A high-grade and low-cost vanadium mine in Brazil wanted to reduce costs from frequent seal mean time between repair (MTBR) on its main process pump. Every four months, maintenance technicians were called to repair damage to the pump’s two dual cartridge seals caused by corrosive chemicals in the pumped product. The vanadium mine needed a long-term solution to the expensive problem.
John Crane’s Expertise
The company relied on John Crane’s knowledge and experience to troubleshoot the problem and implement a resolution. Following a root cause failure analysis, John Crane engineers determined the cause of the high MTBR rate was severe chemical corrosion. The vanadium ore extraction process required volatile chemicals, including ammonium sulfate, which interacted with the wet parts of the dual cartridge seals that came in contact with the pump’s rotating shaft. The mine’s planning technician had confidence in the John Crane Safematic SB2 seals’ rugged design and did not want to change to another seal. John Crane engineers devised a plan to improve the existing Safematic SB2 seals and address the corrosion issue.
The John Crane engineering team recommended upgrading the existing seals wet metallic parts with titanium because of its resistance to ammonium sulfate and other caustic elements found in the pumped product. The metal also made economic sense compared with other potential solutions. In addition to the material upgrade, John Crane also enhanced the mine’s API System Plan with new measuring instrumentation, provided installation and startup training to technicians and supported seal installation and pump restart.
Since the Safematic SB2 seals were upgraded to titanium, there have been no interruptions. In addition, the MTBR improved from every four months to more than a year and counting. The titanium seal upgrade has saved the mine nearly $482,000 in previously lost profits by reducing pump downtime in the first year. The upgrade also saved the mine more than $80,000 in maintenance costs per seal failure for a $240,000 annual cost reduction.
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