Over time, Vale's CCNR product conveyor gallery experienced a significant increase in dust and particulate accumulation.

Initially, the ventilation system comprised a dedicated Makeup Air (MUA) unit, which had been dismantled, and two exhaust fans. At the onset of BESTECH's analysis, the absence of an active ventilation system led to the expulsion of dust-laden air into the environment via the exhaust fans, a practice not aligned with current environmental regulations mandating dust filtration through a baghouse.

The study’s objective was to explore viable solutions to mitigate dust and particulate buildup within acceptable limits. BESTECH’s proposals featured various combinations of a new baghouse and an MUA unit to address the issue effectively.

BESTECH recommended the installation of a 3000 CFM MUA unit atop Vale’s NRC building. This proposal included the replacement of the existing 18’’ duct with a new 20’’ duct extending from the MUA unit into the conveyor system. Additionally, the plan involved establishing six tie-in points along the conveyor through six-inch ducts equipped with perforated diffusers, strategically chosen for their low discharge velocity and evenly distributed to ensure comprehensive coverage.

Moreover, the introduction of a new 3000 CFM baghouse within the NRC building was suggested to accommodate the increased airflow from the roof-mounted MUA unit. BESTECH also advised that the conveyor should be entirely enclosed. This modification, combined with the enhanced negative pressure from the new baghouse and ductwork, would effectively contain dust and particulates, preventing their escape into the product gallery.

The proposal highlighted the advantages of a roof-mounted MUA unit, notably its smaller size, which facilitates easier maintenance. The suggested placement of the makeup air inlet, strategically distanced from the IPC, significantly lowers the risk of introducing air contaminated with Carbonyl into the NRC, underscoring BESTECH’s commitment to enhancing operational efficiency while adhering to environmental standards.