Many cubic meters of water shoot through the pipes, turbines and filters of a hydropower plant every second. Although these components are very durable and specially designed for constant contact with water, corrosion damage is inevitable over time. As hydropower plants are not usually shut down completely, systems and equipment need to be overhauled gradually when necessary. It can take years to refurbish a hydropower plant. High-quality protection systems are therefore crucial to ensure a long service life for the plant.
Protective coatings can protect various components and equipment from deterioration and if suitably selected and applied, can ensure decades of smooth operation of hydropower plants. They act as a protective barrier against corrosion, erosion and cavitation, extending the service life of operating equipment and reducing maintenance costs.
Another advantage of Chesterton’s protective coatings in hydropower plants is that they create a smooth surface over which water can flow easily. This is particularly important for turbines, where a smooth surface means optimization of the flow conditions of the water and thus an increase in hydraulic efficiency. The result is increased power generation at lower operating costs.
Extreme environmental conditions – high demands on the coating systems
The high flow velocities of water combined with friction from entrained solids such as mud, gravel and sometimes even pieces of ice require an extremely abrasion resistant protective coating.
Very low water temperatures with ice formation in winter or permanent exposure to sunlight for exposed components require flexible temperature resistance or UV resistance of the coatings.
With the ARC and Ceramic-Polymer coating lines, Chesterton offers high-quality protection systems specially tailored to meet the requirements of the different areas of application in the hydropower sector.
Chesterton high-performance coatings – protection against corrosion, erosion and cavitation
With the ARC and Ceramic-Polymer range of coatings, you get unique solutions that have been proven to increase the reliability and performance of machinery and equipment, maximizing the efficiency of hydropower components.
The intake structures filter and divert the water for the turbine. The intake systems, such as shut-off devices, bar screens, plenums, valves and penstocks, have large volumes of water flowing through them, sometimes with a high proportion of entrained solids. Chesterton specializes in protecting these systems from premature damage and maintaining maximum efficiency with high-performance coatings.
The turbine is the heart of a hydropower plant. To ensure reliable and efficient operation of the guide vanes, volute casing, turbine blades and draft tubes, these surfaces must be resistant to erosion and cavitation over long periods of time due to the long operating times in this industry. Requirements that the Chesterton Coatings series fully meets.
We provide effective solutions for protecting and rebuilding plant metal and concrete infrastructure and equipment that is subjected to corrosion, wear, and environmental damage.
Our low-VOC, 100% solids, protective coatings are engineered to offer long-term protection to hydro station components and equipment including:
- Trash racks and stop logs
- Penstocks and valves
- Turbine components
- Spillways
- Concrete structures
Proven coating experiences for your success
Choosing the right coating system depends on several factors, including the type of plant, the environmental conditions, the type of surfaces to be protected and other specific requirements. It is important to carefully analyze the requirements of your hydropower plant before coatings are selected and applied. With our versatile portfolio of high-performance coatings, we can help you make the right choice of protection system.
Case Study #1 – Wicket Gates Protected with ARC S1HB
- Our customer was seeking a single layer Ultra-High-Build coating to repair and protect the 45 & 60 year old stay vanes.
- A total surface area of 400 m2 (4400 sq ft) had to be coated.
- Our high-performance coating ARC S1HB, 100% solids, 0% VOC, could be applied by spray application in a single layer with a thickness of at least 3mm (120 mils).
- Another special feature of this coating system is that it contains fluorescent pigments, so that a continuous holiday free application can be easily checked with UV light as it is being applied.
It is a non-destructive visual QC for both wet and cured coatings.
Result of this successful project:
- 3 mm (120 mils) of Chesterton ARC S1HB coating was applied in 12 hours to 400 square meters (4400 sq ft).
- Our customer praised the 0% VOC and odorless factors. Previously, a vinyl coating containing 85% VOC and posing a safety risk was used for the stay vanes.
- The foreman and his team were positive about the ease of application of Chesterton ARC S1HB. They said it was the best high build coating they had ever sprayed. They pointed out the advantage of carrying out visual quality control under UV light.
- The Chesterton ARC S1HB coating will protect the blades of the turbine at the Ice Harbor dam from erosion and corrosion for many years.
Please see the case study on our Website:
Case Study 601453 – Wicket Gates Protected with ARC S1HB
Case Study #2 – Draft Tube Repair with ARC 791
- The draft tube is made out of concrete (sometimes also in solid rock), covered with bolted steel plates. These are also welded together to form a solid construction.
- The diameter of the tube depends on the size of the turbine, often up to 4-5 meters.
- Large amounts of water (up to 50m3/sec) lead to heavy hydraulic forces and vibrations inside the draft tube, which often causes the steel plates to loosen in exposed area and pieces can fall off causing damage to equipment further downstream. To repair
itwith new steel plates is a very time consuming and costly job, and in most cases will not last. - To inspect this area, they need to stop the turbine and empty the draft tube. Today it is also an option to do 3Dscanning. In both cases, it is a very costly operation, especially concerning loss of energy production.
Result of this successful project:
- Solid material, coated directly to the base.
- No need for bolting.
- No risk for mechanical distortion.
- No risk for «air-pockets».
- No additional surface treatment.
- Easier and quicker repair.
- Less downtime, security of power supply and increased income for the plant owner.
Please see the case study on our Website:
Case Study 351041 – Power Plant Draft Tube Repaired and Protected with ARC 791
Case Study #3 – Coating of Lock Gates and further Components of Corumana Dam in Mozambique
- The corroded lock gates and further components like linkages, lashing strips and gate wheels, were refurbished with our high-performance coatings.
- Proguard CN 200 was applied on all metal components
- The metal parts, which are exposed to air and sunlight were additionally coated with Proguard 169, our UV stable topcoat
Result of this successful project:
- Easy application in one layer
- Reliable and durable protection against corrosion in aggressive marine environments according to ISO 12944-2 / classification CX
- High-grade resistances against high mechanical friction
- Best temperature and humidity resistance due to the changing humid climate in Mozambique
Please see the case study on our Website:
Conclusion
The application of Chesterton coatings in the hydropower industry represents a forward-looking solution to increase efficiency and extend the service life of equipment. By protecting against wear, corrosion and reducing friction, these coatings not only contribute to cost efficiency, but also promote sustainability in energy production. The hydropower industry can therefore benefit from the many advantages of this innovative technology and make a contribution to the global energy transition.
We gladly help you in any question regarding surface protection. Please ask our Expert Desk for further information.
Furthermore, on our website you can find this interesting blog article:
https://blog.chesterton.com/wear-protection/industrial-coatings/coating-corrosion-hydropower-facilities/