How could this hazard have been discovered
- using a computer assisted HAZOP analysis?
2017-01-28 20:00 Niels Jensen
Safepark certainly believe the answer to this question is YES. The reason is that MFM models of the unit can easily be developed, and that such models allow the reasoning about causes and consequences of deviations, the results of which would assist HAZOP teams during either a MoC or HAZOP study. A simple model could be developed with less than a days work by an expert in MFM model development.
Safety video show, what happened, but how to prevent it!
That is the largest weakness of a safety video. The video to the right was recently released by the #CSB. A small design change that was performed at the Willams Olefins Plant many years ago to allow a distillation tower to run with just one reboiler instead of two in parallel resulted in 2013 in an #overpressurization and rupture of one of the reboilers. The resulting explosion killed two workers and injured many more. A copy of the CSB Case Study can be downloaded from this page. The pictures are curtesy of CSB.
Design change without MoC or HAZOP spells disaster
The design change resulted in it being possible to isolated the reboiler from its protective safety valve. This hazards was not discovered during a MoC or 3 later PHAs. That different teams of experts did not identify the hazard which caused the explosion in 2013.
It would be relatively easy to construct a functional model using multilevel flow modelling (MFM) to investigate possible over-pressure scenarios, and hence identify the hazard, which humans overlooked. Safepark was involved with a Danish research group at DTU, which is working to make computer assisted HAZOP a reality for situations, such as this one.
2016 10 19 CSB_Case_Study Williams_Geismar_Olefins_Plant