Читать книгу Industrial Environmental Management - Tapas K. Das - Страница 77

On Saturday, 1 June 1974, the Nypro (UK) site at Flixborough was severely damaged by a large explosion. Twenty‐eight workers were killed and a further 36 suffered injuries. It is recognized that the number of casualties would have been more if the incident had occurred on a weekday, as the main office block was not occupied. Offsite consequences resulted in 53 reported injuries. Property in the surrounding area was damaged to a varying degree.

The chemical plant was designed to produce 70 000 T/Y of caprolactam, a raw material for the production of nylon. The process used cyclohexane as a feed and oxidized it to cyclohexanol in the presence of air within a series of six catalytic reactors. Under process conditions, cyclohexane vaporizes immediately upon mixed depressurization, forming a cloud of flammable cyclohexane vapor mixed with air. Reactor 5 was found to have a small crack in the stainless steel structure in the series using a 20 in. pipe, even though the reactors are normally connected using 28 in. pipe. The temporary section of piping was not properly supported and it ruptured upon pressurization, releasing an estimated 30 T of cyclohexane in a large cloud. An unknown ignition source caused the cloud to explode, leveling the entire plant facility. The resulting fire in the plant burned for over 10 days. The accident could have been prevented by following proper safety design and operating procedures, including reducing the inventory of flammable liquids onsite (CCPS 1993; Crowl and Louver 1990).