Barrier Coatings for Chemical Attack
This is a transcript of the Belzona “Solve It Session” webinar – Barrier Coatings for Chemical Attack. Take a closer look at each section using the drop-down menu or watch the full webinar recording below:
On almost every industrial site we are likely to find hazardous chemicals – many of which are also corrosive.
Without proper mitigation of the effects of chemically-induced corrosion, assets such as pipelines, storage tanks and process vessels can degrade – eventually leading to leakage. This can introduce environmental issues and endanger personnel.
It is therefore paramount that asset owners take preventative steps to reduce the chances of leaking, and implement backup systems to contain any spillages that do happen.
Yet, each instance can vary depending on a combination of different factors.
Before deciding on the best strategy, it is important to understand the potential severity of the chemical attack. The following factors are crucial when evaluating the conditions:
Chemical & Concentration
Chemical & Concentration
What is the chemical?
Does it have a high level of concentration?
Is the chemical stored and processed at ambient or elevated temperatures?
Is the chemical contact an accidental spillage, incidental contact or constant immersion?
Combination of Threats
Combination of Threats
Is the chemical attack exacerbated by another damage mechanism?
Overall, the most aggressive scenarios will be where there are highly-concentrated, corrosive chemicals in constant contact with an asset – especially if the temperature is elevated. Fluid flow, such as in pipelines, can also introduce additional wear mechanisms and when combined with the chemical attack, this can significantly increase the potential for rapid failure.
There are many options available to protect from chemical attack, all with their own merits and drawbacks.
Glass Flake Linings
Polymer coatings are a popular choice across industry due to their ease of installation and maintenance, both at the new fabrication stage or in situ for existing equipment.
There is a wide range of coatings available on the market, which allows asset owners to select an solution that is optimised for their specific requirements. While this can be an advantage, the wide variety of coatings also introduces a risk for asset owners, due to the potential for improper product selection. The challenge for coating manufacturers is to ensure asset owners receive the technical support both in material selection and installation – so that the performance expectations will be met.
The correct selection is hugely important when it comes to protective coatings. Matching the solution to the unique conditions of each environment. Based on their capabilities, Belzona’s chemical resistant coatings can be separated into three categories.
Continuous Immersion at Ambient Temperatures
Continuous immersion in hydrocarbons, methanol, sour gas, wet H2S & CO2 at ambient temperatures up to 60°C/140°F. As with the majority of these coatings, they are capable of withstanding the harsh effects of erosion and corrosion for the long term.
Continuous Immersion at Elevated Temperatures
Continuous immersion in hydrocarbons, methanol, sour gas, wet H2S & CO2 at elevated temperatures – specifically, over 95°C (203°F) and in some cases up to 160°C (320°F).
These are ideally suited for processing environments, conditions for example you would expect to see in flare drums or desalters within the oil and gas industry. As the pictures point out, these have been successfully used for this type of equipment for a number of years and have been included in specifications for a number of major companies.
Resistance to Aggressive Acids and Alkalis
Resistance to a broad range of chemicals, including organic and inorganic acids. The Belzona 4300 range can accommodate for highly concentrated solutions, including sulphuric acid, which is highlighted in the instances below for the bund and offloading zone.
Suitable for application on wide range of assets, including instances of primary and secondary containment.
All of Belzona’s materials undergo extensive testing and Belzona 4311 is no different. In fact, prior to release it is subjected to 12 months of testing compliant with international standards. And this is coupled with over 30 years of proven experience in the field in all manner of environments.
Ease of application is fundamental to any protective material, with Belzona 4311 benefiting from being cold-curing without the need for any specialist equipment. In addition it is solvent free, which aids application in confined spaces, as well as ensuring there is no shrinkage or distortion due to evaporating solvents.
Most importantly, it sticks! Whether it is a porous substrate like concrete or non-porous metalwork, it demonstrates excellent adhesion to a wide variety of substrates, which the following case studies will highlight further.
This chemical resistant coating has been used throughout industries for over 30 years. During that time, hundreds of applications have taken place, but we wanted to show a snapshot of those from the most troublesome environments.
Belzona Contains 98% Sulphuric Acid
Chemical Plant, Brazil (2011)
The loading bay in question was required to handle contact with 98% sulphuric acid and the maintenance team for the site had installed a chemical resistant coating to protect the area. However, this coating could not handle exposure to the aggressive chemical concentration. The coating failed and the concrete underneath was being eaten away more and more during each spillage.
Belzona’s Brazilian Distributor approached the plant with a solution to rebuild the area and coat with Belzona 4311 for further protection. Application over the entire area was completed quickly, allowing the loading bay to get back into action with fit-for-purpose protection after several years of issues.
Screw Auger Protected From Abrasion And Chemical Attack
Pulp and Paper Plant, Germany (2009, revisited in 2017)
Combinations of chemical attack and other damage mechanisms can have brutal effects on asset lifespans. Our next case study takes us to a German pulp and paper plant whereby the additional force of abrasion was leaving this screw auger in dire need of repair. The option of replacing the equipment was considered but taking the cost and downtime into consideration made it unsuitable.
Using Belzona 4311 in conjunction with a ceramic coating, Belzona 1811, the auger was repaired in situ, which meant that there was also no additional disassembling cost. The speed of the cure and ease of application from both products meant that the auger could be returned to service quickly.
Now, this was initially completed back in 2009 and since that point, it has been revisited in 2017. After 8 years, this original coated auger was still in operation. Testament to the long-term protection on offer from Belzona 4311.
Pump Bases & Containment Area Restored
Copper Mine, USA (2013)
Leaking copper sulfate/electrolyte with 20% sulphuric acid had led to damage of the pump bases and containment area. This spalling had been exacerbated further by the equipment vibration, jeopardising the copper production process.
The pump bases were rebuilt, prior to being coated alongside the entire bund area. This was designed to prevent future damage via chemical attack and overall, reinstated structural stability, ensuring rapid restoration of the copper production.
Vertical Pump Given Extended Lifespan For Acid Service
Refinery, Canda (1998, revisited in 2005)
Vertical pumps handling 93% sulphuric acid had led to chemical attack inside the volute and on the impeller.
Belzona’s solution for acid pumps was originally tested and implemented on one pump in 1998. Following very satisfiying results during inspection in 2005, this led to 5 identical pumps being protected with Belzona 4311, once more proving a very cost-effective maintenance solution.
Belzona 4311 has a proven track record in the field, made clear by the selection of case studies. Yet, we would like to unveil the enhanced formulation of this material with some notable key benefits. Watch the video below which introduces these further:
The addition of being sprayable is one of the application upgrades for this system. Formerly just hand-applied, now it can be compatible with airless single and plural spray equipment, aiding faster application, especially over large areas.
This goes hand-in-hand with the coating having an increased overcoat window. This has been extended up to 24 hours and will not experience any of the negative affects of amine bloom, such as the loss of intercoat adhesion seen on standard epoxy coatings. Overall, this aids a fast back-to-service time.
Finally, the UV resistance of Belzona 4311 has been enhanced. As we mentioned before, extensive testing is a priority for Belzona and this coating was subjected to 10,000 hours in an accelerated weathering test with the coating thickness barely affected. So, in sunny climes where there are high levels of UV exposure, you can be assured that the chemical resistance of the coating will be uncompromised.