A fire broke out at around 9:50 a.m. on the pre-filters of the air system supplying the granulation tower of an agrochemical plant specialised in the production of gelatine. The site was evacuated as a precaution. The fire was limited to the pre-filters, and the emergency services were able to bring it under control at 10:25 a.m. The fire caused the drier to be shut down for five days, for an overall cost of €50,000 including the operating losses and repair costs.

The fire occurred during the granulation tower’s drying phase, after partial washing. During the manual bypass operation of the tower’s dust collector, a weak backdraft of air flowed back to the pre-filters while the air heaters had raised the temperatures above 300 °C. This phenomenon generated the combustion of the paper/polyester filters. The following corrective measures were taken:

• implementation of a maximum heating threshold on the programming of the batteries,
• control of the air flow to the filters
• slaving of the tower’s fans with additional air.