CASE STUDY
POWER STATION BOTTOM ASH SILO REPAIR
Belzona Protects Power Station Bottom Ash Silo from Abrasion
Industry: Power
Application: Bottom Ash Silo Repair
Products: Belzona 1818, Belzona 1812, Belzona 1321
Customer Location: : QLD, Australia
Application Date(s): June 2021 and Oct 2022
PROBLEM
A 750 MW coal-fired power station was experiencing rapid abrasive wear in the lower section and northern wall of its bottom ash silo.
Constructed from 8 mm-thick 3CR12 stainless steel, the silo was losing approximately 0.25 mm of wall thickness each month, with some areas reduced to just 3.8 mm.
A rapid repair solution was required to slow further metal loss and protect the remaining substrate before the silo’s structural integrity was compromised.
Power station bottom ash silo requiring abrasion protection
APPLICATION – June 2021
As there was insufficient time to organise and stage abrasive blasting three storeys above ground, a surface-tolerant, fast-curing and abrasion-resistant material was required to minimise downtime and provide interim protection until more extensive work could be completed during the major shutdown in October 2022.
External views of the bottom ash silo showing areas of abrasion damage
Internal view of the bottom ash silo showing abrasion damage, with the areas of greatest wall-thickness loss marked for repair
Close-up views of Belzona 1818 during various stages of application, showing the material being built up to form a durable abrasion-resistant layer
Belzona 1818 was selected for its suitability for patch repairs in high-erosion and abrasive environments. Its rapid cure allows equipment to return to full mechanical loading in as little as six hours at 30°C after application, helping to significantly reduce downtime.
The material incorporates surface-tolerant technology, providing strong adhesion to steel even where preparation is limited or oil and water contamination may be present.
For this application, the surface was prepared using an angle grinder to expose clean, bare steel before Belzona 1818 was applied. In total, twenty 1 kg kits of Belzona 1818 were applied to the affected areas.
The completed repair system
APPLICATION – October 2022
16 Months later, the lower wear zone of the bottom ash silo was protected using a two-product system comprising Belzona 1321 (Ceramic S-Metal) and Belzona 1812 (Ceramic Carbide FP).
A base layer of Belzona 1321 was first applied to provide a smooth, sound substrate for the abrasion-resistant topcoat.
This undercoat improved adhesion over pitted and corroded steel, made application to vertical and overhead surfaces easier, and provided an additional corrosion barrier.
Belzona 1812 was then applied as the sacrificial wear layer. Its hard ceramic aggregates provide resistance to severe abrasion, while the consistent substrate created by Belzona 1321 helps maintain an even application thickness and maximise performance.
Should the Belzona 1812 wear over time, the underlying Belzona 1321 continues to protect the steel, helping extend the bottom ash silo’s service life.
Belzona 1321 applied as a continuous wet-out coat to the walls of the entire lower section of the bottom ash silo, providing a smooth, firmly bonded corrosion-resistant base layer for the subsequent abrasion-resistant coating system (left and middle). Belzona 1812 being applied over the cured Belzona 1321 base layer (right)
OUTCOME
During both application stages, the repairs were completed quickly, allowing the silo to return to service with minimal downtime.
Belzona 1818 provided a durable, abrasion-resistant barrier to reduce further metal loss, while the combined system incorporating Belzona 1321 and Belzona 1812 delivered additional corrosion protection and helped extend the silo’s service life.
At the completion of the 2022 shutdown, a small inspection hole was drilled through the coating to establish its initial thickness. During a subsequent outage in January 2024, the customer re-inspected the same location using the original hole to assess the remaining coating thickness, adhesion and internal condition of the vessel.
No measurable wear, voids, cracking, delamination or further substrate deterioration were identified, confirming that the repair system remained firmly bonded and continued to protect the bottom ash silo.
Completed Belzona 1321 and Belzona 1812 system, forming a durable barrier against severe abrasion
More Information?
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Products
Belzona 1818
Belzona 1818 is a fast curing, surface tolerant, abrasion resistant system ideal for patch repairs on surfaces subject to high erosion and abrasive environments. Its fast curing properties results in minimal downtime for damaged equipment, and the product can experience full mechanical loading in as little as two hours after application.
Belzona 1812 (Ceramic Carbide FP)
A 2-part epoxy-based composite material combining extremely hard closely packed abrasion resistant ceramic aggregates in a polymeric binder for the repair and protection of equipment damaged by fine particle abrasion..
Belzona 1321 (Ceramic S-Metal)
A 2-part ceramic filled epoxy coating designed to provide erosion and corrosion resistance of metal surfaces.
This solvent-free epoxy coating has outstanding chemical resistance and will bond to almost any rigid surface. Due to its high compressive strength it can be also used to create a perfect shim. This material is easy to mix and apply without the need for specialist tools and it cures at room temperature eliminating the need for hot work..
About Rezitech
Established in 1968, Rezitech is the sole Australian Distributor for Belzona. Rezitech offers a comprehensive range of industrial protective coatings and epoxy metal repair composites to many different industries including: oil and gas, mining, power, water and waste water, pulp and paper, marine, manufacturing among others.
Frequently asked questions
What caused the bottom ash silo to require abrasion repair?
The 3CR12 stainless steel silo was experiencing rapid abrasive wear in its lower section and northern wall, with approximately 0.25 mm of wall thickness being lost each month. In the most severely affected areas, the original 8 mm-thick steel had been reduced to just 3.8 mm.
How was the power station bottom ash silo repaired without abrasive blasting?
For the initial repair, the steel was prepared using an angle grinder before Belzona 1818 was applied to the damaged areas. Its fast-curing, surface-tolerant and abrasion-resistant properties made it suitable where abrasive blasting could not be organised at short notice and a rapid return to service was required.
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