This article's table of contents introduction:
- Interpretation of Specifications
- Fan Type Required
- Performance Parameters (Estimated)
- Key Design Features for "High Efficiency" & "Boiler"
- Critical Checklist for Procurement
- Important Warning:
Based on your query, you are looking for a High Efficiency Fan designed for a Boiler application, which operates at 440V (likely a typo for the main motor, as 10kV is the supply) and handles an air volume of ≤ 900,000 m³/h. The "SA" likely refers to Secondary Air fan in a boiler system.
Here is a breakdown of the specifications and the likely type of fan required.
Interpretation of Specifications
- High Efficiency: This implies the fan must meet modern energy efficiency standards (e.g., IE4/IE5 motor efficiency, high aerodynamic efficiency for the impeller).
- 440V: This is likely the control voltage or a lower voltage for a smaller auxiliary fan. For a fan moving 900,000 m³/h, the main motor is almost certainly 10kV (as stated).
- 10kV: This is the standard high voltage for the main drive motor (typically 1,500 kW to 3,000 kW+).
- SA FAN: Secondary Air Fan. In a boiler, this fan supplies air to the burners above the primary air to ensure complete combustion. It must overcome the pressure drop in the air heater, ducts, and burner registers.
- Air Volume ≤ 900,000 m³/h: This is a very large fan. For context, a typical 300 MW thermal power plant boiler might have SA fans in the range of 400,000 - 600,000 m³/h. This fan is suitable for a large utility boiler (e.g., 600-1000 MW class) or an industrial boiler with high capacity.
Fan Type Required
For this high volume and the specific boiler application, the standard design is a Centrifugal Fan with Backward-Curved (BC) or Airfoil (AF) Blades.
- Type: Centrifugal, Double Inlet (DI), Double Width (DW).
- Blade Profile:
- Backward Curved (BC): High efficiency, non-overloading power curve, good for variable volume control (inlet vanes or VFD). Most common for SA fans.
- Airfoil (AF): Highest efficiency possible, but blades are hollow and more expensive; very common in large power plants.
- Control: Typically Inlet Guide Vanes (IGV) or a Variable Frequency Drive (VFD) on the 10kV motor to match boiler load.
Performance Parameters (Estimated)
To specify this fan completely, you need the Static Pressure or Total Pressure. Assuming a typical SA fan for a large boiler:
- Flow Rate: 900,000 m³/h (15,000 m³/min or 530,000 CFM)
- Static Pressure: Approx. 3,500 to 5,000 Pa (14 to 20 inches w.g.)
- Estimated Motor Power: 1,500 kW to 2,500 kW.
- Calculation: $P = \frac{Q \times p}{\eta}$ (where $\eta$ is ~85%).
- Motor Voltage: 10,000 V (10 kV), 3-Phase, 50Hz or 60Hz.
Key Design Features for "High Efficiency" & "Boiler"
| Feature | Requirement |
|---|---|
| Efficiency | Impeller efficiency ≥ 88% (static). Motor efficiency ≥ IE4 (Super Premium) or IE5. Fan should meet ISO 12759 or AMCA 205. |
| Construction | Heavy-duty steel casing (6-10mm thick) with wear-resistant lining at the inlet/outlet. |
| Shaft & Bearings | Forged steel shaft. Double row spherical roller bearings with forced lubrication or oil mist (for 10kV reliability). |
| Seals | Labyrinth seals or carbon ring seals to prevent dust leakage into bearings (critical for boiler applications). |
| Speed | Low speed (e.g., 500-750 RPM) to keep noise and wear low for a fan this size. |
| VFD Capability | If using a VFD, the motor must be inverter-duty (to handle harmonics and high dV/dt). |
Critical Checklist for Procurement
If you are sourcing this fan, provide the following to manufacturers (e.g., Howden, TLT-Babcock, Zibo, or New York Blower):
- Current Specification:
- $Q = 900,000\ m^3/h$
- Required Static Pressure: Pa (fill in)
- Ambient Temperature: °C (Boiler room can be 40-50°C)
- Altitude: m (affects air density)
- Fan Selection:
- Fan Model: SISW (Single Inlet Single Width) or DIDW (Double Inlet Double Width)? Answer: DIDW.
- Impeller Diameter: Approx. 2,500 mm to 3,200 mm.
- Motor Specification:
- Voltage: 10 kV / 3Ph / 50Hz
- Motor Type: Synchronous or Induction (Synchronous is more efficient for large 10kV fans).
- Protection: IP54 or IP55 minimum.
- Accessories:
- Silencer (Attenuator) at the inlet/outlet (noise levels).
- Flexible Connections (to prevent duct vibration).
- Expansion Joints (for thermal growth).
- Drain valves (to remove condensation before start-up).
Important Warning:
- "440V" : Do not specify a 440V motor for a 900,000 m³/h fan. The current draw would be huge ( > 2,000 Amps). The main motor must be 10kV. 440V is sometimes used for the fan's auxiliary oil pump or control system.
Summary: You need a Double Inlet, Double Width (DIDW) Centrifugal Fan with Airfoil (AF) blades, driven by a 10kV motor (1.5MW - 2.5MW), with a control system using Inlet Guide Vanes or VFD. Ensure the supplier is certified for boiler-draft applications (ISO 1940 G6.3 balance grade minimum).
