Hilchenbach, July 25, 2017

Innovative filter solutions for aluminum rolling mills

Practical experience shows that investment in an Airwash™ exhaust air purification system pays for itself through the recovery of rolling oil after just a few years. This economic incentive of course makes our technology particularly attractive. Abdelaziz Chettouh, expert on filter and exhaust air purification systems at SMS group
Ecologically and economically beneficial

Thanks to the excellent recycling options it provides, aluminum is predestined to be a material for the future. But it is not only lightweight construction using aluminum and the excellent recycling options that contribute to sustainability; resource-efficient and energy-saving processing methods are just as crucial. 

With the Airwash™ exhaust air purification system and the Multi-Plate® filter system for rolling oils in cold rolling mills, SMS group provides two globally successful solutions that combine both ecological and economic benefits.

The systems do not only clean. The Airwash™ exhaust air purification system makes a substantial contribution towards the recovery of rolling oils and therefore optimized recycling management in aluminum plants. With their special properties, both systems represent a success story for SMS group: The current reference list is filled with 28 Airwash™ exhaust air purification systems and 57 Multi-Plate® filters from the SMS specialists. And the trend is set to continue upward.

Clean air that pays off

The SMS group Airwash™ technology makes a fundamental contribution to the environmental compatibility and efficiency of an aluminum cold rolling mill. This applies not only to new plants, but also to existing rolling mills which are retrofitted with this technology. However, it is not only the environment which benefits from it. Abdelaziz Chettouh, expert on filter and exhaust air purification systems at SMS group: "Practical experience shows that investment in an Airwash™ exhaust air purification system pays for itself through the recovery of rolling oil after just a few years. This economic incentive of course makes our technology particularly attractive."

What Airwash™ achieves for the plant operator is illustrated by one of the most recent SMS group orders. The SMS group has retrofitted two existing aluminum rolling stands with an Airwash™ system for a well-known aluminum rolling mill in the USA. With the new solution, the customer can now recover about 17,000 liters of rolling oil per month and use it for the rolling process. With the old system, the oil that had been removed was lost to the rolling process.

The SMS group Airwash™ technology combines two processes: exhaust air purification and washing oil treatment. During the cold rolling of aluminum, some of the rolling oil used evaporates. The vapors are extracted and channeled into the Airwash™ system. The rolling oil contained in the exhaust air is predominantly gaseous and also, to a lesser extent, liquid in the form of droplets. In contrast to mechanical filters and separation systems which exclusively separate droplets, the Airwash™ system separates liquid droplets and gaseous matter from the air, which is recovered as reusable material. For this purpose, the oil vapors are passed through separation elements in which the rolling oil is washed out with washing oil and collected in the absorption column. Rolling oil and washing oil are then separated from one another by means of a rectification process – and are both available again to the process.

The compact long-term filter favorites

SMS group Multi-Plate® filters are used for cleaning cooling lubricants during the cold rolling of aluminum. Although only made ready for the market in 2003, 57 systems have already been installed until today. "We are setting standards in the market worldwide with our Multi-Plate® filters," proudly explains Jan-Peer Remy, an SMS group expert in the field of flat rolling mill process technology. Jan-Peer Remy does not consider one individual advantage to be the reason for the sales success, but rather a combination: "Our modular solutions are distinguished by their efficiency, performance and flexibility. And that in a very compact form." According to Jan-Peer Remy, the filters are a long-term favorite in practical applications, immediately from the day of commissioning. "Each filter is subjected to a multi-stage function test by our SMS experts before delivery, which shortens the on-site commissioning process and provides the customer with a high degree of reliability," says Jan-Peer Remy.

The special feature of the filters can be found inside: the filter plates are made of high-performance plastic. This plastic makes the SMS group filter systems many times lighter than conventional filters, resulting in reduced costs for transport and foundations. SMS group offers a modular range of solutions for Multi-Plate® filters with filter performances ranging from 1,400 to 12,500 liters of rolling oil per minute, depending on customer requirements.

Key technologies for environmental life-cycle assessment and value creation

Airwash™ and Multi-Plate® are two examples from the extensive SMS group portfolio for aluminum production. Being so-called "auxiliary systems", they mostly are not in the spotlight. However, that does not mean that they are sidelined at SMS group. On the contrary: The aluminum specialists at SMS group are very committed to the continuous development and optimization of filter and recovery technologies. The cleaning and recovery systems are crucial to any further improvement in the future regarding the environmental life-cycle assessment of aluminum.