Metals business reduces risk and improves performance

Nyrstar is a leading global multimetals business, producing significant quantities of zinc and lead as well as other products. Nyrstar’s Port Pirie smelter is located on the eastern side of the Spencer Gulf in South Australia, approximately 200 kilometres north of Adelaide, and has been in operation for over 120 years.

The Port Pirie smelter is an integrated multimetal blast-furnace smelter and refinery with the flexibility to process a wide range of metals from lead-dominant feedstock. With 670 full-time employees and 110 contractors, this large smelter produces refined lead, silver, zinc, copper and gold.

The operating environment is a particularly aggressive one that exposes equipment and personnel to extremes that include corrosive chemicals, dust, heat and humidity. Critical to the management of such a large and extreme operation is a reliable automation system. Nyrstar’s automation platform consisted of over 20 Modicon PLCs that had been installed in the 1990s and almost 350 variable speed drives (VSDs), and it required a solution that would upgrade the site’s automation systems in accordance with its maintenance schedule, downtime and budget.

As a consequence of limited preventive maintenance, Nyrstar was also experiencing a high incidence of premature failure of its drives. In order to reduce this risk, Nyrstar wanted a partner that could develop and manage a preventative maintenance program that would:

• extend drive life
• have readily available spares for current and legacy drives
• provide a future upgrade path for same footprint changeover
• provide relevant training for Nyrstar maintenance personnel

Nyrstar was looking for cost-effective methods of preserving its existing hardware and programming investment while extending component life and improving the manufacturing process.

Schneider Electric proposed a solution that would enable Nyrstar to progressively modernise the site’s PLCs with minimum disruption. Partnering with Schneider Electric Services, and implementing new Modicon Quantum PLCs, meant that Nyrstar was able to choose between a complete, phased or partial equipment migration on a case-by-case basis.

The choice of migration methods, combined with the openness and interoperability of Schneider Electric’s Unity platform, allowed Nyrstar to evaluate the scope and cost of each migration project and better manage it to fit the site’s maintenance schedule, downtime and budget.

Nyrstar required the migration to proceed in the shortest possible time frame, making the availability of spare parts a critical component of the solution. The open-ended commitment from Schneider Electric meant that Nyrstar was able to coordinate directly with Schneider Electric to ensure that parts not yet migrated would still be available.

In conjunction with system integrator GPA Engineering Pty Ltd, one of Schneider Electric’s Gold Alliance Partners, the PLC migration was completed in 12 months with minimum downtime.

Maarten de Vries, Nyrstar’s Senior Electrical Engineer, says, “The comprehensive services provided by Schneider Electric allowed us to progressively migrate our automation platform to suit our business requirements. This enabled us to time the changes so that we could schedule the migration to coincide with planned maintenance downtime.”

At the same time that the PLC migration strategy was implemented, Schneider Electric provided a preventive maintenance program for the variable speed drives. In order to develop a strategy that would address the specific needs of the site, an installed base audit was undertaken to assess the current situation and propose recommendations that would support the life cycle of the drive equipment. Following this audit, Schneider Electric’s drives servicing team proposed a strategy designed to extend the MTBF.

Nyrstar’s drives maintenance program now includes a spare parts contract that ensures replacement parts are readily available for both current and legacy PDL drives within agreed contractual time frames; and an upgrade path for ‘same footprint’ changeover.

In addition, a comprehensive on-site training program was implemented to educate Nyrstar’s maintenance personnel. The training addressed various topics including operator training, commissioning, maintenance checks and basic on-site repairs.

All legacy PDL drives can now be serviced and spare parts can be conveniently supplied from Schneider Electric’s service workshop in Adelaide. In addition, a number of PDL and Telemecanique drives are available for use as service drives. These are used by Nyrstar to reduce downtime during breakdowns or for temporary replacements during routine maintenance.

In the event that legacy drives cannot be repaired, Schneider Electric has developed a simple adaptor plate for the installation of an equivalent Altivar drive from Schneider’s current product range. This adaptor plate is available for the entire PDL legacy drives range, providing a viable solution for migrating legacy drives. Since Nyrstar successfully implemented Schneider Electric’s drives maintenance program, the failure or problem rate has been reduced from high to virtually zero. This has resulted in significant cost savings as there has been little need to replace drives due to failure.

Following the success of the PLC migration and drives maintenance program, Nyrstar is working with Schneider Electric to continue the migration of remaining PLCs when scheduled downtime permits. In addition, work is underway to replace the obsolete drives with Schneider Electric’s Altivar range of drives.