Studies on the Digraph-Based Approach for Fault-Tree Synthesis. 1. The Ratio-Control Systems

2004

IEEE Trans. Rel.

A systematic approach to construct fault trees for advanced process control systems is presented in this paper. For illustration purpose, the proposed method is explained with a specific feedback scheme, i.e., the cascade control strategy. The digraph configuration of a standard system is first described and analyzed in detail. On the basis of a series of qualitative simulation studies, all failure mechanisms can be identified and summarized with a set of generalized fault-tree structures. The fault trees produced with the conventional digraph-based techniques are shown to be not as comprehensive as the ones constructed with the proposed approach. To demonstrate the correctness of our analysis, the successful application of the proposed structures to a heat exchange process is presented. In addition, the resulting fault tree is compared with one obtained from a single-loop feedback control system and the trade-off between the two in system reliability and control performance is assessed accordingly.

Section: Introductionmentioning

confidence: 99%

Constructing Fault Trees for Advanced Process Control Systems—Application to Cascade Control Loops

Chen

2004

IEEE Trans. Rel.

“…Several generic expert systems have also been constructed to produce comprehensive HAZOP reports. − The prerequisite of fault identification in using these methods is basically a qualitative system model. It can be observed from the literature that digraphs are, by far, the most popular choice. − Although the digraph-based approach has been demonstrated to be useful, it is effective mostly in applications concerning continuous processes. This is because digraphs are inherently unsuitable for describing dynamic causal relationships among times, discrete events, equipment states, and system configurations in batch or semibatch processes.…”

Section: Introductionmentioning

confidence: 99%

“…It can be observed from the literature that digraphs are, by far, the most popular choice. [9][10][11][12] Although the digraphbased approach has been demonstrated to be useful, it is effective mostly in applications concerning continuous processes. This is because digraphs are inherently unsuitable for describing dynamic causal relationships among times, discrete events, equipment states, and system configurations in batch or semibatch processes.…”

Section: Introductionmentioning

confidence: 99%

Petri-Net-Based Deductive Reasoning Strategy for Fault Identification in Batch Processes

Wang

2004

Ind. Eng. Chem. Res.

Self Cite

In implementing any hazard analysis method, there is always a need to reason deductively to identify all possible fault origins that could lead to an undesirable consequence. Because of the complex time-variant cause-and-effect relations between events and states in batch chemical processes, a rigorous risk assessment study is labor-and time-consuming, and its results are often error-prone. The aim of this paper is thus to develop deductive reasoning algorithms on the basis of Petri nets for automating such cause-finding procedures. The effectiveness and correctness of this approach is successfully demonstrated with a number of practical examples.

“…Vaidyanathan and Venkatsubramanian 1,2 developed a systematic approach to automatically perform HAZOP analysis for continuous processes. Chang et al , improved the Lapp−Powers algorithm with qualitative simulation techniques. Khan and Abbasi built an expert system OPTHAZOP for hazard identification and verified it with the chloroalkali process.…”

Section: Introductionmentioning

confidence: 99%

Petri-Net Models for Risk Analysis of Hazardous Liquid Loading Operations

Balasubramanian

Wang

2002

Ind. Eng. Chem. Res.

Self Cite

A vigorous hazard assessment is almost mandatory for the safety and risk-free operation of any chemical plant. A systematic approach has been developed in this study to construct a generic Petri-net (PN) model for analyzing the liquid ammonia loading process. A set of sub-PNs were first built for all components in the system. Failure mechanisms were then developed and incorporated into these component models. On the basis of predefined hazardous conditions, the critical fault propagation scenarios were identified accordingly with simulation studies. It is observed from the simulation results that the proposed model can be effectively used for hazard identification in the sequential operations.