Dependability modelling and evaluation by using stochastic Petri nets: application to two test cases

“…When the transition is fired the input place tokens are redistributed and the net achieves a new state. The features of Petri net modelling are described by Malhota [12] and Dutuit [13]. An overview of Petri nets and their applications in batch processes is given by Gu and Bahri [14].…”

Section: Expert Systemsmentioning

confidence: 99%

An automated system for batch hazard and operability studies

Palmer

Chung

2009

Reliability Engineering & System Safety

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A widely used hazard identification technique within the process industry is HAZOP (hazard and operability study). To overcome the repetitive and time-consuming nature of the technique automated systems are being developed. This work considers batch processes, in which material undergoes processing in distinct stages within the plant equipment items according to a set of operating procedures, rather than each equipment item remaining in a "steady state", as is normal for continuous plants. In batch plants deviations which can lead to hazards can arise both from deviations from operating procedures and process variable deviations. Therefore, the effect of operator actions needs to be considered. CHECKOP is an automated batch HAZOP identification system being developed as a joint project between HAZID Technologies Ltd and Loughborough University. CHECKOP uses a state-based approach to HAZOP analysis. CHECKOP takes a plant description and a set of operating instructions as input and produces a HAZOP report automatically. The overall system architecture and the details of the major components of the systems will be described. Examples of incorrect plant operation along with the resulting output generated by CHECKOP will be shown. The advantages and limitations of CHECKOP will be discussed.

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“…Most dependability studies are based on a probabilistic approach to dependability, which aims to describe system behavior using state-space methods that allow complex behavior to be represented. Typical approaches to modeling availability of systems use Markov chains, (Trivedi et al, 2006) or Petri nets (e.g., the Fault/Error Handling Model (FEHM) - (Trivedi et al, 1987), the Fault/Repair Model (FRM) - (Hein and Goswami, 1996), (Dutuit et al, 1997)) which allow failure/repair behavior to be modeled. More recently, the degradation dynamic in systems that are subject to wear has been more precisely examined in order to assess system dependability when optimizing maintenance operation (Muller et al, 2006).…”

Section: Related Workmentioning

confidence: 99%