4,000 tubes replaced in primary and secondary air preheaters
The foundation of our track record: revisions, retubing and upgrades inside operating plants, engineered around short shutdowns. The air preheater retubing at AKSA Göynük is one of those jobs.
The plant and the job
Plant: Bolu Göynük 2 × 135 MW fluidized bed. Owner AKSA Göynük Enerji, unit price contract, accepted June 2024. Scope of work: replacement of 4,000 acid-corroded tubes in the primary and secondary air preheaters of Units 1 and 2 with Corten-A tubes.
An air preheater is the heat exchanger that preheats the combustion air going to the boiler with the remaining heat of the flue gas; primary air is fed under the bed for combustion of the fuel, secondary air higher up to complete combustion.
Corrosion and material
The replaced tubes were acid-corroded; the new ones are Corten-A tubes. Acid corrosion appears mostly at the cold end of the air preheater, where the flue gas reaches its lowest temperature.
The same equipment at another plant
At the Çan 2 Power Plant (1 × 330 MW, second-hand plant), the rehabilitation and erection scope also included Luvo air preheaters and final combustion grates; each component in the scope was overhauled first, then erected.
Related projects
Frequently asked questions
- How many tubes were replaced at AKSA Göynük?
- A total of 4,000 tubes in the primary and secondary air preheaters of Units 1 and 2.
- Why does acid corrosion occur in air preheater tubes?
- When the flue gas cools below the acid dew point at the tube surface, sulphur compounds condense; the resulting acid gradually thins and perforates the tube wall.
- What material are the new tubes?
- Corten-A. Corten-A is a low-alloy steel with high resistance to low-temperature acid corrosion.
Source: HECON company profile · pp.18, 19, 21 · All articles