TCS helped reduce annual maintenance expenditures by over 60%
Lost generating days as a result of work performed
The worst erosion in the Transalta fleet of turbines
Regular unscheduled shutdowns due to component failure
Potential to operate 7-8 months a year
Multiple failed attempts to mitigate maintenance costs
Engineering support was needed to fabricate, rebuild and restore components to drawing dimensions
Technical Coating Systems was utilized to redesign, repair, fabricate and resurface with high performance coatings to dramatically increase erosion resistance
Trailing blades eroded to a knife’s edge. The leading edge of blades were eroding away from crown. The runner was found to be 5 times out of balance tolerance, due to asymmetrical erosion wear.
Machined down the outer and center crowns to allow for shrink fit 'wear bands'. Welded each trailing/leading blade edge and ground back to drawing dimensions and balanced runners.
Coated the entire runner substrate with Metallic Alloy Coating 300 MAC 300uwc and heat treated runner for added hardness and wear resistance.
SLIDE 1 OF 6
Heavily eroded facing plate and washed out inside bore. This dramatically decreased efficiency and accelerated wear to downstream components.
Extracted existing stainless steel facing plate. Replaced facing plate with a new fine grain carbon steel plate at a fraction of the cost of a stainless steel equivalent. Welded and machined the bore back to drawing dimensions.
Head cover facing plates were coated with MAC 300 uwc. Head Cover facing plates were subsequently top coated with a proprietary erosion/impact resistant Elastomer that can be repaired indefinitely.
SLIDE 2 OF 6
Outer O-ring channels were completely washed out after one season of operation. The bore was asymmetrically washed out. This damaged was suspected to be causing a pumping action that was tripping vibration sensors. This resulted in regular unscheduled shutdowns.
Although the labyrinth rings remained repairable, the decision was made to fabricate a split design with removable 'wear plates' on the outer O-ring channel out of carbon steel to mitigate future potential down time and expedite maintenance turnarounds.
Due to the severe erosion, TCS' engineering team recommended a full coating of the substrate with MAC 300 uwc. The outer O-ring channel was then selectively brush plated with nickel tungsten and top coated with our signature erosion resistant elastomer.
SLIDE 3 OF 6
The guide vanes were heavily eroded on almost every axis
In particular, the inside and outside vertical substrates were so out of tolerance that accelerated erosion was affecting all downstream components and further resulted in greater loss of efficiency.
One set of (32) guide vanes were welded up and ground/machined back to drawing dimensions. Another set of (32) guide vanes were cast out of fine grain carbon steel at a fraction of the cost of stainless steel fabrication.
Universal fit guide vane sleeves were also fabricated out of carbon steel. This eliminated the need for left/right and upstream/downstream sleeves.
One set of (32) guide vanes were coated with 0.002" of MAC 200 wc, then top coated with our proprietary Composite Polymer System.
The other set of guide vanes were coated with 0.003" MAC 300 uwc, then top coated with our proprietary Erosion Resistant Elastomer.
SLIDE 4 OF 6
The center ring further demonstrates the harsh conditions at Bone Creek, with an average loss of material of 6-8mm per side. Erosion grooves were as deep as 14 mm in the sweep of the guide vanes on either side, this of course lead to loss of efficiency along with accelerated wear of downstream components.
One center ring was rebuilt using a three component ceramic wear compound and ground back to drawing dimensions. The other center ring was field machined down 6-8mm per side using a climax flange facer. Field line boring was also commissioned to correct manufacturing errors. New center ring wear plates were fabricated out of carbon steel. New body bushings were fabricated out of carbon steel.
Both the new wear plates and body bushings were coated with 0.003" MAC 300 uwc. Upon the installation of the wear plates and body bushings, all tolerances were restored to drawing dimensions.
SLIDE 5 OF 6
The PRV Housing and Barrel demonstrated similar erosion damage as other components. However the wear took place over 2-3 seasons. The Barrel housing was not eroded but rather highly corroded with deep pitting.
PRV Housing and Barrel were welded and machined back to drawing dimensions. Both the PRV Barrel and Housing were coated with 0.002" of MAC 200 wc+. The PRV Barrel was coated with 0.002" Metallic Alloy Coating 100 Corrosion Control Plus (MAC 100 cc+).
Both the PRV Barrel and Housing were coated with 0.002" of MAC 200 wc+. The PRV Barrel was coated with 0.002" Metallic Alloy Coating 100 Corrosion Control Plus (MAC 100 cc+).
SLIDE 6 OF 6
THE POWERHOUSE RAN UNINTERRUPTED FOR FULL SEASON FOR THE FIRST TIME SINCE THE PLANT WAS COMMISSIONED.
TCS HELPED REDUCE ANNUAL EROSION RELATED MAINTENANCE EXPENDITURES BY OVER 60%.