Glass manufacturer Ardagh Group has pioneered a number of initiatives to overcome the problems associated with remelting recycled glass cullet, to ensure its furnaces receive the highest quality cullet to maximise energy and carbon savings. The latest problem to be tackled is the weather.
After delivery to the plant, cullet is typically stored in outdoor bunkers, where it is subject to variations in the climate, particularly during winter. If it has accumulated significant levels of water, snow and ice, it will require higher temperatures, and energy, to remelt it in the furnace.
Ardagh’s Nienburg plant in Germany sought to find a simple solution: to pre-heat the ‘frozen’ cullet before feeding it into the furnace. But it needed to capture heat already generated elsewhere in the plant, such as around the furnaces.
So Ardagh draws hot air at 80°C across the furnace, blowing it into a specially developed heat exchanger charged with energy to raise the temperature to 120°C and piping it to the bunkers. This has proved the most energy-efficient means of defrosting, drying and preheating the cullet. Annual energy savings of e116,000 have been achieved at Nienburg.
Johan Gorter, Ardagh Group chief executive for glass, Europe, said: “This is one of many planned actions we are taking throughout our European plants as we strive to meet the very highest sustainability performance standards.”