After more than 20 years of service, Australia’s Sell & Parker Recycling Services upgraded its 4 000hp Danieli shredder to reduce energy consumption and cut operational costs while increasing the plant’s productivity. Danieli Centro Recycling’s Inverter Drive technology provided the solution.

This article is part of our latest issue >>

Since its foundation in 1966, Sell & Parker Recycling Services (S&P) has grown into one of the biggest Australian metal recyclers, boasting more than 400 employees across eight facilities. Danieli Centro Recycling (DCR) is a product line of the Danieli Group, a leading supplier worldwide of fully integrated plants for the metalworking industry.

DCR is a unique partner with the technology and expertise to bridge the gap between scrap processing and steelmaking, specialising in designing and manufacturing advanced plants to handle ferrous and non-ferrous scrap.

Over the years since 2000, DCR has established a significant relationship with S&P, supplying scrap processing plants and equipment.

ENERGY AND PRODUCTIVITY BOOST

Recently, after more than 20 years of service, S&P upgraded its existing 4 000hp Danieli shredder to reduce energy consumption and cut OpEx, and to increase the plant’s productivity.

The upgrade mainly focused on limiting the power, voltage peaks, and fluctuations of the main motor and on improving the overall efficiency of the drive line by removing the old hydraulic coupling which was a source of significant energy dissipation.

Danieli exceeded S&P’s expectations with its patented Smart Power technology. This converted the existing fixed-speed, three-phase, asynchronous motor into a state-of-the-art variable-speed drive system. The result was energy savings, improved productivity and a reduced impact on the distribution network.

Before the revamp, analysis of the power measurements was conducted. It revealed that during normal operations the shredder motor could easily reach peaks of current up to 160% of the nominal power, causing electrical issues such as flickering, voltage, and power factor fluctuations.

‘We’re seeing a 20% tonnes-per-hour increase’

Luke Parker, ceo of Sell & Parker Recycling Services, is eager to share his experiences regarding the shredder drive upgrade.

‘We’ve known Danieli for a long time. In addition to our shredder, we operate three 1 400 tonne cutting force Danieli shears. When we first heard about the variable frequency drive (VFD) system, we were very interested to learn more. We visited an operating site and the company’s factory in Buttrio in Italy learn more. The system was scoped out for our plant and we placed the order.’

‘Unfortunately, Europe’s hot summer placed strains on the HVAC supply and our system was delayed a little, but we were kept informed and we were delivered a great system. With careful planning, we were able to replace our entire drive system and be operational in less than 14 days. A week for tuning, and we were at full production.’

WHAT CONCERNS DID YOU HAVE ABOUT THE UPGRADE BEFOREHAND?

‘To be honest, I didn’t have doubts. It made sense to me and other smart operators were installing multiple units. I figured if the smartest companies were rolling them out across their fleets of shredders, they must be good.

Of course, the required investment had to meet our financial hurdles and, in our case, we also considered how an upgrade would give us extra production and would postpone the need for a complete shredder upgrade for years down the road.’

CAN YOU DESCRIBE IN MORE DETAIL THE IMPROVEMENTS IN PERFORMANCE AFTER THE UPGRADE?

‘Take our instantaneous power demand curve. We used to have big spikes when a surge of material got into the shredder and then we also had ‘valleys’ where the mill was hungry for material. The spikes represent a momentarily increased demand on the grid, which upsets the electricity supplier.

Spikes also occasionally tripped our mill, which resulted in lost production and required our crew to dig the scrap out of the mill. That’s a tough job often made tougher by unfavourable weather. The valleys represented wasted opportunity: machine capacity, if not utilised, is lost forever.

The VFD and upgraded drive system have addressed both issues. Spikes have been completely eliminated. Additionally, the direct drive recovers much faster so we can restart the feed quicker and avoid the valleys. While running, we’re seeing about a 20% increase in tonnes per hour and we have had an even greater increase in production across the month as downtime is reduced.’

WHAT ASPECT PERFORMED BETTER THAN EXPECTED?

‘While the VFD performs as promised, as someone without an electrical background, I find it amazing that the peak electrical demand is capped even when we are belting scrap into the shredder. For me, it’s sorcery.’

DO YOU HAVE ANY CONSIDERATIONS REGARDING THE DOWNTIME DURING THE UPGRADE?

‘We had hoped to install during our traditional summer shutdown for Christmas/New Year but, with the HVAC delay, the equipment arrived in the middle of the year. We opted to install immediately. We did as much pre-installation work as possible while the plant was running so the shutdown would be quick. I can’t praise my team or Danieli’s enough for a great shutdown.

The biggest issue was managing unprocessed feedstocks. No-one wants large stockpiles, as they present a fire risk, but they are inevitable with downtime. On the upside, when we restarted, we had plenty of feedstock that allowed us to truly test the capacity of the VFD. We were back to normal within a couple of weeks.’

AS A CUSTOMERS AND USER, WERE THERE ANY ADDITIONAL BENEFITS THAT YOU COULD HIGHLIGHT, AND HOW DID THE EXPECTATIONS ALIGN WITH THE RESULTS?

‘Full box shredding has improved our performance downstream. The scrap is shredded more densely and more consistently. Scrap on the belts is more even, with no surges or ebbs. This makes the downstream perform better.’

Have you read our latest issue yet? Find it here >>