Hazard process development

Reducing and eliminating hazards and their associated risks is the second major objective. Applying inherent safety principles early in the product/process development effort provides the greatest opportunity to achieve the objectives of the inherent safety review process for the project at hand. If these principles are applied late in the effort the results may have to be applied to the project after next as the schedule may not permit implementation of the results. 

Implementing an inherent safety review process is one mechanism companies can use to institutionalize inherent safety. The review process should integrate well with company systems for process safety management, new product development, and project execution. Safety, health, and environmental considerations in the new product or process development effort can be strengthened via the introduction of the inherent safety review. Companies may also build inherently safer design concepts into their existing process safety management system and process hazard reviews. 

This process is perhaps best illustrated by a simple example. Fi 14-1. shows a hazard tree developed for the hazard" of injury ... 

In between, there will almost certainly be a numb of cases that are far less clearcut. For example, you may find situations in which PSM programs are well developed but fail to fully address a high-hazard process or a worst-case scenario in others, a facility engaged in relatively low-hazard operations may have a proportionately low level of PSM systems. 

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 ... 

Analyze Process Hazards by Developing Accident Scenarios... 

The advantage to this approach is that it provides a more complete identification of the hazards, including information on how hazards can develop as a result of operating procedures and operational upsets in the process. Companies that perform detailed HAZOPs studies find that their processes operate better and have less down time, that their product quality is improved, that less waste is produced, and that their employees are more confident in the safety of the process. The disadvantages are that the HAZOP approach is tedious to apply, requires considerable staff time, and can potentially identify hazards independent of the risk. 

The book is directed to those persons involved in research, process development, pilot plant scale-up, process design, and commercial plant operations. It is important for technical people considering alternative process routes to know the potential hazards from the main reactions and from the unwanted side reactions in each case so that the hazards of reactivity are included in the factors reviewed in developing and selecting the final process route. 

Fire and Explosion Index (E E1) A hazard index developed by Dow Chemical Company used to rank fire and explosion hazards in a chemical process. 

Realistically, the information available to perform risk studies varies over the lifetime of a process. During the early stages of process development, analysis teams may only have access to basic chemical reactivity hazard data, such as may be obtained from suppliers and literature resources. By the time a facility reaches the detailed design phase, most of the basic design and operating information should be available and used in any study of the facility hazards and risks. 

Mosley, D.W., A.I. Ness and D.C. Hendershot. 2000. "Screen Reactive Chemical Hazards Early in Process Development." Chemical Engineering Progress (96) 11 51-65. November. 

Mosley, D. W., A. I. Ness, and D. C. Hendershot (2000). "Tools for Understanding Reactive Chemical Hazards Early in Process Development." Proceedings of the 34th Annual Loss Prevention Symposium, March 5-9, 2000, Atlanta, GA, ed. E. Scheier and D. C. Hendershot, Paper LPS 3d (45d). New York American Institute of Chemical Engineers. 

The CSB investigation determined that BP Amoco was unaware of the hazardous reaction chemistry of the polymer because of inadequate hazard identification during process development. This lack of awareness is a commonly cited cause of reactive incidents within the CSB data. The BP Amoco incident also involved an endothermic (or heat consuming) reaction rather than the more commonly recognized exothermic (or heat producing) runaway chemical reaction. 

Understanding and identifying reactive hazards is a key component of process knowledge. It is often the first activity in managing reactive hazards and may occur early in product research or in process development. Ineffective hazard identification is commonly cited as a cause of reactive incidents. Where... 

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... 

The first stage of the site characterization process is the customization of the generic plan developed as part of planning and preparation for responding to contamination threats. In general, the incident commander will develop the customized plan in conjunction with the site characterization team leader. The steps involved in the development of the plan include (1) perform an initial evaluation of information about the threat, (2) identify one or more investigation sites, (3) assess potential site hazards, (4) develop a sampling approach, and (5) assemble a site characterization team. 

Envirocare of Utah, Inc. (Envirocare) has commercialized the polyethylene encapsulation process developed by Brookhaven National Laboratory (BNL) as an ex situ stabilization technology for hazardous and mixed wastes (wastes with both hazardous and radioactive components). 

Further information and examples of inherently safer design methods are given in references 3, 5 and 6. It should be noted that the successful incorporation of such measures normally depends oh the hazard assessment procedure starting at an early stage in the process development. 

Figure 3.5 displays the total wastes produced by the pharmaceutical industry and shows results similar to those in Figure 3.4. Figure 3.5 includes the on-site and off-site disposal, treatment, and release of toxic and hazardous materials. With the implementahon of green engineering and chemistry practices, there have been many improvements in the areas of process development and solvent selection. These innovations have led to solvent and energy reductions in many processes used today and the subsequent reduction of process waste disposal. Between 1995 and 2006, there was an approximate 47.6 million kilogram decrease in the total yearly amount of waste disposed of from the pharmaceutical sectors. 

The research role in safety and loss prevention goes far beyond identifying hazards. Research is instrumental in the discovery of less hazardous materials and in the development of less hazardous processes. For example, research at Dow led to a new processing technique which reduced the hazard of a process by reducing the maximum inventory of instantaneously hazardous materials. (See more detailed description in Ref. 3.) While inventory itself is rarely the source of an accident, the severity of human injury and property damage is largely determined by the quantity of hazardous materials released by the incident. 

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