3 FRP Centrifugal Fans Connected to Stripping Towers for Corrosive Process Gas Handling
Project Overview
An aluminum processing plant required three large centrifugal fans for its process ventilation and gas treatment system.
The fans were connected directly to stripping towers, where they needed to continuously move process air containing corrosive components through the treatment system.
This created two key requirements: the fans had to deliver the specified airflow against the resistance of the stripping towers and ductwork, while the materials exposed to the process gas had to provide suitable corrosion resistance.
Fan Specifications
| Fan | Airflow | Static Pressure | Motor Power |
| Fan 1 | 30,000 CFM | 871 Pa | 37 kW |
| Fan 2 | 20,000 CFM | 871 Pa | 18.5 kW |
| Fan 3 | 5,000 CFM | 623 Pa | 4 kW |
Application: Stripping Tower Ventilation
Gas Condition: Corrosive Process Air
Wetted Parts: FRP
Impeller: FRP
Fan Casing – Gas-Contact Area: FRP
Support & Base: Stainless Steel 316
Challenge
This was not a standard factory exhaust application.
The process air contained corrosive components, so using conventional metal construction for gas-contact parts could increase the risk of corrosion during long-term operation.
At the same time, all three fans were connected to stripping towers and ductwork.
The fans therefore needed sufficient static pressure to overcome system resistance while maintaining the required airflow at three very different operating points—from 5,000 CFM to 30,000 CFM.
The challenge was to balance:
· Corrosion resistance
· Required airflow
· System static pressure
· Structural reliability
· Continuous industrial operation
Our Solution
We approached the project from both fan performance and material compatibility.
1. FRP for Gas-Contact Components
The fan casing surfaces exposed to the process gas and the impellers were manufactured from FRP (Fiberglass Reinforced Plastic).
By using FRP for the wetted parts, the components directly exposed to the corrosive gas are better protected against chemical attack compared with conventional untreated metal construction.
2. SS316 for Structural Components
For the fan supports, bases and other structural components outside the main gas-contact area, we used 316 stainless steel.
This combination allowed us to use different materials according to the actual function and exposure conditions of each component:
FRP where corrosion resistance is critical.
SS316 where structural support and environmental corrosion resistance are required.
3. Three Fans Matched to Three Duty Points
Instead of applying one standard fan specification across the entire project, each centrifugal fan was selected according to its actual operating requirement.
The largest unit delivers 30,000 CFM at 871 Pa, powered by a 37 kW motor.
The second delivers 20,000 CFM at 871 Pa, powered by an 18.5 kW motor.
The third delivers 5,000 CFM at 623 Pa, powered by a 4 kW motor.
This ensured that each fan was matched to the airflow and resistance requirements of its corresponding stripping tower system.
Solution & Results
The three corrosion-resistant centrifugal fans were successfully integrated with the plant's stripping tower systems.
The FRP gas-contact components provide a more suitable solution for handling the corrosive process air, while the SS316 supports and bases provide a robust structural foundation for industrial operation.
At the same time, each fan delivers the required combination of airflow and static pressure for its individual system.
The result is not simply three fans with different capacities, but a material- and performance-matched ventilation solution designed around the customer's actual process conditions.
Key Results
Corrosion-Resistant Gas Path
FRP impellers and gas-contact casing surfaces help protect critical components exposed to corrosive process air.
Robust SS316 Structure
Stainless steel 316 supports and bases provide reliable structural support for the fan assemblies.
Up to 30,000 CFM Airflow
The largest centrifugal fan handles the high-volume airflow requirement of the stripping tower system.
Up to 871 Pa Static Pressure
The fans provide the pressure required to overcome resistance from the towers and connected ductwork.
Three Individually Matched Duty Points
Each fan was selected according to its own airflow, pressure and system requirements.
Not Just Fan Selection — Material Selection Matters Too
When handling corrosive process gases, selecting the correct airflow and static pressure is only part of the solution.
What the gas comes into contact with matters just as much.
For this aluminum processing plant, we combined FRP gas-contact components, SS316 structural parts and three individually selected centrifugal fan duty points to create a solution matched to both the gas conditions and the ventilation system.
