Non-ferrous Case Studies

On-site analysis, teamwork and customized computer modeling provide welcome relief for aluminum producer's cast house challenges.

Issue: As the economy rebounded and demand increased, an aluminum customer’s cast house became a bottleneck. Air Products had previously presented the benefits of oxy-fuel combustion for their operation, so the customer re-engaged Air Products in search of a production increase of 25% for one of their reverberatory melting furnaces.

Solution: After spending time onsite with the customer’s engineers and operators, Air Products had the necessary data to build a computer model of the furnace. The computational modeling was critical, allowing us to simulate the furnace temperature and melt rates if oxy-fuel burners were installed at the plant, in conjunction with their regenerative air-fuel burners. Visiting Air Products’ Combustion Labs in Allentown, Pennsylvania, the maintenance manager for the facility was very clear, stating “We need a partner, not a supplier.” He stated that their specialties are melting metal, casting billets and making aluminum extrusions, not oxy-fuel combustion. With Air Products’ oxy-fuel system and the new collaborative relationship, the project was a success and the customer is now melting 25% more metal per day, resulting in more extrusions and higher profits. Based on this success, they are looking to expand the use of our oxy-fuel systems to their other furnaces.

True cooperation delivers outstanding yield improvements and advanced controls development.

Issue: Air Products has been supplying technology to the secondary aluminum industry for over 30 years. In fact, most companies using oxy-fuel systems in this industry are using Air Products technology. Air Products’ patented High-Yield Oxy-fuel Burner was developed for use in rotary furnaces to minimize melt losses and flux usage, while increasing productivity. The benefits were proven in several beta sites and commercial installations in the US and Europe. To take it to the next level, and further quantify the benefits under various operating conditions, Air Products sought a forward thinking manufacturer.

Solution: Air Products turned to a secondary aluminum industry leader with unique capabilities. As yield is a very difficult parameter to measure accurately, we knew this cutting-edge company would be up to the challenge. Through proprietary software of their own, they were able to track the benefits of the innovative burner, by scrap type, in one of their rotary furnaces. Now they are converting all their furnaces to the new burner design. They are not only advocates of the yield improvement but are working with Air Products engineers to develop the next generation of advanced controls.

Producer of aluminum remelt secondary ingot (RSI) gets faster cycle times and fewer emissions with Air Products' custom-fit burner design.

Over fifteen years ago, Greenway Industries recognized a need for a rotary furnace operation in Ontario, Canada and stepped up to fill the void. From the beginning, Greenway has been committed to progressive technology, believing that would translate into better yields and happier customers. To do this, Greenway turned to Air Products for its proprietary oxy-fuel burners. “We have a good working relationship with Air Products, both from a technical and sales standpoint,” states Rob Rakovsky, Vice President at Greenway Industries, continuing “We are now on our third rotary furnace using Air Products’ oxy-fuel technology and currently operate a 27,000 pound furnace and a 36,000 pound furnace boasting an empirical capacity of 10-12 million pounds of metal production per month.”

Greenway Industries makes aluminum remelt secondary ingot (RSI) in a multitude of grades, including at this time, 380, 356, 6061, 6063, 3104, 3105, and 3003. The RSI is cast into 2000 pound sows which are sold to the automotive foundries, die casters, rolling and sheet mills, and billet casters. The scrap material being recycled is processed in two rotary furnaces which have the oxy-fuel burner mounted on the door. Once the door is closed, the furnace becomes a closed vessel where computer monitoring is used to adjust the stoichiometric ratios, controlling the atmosphere in the furnace. This controlled furnace atmosphere produces less oxidation and therefore better yields with fewer emissions according to Greenway’s Rakovsky. “We believe that the oxy-fuel system gives us a faster cycle time than with natural gas (and ambient air) alone,” says Mr. Rakovsky, continuing “and it creates a win/win/win situation for our customers, our business, and the environment.”

As experienced by Greenway, Air Products offers state-of-the-art oxy-fuel burner systems with flame shape, size, luminosity and oxygen retention all designed specifically for rotary furnaces. The company’s proven burner, flue arrangements and door designs are in use at more than 25 rotary furnaces in the United States alone. These burners process a variety of feeds including dross, scrap and contaminated materials. Air Products’ melting experience in single and double pass rotaries and reverb furnaces — coupled with our burner’s flame characteristics — have been proven to deliver higher production rates and improved recoveries than can be obtained using natural gas and ambient air.

Using a dedicated team of specialists, Air Products’ continually develops innovative new offerings to meet its customers’ needs, while being a leader in both delivery reliability and safety. “Our goal is to deliver results,” explains Frank Romano, Lead Engineer at Air Products, continuing, “We put our experience to work for our customers, whether it’s higher production rates, greater yields, improved emissions or troubleshooting a problem. Our dedicated team of aluminum specialists and local account support will work together to meet your needs.”

Greenway Industries’ Rakovsky summarizes the technology this way, “Air Products’ oxy-fuel system burns hotter, burns cleaner and with less emissions,” enabling Greenway to focus on its mission of providing quality products to its customers, while growing its market share.

To learn how Air Products’ state-of-the-art oxy-fuel technology can help you increase your production and lower your costs, contact us.

Note: Since the writing of this article, Greenway has discontinued operations.

Detailed computer analysis and process evaluation yields a custom solution.

Issue: A large secondary aluminum processor with multiple rotary furnaces wanted to increase yield and production. Already highly successful, they looked to Air Products for further improvement to help their bottom line.

Solution: Air Products scientists and applications engineers welcomed the challenge. During several site visits and working to understand the customer’s requirements, our team evaluated everything that can influence combustion in the operation, including flue size, burner types, burner placements and orientation, firing rate setpoints, stoichiometric ratios and more. This extensive analysis, combined with computer modeling of the furnace, identified that our High-Yield Oxy-fuel Burner would be a good fit for their operation. This patented burner*, designed specifically for aluminum rotary furnaces, can provide even heating throughout the entire furnace, as well as the ability to keep the free oxygen within the flame envelope, thereby minimizing any oxidation of aluminum that can result in yield loss.

* U.S. Patent No. 8404018

Implementation of world class technology doubles productivity for precious metals producer.

Issue: When an existing precious metal producer hired a new metallurgist, he realized that there was a lot of opportunity for productivity improvement as precious metal prices increased and looked to Air Products for assistance.

Solution: Air Products knew that with the value of precious metals increasing, the economics of implementing our world class technology could increase the customer’s productivity and maximize their return. Our applications engineers devoted several months to educating our customer on potential process and technical improvements, including escorted trips to visit other sites utilizing these advanced practices and technologies. The customer embraced the recommendations and has doubled their productivity in the last year with just process improvements alone. Productivity is expected to further improve once the oxygen-based technology improvements are completed later this year.

Identification and correction of calibration and control logic errors, and installation of a new burner delivers higher production, better recoveries and lower flux usage.

Issue: We visited an aluminum processor with rotary and reverb furnaces which was supplied by a competitor. After discussing our latest technology we were invited to take a plant tour to see if we could improve their operation.

Solution: Based on the short tour Air Products applications engineers arranged to come back to the site for a thorough overview of the operation. The team spent several days onsite and identified many operational issues, equipment problems and opportunities to improve the combustion technology, which had not been upgraded in over a decade. The team found numerous calibration and control logic errors during a full inspection of the existing oxygen and gas flow trains—leading to both inaccurate control and unresponsive control of valves. Once issues with the equipment and controls were fixed, the Air Products team installed a new burner better suited for the process. With this combination of Air Products recommendations and improvements, the company has realized higher production, better recoveries and lower flux usage. The implementation was so successful that the company is now working with Air Products to evaluate new burner developments so they can continue to make enhancements.