Process development hazards evaluation

In this study detailed fault trees with probability and failure rate calculations were generated for the events (1) Fatality due to Explosion, Fire, Toxic Release or Asphyxiation at the Process Development Unit (PDU) Coal Gasification Process and (2) Loss of Availability of the PDU. The fault trees for the PDU were synthesized by Design Sciences, Inc., and then subjected to multiple reviews by Combustion Engineering. The steps involved in hazard identification and evaluation, fault tree generation, probability assessment, and design alteration are presented in the main body of this report. The fault trees, cut sets, failure rate data and unavailability calculations are included as attachments to this report. Although both safety and reliability trees have been constructed for the PDU, the verification and analysis of these trees were not completed as a result of the curtailment of the demonstration plant project. Certain items not completed for the PDU risk and reliability assessment are listed. 

After tlie system has been defined, a hazard evaluation technique can be used to identify different types of hazards within tlie system components and to propose possible solutions to eliminate the hazards. This topic is treated in more detail in the next t o chapters. These procedures are e.xtremely useful in identifying system modes and failures that can contribute to the occurrence of accidents diey should be an integral part of different phases of process development from conceptual design to installation, operation, and maintenance. The hazard evaluation tecliniques tliat are useful in tlie preliminary and detailed stages of tlie design process include ... 

It is difficult to identify all of the possible events and their consequences in a complex chemical processing plant without the application of systematic procedures and proper management techniques. Several hazard evaluation procedures have been developed. Most of these procedures are described in other AIChE/CCPS publications such as Guidelines for Hazard Evaluation Procedures [2,3] and Guidelinesfor Quantitative Risk Analysis [4]. Other publications on hazard evaluation techniques include [246,247]. 

Most survey respondents indicated that they perform reactive hazard evaluation studies during specific life-cycle phases of a process or product. These phases include process development, commercial process design, periodic re-evaluation, and before proposed modifications. The protocol for hazard evaluation of reactive systems varies from company-to-company. At a minimum, all surveyed companies employ qualitative hazard evaluations.58... 

A general account of how the CHETAH program may be applied to estimation of chemical hazards in relation to process research and development has been given [10], Progressively enhanced and user-friendly versions of CHETAH, which give an overall hazard assessment and are capable of running on personal computers are available from ASTM [11], Comments critical of the criteria used for hazard evaluation in the 1994 CHETAH program [12] led to amendments and enhancements incorporated in the 1998 Windows version. The pure compound physical properties databank has since been expanded from 400 to 1500 compounds and the... 

We think it is valuable to consider the techniques and approaches used in the rocket propulsion areas since many of the concerns, and the devices and approaches developed to cope with these concerns, can be used by the chemical industry. This is perhaps particularly true when one considers hazard evaluation. The procedures developed in the propellant industry to assess explosive and fire hazards are directly applicable to the chemical process industry. In addition, some of the techniques developed for measuring the properties of liquid propellants, particularly at elevated temperatures and pressures (and frequently on materials which can decompose or even detonate), can be used in similar studies with actual commercial chemicals. 

A large number of other tests and hazard evaluation techniques have been developed, both within Dow and by outside organizations. The owner of materials and processes should work with the local RC/TA/PP partner to determine what additional data are needed beyond those obtained from the basic screening tests. 

The Chemical Development Drug Evaluation branch of Johnson Johnson Pharmaceutical Research Development LLC in Raritan, USA, investigated the ring-expansion reaction of N-Boc-4-piperidone with ethyl diazoacetate in a microreactor system as an example of processing hazardous substances [34],... 

The Dow index applies only to main process units and does not cover process auxiliaries. Also, only fire and explosion hazards are considered. Recently the index has been expanded to include business-interruption losses. The principles and general approach used in the Dow method of hazard evaluation have been further developed by Mond in the United Kingdom to include toxicity hazards. This revised Mond index is described in a paper by Lewis ... 

Brannegan, D. P., Hazards Evaluation in Process Development, Chemical Process Hazards Review, p. 18. American Chemical Society, Washington, DC, 1985. 

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