Air Preheater Repair & Refurbishment
Repair, refurbishment, and performance restoration of rotary regenerative and tubular air preheaters in coal, gas, and biomass-fired power generation facilities.
Air preheaters are among the most maintenance-intensive components in a coal or gas-fired boiler system. These large heat exchangers recover thermal energy from flue gas by preheating combustion air — and their condition directly impacts overall boiler efficiency, emissions performance, and fan energy consumption. A degraded air preheater can reduce boiler efficiency by 1–3%, translating to millions of dollars in annual fuel cost increases for a large utility unit.
MAC Industrial Services provides comprehensive air preheater repair and refurbishment services covering the full range of failure modes: seal wear and leakage, element fouling and plugging, basket element corrosion, structural basket plate damage, bearing wear, and drive mechanism issues. Our crews work in both tri-sector and bi-sector Ljungström-type rotary regenerative air heaters as well as tubular (recuperative) designs common in smaller industrial boilers.
A typical MAC air preheater refurbishment scope includes pre-outage performance assessment (inlet and outlet gas temperature analysis, leakage quantification), element basket inspection and replacement, radial and axial seal replacement, hot-end and cold-end sector plate inspection, and post-refurbishment commissioning with leakage verification. We coordinate NDE services for structural components and provide a complete outage report with before/after performance data.
What We Deliver
Technical Q&A
How do I know if my air preheater needs refurbishment?
Key indicators include rising outlet gas temperature (reduced heat transfer), increased air-to-gas leakage measured by O₂ differential across the APH, increased pressure drop across the element baskets, or visible physical damage during walkaround inspection. MAC can perform a pre-outage performance assessment to quantify degradation and build a refurbishment cost-benefit case.
Can MAC replace individual basket elements without a full refurbishment?
Yes. Partial element replacements are common where only specific sectors show elevated corrosion or plugging. We target replacement to the cold-end elements where low-temperature corrosion is most severe, allowing clients to stage refurbishment investment over multiple outage cycles.
How long does a typical air preheater refurbishment take?
A typical tri-sector regenerative APH refurbishment with element replacement and seal work takes 7–14 days depending on the unit size, the extent of basket damage, and concurrent mechanical work on the drive and bearing systems. MAC's outage planners can develop a detailed schedule as part of pre-outage planning.
Related Service Lines
Outage Services
Expert management of planned and forced outages, delivering rapid mobilization and efficient execution to minimize your downtime.
Industrial Maintenance
Comprehensive maintenance services designed to maximize uptime, reduce operational costs, and extend the life of your industrial assets.
Industry Applications
- Coal-fired utility boilers
- Gas and oil-fired industrial boilers
- Biomass and waste-to-energy boilers
- Combined-cycle HRSG auxiliary combustion air systems
- Cement kiln preheater towers (recuperative)
Codes & Standards
- ASME PTC 4 – Fired Steam Generators Performance Test Code
- ASME B31.1 – Power Piping (connected ductwork and expansion joints)
- OSHA 1910.146 – Permit Required Confined Space Entry
- Client-specific APH maintenance procedures and acceptance criteria
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