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Layup Options for Cooling Water Systems

January 6, 2022

Cooling towers are an integral part of any cooling system and must work within the design specification for the system to properly function.  A cooling tower operating outside its specifications will increase the overall costs of operations due to higher energy and water usage. When it comes time to lay the system up, much thought and consideration is given to protecting the water side of the system (i.e., piping, pumps, valves, heat exchangers, and other associated equipment). However, little attention is paid to exterior surfaces of the equipment, associated control panels, and the cooling tower structure. Excess corrosion on any of these surfaces over time can lead to system failure and expensive non-budgeted repairs or equipment replacement.

This guide outlines strategies to provide an integrated approach to protect the entire system, not just water side components.

C3 - Cortec CorporationThe cooling tower structure consists of the following components:

  1. Fan Blades – Fiberglass reinforced polyester (FRP), aluminum, galvanized steel
  2. Rotating Shaft – Steel
  3. Motors
  4. Louvers – Typically FPR but can be galvanized steel or stainless steel
  5. Fill – Plastic sheet
  6. Structure – Normally galvanized steel, but can be stainless steel or fiberglass reinforced polyester (FRP)
  7. Drift Eliminator – Polypropylene material filled with carbon black
  8. Cold Water Basin – Concrete, galvanized, FRP, or stainless steel
  9. Sump – Same material as cold-water basin; receives water from the basin
  10. Hinged Access Door – Steel
  11. Walkways and Ladders – Galvanized steel
  12. Casing – Fiberglass
  13. Inlet Header
  14. Fan Cylinder – Fiberglass reinforced plastic (FRP)
  15. Railing – Galvanized steel
  16. Gearboxes
  17. Spray Nozzles – Plastic feed by steel pipe
  18. Piping – Painted and/or insulated
  19. Control Panels
  20. Hot Water Basin (Crossflow Towers) – Galvanized steel, FRP, or stainless steel

Other components of a cooling water system:

  • Chemical Injection Skid
  • Pumps
  • Piping
  • Controls
  • Valves
  • Heat Load
SEASONAL LAYUP (3-6 Months)
Component Product Comments
Structure VpCI®-373
VpCI®-396		 Prime galvanized and stainless with VpCI®-373 prior to topcoat of VpCI®-396
Louvers VpCI®-373
VpCI®-396		 Prime galvanized and stainless with VpCI®-373 prior to topcoat of VpCI®-396
Piping VpCI®-396
VpCI®-658
  • Coat exposed steel pipe surfaces with VpCI®-396
  • Inject VpCI®-658 into pipe insulation
Fan Blades VpCI®-373
VpCI®-396		 Prime galvanized and aluminum with VpCI®-373 prior to topcoat of VpCI®-396
Motors VpCI®-391
VpCI® Emitters
  • Coat exposed machined surfaces with VpCI®-391
  • Install appropriate size emitter into junction box.
  • VpCI®-101 – 1 ft3 (28 L)
  • VpCI®-105 – 5 ft3 (0.14 m3)
  • VpCI®-111 – 11 ft3 (0.31 m3)
Gearbox M-531
VpCI®-391		 Wet layup:

  • Add to oil at 2.5% by volume to existing oil and circulate prior to shutdown
  • Drain and fill with fresh oil prior to startup

Dry layup:

  • Fog into gearbox at 0.3-0.5 oz/ft3 (0.3-0.5 L/m3)
  • Coat exposed machined surfaces with VpCI®-391
Control Panels ElectriCorr™ VpCI®-239
VpCI® Emitters
VpCI®-308 Pouch
  • Lightly spray all exposed metal surfaces (contacts) with ElectriCorr™ VpCI®-239.
  • Install appropriate size emitter into panel.
  • VpCI®-101 – 1 ft3 (28 L)
  • VpCI®-105 – 5 ft3 (0.14 m3)
  • VpCI®-111 – 11 ft3 (0.31 m3)
  • VpCI®-308 Pouch – 35 ft3 (1 m3)
Walkways, Railings, and Ladders VpCI®-373
VpCI®-396		 Prime galvanized with VpCI®-373 prior to topcoat of VpCI®-396
Hot Water Basin VpCI®-373
VpCI®-396		 Prime galvanized and stainless with VpCI®-373 prior to topcoat of VpCI®-396
Cold Water Basin VpCI®-395
VpCI®-2026
VpCI®-373
VpCI®-396
  • Apply either VpCI®-395 or VpCI®-2026 to concrete
  • Prime galvanized with VpCI®-373 prior to topcoat of VpCI®-396
Other components of a cooling water system:

  • Chemical Injection Skid
  • Pumps
  • Piping
  • Controls
  • Valves
  • Heat Load
  • Exposed Shafting
  • Hinged Access Door
 VpCI®-391
VpCI®-369 D
ElectriCorr™ VpCI®-239
VpCI®-126 HP UV Shrink Film
  • External machined surfaces should be coated with VpCI®-391
  • Valve stems and bushings should be coated with VpCI®-369 D
  • Finned sections of heat load can be sprayed with ElectriCorr™ VpCI®-239 and wrapped with VpCI®-126 HP UV Shrink Film
Product Name Product Data Sheet
ElectriCorr™ VpCI®-239 https://www.cortecvci.com/Publications/PDS/ElectriCorr-VpCI-239.pdf
M-531 https://www.cortecvci.com/Publications/PDS/M-531.pdf
VpCI®-101 https://www.cortecvci.com/Publications/PDS/VpCI-101.pdf
VpCI®-105 https://www.cortecvci.com/Publications/PDS/105.pdf
VpCI®-111 https://www.cortecvci.com/Publications/PDS/VpCI-111.pdf
VpCI®-126 HP UV Shrink Film https://www.cortecvci.com/Publications/PDS/VpCI-126_HP_UV_Shrink_Film.pdf
VpCI®-2026 https://www.cortecvci.com/Publications/PDS/VpCI-2026_Top_Coat.pdf
VpCI®-308 Pouch https://www.cortecvci.com/Publications/PDS/VpCI-308_Pouch.pdf
VpCI®-369 D https://www.cortecvci.com/Publications/PDS/VpCI-369_D.pdf
VpCI®-373 https://www.cortecvci.com/wp-content/uploads/VpCI-373NEW.pdf
VpCI®-391 https://www.cortecvci.com/wp-content/uploads/VpCI-391.pdf
VpCI®-396 https://www.cortecvci.com/Publications/PDS/VpCI-396.pdf
VpCI®-658 https://www.cortecvci.com/Publications/PDS/VpCI-658.pdf

Citations

Figure 1: Netto, Adherbal Caminada, et al. “Petri Net Based Reliability Analysis of Thermoelectric Plant Cooling Tower System: Effects of Operational Strategies on System Reliability and Availability.” White paper featured at ICVRAM ISUMA UNCERTAINTIES conference in Brazil, April 8-11, 2018. <https://www.researchgate.net/figure/Cooling-Tower-System_fig1_324531183>. All rights reserved.

Figure 2: Courtesy of CASE GROUP. 1993. <https://www.casepl.com/coolingtowewooden_singleproduct_details.htm>. All Rights Reserved.

Figure 3: Courtesy of YouTube. <https://i.ytimg.com/vi/G7Y3l16ywd0/maxresdefault.jpg>. All Rights Reserved.

Figure 4: Courtesy of EnergyPurse. “Which is a better counter or crossflow cooling tower??” <https://www.energypurse.com/which-is-a-better-counter-or-cross-flow-cooling-tower/>. All Rights Reserved.

Keywords: Cooling tower, seasonal layup, cooling system, heat exchangers, corrosion, cooling system repairs, non-budgeted repairs, avoid system failure, cooling tower exterior protection, Cortec

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