Process Safety Strategy - Chemical Reaction Hazard

It has been some time since I wrote my last post. I was on leave for my marriage. I have returned to the office now and I am back with another post on Chemical Reaction Hazards. Many times, I have come across people asking us what steps should be followed for identifying and mitigating the chemical reaction hazards. Today we will be talking on the same.

First, of all, I would like to thank Fauske & Associates LLC (FAI) for their continuous support and for publishing my last blog post on their website. If you have missed the same, you can access it by clicking on the link below

https://www.fauske.com/blog/should-set-point-for-pressure-relieving-device-be-equivalent-to-design-pressure

As per the research conducted by Dr Phil Nolan (South Bank University, UK) and Dr John Barton (UK Health and Safety Executive) and graduate students based on data analysis, the following four gaps have contributed equally i.e. 25% each to thermal runaway reactions leading to multiple incidents in past:

1. Lack of proper understanding of the thermochemistry (heat of reaction) and chemistry (balanced chemical equation)
2. Insufficient engineering design for reactor heat transfer system
3. Inadequate control and safety back-up systems including emergency relief systems, process vent, and other engineering controls
4. Poorly written batch procedures and insufficient operator training.

Concept Sciences Inc. Explosion

Hence, it is imperative to develop a process safety strategy to address these four gaps. A process safety strategy should include the following:

Relief Device Sizing and worst case scenario of Over-Pressurisation

Thanks to all for overwhelming responses to the recent update on Partial Inerting and Operator Earthing.

Looking at recent incidents that have happened in India, this topic was long due to being covered here on my blog. If we look at the Hyderabad Reactor Explosion or Tarapur Explosion or the more recent Moosapet Explosion, all have been suspected to be reactor explosion because of overpressurization.

The companies who are into manufacturing sector usually size their relief devices in the designing stage, when the process to be followed is not finalized and hence they assume a base solvent and size the relief devices for its vaporization in case of an external fire.

Now if we consider the T2 Laboratories accident where MCMT (Methylcyclopentadienyl Manganese Tricarbonyl) was being manufactured, an explosion which was equivalent to 1400 pounds of TNT was a case of a runaway reaction and killed 4 employees of T2 laboratories and injured 32 others. The impact was heard till 15 miles, the debris was found up to one mile away & buildings were damaged till one-quarter of a mile.