ISSN:1066-8527    

DOI:10.1002/prs.680170402

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

摘要:

AbstractA new method is described to enhance the management of process safety risks such that the number and type of safety systems protecting against any hazard are consistently predicated upon risk. Further, that such an assignment of safety systems can be made consistent throughout an organization. This consistency is gained through standardization of qualitative risk ranking and by setting company guidelines.

ISSN:1066-8527    

DOI:10.1002/prs.680170403

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

摘要:

AbstractThe Brazoria County Petrochemical Council, 13 companies that are working together to enhance relations between industry and the community, united in a joint effort at complying with the EPA's Risk Management Program. One of the significant issues the group had to address was the need to develop meaningful hazard assessment for presentation to the public. The EPA's “Table Look‐Up Approach” found in the Offsite Consequence Analysis Guidance document is certainly a good tool; however, the built‐in conservatism results in over‐estimates of potential hazard areas. Much more meaningful results are shown to be obtained using one of the hazard release models.The value of using a credible scenario with realistic meteorological data is demonstrated through the consistently smaller areas predicted by the PHAST Model for planning purposes. Realistic scenarios/failure modes and realistic model parameters are important so that the risk to the public is not overstated. Proprietary models such as PHAST are invaluable in providing more meaningful consequences for planning

ISSN:1066-8527    

DOI:10.1002/prs.680170404

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

摘要:

AbstractResearch was carried out to develop improved protection guidelines for silane handling systems through enhanced understanding of the behavior of releases of this pyrophoric gas. The approach involved addressing three aspects of the problem: the prompt ignition behavior of silane; the reactivity characteristics of quiescent silane/air mixtures; and the rates of reaction of silane leaked into enclosures with and without explosion venting, in the presence of ventilation air flow. A first conclusion, reached from tests in a ventilated cabinet, was that, contrary to prevailing belief, the ventilation flow has no measurable effect on the prompt ignition of the release. From experiments in a 5.1‐liter (311‐in.3) sphere it was found that silane/air mixtures of concentrations between 1.4 and 4.1% (by volume) are explosive but stable. In this case, piloted ignition tests yielded laminar burning velocities up to 5 m/s (1000 ft/min). Mixtures between 4.5 and 38% (the maximum reached in the tests) were found to be metastable, and would undergo spontaneous ignition after a delay ranging from 15 to 120 seconds, with the shorter values corresponding to higher silane concentrations. Experiments were also performed in a 0.645‐m3(22.8‐ft3) vessel both with and without explosion venting, to measure the rates of energy release associated with impulsively‐started silane leaks from 1/8 and 1/4‐in. (3.2 and 6.4‐mm) lines. A method for the prediction of the venting requirements of partial‐volume deflagrations (PVD) was evolved into a tool to quantify the pressure rise from ignition of silane leaks in enclosures. These results represent a significant step toward updating existing design recommendations which prescribe ventilation requirements that are based on outdated and, in some instances, misi

ISSN:1066-8527    

DOI:10.1002/prs.680170405

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

摘要:

AbstractCase histories of 65 incidents in runaway reactions and emergency relief in Taiwan were analyzed and classified into several categories according to their causes, materials involved, equipment types, reaction types, and ignition sources. The cases in reactors and storage tanks were examined in more detail owing to the higher probability or larger potential hazard in these two types of equipments. The most common consequence of the incidents are explosions, fires, and atmospheric release of toxic chemicals. The most severe case was a thermal explosion from an organic peroxide storage area which caused the death of 33 persons. Popping and direct releasing of process chemicals to the atmosphere from relieving devices cause the greatest environmental concerns to the community close to the plants. Runaway reactions in batch type reactors occur frequently due to various operational mistakes. Heat of reaction is the most frequent ignition source of runaway reactions and emergency relief.

ISSN:1066-8527    

DOI:10.1002/prs.680170406

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

摘要:

AbstractSome of the hazards encountered by process plant operators involve the operation of in‐line valves to control, start, and to stop flow. Torque required to operate valves may vary according to valve wheel size, in‐line pressure, and valve flange position (open/closed). This study determined how valve wheel size, in‐line pressure and valve position (open/closed) affect torque required to actuate a valve. Data were gathered with each combination of size, pressure and position for 336 valves in an operating petrochemical process facility. The results indicate that the main effects of valve wheel size, the in‐line pressure, and open/closed valve position significantly affect operational torque requirements. In addition, the interaction between position and pressure was significant for operational torque. The implication of these results is that operators are exposed to operational torque requirements that exceed maximum acceptable capabilities that have been determined in previous

ISSN:1066-8527    

DOI:10.1002/prs.680170407

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

摘要:

AbstractEPA's Risk Management Program regulation, promulgated in June 1996 as 40 CFR Part 68 requires subject industries to submit Risk Management Plans by June 1999. This plan requires hazard assessment of the operations of a facility using worst case scenarios and alternative releases. EPA has provided an Off‐site Consequence Analysis (OCA) guidance to help facilities in their hazard assessment.OxyChem will be significantly impacted by the RMP rule. This paper outlines OxyChem's general experience and its strategy in planning to comply with this rule. OxyChem's approach in the development of the scenarios required by the rule is described in this paper. Limitations involved in the use of EPA's look‐up tables or a single modeling solution for conducting all of the OCA are discussed. A three tiered OCA approach is presented as a possible alternat

ISSN:1066-8527    

DOI:10.1002/prs.680170408

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

摘要:

AbstractGas explosion simulators are often used as tools in process plant design. This article presents some properties of gas explosions found using the EXSIM simulation software on three offshore modules with a total of nearly 10,000 simulations. The selected results are chosen for their supposed applicability to structural design in the process industries.Generalized data are presented for the effect of gas cloud size, explosion impulse vs. explosion pressure, pressure and impulse vs. duration, the probability of a “short” explosion, loading rate, pressure‐time “shape” function, and the effect of introducin

ISSN:1066-8527    

DOI:10.1002/prs.680170409

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

摘要:

AbstractAn ammonia storage tank was built at the BASF Antwerp site in 1969 on land reclaimed from the sea. After several years of operation uneven foundation settlement, of up 2, occurred. In order to assure stability of this area for the next operation period (at least 10 years) measures were taken to ensure continued safe operation. One key measure was strain gauge monitoring at the location of maximum stress.

ISSN:1066-8527    

DOI:10.1002/prs.680170410

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

摘要:

AbstractThe Baker‐Strehlow methodology was developed to provide an objective approach to prediction of blast pressures from vapor cloud explosions. The complete methodology was first published in 1994 [1]. Since then, it has evolved through ongoing research and use in VCE hazard analyses, facility siting studies and accident investigations. This article gives a brief overview of a paper on recent developments in the Baker‐Strehlow methodology presented at the 31st Loss Prevention Symposium in Houston on March 9‐13, 1997. Because the entire paper is too lengthy to be presented here, the following discussions may be lacking in some details. A copy of the complete paper can be obtained from the American Institute of Chemical Engineers (AIChE).Since the Baker‐Strehlow method was first published, it has been used extensively in VCE hazard assessments in refineries and chemical plants. As expected, many practical lessons have been learned during the course of the hazard assessments, and the Baker‐Strehlow method has evolved as a result. The changes have been evolutionary, not revolutionary. In keeping with the goals of the original study in which the methodology was developed, all changes have been incorporated with the intent of achieving an objective methodology to provide consistent prediction of VCE blast effects.The revisions to the Baker‐Strehlow method resulting from experience gained during plant walk‐downs and hazard assessments include:Systematic identification of “potential explosion sites” or “PESs,”Selection of the level of confinement for mixed zones of 2D and 3D confinement,Deciding on flame expansion when confinement is elevated above the vapor cloud,Selecting the reactivity for a fuel that is a mixture of fuels with differing reactivities,Predicting blast loads when there are multiple PES's within a vapor cloud considering different igni

ISSN:1066-8527    

DOI:10.1002/prs.680170411

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY