Dr Martin Lawrence, Combustion Development Specialist at Air Products, discusses how Industry 4.0 technology can be used to enhance the effectiveness and efficiency of the aluminium recycling process.
If there’s one thing we’ve learnt during the last year, it’s about how we can use technology to work smarter, faster and be more productive to generate better results.
From the corporate world to industry, many of us have been making these improvements for the better. Let’s look at aluminium recycling as an example. Aluminium is an important asset to many industries, not least due to the way its sustainable and lightweight properties can reduce environmental impact.
As the metal is 100 per cent recyclable, it can therefore contribute to the circular economy and, for example, use 95 per cent less energy than is needed to produce primary aluminium.
However, while this is all good news, it’s also essential for manufacturers to consider the carbon footprint of the aluminium itself, with a renewed focus on it being as sustainable and environmentally friendly as possible. In fact, aluminium recycling has become key for those keen to continue using the material while cutting down on the environmental impact of their activities.
For secondary aluminium production, the efficiency and effectiveness of remelting furnaces can be enhanced with oxygen-enhanced combustion technology – which can be further improved thanks to Industry 4.0 technology.
For secondary aluminium production, the efficiency and effectiveness of remelting furnaces can be enhanced with oxygen-enhanced combustion technology – which can be further improved thanks to Industry 4.0 technology.
At Air Products, we work closely with the secondary aluminium industry to improve this increasingly popular remelting process and have developed a range of oxygen enhanced combustion technologies aimed at improving efficiency and reducing environmental impact.
Using Industry 4.0 technologies, we work in partnership with our customers to identify and overcome challenges, ensure continuous improvement and deliver sustainable solutions.
Traditionally, operators at aluminium recycling plants use their skills and experience to predict when the aluminium has reached tapping temperature. The significant variability in the remelting process however can often mean that these predictions aren’t always fully accurate, which in turn can contribute to longer cycle times, reduced energy efficiency and increased aluminium losses.
This is where data can provide a wealth of information and play a key role in helping to tackle this inefficiency.
By using smart technology, we’ve developed a system that can address these challenges, accurately predicting the optimum temperature to prevent the metal overheating, which can save time, energy and improve yield.
Melting performance can also be improved by reducing the frequency of opening the furnace door to check melting progress, resulting in lower energy losses and less idle time.
Embracing the fourth industrial revolution
The use of Industry 4.0 technology is a brand-new innovation in the aluminium recycling process, bringing an exciting new way of working into the sector and utilising the latest advanced technology to drive efficiencies and improve the triple bottom line: safety, productivity and environmental performance.
For example, smart technology can be used to log key performance and operational parameters over time, creating a ‘digital twin’ virtual representation (or model) of the equipment or melting process to improve efficiency and reduce maintenance time.
A digital twin model uses the data to determine the efficiency of the melting process and calculate when the metal inside the furnace has reached its optimal yield conditions. Real-time closed or open-loop feedback is provided, to either automatically shut-down the burner or to alert the operators that the metal has reached the required temperature for pouring.
Accurate end-of-melt prediction, combined with timely burner shutdown control, can provide significant benefits, including improved yield, increased productivity, energy savings and reduced carbon dioxide (CO2) emissions.
Critically, as new data continues to feed into the model, machine learning technology improves its predictions over time. It is the consistent advancement and upgrade to technology that means that manufacturers can continue to shape and scale their activities, while taking into account the environmental impact of working with materials such as aluminium.
Working in tandem with Tandom
This process has been explored by Air Products and Tandom Metallurgical Group to monitor the impact of using Industry 4.0, sensors and process data to achieve greater efficiencies and energy savings.
The Cheshire-based company, which produces aluminium alloys, master alloys and recycles aluminium products, scrap and dross, took part in a 10-month study with Air Products to test the technology.
A digital twin model was developed and implemented on a tilt rotary furnace (TRF) used to remelt aluminium dross materials. The data collected was analysed to determine aluminium oxidation losses over a large number of cycles, and regression analysis showed an exponential relationship between yield loss and metal tapping temperature.
Baseline data was compared with data from cycles that were completed using the digital twin, which found that an accurate model of end-of-melt prediction, combined with timely burner shutdown control, provided significant benefits in production and yield, as well as energy savings.
The importance of tapping temperature on aluminium loss was also revealed. For example, tapping liquid aluminium at 900°C (1,652°F) as opposed to 750°C (1,382°F) for a charge material with 80 per cent aluminium content, will lead to an additional yield loss of about three per cent.
It is the consistent advancement and upgrade to technology that means that manufacturers can continue to shape and scale their activities, while taking into account the environmental impact of working with materials such as aluminium.
The patented Air Products Process Intelligence (APPI) Process Advisor system was used to better predict when the material inside the furnace is ready to be tapped, thereby reducing tapping temperature and improving aluminium yield.
More than 1,400 cycles were analysed and compared with base data from over 1,000 cycles, and the overall average tapping temperature was successfully reduced by 44°C. The improvement in yield was noted to vary depending on the materials in the furnace. The average reduction in temperature corresponds to a yield improvement of 0.5 per cent.
Reducing the metal tapping temperature also led to a dramatic reduction in energy consumption, with an average reduction of 15 per cent. Energy usage goes hand-in-hand with carbon dioxide emissions and 15 per cent energy savings is equal to the same percentage reduction in CO2 emissions. Furthermore, an average time saving of 5.7 per cent was also achieved, due to using the digital twin, where some materials performed better than others.
Looking ahead
It’s incumbent on all of us across the supply chain to deliver improvements to efficiency, embrace technological advances, streamline our work and ultimately reduce the environmental impact of our activities.
The benefits of introducing Industry 4.0 technology into industrial processes are clear. By embracing the use of data, the industry can be empowered to make more informed decisions to improve processes and drive efficiencies.
The net result: more sustainable performance, heightened productivity, better quality products, reduced energy usage, lower emissions, and less landfill. That’s the sort of future we all need to invest in.
