A mischarging incident occurred in a reaction between chloroacetyl chloride and an amine. In the desired process solvent and amine were charged and cooled to 10-12°C. 30% of chloroacetyl chloride charge was then added, followed by the remainder of the chloroacetyl chloride addition maintaining pH at 5-7 using 47%NaOH.
In the incident, the solvent was charged but then the wrong valve was opened and the amine was not charged. The acid chloride was added and the caustic added to adjust pH. There was a rapid gas evolution and over-pressurisation of vessel. No one was injured but there were significant financial penalties.
Root cause analysis of the incident concluded that:
- The process instructions were imprecise
- The plant layout was confusing
- There was no data on maloperation
- The relief system was not sized correctly