VersaFlex Supplies Polyurea Coating for Rehab of Power Station Water Cooling System

AMARILLO, TX - May 1, 2012 - Minneapolis-based Xcel Energy's Harrington Station location had been experiencing through-wall corrosion of the carbon steel piping used in their circulation water system. This effluent cooling water is typically run at 50 psi (380kPa) and 55-110° F (13-44° C). Because the replacement of existing pipe can be extremely costly and result in long shutdown times, the use of the Robotic Spray-In-Place-Pipe Lining (SIPP) polyurea technology was chosen as the solution.

The pipes in need of rehabilitation were 8", 36", 72", and 96" in diameter (0.2m, 0.9m, 1.8m and 2.4m, respectively). The internal surface area of the project totaled 10,000 sq. ft.

Chosen for lining the piping was StructrLine SS, a specialty formulated aromatic polyurea spray elastomer system designed exclusively for robotic pipe lining rehabilitation work. This material is semi-structural in nature, with retained elastomeric qualities for superior abrasion, future corrosion protection and design pressure rating for compete internal lining rehabilitation of industrial pipe structures.

InspaTech Services was contracted to carry out the application. Prior to installation, the pipe required cleaning and preparation. The major areas of corrosion and tuberculation were removed via SSPC-SP 2 hand tool, where accessible. For abrasive blasting, SSPC-SP 10/NACE No. 2 standard was employed, yielding a 4-5 mil (100-130 mm) profile. Because of the type of water used in the cooling system, soluble salt testing was preformed where accessible, per SSPC-TU 4 / NACE Pub 6G186.

Special challenges for the robotic installation included the design of both 45° and 90° singular bends, compounded drops & elevations, and the "T" areas in the pipe system. The patented robotic head easily maneuvered these areas while maintaining consistent, void-free film application.

For installation of the StructrLine SS polyurea spray system, GRACO H-XP3 and PMC PHX-40 proportioning units were used. The StructrLine SS was applied using patented robotic spray heads to a minimum average 500 mils (1.3 cm).

Roughly 3,000 gallons (11,400L) of material was used over the course of the application, being supplied in 265 gallon totes. Subsequent adhesion testing of the applied lining, ASTM D 4541, gave average values of 1345 psi (9.3 mPa). The rehabilitation was completed in March 2012, though additional pipe lining work is planned for Xcel Energy.

About VersaFlex Incorporated: VersaFlex is a manufacturer of rapid-curing polyurea elastomer sealants, polyurea repair material, and fast set polyurea spray materials. The company prides itself on its tradition of technical service and on-site supervision. For more information, please use the links listed below.