Assessing a runaway of a Grignard reaction

The venting and control strategies of a Magnesium Grignard formation reaction were assessed by theoretical predictions of the exotherm and the reaction rate, by simple laboratory measurements of the self heat rate, and by Leung's simplified equations and SAFIRE evaluations, based on DIERS methods. SAFIRE computations showed that the 150 mm dia vent was capable of keeping the reactor pressure below its maximum (MAWP) of 860 kPa for the worst‐case exotherm. The response to this evidence was to increase safety protection in the automatic control strategy, following a quantified fault tree analysis of the worst‐case runaway scenario.