysis and risk assessment of the potential for significant relief valve overpressure.
Learning from concepts and ideas presented in Process Safety Progress
Authors: Clark David G.
Published: April 2004

Magazine articles, such as those in Process Safety Progress (PSP), are a source of new ideas as well as old ideas restated and emphasized. While busy schedules increasingly interfere with getting the most out of these types of information sources, studying such published papers should not be given a low priority. Presented below are ideas and thoughts (some garbage, some gems) on a variety of subjects from just one such issue (September 2001 of PSP). They include:

comments on the probabilistic nature of electrostatic ignition,

the domino effect in explosion scenarios,

MY Tree analysis of accidents,

an argument from the viewpoint of the industrial ecosystem in support of a fault data bank,

the prescriptiveness of performance‐based standards,

the applicability of HAZOP to analogous systems different in scale and purpose,

keys to a good HAZOP and a good FMEA,

an argument in support of a universal effort to improve process safety by throwing cash at the hazards,

initiator/enabler concepts,

the use of a bar chart to effectively present the relative effectiveness of strategies used to control overall plant risk,

the flammability diagram: a living, pulsating thing, and

comments on the relationship between minimum ignition energy and turbulence.
Security risk analysis for chemical process facilities
Authors: Lemley J. R. , Fthenakis Vasilis M. , Moskowitz Paul D.
Published: April 2004

In response to the events of September 11, many companies stepped up security efforts in chemical process facilities and other installations. Since resources are limited, a system for ranking relative risk would be useful in establishing priorities for implementing physical‐security infrastructure and programs. This paper presents the elements of a relative risk assessment that can augment conventional process hazard analysis (PHA). This assessment is based on categorizing threat, vulnerability, and the consequences of deliberate actions by terrorists, disgruntled employees, and others.
Evaluation of safety instrumented systems using reliability analysis
Authors: Jin Sang Hwa , Yeo Yeong‐Koo , Moon Il , Chung Yonsoo , Kim In‐Won
Published: April 2004

The authors have developed a new safety instrumented system (SIS) evaluation method based on reliability analysis. It evaluates the Safety Integrity Level (SIL) using Fault Tree Analysis (FTA). When the SIL falls short of the system's target level, this method can raise it through reliability analysis and system retrofit. A hazard evaluation was carried out on the 415V diesel bus to verify the SIL evaluation method. The availability of the original 415V diesel bus was 99.40%, which comes under the category of SIL 2. After exchanging the diesel generator and the isolator switch using the developed evaluation method, the availability rose to 99.94%, SIL 3.
Fires and explosions in vapor control systems: A lessons learned anthology
Authors: Myers Timothy J. , Kytömaa Harri K. , Martin Richard J.
Published: April 2004

As new environmental technologies have been introduced, and as older technologies have been applied in new ways to meet specific combinations of environmental and process needs, new failure modes have evolved, some of which can contribute to increased risks of explosion, fire, and chemical release. This paper presents anecdotal accounts of losses involving vapor control systems installed at processing plants specifically for environmental considerations. From this experience base, the authors discuss the importance of good process safety management practices as applied to environmental technologies, and offer guidance to plant management in selecting appropriate environmental technologies.
Know when to say “when”: A review of safety incidents involving maintenance issues
Authors: Wallace Stephen J. , Merritt Carolyn W.
Published: April 2004

Utilizing information from investigations conducted by the U.S. Chemical Safety and Hazard Investigation Board, the authors offer insights on the hazards inherent in plant maintenance activities. Lessons learned from these investigations are presented with examples from actual case histories.