THE SOLUTION FOR CORROSION UNDER INSULATION (CUI)
Corrosion Under Insulation (CUI)
CUI has been recognized as a problem in many industriesInsulation is a necessary component of the system and is
designed to:Save energyControl process temperaturesProtect workers from high temperatures
NACE Standard SP0198-2010 is a good source of information, but electrolytes will eventually find their way into even the best system
Anti-Corrosion Gel Performance
Operating Temperatures – over 350° F/177 ° C Moisture Resistance – Hydrophobic Anti-Corrosion Properties – Mineralization, Inhibitors & Buffering Technology
Application Surface Prep – no sandblasting, free of oils/greases Cure Time – None, visual inspection easy and non-destructive Equipment – Brush, PVC glove or spray Environmentally benign
Cost Total application cost is typically lower than other systems Line shutdown not required
Technology
Barrier system – The specially formulated products have great adhesion characteristics (requiring minimal surface prep) and are hydrophobic to help keep moisture away from the substrate. Never cures thus microscopic air pockets don’t form.
Mineralization - Growing an engineered surface, or surface conversion – creating a surface which resists corrosion even if moisture gets to it. Undercutting cannot occur.
Buffering system – If moisture migrates through the gel through vapor drive, it is buffered to a high pH which is alkaline enough not to corrode metal. Gel also contains a number of corrosion inhibitors.
How the reactive gel corrosion treatment works:
When the ferrous (steel) surface (1) is covered with a layer of reactive gel (2), the metal surface reacts with components in the gel to form a mineral layer (3). This thin glasslike layer (3) acts as a barrier between chlorides and the metal surface, thus providing corrosion resistance.
The mineral layer (3) has a thickness of 50-200 angstroms, only 0.01% as thick as a piece of paper.
Although the thin mineral layer can be damaged by mechanical abuse, there is extra protection built into the system, i.e.:
• If the mineral surface is scratched or damaged, and there is residual gel in contact with the area, the mineral layer will be regenerated by the gel ingredients.
• The gel contains a buffering agent, which raises the pH of water at the surface of the steel to 10 or above, a level unfavorable for corrosion of ferrous substrates. (Another formulation for aluminum adjusts the pH to 6-8).
Surface Formation
Untreated steel surface Mineralized steel surface
10 um10 um 10 um10 um
• Automotive– Technology has been used in automotive applications for >30 years. Originates before Second World War.
– Crevice Corrosion on Brake Cables
• Industrial Applications– First industrial application was with the US Navy. Solved their #1 and #2
corrosion maintenance problem.– Watertight Door Latching Mechanisms– Deck Edge Elevator Wire Ropes– Other specific areas
History of the Technology
9
2 Year Salt Water Immersion Test
Samples in Aerated 5% salt solution
10
2 Year Salt Water Immersion Test
Samples in Aerated 5% salt solution
11Non-Bead Blasted Pipe Bead Blasted Pipe
2 Year Salt Water Immersion Test
Stress Crack Corrosion on SSStress Crack Corrosion on SSControl Sample Typical Stress Cracking
with in 100 hours of exposure
Per ASTM C 692
EDC 2400 Treated Sample
No Cracking after 100 Hours
Exposure Per ASTM C 692
Gel Treated SampleNo Cracking After 100 Hours
Exposure Per ASTM C-692
Ammonia Lines
Ammonia Test Site Flange Remediation
North Slope
AMMONIA SYSTEM INSTALLATION EXAMPLE ON OPERATING SYSTEM
USING:
PICTORAL INSTALLATIONPICTORAL INSTALLATION
REMOVING METAL JACKET
PRIMER ON INSULATION
CORROSION ON PIPE
REMAINING PRIMER EASILY REMOVED
INSTALLING RG-2400 LT
Pipe temperature thickens the RG-2400 LT quickly. After 3 passes over an area it gets difficult to spread and achieve adhesion.
The slight frost on the pipe left some voids, however fresh “warm” material could be put over these areas and achieve ahesion.
A WELL COATED PIPE READY FOR INSULATION
CONCLUSIONSCONCLUSIONS
•COATING A 24° PIPE IN OPERATION IS POSSIBLE IN SMALL SECTIONS.
•RG-2400 MUST BE WARM TO IMPROVE COVERAGE AND EASE OF APPLICATION
•INSULATION MUST BE INSTALLED IMMEDIATELY UPON ACHIEVING COVERAGE TO PREVENT CONDENSATION FROM FORMING ON THE RG-2400
•INSULRAP OR FABWRAP VAPOR BARRIER SHOULD BE USED TO KEEP OUT MOISTURE
•TESTING WILL CONTINUE ON -15° F LINES IN OPERATION AND -50° F LINES IN OPERATION. RESULTS WILL BE ADDED TO THIS PPT PRESENTATION.
•GLYCOL WILL BE TESTED TO REMOVE FROST ON THE COLDER LINES.
The tank was completely sprayed in approximately one hour
Product Application - Tank
Tank Chime Application – Texas City, Texas
Conoco/Phillips Well CasingConoco/Phillips Well Casing
WELLS WERE FIRST FLUSHED WITH 55 BARRELS OF 120° F CLEAN WATER TO REMOVE SLUDGE, WATER WAS PUMPED OUT AT END
OF FLUSH CYCLE.
Companies WithCompanies With Product Installations/specifications Product Installations/specifications
• OxyChem• Ernst & Gallo• Equistar• Union Carbide• Cytec• Phillips• MODOT• Nicor• Monarch Foods• US Navy • Kraft Foods• ConocoPhillips • Coors Brewing• Canada Hydro• Indiana University
• Anheuser Busch• General Mills • Jolly Green Giant• British Petroleum• Best Brands Foods• Philadelphia Gas• Fred Meyer Foods• Unocal• Dot Foods• Exxon Mobil• CODELCO• Tuborg• Efes Pilsen• GlaxoSmithKline• Shell
Benefits of the Technology:
Practical application – simple non-curing gelMultiple delivery systems (spray, glove, brush)Insensitive to surface preparation and application
conditions Demonstrated superior anti-corrosion performanceEnvironmentally benignEasy to inspect