Runaway exothermic resin reaction - issue 256

Issue Number: 256


A runaway exothermic reaction occurred on a Teesside ICI resin plant in 1976 when a batch of unsaturated polyester resin alkyd was being transferred from a reactor to a thinning vessel. The relief system did not cope with the pressure generated and resultant over pressuring of the equipment occurred, causing various joints to fail and releasing vapour and decomposing liquid alkyd into the atmosphere. There was no fire and no personnel on the plant suffered injury, though several personnel on neighbouring areas were affected to a minor degree by the fume emission. In re-reviewing the incident from a historical perspective, the author notes that the process operated on an incorrect assumption that an exotherm could not occur in the full scale plant (despite occurring on a laboratory scale), highlighting a tendency towards over-optimism and believing evidence supports the desired outcome.

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