Alignment of traveling grate restores full operational reliability and productivity at Vale, Nibrasco Pellet plant

Rectifying a traveling grate after years of operation by replacing key components and re-aligning the complete mechanical system is a very complex task. 

We were able to support our customer Vale with prompt technical expertise during the shutdown of the Nibrasco pellet plant to renovate the traveling grate to its original condition and to keep the tight shutdown schedule.

About the mine/customer

The relationship between Outotec and Vale dates back to the expansion of  Vale’s iron ore business from pure ore supply to the production and shipment of iron ore pellets. In 1966, the company inaugurated in Espírito Santo, Brazil the Port of Tubarão, which is still Vale’s most important port. In the same year, the construction of the first pelletizing in Brazil started.

Outotec and it’s former acquisitions have been involved in the design and delivery of all 11 Vale pelletizing plants in Brazil. In recent years we designed the pellet plant in São Luis (at this time with its indurating machine of 768 m² and 6 Mtpy capacity the largest plant in the world) and delivered the pellet plant of Vargem Grande in Minas Gerais.  We also provided complete engineering for the latest of the 8 pellet plants in Tubarão.

We have a service and competence center situated close to the site in Tubarão, we supplied Vale with technical services, maintenance and shut-down support for the pelletizing plants, as well as for the grinding and filtration areas over the last couple of years.

Over the past 2 years, we have executed 18 large service projects under a framework agreement during shutdowns.  These projects have included 120,000 man-hours at the site and fulfilling Vale’s highest safety requirements with the important KPIs TRIR (Total Recordable Incident Rate), LTIR (Lost Time Injury Rate) and FAC (First Aid Cases), where we have achieved zero rates under all three safety KPI’s.

Scope

Vale recognized the need for additional expertise and support for the replacement of key components during the 40-day shutdown of the Nibrasco pelletizing plant. The re-alignment of the traveling grate plays a vital role in availability, plant productivity, product quality, and maintenance costs.  Vale approached us for support due to the experience gained during the design, construction, assembly, commissioning, maintenance and shutdown services of their numerous pelletizing plants.

We promptly deployed a technical team to execute the following scope:

• Replace tooth segments of the gear rims at drive and tipping station
• Measure and re-align gear rims and curved trails;
• Manufacture on-site devices for adjustment, alignment, and leveling of toothed segments with the curved rail
• Reuse components where possible
• Check and adjust thermal expansion system with counterweights

After a mere 15 days after the contract agreement, we were able to finalize the project within the original shutdown schedule.

We were very pleased to receive positive feedback from Vale operational and maintenance staff, that the 45-year-old plant exhibited a tremendous improvement of the mechanical functionality.

*This case study has been written prior to the merger of Metso and Outotec.