Plant Safety Modeling Approach

Part I presents an overview of the book where scope, problem definition and solution significance are explained. It presents the background and similar research work done in this area. Also it describes the approach followed along with the theoretical and methodological framework developed to achieve the stated research objective. In this section, the plant safety model is presented as the base of designing CAPE-SAFE within PEEE. 

As the proposed plant safety model is aiming to cover all activities in the plant lifecycle to ensure safe plant activities, it is difficult to achieve that without having a systematic approach to abstract plant lifecycle... 

The problem and the required solution will dictate the experimental and modeling approach adopted. Many trade-offs driven by the need to balance economical operation against public/personnel safety must be made. When cost is the predominant driving force, engineering expediency leading to short-term solutions based only on qualitative assurances often dominate. Models for plant behavior must be based on accurate and realistic data to avoid unnecessary and costly shutdowns due to overly conservative predictions. Often, in this context, accurately measured but empirical data may be more valuable than a fundamen-... 

Second, in the case of chemical plants, it is often possible to eliminate hazards at source by careful design of the system. The safety case approach stresses this idea of getting it right in the first place and is therefore particularly appropriate. In contrast, the hazards of coal mining are not man-made and are not as easily eliminated. The emphasis must therefore be on the ongoing management of these hazards, for which the trigger event model is particularly appropriate. 

It is no longer simple deterministic thinking that governs safety evaluations. The use of probabilistic approaches has become a commonly accepted practice. Probabilistic ranking is accepted for ranking deterministic evaluation. Probabihstic models also permit testing of the sensitivity of a specific safety aspect when compared with overall plant safety. 

In this section, highlights on plant lifecycle modeling using object-oriented approach as well as the conceptual safety model that covers all safety aspects within the plant lifecycle will be explained. 

As a part of the plant safety framework, common data component is proposed to manage all common data for the plant safety framework and to accumulate the safety-related common data across plant activities. This component is a part of the data warehousing for the plant-wide activities across the plant lifecycle. The object-oriented modeling approach is used to abstract these common elements within the plantwide conceptual model while the physical data are within the data warehouse frame. The safety common data (SCD) component includes (but not limited to) the possible source of data errors, documentation standards (vocabulary), generic cause-consequence for each component type, checklists for operation-type jobs, and standard safety interlock levels. The common data are essential to be organized and formatted in a... 

The approach starts with the contextual modeling of the As Is business model, which describes the current profile of the plant safety division. The profile includes business segments, products/services, customers, suppliers, and other forces impacting the business. 

Gabbar, H.A. (2000h), Suzuki, K., Shimada, Y. Unit Operation Modeling Approach For Plant Safety Practices, Conference Proceedings of Society Of Plant Engineers in Japan (SOPEJ), Nov-2000, No. 3, pp 27-32. 

Figure 1 attempts to define the key stages in the development of corrosion models. Irrespective of whether the key concern is safety or operating efficiency, the steps involved in model development are common up to the point where data reliability must be accounted for (stage 8). At this juncture, the approaches deviate. When public/personnel safety is the key issue, one would adopt conservative assumptions (stage 9A) to cover the uncertainties that will inevitably permeate one s model. If plant efficiency is the key issue, then at this juncture it is necessary to refine one s data input by a combination of further experimentation and the careful consideration of information from plant inspection records (stage 9B). 

Undoubtedly, this new kind of integrated approach is well representative of what should be membrane engineering, with final objectives clearly defined, the right hypothesis and choice of simple equations for modeling, a realistic representation of real complex solutions and the set-up of efficient simulation tools involving successive intra- and extrapolation steps. It appears to be easily extended to other membrane operations, in other fields of applications. It should provide stakeholders with information needed to make their decision costs, safety, product quality, environment impact, and so on of new process. Coupled with the need to check the robustness of the new plant and the quality of final output, it should constitute the right way to develop the use of membranes as essential instruments for process intensification with industrial units at work. 

Safety Authority will take responsibility in this area. How this will work out has to be seen in the near future. Nevertheless, the straightforwardness of the approach does not hide the relatively complex methods that are used or have to be used. The models applied in the determination of the PEC are far from simple they contain the current state-of-the-art of the scientific description of chemical, physical and microbiological processes in the environment. The methods will be kept update and communications with the research institutes and the users of the models will continue. The main aim is to keep having available a system of methods to carry out risk assessments for plant protection products. 

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