Forced draft fans rated for continuous operation at 250°C were supplied for a gas turbine power plant in Baghdad, Iraq, the order confirmed in September 2025.
In a gas-turbine or boiler auxiliary system, forced draft fans push pre-heated combustion air and must run hot by design, so the impeller and bearings face sustained temperature that a standard fan would survive only briefly; a 250°C continuous rating means the unit is built for that duty day after day, not for a one-off excursion. The fan is also critical to plant output, because if it cannot deliver the required air mass flow at temperature, combustion suffers and generation drops, and at 250°C the air density is far lower than at ambient, so the unit must be selected on the hot-air duty or it will under-deliver exactly when the plant needs full output.
Why Forced Draft Fans Run Hot
In a boiler or gas-turbine auxiliary system, forced draft (FD) fans push combustion air into the furnace or system. That air is pre-heated and can sit far above ambient, so the fan must handle sustained high temperature without the impeller distorting or the bearings failing. A 250°C continuous rating means the unit is built for that duty day after day, not just brief excursions that a standard fan might survive once.
The FD fan is critical to plant output: if it cannot deliver the required air mass flow at temperature, combustion suffers and generation drops, so reliability and correct duty selection are paramount. In a power plant, a fan outage can take a unit off the grid, which carries a visible cost in both fuel and lost revenue.
Temperature also changes the air itself. At 250°C the density is much lower than at ambient, so the fan must be selected on the hot-air duty, not the comfortable workshop condition, or it will under-deliver exactly when the plant needs full output.
Fan Duty and Construction
The supplied fans were specified for hot, continuous service, as shown below.
| Parameter | Rating | Design action |
|---|---|---|
| Temperature | 250°C continuous | Heat-resistant impeller |
| Type | Centrifugal FD | Pressure for combustion |
| Airflow | High volume | Plant air demand |
| Bearings | Cooled, remote | Isolated from heat |
Keeping the bearings out of the hot airstream, through an extended shaft or cooling path, is the usual way to protect them; the impeller material and balance must also tolerate thermal growth without inducing vibration that would shorten the machine's life. A bearing that sees 250°C air fails quickly, so isolation is non-negotiable.
The impeller clearance must cope with expansion. As the wheel heats, it grows, so the design leaves controlled clearance that closes but never seizes, which is a detail easy to get wrong on a unit adapted from a cold-duty model.
Checklist for High-Temperature Fans
Specifiers should verify these points before releasing an order for hot-duty fans:
- Confirm the rating: 250°C continuous differs from intermittent peak; know which you need, because the construction differs.
- Protect bearings: Ensure they sit outside the hot zone or are cooled, since bearing life collapses in sustained heat.
- Allow thermal growth: Impeller clearance must cope with expansion so the wheel does not seize as it heats.
- Size on hot air: Account for lower density at 250°C in the duty point, or the fan under-delivers at the plant.
- Plan maintenance: High heat accelerates wear; set inspection intervals and keep spare rotors available.
- Verify the test: Ask whether the unit was run at temperature or only at ambient, because the difference is real.
Significance for the Plant
Keruite manufactures centrifugal fans, including the 9-19 and 9-26 high-pressure series suited to demanding duties, at its 80,000 m² Dezhou facility, and the Iraq order shows the product serving critical power infrastructure. With 30+ years of fan manufacturing and ISO 9001:2015 certification, the company supports applications where downtime is costly.
For plant engineers, the takeaway is to specify the fan for the actual continuous temperature, not the comfortable ambient assumption, and to confirm the bearing protection explicitly. the company supports the selection with in-house performance testing so the quoted hot-air duty is measured, which is what a power plant procurement team needs to see.
For plant engineers, the selection rules are to specify the fan for the actual continuous temperature rather than a comfortable ambient assumption, to keep bearings outside the hot zone or actively cooled because bearing life collapses in sustained heat, and to leave controlled impeller clearance for thermal growth so the wheel does not seize as it heats. High heat also accelerates wear, so set inspection intervals and keep spare rotors available, and ask whether the unit was run at temperature or only at ambient during test. With 30+ years of fan manufacturing and ISO 9001:2015 certification at the 80,000 m² Dezhou facility, exports to 50+ countries, and engineers who respond to selection enquiries within 24 hours, the company supports applications where downtime is costly with in-house tested hot-air duty.
Engineers in Dezhou respond to selection enquiries within 24 hours, and the factory ships most standard fans from its 80,000 m² site within agreed lead times.