Critical support structure for 40 year old overhead pipe services into turbine hall
Products:
Epo-chem RS 500P™ a wet and surface tolerant mio epoxy primer and Epo-chem™ RA 500 series, a moisture tolerant glass flake filled epoxy top coat, providing excellent long term corrosion resistance.
Environment:
15°C – 60°C sea water
Challenge:
The original coating specification was considered as an atmospheric environment, upon inspection it was found that regular leaks changed the structural steel exposure to immersed causing the original paint systems to fail.
Budget restrictions, access difficulties and age were all a consideration. No abrasive blasting was possible as the costs would’ve been prohibitive with containment and clean up.
Typical extent of corrosion foundIllustrating general corrosion pitting and holesProgress of treatmentCritical support structure now protected
Reclassify from atmospheric exposure to immersed due to the regular salt water leaks.
High pressure water blast up to 20,000 psi using our small foot print machine after mechanical clean in the difficult to reach areas.
Application of Epo-chem™ RS 500P to a nominal thickness of 100µm and top coat using Epo- chem™ RA 500 with a nominal DFT of 350µm
Results:
Saved hundreds of thousands of dollars in replacement costs and the asset owner is rest-assured that Chemco will provide long term corrosion protection, evident through the years of applications around the power station.
RC 200 Anti Foul, copper pigmented polyester resin & Externals with RL 500PF a surface/wet tolerant zinc rich epoxy.
Environment:
Sea Water,
Challenge:
Our clients strainer has been in service for 30 years. Upon inspection of the strainer body, back wash covers & critical dimensions found the substrate to be severely corroded, illustrated by the extent of graphitised cast iron, holes through the casting and diminishing wall thickness.
Externals on arrivalDegree of pitting after repetitive hot wash and abrasive blastingInternals near completion, build up shaft landsBack Wash Cover assembly
Pre-abrasive blast and machine datum points to ensure reference points remain for post machining, sealing ring & shaft lands. Needle gun/scabble graphitised material prior to Hot Wash and abrasive blast cycle to reduce soluble salts to an acceptable level.
Scope:
Mask up critical dimensions.
Abrasive blast to AS 1627.4 Class 3
Application of RB 332 to the internals including flange, rebates and shaft landing areas.
Reinforce casting using Composite repair techniques to reinstate original strength.
External coating application to System A which includes the application of RL 500PF @ 300um
Application of RC 500GTC Jade Green
Packaging and protection for transport
Results:
Refurbishing the Hicks Hargraves Strainer saved the company up to $150,000. RB 332 will provide long term protection coupled with the non-toxic anti-foul coating will prevent marine growth for a minimum of 5 years.
The client required an external coating system to provide long term protection to their newly purchased multi-stage pump assemblies against an aqueous ammonia environment at elevated temperatures. The coating system was required to act as a corrosion barrier for the pump case should any leaks occur whilst in service. Abrasive blasting could not be deployed due to the risk of damaging critical components.
Pump with factory shop primerCompleted coated pumpComplete coating of pump, coupling guard, channel base frame & two pole motor
We recommended RL 500PF which primes and finishes in 1 coat. This coating system requires minimal surface preparation. It is moisture/surface tolerant coating is ideal for site maintenance contracts. Rain or high humidity has no effect on painted surfaces.
We followed this with RW 500, a solvent-free epoxy Novolac which imparts outstanding protection to metal substrates. It forms a durable barrier resistant to abrasion, erosion, thermal shock, and the most aggressive environments of high temperature and chemicals in immersed and non-immersed conditions.
Scope:
Mask off seal areas, ID plates and critical exposed fittings. Mechanically prep surface, solvent wash with MEK
DFT checks, mount onto base frame, assemble coupling guard
Results:
The two product systems applied by skilled applicators resolved the no abrasive blasting issue and currently provides durable protection against a high temperature corrosive aggressive environment.
The internals of a sea chest located in the engine room were heavily corroded and required refurbishment. This included encapsulation and effective dust extraction to prevent mechanical damage inside the engine room. Work had to be completed within 20 hours to prevent disruption to existing schedule.
Corrosion on cast iron sea chest prior to treatmentSea Chest after abrasive blastingSea Chest after 3 coats of RB 300 Series & 2 coats of RC 200 to prevent marine growth
Chemcote’s Solution:
We recommended the use of RB 300 series @ 1200μm nominal thickness. The top coatapplied contains a non-toxic anti-foul. Applied @ 300μm it will provide excellent protection against salt corrosion
Scope:
Pre-abrasive blast to remove graphitised metal
Hot pressure wash and re-grit blast to ISO 8501-1 cleanliness standard with a minimum 75µm profile
Application of 3 coats of RB 300 series providing peace of mind for at least the next 10 years
Application of Copper based epoxy in two coats to prevent marine growth
Results:
With Chemco Australia’s successful application, many other components have been refurbished using similar methods. This can be done both on board, and within our fully equipped workshop located in Wollongong.
The ammonia lines had been in service since the plant was built. This has caused severe external corrosion caused holes to form in the pipe and there were no spare lines for the plant to be shutdown. Very expensive pipe sealing clamps were in use and the condition of the rest of the pipelines were deteriorating rapidly as the pipes are constantly cold and very wet. Engineers had put corrosion protection of the pipes in abeyance which was just exacerbating the problem.
Moisture-Tolerant and Solvent-Free epoxies RS 500P and RA 500M were recommended as this system requires minimum surface preparation (i.e. no dry grit blasting) and solvent-based materials were not allowed. These epoxies are ideal for confined spaces.
Rain, water, condensation or high humidity has no effect on freshly painted surfaces and its environmentally friendly properties allowed work to continue throughout the Queensland Wet Season. Areas were high-pressure washed at 500bar to a WJ4 standard. Coating was applied to an average DFT of 300µm.
Results:
This coating system is relatively new to Australia and is a prime example of innovative technology being used to save the existing plant from the possibility of catastrophic failure. Despite the extreme weather experienced in Queensland and the complex layout, the coating work was finished on time and within budget. As a result, there will be considerable savings in the cost of pipe sealing clamps in the future and improvement in plant safety has exceeded the engineer’s expectations.
Existing pipe lasts 4 weeks in service before a hole appears and valves an estimated 18 months service.
Internals illustrating erosion damage and rebateAbrasive blasted and primed internal and externalBasalt Fibre Applied to externals InD-Coat internalPipe re-installed after 2 days now ready for service
A new addition to the Chemco International range, illustrating further coating advancements based on research and development, we now have InD-cote™; a Ceramic Bead Filled High Temperature epoxy, designed to provide protection to aggressive sliding abrasion applications, reinforced with a wrap of woven basalt fibre and top coated with RP 500 AR.
Scope:
Machine rebate on flanges.
Abrasive blast to AS 1627.4 as per Chemco requirements.
Application of InD-cote™ and top coat using RP 500AR.
Application of Basalt Fibre wrap using RP 500 AR Series
Machine coated rebates
Results:
Based on the success of previous applications with a combination of our Abrasion Resistant composite systems using basalt fibre in abrasive environments a solution was sought after using the Chemco range of products and expertise. After regularly replacing these sections of pipe on a monthly basis the plant maintenance team are very happy with 9 months of service and still going. Stay tuned by sending us an email if you want to find out more.
Methane gas co-generation plant exhaust stack trials.
Challenge:
15 year old plant was showing signs of premature corrosion within 3-4 years of commissioning. Spark free surface preparation was a strict requirement. Plant outage was not possible and work was required to proceed whilst online with an estimated 105°C on the surface.
Methane Gas Power PlantCorroded exhaust pipes and manifoldsExtent of surface corrosionExhaust stacks after 5 years in service
Chemco’s Solution:
Chemco’s application of wet & surface tolerant coatings was carried out with minimal disruption to the everyday activities with an expected life in excess of 10 years before any signs of corrosion are visible.
Scope:
Mobilize to site and work in with plant maintenance personnel to ensure all risks are assessed and reduced where possible. Obtain safe access and mechanically clean, using a wire brush only. Application of 2 coats of RL 500PF with a nominal DFT of 300µm.
Results:
Many other coatings were trialled and failed within a 3 month period. The site has been revisited many times over the past 5 years with no signs of coating failure. Plant Maintenance Engineers are pleased with the results and look forward to solving other corrosion issues.
Working around the clock and the application of proven RB 300 series, a glass flake filled vinyl ester with excellent resistance to chemical and abrasive protection.
Scope:
Grind welds and sharp edges. Machine rebate to all flange faces to prevent crevice corrosion caused by misaligned gaskets.
Abrasive blast to Class 3 AS 1627.4 75micron profile (nominal) Apply of 2 coats of RB 300 Series to a DFT (dry film thickness) of 1200 microns.
Carry out QA including holiday test @ 8kV and confirm thickness.
Externals protected with 1 coat of RL 500PF
Results:
Extremely fast turnaround and cure time – back in production in 3 days. Expected to exceed life requirement of 25 years, plus reduce maintenance cost in the future.
1,000°C Coking Coal transport wagon and moved to the quenching station, where 80°C recirculated water is used.
Challenge:
Major structural steel repairs are carried out every two years due to the aggressive nature of this environment, the regular thermo cycling in service exceeds many coatings limitations. Oven temperature Coke is pushed in the Hot Car wagon where all of the coated surfaces are protected with sacrificial wear plates acting as heat shields where it is transported to the quenching area and an estimated 80 tonnes of recirculated water is dumped onto the Hot Coking Coal.
Engineers have tried and tested many different coatings with varied results. Main challenges are most of the work is carried out on site where abrasive blasting is not always possible due to the tight time schedule whilst other trades are working alongside the Chemco Applications Team.
Hot Car approaching quench areaAccess provided for fabrication & coating repairsRE 500P applied to mech clean surfaceUnplanned field welds requiring repairAfter being in service for 3 weeks
We recommended Epo-chem™ RE 500P a high temperature resistant surface tolerant, Novolac Epoxy primer. Top coated with Epo-chem™ RW 500, glassflake filled, high temperature resistant Novolac Epoxy. The coating system provides excellent corrosion/erosion resistance against this environment.
Scope:
Abrasive blasting to AS 1627.4 Class 3, 60µm profile on new sections in our workshop.
All areas on site were mechanically cleaned using a scabbler, needle gun and bristle blaster to thoroughly remove all signs of corrosion. Application of RE 500P in one coat at 100µm nominal and application of RW 500 at 350µm Dry Film Thickness (DFT).
Results:
Most linings were failing within a short period of time, between 2 & 8 weeks of service. An inspection of ChemcoInternationals high temperature coating systems after 2 weeks has indicated the lining is in excellent condition.
Tube sheets of this chiller were severely corroded due to a galvanic reaction between dissimilar metals. A 72 hour shutdown period was utilised to complete the work. The tube internals had to be protected from abrasive blasting damage. There was also severe pitting corrosion on sealing faces.
Tube internals were protected by inserting specially designed plastic caps.
The entire chiller face was abrasive blasted to ensure surface is clean and free of contamination. RB 300 was applied to tube-sheet face, followed by post machine sealing faces to ensure division plates mate, preventing interference and by-passing. Caps were removed. Chemco also supplied nylon inserts to prevent tube end corrosion & cavitation.
Results:
This client has become one of our regular customers. Chemco Australia has now conducted numerous jobs for this client over the past years, including multiple heat exchanger units. The photo to the left was taken during a 4 year inspection of another chiller unit coated with the same coating and showed no signs of deterioration.
Highly corroded carbon steel decks would have taken 12 months to re-surface with riding crew permanently on board. Corrosion would have re-appeared upon completion under high humidity and rain conditions.
Corroded DeckWet Abrasive blastingCompleted coating on section of deck
Chemco’s Solution:
Chemco’s application of wet & surface tolerant coatings was carried out with minimal disruption to the everyday activities and came with a 10 year warranty, much to the rig manager and asset owner’s satisfaction.
Scope:
15,000 – 19,000 psi water blast with small footprint machine
Wet abrasive blasting to reduce metallic salt content
Perforations were found in accommodation quarters and other critical areas
Applied 1 coat RS 500P and laminated using 600gm/m2 multi-directional matting
Applied 1 coat RA 500M with a nominal thickness of 500μm—700μm
Results:
Application was complete within client’s time frame, and asset owner also saved 12 months of downtime and repetitive painting costs. Chemco Australia has been awarded continuous work on the rest of the problem areas and other rigs from the same client.
This heat exchanger vessel was manufactured in 1981 and installed shortly after. Fatigue cracking was found in some welds and localised corrosion was discovered on the tube bundle guides. The unit was exposed to inclement weather.
32 Year old heat exchanger vesselMechanical damage with heavy pitting on heat exchanger vesselApplication of RS 500P a moisture/surface tolerant primerApplication of RA 532 a moisture tolerant glass flaked filled epoxy
Identify damaged areas and check existing specification thickness
Bristle blast damaged surface area
Solvent wipe and square off using masking tape
Application of RS 500P in one coat to a nominal DFT of 100µm
Application of RA 532 in one coat to a minimum DFT of 250µm
Results:
Chemcowas able to carry out the repairs to the internals of the heat exchanger vessel within the strict time frame provided by the client. This application will provide at least 10 years of corrosion free service.
Ceram-chem™ RP 500 – Ceramic filled epoxy designed to improve lumber flow,
Environment:
Ambient Sea Water,
Challenge:
Original pumps were suffering severe corrosion and cavitation.
After masking & abrasive blastingRe-mask & coating applicationEye of the impeller was treated using Kevlar, RB 300 & RP 500After external coating application
We recommended the use of RB 300 series @ 1200μm nominal thickness and top coat with 2 coats of RP 500 @ 300μm.
Scope:
Pre machine critical dimensions
Abrasive blast to ISO 8501-1 cleanliness standard with a minimum 75μm profile.
Mask and protect all area not to be coated
Application of 2 coats of RB 300 series
Application of RP 500 in two coats to improve fluid efficiency
Post machine to allow re-assembly
Balance impeller as required
Results:
Some engineering changes were made to the strainer system prior to the installation of these 3 pumps. Coupled with our coating system, these pumps can now expect long term protection – with minimal maintenance. Tube sheets, pipe-work and many other components have been protected using similar methods both on site and within our fully equipped workshop located in Wollongong.
Heavily corroded steel rig decks would have taken 12 months to re-surface with riding crew permanently on board. Corrosion would have re-appeared upon completion due to high humidity and rain conditions.
The Rig Ultra high water blasting One section completed
Chemco’s Solution:
Chemco Australia recommended the use of moisture surface tolerant glass-flake filled epoxies, applicable to wet and corroded surfaces providing long term corrosion protection.
Scope:
15,000-19,000 psi water blast with small footprint machine
Wet abrasive blasting to reduce metallic salt content
Perforations were found in accommodation quarters and other critical areas
Applied 1 coat RS 500P and laminate using 600gm/m2 multi-directional matting
Applied 1 coat RA 500M with a nominal thickness of 500μm-700μm
Results:
Application was done within client’s time-frame and also came with a 10 year warranty, much to the rig manager and asset owner’s satisfaction. Asset owner saved 12 months of downtime and re-coating costs. An estimated 20,000 m² of rig deck has been coated to date. Chemco Australia has also been awarded continuous work on the rest of the problem areas and other rigs from the same client.
Chem-glass RC 200 Anti foul – Copper pigment based polyester resin
Environment:
Ambient Salt Water,
Challenge:
To extend the operating life of heavily corroded, 30 year old suction tubes, the 15-20mm deep pitting requires pit filling and reinforcement using composites.
We recommended the application of RB 308 to fill deep pitting by extensive trowelling. Intermediate coat using RB 332 and top coat using RP 500, a ceramic filled epoxy designed to provide improved efficiency and reduced growth.
Scope:
UHPWB at 20,000psi to remove graphitised material and abrasive blast cycle to reach <25ppm chloride levels.
Abrasive blast to AS1627.4 Sa2.5 with a nominal surface profile of 75µm.
Application of RB 300 primer in one coat.
Application of RB 308 to fill pits and RB 332 to ensure smooth internals.
Carry out QA to ensure no holidays exist, repair where required.
Top coat, 2 coats of RP 500
External coating system is repeated, except for the topcoat where RC 200 antifoul is applied to prevent marine growth.
Results:
Pump efficiency has improved with the additional protection of the complete Chemco coating system. In addition Chemco has managed to reduce downtime and save thousands of dollars in replacement costs.
The original sea water volute pumps were suffering severe corrosion and cavitation. The pumps would require refurbishing and machining to original profile.
Volute after blasting Impeller eye coated External coating completed
Chemco’s Solution:
We recommended the use of RB 300 series @ 1200μm nominal thickness and top coat with 2 coats of RP 500 @ 300μm
Scope:
Pre machine critical dimensions
Abrasive blast to ISO 8501-1 cleanliness standard with a minimum 75μm profile.
Mask and protect all area not to be coated
Application of 2 coats of RB 300 series
Application of RP 500 in two coats to improve fluid efficiency
Post machine to allow re-assembly
Balance impeller as required
Results:
Some engineering changes were made to the strainer system prior to the installation of these three sea water volute pumps. Coupled with our coating system, these pumps can now expect long term protection -with minimal maintenance. Tube sheets, pipe-work and many other components have been protected using similar methods both on site and within our fully equipped workshop located in Wollongong.
The vessel was experiencing severe corrosion and metal loss. We had a short window to machine rebates in all flange faces to allow coating to be applied from the internals out onto the flange face.
Vessels on arrival External coating Internal lining
On close inspection, deep pitting was found in a number of areas, particularly in the bottom part of the vessel. Weld repairs would have delayed the project so Chemco recommended pit-filling to be carried out to reduce down time and the use of composite fibres to increase strength. RF 300 series was recommended as the coating requires low maintenance and ease of repair-ability. It will also provide 20 years of corrosion protection.
Scope:
Abrasive blast to AS 1627.4 2005 75
Reduce metallic salts using 90°C high pressure water. Re-abrasive blast to above standard.
Application of 1200µm of RF 332: A glass flake filled high temperature vinyl ester designed to provide long life corrosion protection.
All internal and external flange faces are coated to ensure full protection.
High Voltage spark test @ 8kV DC & rectify defects
Application of RL 500PF in two coat and RC 500GTC.
Results:
The intercooler vessel was inspected 4 years and again 8 years after original application and found in excellent condition. There were no signs of corrosion or coating breakdown. Some mechanical damage to the internal lining required repairs where the tube bundle installation/inspection impacted on the lining integrity on the guides.
The original coating was failing with osmosis blistering and exposure of the substrate to the cargo which caused localised corrosion pitting. Remedial work for this job needed to be completed along side ongoing repairs to ensure that the vessel arrived in Singapore in 2 years time for a refit. Corrosion rates of 2-3 mm per year would have reduced vessel’s corrosion allowance to zero resulting in a vessel perforation.
Removing original coat Pinholes Completed internals
Chemco’s Solution:
Chemco Australia recommended that the affected areas be abrasive blasted and treated with repeated high pressure hot washes. A steam lance would heat the vessel up with steam to 400°C to remove salt from the pin-holes. Measurement of pinholes would ensure glass-flake epoxy coating filling. During the application of the coatings, metallic salt, environment and high voltage spark testing would be carried out to guarantee long life protection.
Scope:
Abrasive blasting to remove coating
Salt tests revealed metallic salts, contaminated areas
After water washing and drying, abrasive blast to whip surface back to class 2.5.
Spigots were blasted using angle nozzle
Whip blasting of floor and spigots for salt test
Area carefully hand painted to fill pinholes
Coating inspected and declared fit for purpose
Vessel boxed and pressure tested
Results:
Pinholes affected the ‘wash area’ in an 800‐1000mm wide band below the tank’s centerline. Osmosis blistering resulted in crevice corrosion which was invisible at the coating application stage. These pin-holes measured 3-4 mm in depth and .5-1mm wide. Previous coating failure had developed a concentration cell with a difference in aeration, depleted of oxygen, which led to a highly corrosive condition in deepening the pinhole.
The vessel’s internal lining was replaced with corrosion resistant glass-flake filled epoxy resin. This film will protect the substrate and prevent further metal loss. The Chemco team carried out the job successfully despite many challenges and maintained final coating quality much to client’s satisfaction. The pin-holing challenge was resolved by pit-filling and is to be reviewed in future NFT programs.
Ambient sea water inlet side and 60-80°C outlet side.
Challenge:
The cooling water system was severely corroded and required refurbishment. The tube sheets were corroded due to a galvanic reaction between dissimilar metals. A 72 hour shut down period was utilised to complete the work. The tube internals required protection from abrasive blasting damage. Sealing faces were suffering severe pitting corrosion also.
Tubesheet on arrival On completion Condenser water boxes
Chemco’s Solution:
Tube internals were protected by inserting rubber bungs from internal damage the surface treatment process.
The entire face was abrasive blasted to ensure surface is clean and free of contamination. RB 300 was applied to tube-sheet face, followed by post machine sealing faces to ensure division plates mate, preventing interference and by-passing. Caps were removed. Chemco also supplied nylon inserts to prevent tube end corrosion & cavitation.
Results:
This client has become one of our regular customers. Chemco Australia has conducted numerous jobs for this client over the years, including multiple heat exchanger and condenser units. During a routine 4 year inspection, other cooling water systems coated with the same coating which showed no signs of deterioration.
The challenge was to refurbish heavily corroded steel reinforcement within concrete pillars and to protect against future corrosion attack. The application of corrosion protection needed to be carried out in a high humidity environment and onto the wet surface of the steel.
Exposed reinforcement Neutralising pH Ready for concreting
Chemco’s Solution:
Chemco proposed to gain access to steel reinforcement requiring corrosion protection by physically removing the deteriorated concrete. The steel reinforcement required pH neutralising using an Alkaline cleaner solution. The concrete reinforcement would then be protected against corrosion with an application of RS 500P onto the wet steel surfaces.
Scope:
Jack pick/hammer all deteriorated concrete.
Ensure reasonable access to all affected areas of reinforcement.
Application of rust converter allowing it to sit overnight.
Neutralise pH of steel surface.
Application of RS 500P.
Results:
Work on the concrete reinforcement was carried out within a tight time frame allowing civil contractors to return to build form-work and encapsulate with concrete. The ease of application of RS 500P onto wet substrates together with its corrosion protection properties makes this coating ideal for structures in this environment.
The vessel was originally rubber lined. Osmotic blistering found during an inspection raised concerns about metal loss due to the loss of lining integrity. Over the years the rubber lining had been patched & repaired to the point it was no longer serviceable. The vessel would take 2 weeks to replace. Chemco recommended an alternative solution which was faster and less disruptive.
Osmotic blistering Coating completed Re installation of lateral pipe
Chemco’s Solution:
On close inspection, deep pitting was found beneath the rubber lining. Weld repairs would have delayed the project so Chemco recommended pit-filling to be carried out to reduce down time. The RB 300 series was recommended as the coating requires low maintenance and ease of repair-ability. It will also provide 20 years of corrosion protection.
The entire project was carried out on site over a period of 36 hours allowing a fast return to service with minimum disruption to production. The vessel was ready for use 12 hours after completion.
Scope:
Remove rubber lining.
Abrasive blast to AS 1627.4 2005 75
Reduce metallic salts using 90°C high pressure water.
Application of 1200µm of RB 332: A glass flake filled vinyl ester designed to provide long life corrosion protection.
All internal and external flange faces are coated to ensure full protection.
High Voltage spark test @ 15kV DC & rectify defects
Re-installation of the lateral pipe work.
Results:
The cation vessel was inspected 18 months and 5 years after original application and found in excellent condition. There were no signs of corrosion or coating breakdown.
This petrochemical client had 40m diameter fuel oil storage tank with floor and 2m wall which required re-coating. The coating system requirement was for one which offers a long term corrosion solution that will provide in excess of 15 years of service. Time-constraint as the tanks had to return to service as soon as possible.
Coating of oil storage tank floor and walls completed
We recommended coating with Chemco RA 564, a glass-flake reinforced epoxy resin system that can provide long term corrosion protection in the storage tank for more than 15 years. This coating also provided extremely fast turnaround and cure time, the oil storage tank could be returned to production quickly. The coatings moisture tolerance meant there was no requirement for de-humidification, hence cost is reduced and no delays with weather.
Scope:
Abrasive blast to Class 2.5 AS1627.4,
Application of 2 coats of RA 564 to a DFT of 100 microns
Results:
This solvent free, no odour, no VOC coating solution also meant there were reduced OHS concerns, and no impact on the environment and no restrictions with surrounding trades. The coating’s long term protection also meant the client’s future maintenance costs have been reduced dramatically.
The client’s pump had dropped off in efficiency. This was due to the combination of corrosion and mechanical fatigue. The client was looking to improve efficiency and reduce power consumption.
After abrasive blast Internal Coating Completed Re-assembly
After 25+ years in service the substrate was heavily contaminated with metallic salts. This required heat treatment and a number of abrasive blasts to reduce salts below 25ppm. We then recommended the application of 2 coats of RB 332; a glass flake filled vinyl ester providing an excellent corrosion barrier and long term protection. We then applied 2 coats of RB 300GL to enhance fluid efficiency in turn reducing power consumption.
Scope:
Strip and assess
Manufacture template to ensure mating faces match
Grind rebates on all flanged faces, allowing the coating to be applied on the flange face preventing future crevice corrosion.
Protect critical dimensions
Abrasive blast and treat to reduce metallic salts by hot washing and re-abrasive blast.
Apply corrosion barrier RB 332
QA included spark testing
Rebuild gland packing areas
Apply top coat of RB 300GL
Results:
Pump repairs were achieved and by coating with RB 300, future corrosion is prevented with a reduced amount of friction through composite technology. The pump now functions more efficiently when in use and consumes less power, which led to carbon credits and greenhouse gas reduction. The payback period of the entire refurbishment worked out to be only 14 months.
Mild Steel water boxes & mild steel tube sheet with a copper alloy combination tube,
Products:
Chem-tect™ RB 300 series,
Environment:
60-80°C, sea water,
Challenge:
Tube sheets were corroded due to a galvanic reaction between dissimilar metals. These were treated on site by scaffolding and encapsulation to prevent dust in the station. A two week outage allowed time for removal of the condenser water box units from site, fabrication repairs to corroded areas and machining of rebates prior to deliver to our workshop. There was a large amount of work to be completed within a tight time frame.
Condenser water boxes in the workshop
Chemco’s Solution:
Work commenced on a round the clock basis, an understanding of the required deadline
Abrasive Blast to AS 1627
Application of primer to all surfaces
Pitfill all corroded areas and reinforce using composite materials i.e. fibreglass
Application of RB 332 in 3 coats
Carry out QA to ensure coating longevity
Application of RC 500 to prevent marine growth
Results:
This client has become one of our regular customers particularly for its cooling water systems. Chemco Australiahas now conducted numerous jobs for this client, including multiple condenser water box units. During a routine inspection, it was noted that another unit with the same coating showed no signs of deterioration.
The internals of the valve were heavily graphitised requiring refurbishment as a replacement would have taken up to 12 weeks because this is an imperial non-standard item. Guide channel for the valve was entirely corroded away. Coating and refurbishment had to be completed within 120 hours to prevent disruption to existing shutdown schedule.
Valve prior to treatment
Corroded valve body Coating on flanges Coating completed & valve installed
The valve was refurbished, saving the client replacement costs and waiting time. The client was extremely satisfied with this job and have since awarded other items to be refurbished by Chemco using similar methods.
A short time frame requiring quick turnaround. Pipe spools required long term corrosion protection.
Convoluted Pipe Rebated flange Copper based coated pipes
Chemco’s Solution:
Working around the clock, preparing surfaces and coating pipe spools with RB 300 series, a robust glass flake filled vinyl ester and top coating with a non toxic anti foul copper based epoxy preventing marine growth.
Scope:
Grind welds and sharp edges.
Grind rebate to all flange faces to prevent crevice corrosion caused by misaligned gaskets.
Abrasive blast to Class 3 AS 1627.4 75 micron profile (nominal)
Apply of 2 coats of RB 300 to a DFT of 1200 microns and 1 coat polymer copper.
Carry out QA including holiday test @ 8kV and confirm thickness.
Externals protected with 2 coats of RL 500PF and topcoat PU
Results:
An extremely fast turnaround and cure time meant that the pipe spool was back in production quickly (in this case, 3 days). With Chemco’s protective coatings, the pipe is expected to exceed life requirement of 25 years as well as reduce maintenance cost in the future. No fouling of internals from marine growth for many years to come.
Inspection of the strainer found there to be a large amount of external corrosion and severe localised pitting on the internals, particularly around the sealing ring.
Externals on arrival Rebuilt sealing land Completed strainer
Due to the amount of metallic salts found after the preliminary abrasive blast it was necessary to hot wash the strainer components in an attempt to lower the salt content. Re-abrasive blasting was carried out and composite materials were chosen to rebuild the metal loss found on the tube plate support ring. Rebuilding this metal loss using our reinforced glass technique. Chemco ensured the tube plate had a flat area to rest on the mounting/sealing ring, in turn reducing costs and the additional time involved with machining.
Scope:
Abrasive blasting to Chemco standards
Application of RB 332 to the internals including the rebates
External coating application to System A which includes the application of RL 500PF @ 300um
Application of RC 500GTC Jade Green
Packaging and protection for transport
Results:
Strainer was completed in time for re-assembly. RB 332 will provide long term protection coupled with the non-toxic anti-foul coating will prevent marine growth for a minimum of 5 years.
Atmospheric –buried low or high pH soil depending on location,
Challenge:
Metal loss was detected on some legs of the transmission towers while other legs showed signs of severe corrosion at the highly susceptible natural air/ground interface of the steel members.
The client needed help in strengthening the legs of the affected transmission towers and was looking for a solution that would last 50 years. This was highlighted as a necessity for the towers that are in areas exposed to varying pH level soil & prone to poor water drainage and flooding.
Metal loss detected Splicing corroded members After coating
We recommended coating with RB 300, a glass-flake filled vinyl ester, which has excellent resistance to corrosive environments. It provides a tough impermeable barrier suitable for steel and concrete surfaces. This system, once applied, can prevent future corrosion on the steel legs of the transmission towers for the next 50 years.
Scope:
Excavate and break out foundation, removal of earthing strap if required.
Install wire rope sling on transverse face according to wind direction, rope tension – 3.5kN, min SWL – 23kN
Remove tower bolts and clamp reinforced angle steel inside existing leg, match drilling process
Holes sprayed with Cold Gal & high tensile bolts used
Punched bolts so that nuts don’t come loose
Abrasive blast & apply RB 332 as per specification.
K-brace strengthening
Polymer concrete independently tested and rated up to 65 MPa (NATA certification)
Non-shrink to prevent gap between concrete and steel surfaces
Results:
The customer was most satisfied with the outcome. Chemco Australia has been awarded subsequent jobs due to the success of these repairs.
The end covers were originally coated by another contractor with varying results. Some items were made from exotic materials and had minor pitting along the sealing face and localised areas.
End cover pitted & corroded Sealing face built up Rebates filled
To prevent long term corrosion by applying RB 332 to the internals of the end covers. Sealing areas showing signs of corrosion pitting were pre-machined to allow for 1mm of coating to be applied and post machined on completion.
Scope:
High pressure washed internal & externals
Inspection of damaged/heat affected areas
Abrasive blasting to better inspect man hole cover
Pitfill application of RB 332 series in 2 coats
Thickness tested to ensure a minimum of 750µm and holiday test at 6Kv
Externals: Application of 2 coats of RL 500PF to a nominal thickness of 300µm
Application of 2 coats of N35 Luxathane R
Results:
Chemco delivered a fast turnaround, reducing down-time for the client in the short term and delivering the end covers with expected long term corrosion protection.
To provide a cost effective coating system offering a long-term anti-corrosion solution that will ensure in excess of 15 years’ service life for an aerobic reactor.
Plant in operation Corroded Floor Application of top coat
We recommended priming with RS 500P, followed by RA 500 top coat.
Scope:
Abrasive blast to AS 1627.4 with a nominal 50-75µm profile.
Application of 1 coat of RS 500P with a nominal DFT of 60-100µm.
Check film thickness in a grid pattern (between coats)
Strip coat using RA 500 Series on all welds and changes in direction to ensure coverage.
Application of 1 coat of RA 500 Series with a nominal total DFT of 300µm.
Carry out holiday test at 1.5kV to ensure no faults.
Demobilise from site and removal of trade waste
Results:
Application costs for the aerobic reactor were kept to a minimum as the specified coating systems, RS 500P & RA 500 both feature moisture tolerant qualities during application. For this reason humidity and dew point are not a concern, negating the need for de-humidification. The coating system is easy to maintain with an expected life in excess of 15 years.