bluuebunny/crossref_metadata_2025_split huggingface dataset:
Safety aspects in urea plants: The stamicarbon Y2K update
Authors: Meessen J. , Donker R. , Vlake H. , Van Den Aarssen A. 
Published: April 2004

AbstractAdding oxygen to the urea process has proven to be an effective and reliable way to minimize corrosion to the stainless steels used in plants. However since the introduction of this technology in the early 1950s, the fire and explosion risk associated with oxygen (air) in urea synthesis has required special attention in design and operation. Experience and knowledge on safer operating procedures has grown over the years, through experience gained in operating plants, as well as through fundamental research. At the same time, the chemical process industry has needed to comply with stricter safety regulations. Let there be no doubt, Stamicarbon thinks these increased demands on safety related topics certainly are justified. The combination of growing insight on the one hand, and increasing demands on the other hand, justifies a regular update of safety guidelines and standards.
Case histories of pump explosions while running isolated
Authors: Giles Douglas S. , Lodal Peter N. 
Published: April 2004

AbstractStandard industrial centrifugal pumps that isolate process material (i.e. “deadheaded” with both suction and discharge valves closed) inside the pump casing can explode catastrophically if the pump is inadvertently started and left running.Case histories and lessons learned at Tennessee Eastman Division (TED) involving pump explosions while running isolated will be presented in this paper. Case histories involve both combustible and non‐combustible process streams where the pump was inadvertently started and allowed to run isolated until the process material heated up and built enough pressure to rupture the pump housing creating a BLEVE (Boiling Liquid Expanding Vapor Explosion). Incident learnings will be presented for each case.
Dust explosion case study: “Bad things can still happen to good companies”
Authors: Pickup Richard D. 
Published: April 2004

AbstractIn recent years, the general level of awareness of dust explosion hazards within the process industries has greatly improved. In light of this, many companies have incorporated recognized techniques to prevent or mitigate the damaging effects of dust explosions into their designs and procedures. However, a recent investigation of an incident at an agrochemical formulation facility demonstrates, unfortunately, that “bad things can still happen to good companies”.
Application of fire protection measures to new and complex chemical facilities
Authors: Slye Orville M. 
Published: April 2004

AbstractOriginally this paper was intended to be a review of fire protection measures and requirements for new and complex facilities. However, on reflection, I realized that the protection requirements for new complex facilities were really no different than for other facilities in the chemical industries. Fire safety challenges are equally daunting in all segments of the industry. This paper reviews methods commonly used to design fire protection measures for chemical plants, and proposes the use of performance‐based fire protection analysis and design as an alternate to specification design methods.Loss prevention techniques have been partially eclipsed by process safety management efforts launched to meet OSHA Process Safety Management (PSM), and EPA Risk Management Program (RMP) requirements. But, fire protection, prevention, and explosion safeguards must continue to be included in plant design and operations to assure overall plant safety.
Process hazard analyses of control and instrument systems
Authors: Freeman Raymond A. 
Published: April 2004

AbstractThe OSHA process safety management (PSM) and EPA risk management program (RMP) standards require that process hazards analyses (PHAs) be performed on processes that contain listed toxic or flammable chemicals. A number of PHA techniques are listed in both standards that can be used to satisfy this requirement. Typical PHA studies use analysis techniques, such as hazard and operability (HAZOP), what‐if, and checklists, to review potential hazards, such as deviations from normal process conditions of flow, temperature, pressure, etc. The influences of control and instrument system failures on process system safety are usually considered indirectly. This paper reviews some of the considerations needed to conduct a PHA that includes control and instrument system failures. Information on (1) how to organize the review analysis team, (2) what type of documentation is needed, and (3) the special considerations needed in a control and instrument system review are included in this paper. The wide use of advanced programmable and electronic systems in the chemical process industry introduces a number of special considerations that must also be included in a review. These considerations are also discussed in this paper.
Fault management analysis
Authors: Summers Angela E. 
Published: April 2004

AbstractIn the chemical process industries, intrinsically safe operations must be the process engineer's goal, but, in reality, it is often not feasible, either technically or economically. In these cases, safety instrumented systems (SIS) are often used to detect and respond to process risk. SISs have many components that must work as designed in order to mitigate potential hazardous incidents. Over the years, many of these components have evolved from simple electro‐mechanical devices to complex mechanical, electrical, and programmable devices. What makes these devices fail must be examined in order to understand how each component failure can propagate into fail‐safe and fail‐dangerous conditions.This paper proposes the use of fault management analysis (FMA) for the assessment of proposed SIS designs. An FMA identifies not only the failure modes of each component, but also determines how to appropriately manage the identified failure. This paper demonstrates how proposed design, diagnostics, inspection, maintenance, and testing programs should be modified to improve the SIS performance.
Influence of turbulent flow conditions on the ignition of flammable gas/air‐mixtures
Authors: Horstmann Tilo , Leuckel Wolfgang , Maurer Bodo , Maas Ulrich 
Published: April 2004

AbstractWe investigated spark‐induced ignition of methane/air‐and propane/air‐mixtures under turbulent conditions in a pipe‐flow system where turbulence was increased by the use of grids. A laser‐doppler‐anemometer was used to characterize turbulence in the test facility. To determine the actual energy released by the spark ignition source, we measure delectrical current and voltage during spark discharge. The results show that turbulent fluctuations have the greatest influence on the ignition process, whereas the convective part of the flow (up to velocities of 40 m/s) exerts little influence. For numerical work, a one‐dimensional simulation program, including detailed chemistry and multi‐species molecular transport is used. It is shown that the main influence on the ignition is due to the rms‐value of turbulence. Further more, the influence of increased flow velocity on flammability limits, and of diff e rent spark duration times and macrolengths on the ignition process, are demonstrated.
Combustion safeguards test intervals—risk study and industry survey
Authors: Kauffman Jeff , Oakey Thomas L. , Price Kenneth , Johnson Robert W. 
Published: April 2004

AbstractAs standard practice, The Procter&Gamble Company tested combustion safeguards on a monthly basis. The study summarized in this paper examined the risk impact of varying the safeguard test interval. Among the consequences considered were fuel explosions, flue gas/burning outside a combustor, steam‐side overpressurization, water tube/fire tube rupture, and bringing the combustor down for testing when at full utilization. Abnormal situations in lightoff, continuous operation, and shutdown modes were modeled using fault tree analysis. Gate‐to‐gate and common mode calculations were implemented in an Excel® spreadsheet for determining the likelihood of each consequence, the overall loss rate, and the effect of changing the test interval. Results of the study indicate, for the particular combustor selected for analysis, increased risk if safeguards are tested either more than once a month or less than once a year. Survey results from 25 Council of Industrial Boiler Operators (CIBO) member companies indicated that annual testing of combustion safeguards is the predominant industry practice. Procter&Gamble is in the process of changing its standard practice worldwide to a three‐month or sixmonth combustion safeguards test interval, depending on the type of combustor.
Application of relational chemical process safety databases for lowering mean failure rates
Authors: Al‐Qurashi Fahad , Sharma Gaurav , Rogers William J. , Mannan M. Sam 
Published: April 2004

AbstractThis paper proposes a linkage among accident, failure rate, and reactivity databases for process safety applications. The objective of the relationships among these databases is to bring all relevant information on both equipment and chemicals into one relational database. Such a database will make possible a better understanding by plant personnel about the reliability of plant equipment and the potential danger of process chemicals. Consequently, accidents should be reduced.This research shows that relationships can be established among the three databases, and the examples presented demonstrate how it is done. Improving equipment reliability, calls for an approach of meeting the mean of failure rate data rather than the “industry best practice.” Modifications of current accident databases are proposed to develop effective relational databases that can help improve the safety performance of industry.
Two hundred years of flammable limits
Authors: Britton Laurence G. 
Published: April 2004

AbstractThis article discusses flammable limit test methods with reference to the past 200 years of research. Critical examination is made of the various pressure rise criteria currently used to determine whether flame propagation has occurred in closed test vessels. Of these, the most appropriate, with respect to vessels of 5‐20 liters volume, is judged to be the “net 7%” pressure rise criterion described in ASTM E‐2079. Since the tests are typically carried out in spherical vessels with central ignition, only a small fraction of the limit mixture burns and consequently a small pressure rise criterion must be used. Also, it is impossible to determine the product distribution for near‐limit flames. A small pressure rise criterion may cause the flammable range to be overestimated, particularly at the upper limit. For non‐routine and standardization purposes at least, use of a tall, large diameter, cylindrical vessel with bottom ignition is suggested.European test methods are creating a database of flammable limit values outside the range of compositions at which flames can self‐propagate. The objective of flammable limit measurement should be to obtain close agreement with large‐scale observations and, ultimately, with theoretical models for self‐propagating flames. It is recommended that “flammable limits” measured using DIN 51649 and European Standard prEN1839 (or closed vessel methods striving to obtain values consistent with these) not be mixed with the existing database because they correspond to fuel concentrations that do not support flame propagation in any orientation.
Using heats of oxidation to evaluate flammability hazards
Authors: Britton Laurence G. 
Published: April 2004

AbstractThe heat of oxidation is the net heat of combustion per mole of oxygen consumed. For complete combustion it is given by “ΔHC/S” (kcal/mol oxygen), where “ΔHC” is the net heat of combustion (kcal/mol fuel) and “S” is the stoichiometric ratio of oxygen to fuel as written in the stoichiometric equation. Although previously unrecognized, the heat of oxidation “ΔHC/S” is the single most powerful parameter for evaluating the flammability hazards of fuels.This article derives and discusses eight simple rules for estimating flammability parameters of single or mixed organic fuels in air under atmospheric conditions. The rules apply to fuels containing combinations of C+H+O+N atoms that burn to carbon dioxide plus water. Apart from the trivial First Rule, each rule is expressed in terms of the heat of oxidation.Two Rules are presented for lower flammable limit (LFL) estimation. The First Rule is approximate and requires only the stoichiometric ratio of oxygen to fuel “S.” Although it outperforms Lloyd's Rule, it similarly overestimates the LFLs of energetic fuels such as acetylene and ethylene oxide.The Second Rule requires both “S” and the net heat of combustion “ΔHC.” It is shown that the LFL is inversely proportional to the product of heat of combustion and heat of oxidation. LFL predictions are typically within experimental error of reported values, including energetic fuels such as acetylene and ethylene oxide.The Third Rule shows that lower limit flame temperatures decrease linearly with increased heat of oxidation and increase stepwise between hydrocarbons and other organic fuels containing oxygen and nitrogen atoms.The Fourth Rule shows that the Limiting Oxygen Concentrations (LOCs) of non‐decomposable fuels decrease with the inverse square of heat of oxidation. It is proposed that the optimum fuel concentration at the LOC is related via diffusivity ratio to the stoichiometric concentration. A fuel‐oxygen Cartesian flammability diagram is suggested for presenting LOC data.The Fifth Rule shows that maximum flame temperatures increase linearly with increased heat of oxidation and decrease stepwise between hydrocarbons and other organic fuels containing oxygen and nitrogen atoms.The Sixth and Seventh Rules address fundamental burning velocity “Su” and lowest minimum ignition energy (LMIE), second order polynomial expressions being presented for easily calculating these parameters. It is shown how the calculated Su can be used to estimate normalized rate of pressure rise “KG” data. It is also demonstrated that many published LMIE and quenching distance values are too high.The Eighth Rule gives a tentative expression for quenching distance, which decreases linearly with increased heat of oxidation. A scheme is presented for ranking fuel hazards in terms of heat of oxidation. Demarcations are made in terms of Su, LMIE and Class I NEC and Zone Groups. It is shown how the approach might be extended to deflagration and detonation arrester selection.
Software‐implemented safety logic
Authors: Summers Angela E. 
Published: April 2004

AbstractProcess industries rely on various safeguards to minimize the potential and consequence of hazardous incidents. Active safeguards, such as safety instrumented systems (SIS), fire and gas systems, and emergency vents, use sensors to detect process upsets, then take action to bring it to a safe state.Many users implement active safeguards using programmable logic controllers (PLCs). The PLC uses a combination of hardware and software to respond to inputs (process variables) by generating outputs (safety actions). The execution of the safe state logic is dependent on the application program integrity, which may be developed by the PES vendor, engineering contractor, system integrator, or the user. Successful implementation and thorough verification of the application program is essential for correct SIS operation.This paper will first discuss the various types of SIS software, including full variability, limited variability, and fixed programming languages. It will then look at proposed application program requirements, and guidelines in the international process industry sector standard, draft IEC 61511.
Development of an engineering tool to quantify the explosion hazard of flammable liquid spills
Authors: Tamanini Francesco 
Published: April 2004

AbstractFlammable liquid spills, or slow heavy vapor releases, produce flammable layers which, if ignited, can cause damage to the enclosure containing the release. The question of pressure development in the ensuing explosion has been addressed in a previous paper. This paper describes a model to predict the fuel distribution in the flammable layer as a function of the parameters that define the spill (or fuel release) scenario. Since the model is intended for use in engineering predictions, it is designed to be easy to use and compatible with widely available computer resources. Accordingly, the flow field is treated as one‐dimensional taking only variations in the vertical direction into account.This simplifying assumption is supplemented by special adjustments for effects not accurately addressed without the horizontal gradients. This includes sub‐models to deal with forced ventilation and cases where the vaporizing pool occupies only a fraction of the floor area of the enclosure.The model has been validated by comparison with available data from vaporizing pools, and for diffusing heavy vapors. Overall agreement with the experiment is satisfactory, and generally on the conservative side. On the basis of these results, the formulation has been judged suitable for use in combination with the method to predict the pressure increase from combustion of the flammable layer. These two elements are part of an integrated tool developed for use by FM Global Loss Prevention Consultants. The paper discusses the implications of this modeling approach in terms of protection design.
Evaluating vent manifold inerting requirements: Flash point modeling for organic acid‐water mixtures
Authors: Garland R. Wayne , Malcolm Michael O. 
Published: April 2004

AbstractWe wanted to reduce risk to very low levels in our manufacturing operations. We also needed to predict the effect on risk of potential future process changes. A survey was done on all processes to determine where flammable and combustible materials may be used. Process vessels were screened to determine which may be operating above the flash point without inert blanketing and with sufficient vapor space to generate a significant fire or explosion. This work was needed to ascertain whether or not to inert the process vessel, as well as its potential effect on the vent manifold system. An accurate assessment requires data on chemical flash points, but available data was limited primarily to pure components, not the mixtures—organic acids with water or anhydrides—with which we were dealing. Assessments using pure component data would have been very conservative, but also would have resulted in process modifications requiring large capital expenditures. To generate more accurate data we ran a four‐component experiment designed for organic acid: water mixtures. Two different models were required to describe the results due to boundary issues. Excellent correlations were achieved. Results from this study helped us achieve our safety objectives with minimal capital expenditures.
Runaway reactions in aluminum, aluminum chloride, HCl, and steam: An investigation of the 1998 CONDEA Vista explosion in Maryland
Authors: Reza Ali , Kemal Abid , Markey Peter E. 
Published: April 2004

AbstractOn October 13, 1998, an explosion and fire occurred at a 3,000 gallon reactor in the linear alkyl benzene (LAB) process at the CONDEA Vista plant in Maryland. Process materials released from the various vessels and piping fueled a subsequent fire that took approximately two hours to extinguish. The accident investigation revealed that, prior to the explosion, the bottom of the reactor was plugged with approximately 180 gallons of a sludge‐like mixture of coarse aluminum powder, aluminum chloride, and various hydrocarbons. The explosion occurred approximately 10 minutes after steam was introduced at the bottom of the reactor in an effort to break up the sludge accumulation.A series of reduced‐scale chemical reactivity tests were completed to investigate the potential reactions between steam and manufactured sludge similar to what had accumulated inside the reactor. Rapid runaway chemical reactions were observed after steam was injected into this mixture, and pressures in excess of 45 barg (660 psig), and temperatures in excess of 700° F were recorded before the test vessels ruptured. A review of possible chemical reactions between steam, aluminum, and aluminum chloride confirms that the predominant reaction mechanism is the exothermic hydrolysis of aluminum chloride to produce HCl vapor. Significant amounts of hydrogen gas can also be generated as the aluminum reacts with the acid/steam mixture after it is stripped of its protective oxide coating. The investigators concluded that the root cause of this accident was direct and sustained contact between the steam and accumulated sludge at the bottom of the reactor.
Further uses of the heat of oxidation in chemical hazard assessment
Authors: Britton Laurence G. , Frurip David J. 
Published: April 2004

AbstractFlammability: The “net heat of oxidation” technique described in an earlier publication is extended to predicting the lower flammable limits, lower limit flame temperatures, and limiting oxygen concentrations of chlorinated organic fuels having H:Cl ratios greater than unity. A new Rule is derived for predicting the effect of initial temperature on the lower flammable limits and limiting oxygen concentrations of organic fuels. It is suggested that this Rule be used in preference to the modified “Burgess‐Wheeler” Rule. The effect of initial pressure is discussed.Instability: Net heats of oxidation (kcal/mol oxygen) for a series of disparate fuel groups are compared with “ΔHD,” the maximum heat of decomposition (cal/g) calculated using CHETAH methodology. Given the reasonable assumption that CHETAH's “maximum heat of decomposition” cannot exceed the net heat of combustion “ΔHC,” examination is made as to whether the ratio of these parameters (each expressed in units of kcal/mol), coined the “Reaction Heat Ratio” (RH), provides a useful new indicator for instability assessment.Of these parameters, the net heat of oxidation (ΔHC/S) is the best indicator to help assign NFPA Instability Ratings. However, ΔHC/S cannot generally be used to assign ratings for organo‐peroxides. Also, its performance as an indicator for hazardous polymerization depends on the ΔHC/S difference between the reacting monomer and the polymer product, so it should become increasingly unreliable as the monomer ΔHC/S approaches ‐100 kcal/mol oxygen. The ranking method tacitly assumes organic polymers to have a constant heat of oxidation of about ‐100 kcal/mol oxygen. Errors in this assumption must invalidate the ranking approach where ΔHC/S differences are small. Finally, separate “cut‐offs” must be used at each NFPA Instability Rating for organo‐nitrates versus other organics containing combinations of CHON atoms. Additional materials need to be examined to extend this preliminary analysis. The net heat of oxidation would be a useful additional output parameter of the CHETAH program, if only for its application in flammability assessment. No conclusions are drawn regarding the usefulness of net heat of oxidation or RH in conducting CHETAH hazard assessments, since this procedure requires consideration of several variables. However, the analysis may be helpful to the ASTM E 27.07 subcommittee responsible for developing the program. For example, the ‐ΔHD ⩾ 700 cal/g cut‐off used to assign a “high” CHETAH hazard rating typically corresponds to organic materials rated NFPA 1, the second to lowest hazard rating.