The main reason for the complex cleaning process is the fact that hydrocarbon-based rolling oil is used for cooling and lubrication in the foil-making process.

A small percentage of this oil evaporates during rolling and is drawn off along with the surrounding air by the fume extraction equipment. This exhaust air/oil mixture is transferred to the air washer, where the rolling oil is separated from the air stream by absorption using a special washing fluid. 

Most of the rolling oil is subsequently recovered by means of vacuum distillation and returned to the rolling process. The washing fluid is also cleaned and reused in a closed circuit while the purified air is safely released into the atmosphere.

The new equipment, which will be taken into use early next year, will make substantial energy savings and will reduce the environmental impact of Series 2 production significantly, in particular as far as hydrocarbon, odor and acoustic noise emissions are concerned.

It also ensures compliance with new German emissions directives, replacing a first generation of exhaust air cleaning systems that was installed with the commissioning of the Series 2 production line in 1986.

Hydro is a leading supplier of thin and ultra-thin aluminium foil for the packaging industry.