Aqueous Ammonia Storage Tank Lining
Washington
Date of Application: September, 2016
System: Flake Filled Novolac Epoxy Lining
Infrastructure Type: Aqueous Ammonia Storage Tank
Case Studies
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Aqueous Ammonia Storage Tank Lining
Washington
Date of Application: September, 2016
System: Flake Filled Novolac Epoxy Lining
Infrastructure Type: Aqueous Ammonia Storage Tank
Description: The previous coating system had begun to blister over the entire surface of the tank floor. The owner of the facility had requested that the cause of failure be identified and an alternative system be recommended. The cause of failure was recognized as contamination of the surface, additional testing measures were used to ensure the problem did not occur again.
Surface Preparation: The surface was tested for chlorites, sulfates, and nitrates prior to blasting. The chlorite level was outside the acceptable range, so the surface was treated with a neutralizing product. Additional testing revealed that the surface was void of chlorites after the neutralizing wash. The surface was blasted to an SSPC-SP5. Further examination showed that the facility’s water source showed high chlorite levels; this was likely the cause of the initial failure.
Application: The weld seams on the tank floor had sharp edges and slag in some areas; it was necessary to stripe coat the seams at 10-12 mils DFT in order to avoid the times taking process of grinding. The finish coat of novolac epoxy was applied at 25 mils DFT as the striped seams hit B stage.
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Polymer Concrete Pump Pad
Wyoming
Date of Application: March- 2014
System: Saturating Concrete Primer, Novolac Epoxy Polymer Concrete
Infrastructure Type: Industrial Pump Pad
Polymer Concrete Pump Pad
Wyoming
Date of Application: March- 2014
System: Saturating Concrete Primer, Novolac Epoxy Polymer Concrete
Infrastructure Type: Industrial Pump Pad
Description: The structural integrity of the pump pad had been compromised by exposure to corrosive chemicals and mechanical vibration. The customer was concerned that the rapid deterioration of the pad could result in operational failure and cause a shutdown.
Surface Preparation: The pad was chiseled down to expose the rebar; no cracks were observed throughout this portion. A wooden form was built around the pad and coated with a release agent. Primer was applied to the pad and allowed to cure until tacky.
Application: A horizontal blade mortar mixer was used to ensure even distribution of aggregate throughout the product. Product was poured into the form and screeded into place. The form was covered for 24 hours to prevent contamination as the product cured.
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FRP Tank Nozzle Insert
Missouri
Date of Application: October, 2015
System: FRP Insert/Nozzle
Infrastructure Type: Tank
FRP Tank Nozzle Insert
Missouri
Date of Application: October, 2015
System: FRP Insert/Nozzle
Infrastructure Type: Tank
Description: A reinforced vinyl ester tank lining was installed in the tank to cover the majority of the surface area and prevent corrosion. Due to the shape of the nozzle and the application method, the necessary film build was unachievable for the area. The customer submitted a drawing of the nozzle and an FRP insert was fabricated out of the same resin used in the coating system.
Surface Preparation: The interior of the tank was treated with a product to neutralize any contaminants. Testing for chlorites, sulfates, and nitrates was performed. The substrate was blasted with abrasive to an SSPC-SP10.Application: Prior to the installation of the coating system, the exterior of the insert and the back of the flange was coated with a vinyl ester adhesive. The insert was placed into the nozzle. Before the adhesive had cured the flange was tied into the tank interior.
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Coal Pipe Ceramic Reline
Wyoming
Date of Application: Summer, 2015
System: Silicate Cement, Alumina Oxide Ceramic Tile
Infrastructure Type: Coal Piping/Elbows
Coal Pipe Ceramic Reline
Wyoming
Date of Application: Summer, 2015
System: Silicate Cement, Alumina Oxide Ceramic Tile
Infrastructure Type: Coal Piping/Elbows
Description: Coal had worn through several areas of the previous lining in each pipe. Instead of having brand new pipes fabricated, the owner requested that the current elbows have the linings broken out and replaced. Technical drawings were submitted and pre-engineered linings were produced.
Surface Preparation: Air powered chisels were used to break out the previous ceramic linings. A number of the elbows had holes in the steel at the worst areas; these pipes required steel patches. After the ceramic and mortar had been broken out, the weld seams were lightly ground to ensure the new linings fit properly. Finally, the pipes were blown clean with an air gun.
Application: The new linings were dry fit before the application of cement. A heavy layer of silicate cement was applied to the interior of each gore. Individuals worked their way into the center of each elbow to ensure a tight fit at the worst wear areas.
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Structural Steel Maintenance Painting
Wyoming
Date of Application: Summer 2014-16
System: Epoxy Primer, Polyurethane Finish Coat
Infrastructure Type: Coal Fired Power Plant; Structural Steel
Structural Steel Maintenance Painting
Wyoming
Date of Application: Summer 2014-16
System: Epoxy Primer, Polyurethane Finish Coat
Infrastructure Type: Coal Fired Power Plant; Structural Steel
Description: The previous coating system began to chip and peel due to long-term atmospheric exposure. Large areas of bare metal were exposed and had begun to rust.
Surface Preparation: Areas to be coated were solvent cleaned according to SSPC-SP1 and power tool cleaned according to SSPC-SP3. Tightly adhering rust and previous coating were left on the substrate, acceptable conditions for application.
Application: The epoxy primer was applied at 4-6 mils DFT. After the primer had cured, the polyurethane topcoat was applied at 2-3 mils DFT. The equipment used for application varied by circumstance. In locations that had little surface area, such as handrails, brush and roll methods were used to prevent waste loss. Locations with a larger surface area, such as I-beams, were suitable for plural component spray equipment.
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Steel Mill Pickling Vessel
Indiana
Date of Application: October, 2015
System: Vinyl Ester Lining, Carbon Fiber, High Molecular Weight Vinyl Ester Lining
Infrastructure Type: Steel Pickling Vessel
Steel Mill Pickling Vessel
Indiana
Date of Application: October, 2015
System: Vinyl Ester Lining, Carbon Fiber, High Molecular Weight Vinyl Ester Lining
Infrastructure Type: Steel Pickling Vessel
The pickling vessel was leaking from several locations and the problem was dramatically impacting the facility’s productivity. Along with the difficult chemistry, the interior of the structure was also subject to heavy impact in certain areas. The cause of failure was identified as a coating mismatch; the previous systems were not adept to handle the harsh chemical environment.
Surface Preparation: The interior of the tank was treated with product to remove contaminants. It was then tested for chlorites, sulfates, and nitrates. The substrate was then blasted with abrasive to an SSPC-SP5.
Application: The vinyl ester lining was applied to the surface at 40-50 mils DFT. Before the product had cured, a carbon fiber layup was embedded into the coating and saturated with resin. After the first layer had reached a stage B tacky state, the system was repeated for a second layer. Finally, the double layup was coated with a high molecular weight vinyl ester at 25-30 mils DFT. The total system ensured chemical protection, structural integrity, and impact resistance.
