Alunorf in Neuss, the world's largest aluminum rolling and melting plant, plans to build new annealing furnaces in cold rolling operations and to equip them with a highly energy-efficient online process control. Every year, the innovation should save around 4.9 million kilowatt hours (kWh) of electricity and 9.8 million kWh of natural gas compared to the old systems, which leads to the avoidance of emissions amounting to 8,300 tons of CO2.
So far, the annealing furnaces can only be filled with coils that have cooled down after rolling. Cool down to heat it up again? That doesn't sound like high energy efficiency, but today it is necessary for a safe process in which the temperature is only controlled for the entire furnace and is based on metallurgical experience and settings derived from tests.
The new process, on the other hand, is intended to measure the respective temperatures both at several points in the furnace and on the coils before they come into the furnace. The new program calculates in real time the amount of energy that is individually required to anneal each coil. After loading, it controls the heating of the respective oven sections and generates exactly the necessary heat - no more.
“We will avoid the current loss of residual heat when cooling the coils as well as reducing the consumption of specific energy for our annealing furnaces. It is an excellent combination of savings in costs and emissions, good for the result and the environment, ”says Alunorf Managing Director Thomas Geupel.
The new annealing furnaces will be completed in the fourth quarter of this year and the new process control should then work fully in spring 2012.
Also tests with fuel cells
"And we will continue to do nothing to try to develop and implement the most energy-efficient processes," emphasizes Geupel.
Another current project at Alunorf is about fuel cell systems: To what extent can you ensure an efficient and reliable emergency power supply and thus support the maintenance and supply facilities of an industrial company? This is tested on the basis of a few installations with fuel cells at Alunorf: in the crisis center, in the fire station and in the medical center. The project originates from the "Fuel cells for maintenance" initiative and is part of a nationwide research program for this type of energy system.
Recycling is expanding
Since Alunorf partially emits its process heat to heat the nearby Neuss-Allerheiligen district, residents may wonder whether they will get less energy in the future. Geupel: "Don't worry. It is in our smelting plant, a completely different operation of our large location, where waste heat is collected and passed on using the latest heat exchanger technology in order to guarantee the heating comfort of the residential buildings in the whole district - with zero emissions. "
The remelting processes of Alunorf will also increase their contribution to climate protection and resource efficiency, because another double-chamber furnace - just like the first one that has been in operation for Hydro in the recycling center since the end of 2009 - is now being built. It is expected to recycle a further 50,000 tons of painted aluminum scrap and used products every year. Compared to the unique, primary aluminum production, this "always new" recycling saves & nbsp; in the second stage of expansion, emissions of 490,000 tons of CO2 each year.