Avoid Run-Away Reaction

Image © EPSC


Bhopal & Seveso incidents occurred after an exothermic exponential runaway reaction started.

When Important

  • Exothermic batch reactions.
  • Storage of reactive chemicals.
  • Unexpected Polymerization or Decomposition.

Challenges in the Field

  • Chemistry at increased temperature can be different or unknown to operators.
  • Cooling can malfunction or might not be able to cope with the exponential increase of the reaction rate.

Options to Get it Right

  • Understand the chemistry and side reactions at abnormal conditions like elevated temperature.
  • Understand the point where cooling can not cope with the exponential heat of the reaction (point of no return).
  • Assure good design data is available on heat balance of all the reactions involved (like DSC curves).
  • Understand the effect of malfunctioning cooling.
  • Have a reactivity matrix available & make sure operators know the critical combinations of chemicals to avoid.
  • Assure cooling is reliability and have back-up cooling available.
  • Validate inhibitors are present as applicable.
  • Have a last line of defence like Interlocks, Breaker plates, Bunkers.
  • Have an emergency procedure: Run away in a runaway reaction!

This page only summarises the guidance – refer to the EPSC website for further information.

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