QRA of chemical reaction systems: The state of the practice

Abstract

This paper discusses a quantitative risk assessment (QRA) of an exothermic chemical process. Fault tree/event tree techniques were used to estimate the frequency of runaway reactions that could result in over‐pressure and vessel rupture. The paper focuses on the current methodology used in performing this type of study, emphasizing analytical techniques that help avoid potential time‐consuming pitfalls. The challenging problem of predicting how rare sequences of events (e.g., involving failure of several engineered control and safety systems) will develop is systematically modeled using fault trees/event trees, which makes the QRA process a unique and powerful analytical tool. The results of this study provided the guidance for selecting the most appropriate action(s) to implement from a set of various design options for improving the safety of this system. Use of QRA has enabled plant management to have confidence that they are selecting the most cost‐effective safety improvement option.

Synthesis of 4-Chloro-3-nitrobenzotrifluoride: Industrial thermal runaway simulation due to cooling system failure

“…One of the most frequent causes of industrial equipment failure is the breakdown or the loss of control of the coolant pumping system (Gygax, 1988;Farquharson et al, 1997;Svandova et al, 2005;Kidama and Hurme, 2013). This accident involves the absence of cooling liquid circulation into the reactor jacket with the consequent establishment of nearly adiabatic operating conditions.…”

Quantitative risk assessment case study for organic acid processes

“…A contract firm, ABS Consulting, was used to perform the QRA calculations. For more specific information about the QRA method, see “QRA of Chemical Reaction Systems: The State of the Practice: (Ref 4…”

Proximity risk assessment for two sensitive chemical plants based on the accident scenario consequence analysis

“…The widely systematic accepted approach of the risk assessment problem is the so‐called ‘Chemical Process Quantitative Risk Analysis’ (CPQRA), which provides analytical/model‐based tools ‘for the engineer or manager to quantify the plant risk and to analyse the potential risk reduction strategies’ . The CPQRA is part of the risk management system intended for evaluating the risk of an industrial plant, and also aiming at taking suitable actions to prevent, reduce and cope with an accident situation .…”

“…[1] The widely systematic accepted approach of the risk assessment problem is the so-called 'Chemical Process Quantitative Risk Analysis' (CPQRA), which provides analytical/model-based tools 'for the engineer or manager to quantify the plant risk and to analyse the potential risk reduction strategies'. [2][3][4]49] The CPQRA is part of the risk management system intended for evaluating the risk of an industrial plant, and also aiming at taking suitable actions to prevent, reduce and cope with an accident situation. [5] Although hazard assessment concerns evaluation of the past and present evolving preconditions leading to system failure, the risk and plant safety concern evaluations of possible accident scenarios leading to future prevention actions.…”