Genuine 3D Modelling and Simulation Approach to Reduce Risk to Asset and People

Typically, consequences from unwanted process releases have been quantified using simple 2D so-called analytical techniques. Some vendors claim that these tools can do 3D advanced explosion modelling but this is misleading. The reality is that the results are still based on the same simple empirical relationship and represented in a 3D visual interface. The impact of the geometry, equipment items is crucial for explosion modelling and it needs to be included in the explosion modelling not for a graphical effect. It is well accepted in the industry that these simplified tools used either over-predict or under-predict potential consequences and risk associated with major toxic and flammable releases resulting in either unsafe design or excessive project costs without proportional risk reduction. The presentation is about new ways of evaluating safety design issues using an advanced CFD tool called to obtain more accurate consequence and risk results based on the actual genuine plant geometry.

The combination of the 3D geometrical equipment layout and wind effect on the ventilation field cannot be accounted for with analytical models. Local turbulent areas or stagnant regions due to wind shield effect will not be represented. This can have a significant impact in the development of a toxic or flammable cloud, as observed from many major accident investigations. 3D obstacles really matter and need to be accounted for in the calculations not just overlaid on results from predictions that ignore these equipment items, building, beam structures, etc. Besides analytical modelling cannot simulate what will happen when releases are into low wind conditions or impinging on surfaces such as pipping and solid structure, or release into the wind. The same conclusion applies for any radiation or overpressure effects on plant structures.

The development of FLACS® has been sponsored by several major oil operating companies over the last 25 plus years, including Total, BP, Statoil, ExxonMobil and ConocoPhillips to name a few. These operators have been funding the development of the software tool but more importantly the validation work using large scale experiments. By having a detailed analysis and being able to present results in an intuitive manner, operating companies can help authorities to visualize and assess better realistic major hazards risks and ensure compliance with national regulation. Videos and pictures produced from FLACS® accurate predictions do facilitate the communication of findings from the risk analysis.