Process Plant Hazard Review using HAZOP

1 Process Plant Hazard Review using HAZOP 

HAZOP Checklist Consolidation HAZOP reports serve the entire life of the revamp 

The hazard review leader fosters open communication across all functional members during the discussions. The team should ensure that minimum safeguard requirements exist in the design, failing which a recommendation should be made. The responsible person/team is assigned for each of those recommendations and a time frame is stipulated in accordance with hazard review team s agreement with the management. 

Parameter Deviations from intended operation Parameter Deviation from intended operation 

Flow No flow, High flow, Low flow. Reverse flow. Misdirected flow Reaction No reaction. High reaction rate. Low reaction rate, Additional/Incomplete/ ReverseAVrong reactions 

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The hazard and operability analysis (HAZOP) technique was developed to identify both hazards and operability problems in chemical process plants. An interdisciplinary team and an experienced team leader are required. In a HAZOP application, a process or operation is systematically reviewed to identify deviations from desired practices that could lead to adverse consequences. HAZOPs can be used at any stage in the life of a process. 

A HAZOP is used to question every part of a process to discover what deviations from the intention of the design can occur and what their causes and consequences may be. This is done systematically by applying suitable guidewords. This is a systematic detailed review technique, for both batch and continuous plants, which can be applied to new or existing processes to identify hazards. 

A What-if analysis is used to assess consequences of deviations from normal operating conditions by asking "what if... " questions. This approach is often used for reviewing plant or process modifications. Because the procedure is less structured than some other methods, e.g, HAZOP, care should be taken to identify also the less obvious hazards [2,3,255]. 

Hazard and Operability Analysis (Hazop) (Kletz, 1992) is one of the most used safety analysis methods in the process industry. It is one of the simplest approaches to hazard identification. Hazop involves a vessel to vessel and a pipe to pipe review of a plant. For each vessel and pipe the possible disturbances and their potential consequences are identified. Hazop is based on guide words such as no, more, less, reverse, other than, which should be asked for every pipe and vessel (Table 1). The intention of the quide words is to stimulate the imagination, and the method relies very much on the expertise of the persons performing the analysis. The idea behind the questions is that any disturbance in a chemical plant can be described in terms of physical state variables. Hazop can be used in different stages of process design but in restricted mode. A complete Hazop study requires final process plannings with flow sheets and PID s. 

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